10.1007 - 978 94 007 1905 7 PDF
10.1007 - 978 94 007 1905 7 PDF
10.1007 - 978 94 007 1905 7 PDF
Volume 8
Series Editor
Eric Lichtfouse
Sustainable Agriculture
ISBN 978-90-481-2665-1, Volume 1, 2009
Sustainable Agriculture
ISBN 978-94-007-0393-3, Volume 2, 2011
Organic Farming, Pest Control and Remediation of Soil Pollutants
ISBN 978-1-4020-9653-2, Sustainable Agriculture Reviews. Volume 1, 2009
Climate Change, Intercropping, Pest Control and Beneficial Microorganisms
ISBN 978-90-481-2715-3, Sustainable Agriculture Reviews. Volume 2, 2010
Sociology, Organic Farming, Climate Change and Soil Science
ISBN 978-90-481-3332-1, Sustainable Agriculture Reviews. Volume 3, 2010
Genetic Engineering, Biofertilisation, Soil Quality and Organic farming
ISBN 978-90-481-8740-9, Sustainable Agriculture Reviews. Volume 4, 2010
Biodiversity, Biofuels, Agroforestry and Conservation Agriculture
ISBN 978-90-481-9512-1, Sustainable Agriculture Reviews. Volume 5, 2010
Alternative Systems, Biotechnology, Drought Stress and Ecological Fertilisation
ISBN 978-94-007-0185-4, Sustainable Agriculture Reviews. Volume 6, 2010
Genetics, Biofuels and Local Farming Systems
ISBN 978-94-007-1520-2, Sustainable Agriculture Reviews. Volume 7, 2011
Environmental Chemistry
ISBN 978-3-540-22860-8, 2005
Rédiger pour être publié! Conseils pratiques pour les scientifiques 2009
Forthcoming
Environmental Chemistry for a Sustainable World
Volume 1. Nanotechnology and Health Risk
ISBN 978-94-007-2441-9, 2012
Environmental Chemistry for a Sustainable World
Volume 2. Remediation of Air and Water Pollution
ISBN 978-94-007-2438-9, 2012
v
vi Contents
Olivier De Schutter
Abstract The reinvestment in agriculture, triggered by the 2008 food price crisis, is
essential to the concrete realization of the right to food. However, in a context of
ecological, food and energy crises, the most pressing issue regarding reinvestment is
not how much, but how. This manuscript explores how agroecology, understood as
the application of the science of ecology to agricultural systems, can result in modes
of production that are highly productive, highly sustainable and that contribute to
the alleviation of rural poverty and, thus, to the realization of the right to food.
Drawing on an extensive review of the scientific literature published in the last
5 years, the study shows how agroecology can benefit in particular the most
vulnerable groups in various countries and environments. Moreover, agroecology
delivers advantages that are complementary to better known conventional approaches
such as breeding high-yielding varieties. And it strongly contributes to the broader
economic development. Appropriate public policies can create an enabling environ-
ment for sustainable modes of agricultural production. These policies should
prioritize the procurement of public goods in public spending rather than solely
providing input subsidies. They should invest in knowledge and in forms of social
organization that encourage partnerships, including farmer field schools and
farmers’ movements innovation networks.
This chapter is a short and revised version of the report I presented, in my official capacity as
*
United Nations Special Rapporteur on the right to food, at the 16th session of the Human Rights
Council (UN doc. A/HRC/16/49).
O. De Schutter (*)
UN Special Rapporteur on the right to food, Faculty of Law, UCL,
Place Montesquieu, 2, B-1348 Louvain-la-Neuve, Belgium
e-mail: Olivier.Deschutter@uclouvain.be
1 Introduction
Agriculture is at crossroads. For almost 30 years, since the early 1980s, neither the
private sector nor governments were interested in investing in agriculture. This is
now changing. Over the last few years, agri-food companies have seen an increase
in direct investment as a means to lower costs and ensure the long-term viability of
supplies (Reardon and Berdegué 2002; Reardon et al. 2007, 2009): FDI in agriculture
went from an average of US$ 600 million annually in the 1990s to an average of
US$ 3 billion in 2005–2007 (UNCTAD 2009). The global food price crisis of
2007–2008 also pushed governments into action. In July 2009, the G8 Summit in
L’Aquila produced a Food Security Initiative, promising to mobilize US$20 billion
to strengthen global food production and security; and the Global Agriculture and
Food Security Program (GAFSP) was established as a multilateral financing mecha-
nism to help implement these pledges. Other initiatives at global and regional levels
are underway, such as NEPAD’s Comprehensive Africa Agriculture Development
Program (CAADP) in Africa. Governments are paying greater attention to agriculture
than in the past. The ‘urban bias’ (Lipton 1977) is still very present, as most govern-
mental elites still depend on the political support from the urban populations for
their stability ; but the prejudice against agriculture is slowly being overcome.
However, investments that will allow to increase food production will not allow
significant progress in combating hunger and malnutrition if it is not combined with
higher incomes and improved livelihoods for the poorest – particularly small-scale
farmers in developing countries. And short-term gains will be offset by long-term
losses if it leads to further degradation of ecosystems, threatening future ability to
maintain current levels of production. The question therefore is not simply how
much, but also how. Pouring money into agriculture will not be sufficient: we have
to take steps that facilitate the transition towards a low-carbon, resource-preserving
type of agriculture that benefits the poorest farmers.
In this chapter, I explore how agroecology can play a central role in achieving this
goal. I argue that it is possible to significantly improve agricultural productivity where
it has been lagging behind, and thus to raise production where it needs most to be
raised (in poor, food-deficit countries), while at the same time improving the live-
lihoods of small holder farmers and preserving ecosystems. This would slow the trend
towards urbanisation in the countries concerned, which is placing stress on public ser-
vices of these countries. It would contribute to rural development and preserve the
ability for the succeeding generation to meet its own needs. And it would contribute to
the growth of other sectors of the economy, by the stimulation of demand for non-
agricultural products that would result from higher incomes in the rural areas.
2 A Diagnosis
Most of the attention since the global food price crisis has been to increasing overall
production. The crisis has been seen as resulting from a mismatch between supply
and demand : as a gap between slower productivity growth and increasing needs.
Agroecology, a Tool for the Realization of the Right to Food 3
A widely cited estimate is that, taking into account demographic growth, as well as
the changes in the composition of diets and consumption levels associated with
increased urbanization and higher household incomes, overall increase in agricul-
tural production should reach 70% by 2050 (Burney et al. 2010).
We should treat this estimate with caution. First, it takes the current demand
curves as given. At present, nearly half of the world’s cereal production is used to
produce animal feed and meat consumption is predicted to increase from 37.4 kg/
person/year in 2000 to over 52 kg/person/year by 2050, so that, by mid-century,
50% of total cereal production may have to go to increasing meat production (FAO
2006a). Therefore, the reallocation of cereals used in animal feed to human con-
sumption, an option highly desirable in developed countries where the excess ani-
mal protein consumption is a source of public health problems,1 combined with the
development of alternative feeds based on new technology,2 waste and discards,
could go a long way towards meeting the increased needs (Keyzer et al. 2005). The
United Nations Environmental Programme (UNEP) estimates that, even accounting
for the energy value of the meat produced, the loss of calories that result from feed-
ing cereals to animals instead of using cereals directly as human food represents the
annual calorie need for more than 3.5 billion people (UNEP 2009: 27, based on
figures from FAO 2006b). In addition, as a result of policies to promote the produc-
tion and use of agrofuels, the diversion of crops from meeting food needs to meeting
energy needs contributes to tightening the pressure on agricultural supplies.
Second, waste in the food system is considerable: for instance, the total amount
of fish lost through discards, post-harvest loss and spoilage may be around 40% of
landings (Akande and DieiOuadi 2010). Food losses in the field (between planting
and harvesting) may be as high as 20–40% of the potential harvest in developing
countries due to pests and pathogens, and the average post-harvest losses, resulting
from poor storage and conservation, amount at least to 12% and up to 50% for fruits
and vegetables (UNEP 2009: 30–31).
Third, even though food availability may have to increase, the focus on increas-
ing production should not obfuscate the fact that hunger today is mostly attributable
not to stocks that are too low or to global supplies unable to meet demand, but to
poverty : increasing the incomes of the poorest is the best way to combat it. We need
to invest in agriculture, not only in order to match growing needs, but also in order
to reduce rural poverty by raising the incomes of small-scale farmers. Because pov-
erty remains so heavily concentrated in the rural areas, GDP growth originating in
agriculture has been shown to be at least twice as effective in reducing poverty as
GDP growth originating outside agriculture (World Bank 2007: 6; Alston et al.
2002). The multiplier effects are significantly higher when growth is triggered by
higher incomes for smallholders, stimulating demand for goods and services from
1
In developing countries, the consumption of meat is much lower, and meat can be an important
source of proteins important for child development (Neumann et al. 2007).
2
Such as glucose from the degradation of cellulose, a technology that is currently being
developed.
4 O. De Schutter
local sellers and service-providers: when large estates increase their revenue, most
of it is spent on imported inputs and machinery; and much less trickles down to
local traders (Hoffmann 2010: 15). Only by supporting small producers can we help
break the vicious cycle that leads from rural poverty to the expansion of urban
slums, in which poverty breeds more poverty.
Fourth and finally, agriculture must not compromise its ability to satisfy future
needs. The loss of biodiversity, unsustainable use of water, and pollution of soils
and water are issues which compromise the continuing ability for natural resources
to support agriculture. Climate change, which translates in more frequent and
extreme weather events such as droughts and floods and less predictable rainfall, is
already having a severe impact on the ability of certain regions and communities to
feed themselves; and it is destabilizing markets. The change in average tempera-
tures is threatening the ability of entire regions, particularly those living from rain-
fed agriculture, to maintain actual levels of agricultural production (Stern Review
2007: 67). Less fresh water will be available for agricultural production, and the rise in
sea level is already causing the salinization of water in certain coastal areas, making
water sources improper for irrigation purposes. By 2080, 600 million additional
people could be at risk of hunger, as a direct result of climate change (UNDP 2007: 90).
In Sub-Saharan Africa, arid and semi-arid areas are projected to increase by 60–90
million hectares, and it is estimated that in Southern Africa yields from rainfed
agriculture could be reduced by up to 50% between 2000 and 2020 (IPCC 2007:
Chap. 9). Losses in agricultural production in a number of developing countries,
particularly in Sub-Saharan Africa, could be partially compensated by gains in other
regions, but the overall result would be a decrease of at least 3% in productive
capacity by the 2080s, and up to 16% if the anticipated carbon fertilization effects –
the incorporation of carbon dioxide in the process of photosynthesis – fail to mate-
rialize (Cline 2007: 96). And losses of production in many developed regions will
increase the pressure on the supply side of the global markets.
The current development path of agriculture is worsening this situation. Agriculture
currently accounts for at least 13–15% of global man-made greenhouse gas (GHG)
emissions. It is especially GHG-intensive in the developed countries, where agriculture
is more highly mechanized and relies heavily on synthetic fertilizers. Although some
of these emissions are from energy-related carbon dioxide (CO2) (9% of GHG emis-
sions from agriculture), most are from methane (CH4), which is emitted by rice pad-
dies, livestock digestion, and manure handling (45%), and nitrous oxide (N2O), from
nitrogen-based fertilizers and manure applications to soils (46%).3 That represents only
the emissions at field level: in rich countries, most of the energy use in the food systems
(from 65% to 80%) occurs at other points in the food chain, in the packaging, process-
ing, transport and preparation of food, as well as in production of agricultural inputs
and fixed capital equipment. Deforestation for the expansion of crop areas and pastures
3
CH4 and N2O represent respectively 14.3% and 7.2% of total GHG emissions, and they are par-
ticularly potent in trapping heat: CH4 traps 21 times more heat than CO2, and N2O traps 260 times
more heat (Kasterine and Vanzetti 2010: 87–111).
Agroecology, a Tool for the Realization of the Right to Food 5
Agroecology has been defined as the ‘application of ecological science to the study,
design and management of sustainable agroecosystems’ (Altieri 1995; Gliessman
2007). It seeks to enhance agricultural systems by mimicking or augmenting natural
processes, thus enhancing beneficial biological interactions and synergies among the
components of agrobiodiversity (Altieri 2002). Common principles of agroecology
include recycling nutrients and energy on a farm, rather than augmenting with external
inputs; integrating crops and livestock; diversifying species and genetic resources in the
agroecosystems over time and space, from the field to landscape levels; and focusing
on interactions and productivity across the agricultural system rather than focusing on
individual species. Agroecology is highly knowledge-intensive, based on techniques
that are not delivered top-down but developed on the basis of farmers’ knowledge and
experimentation.4 Agroecological practices require diversification of the tasks on the
farm, linked to the diversity of species (including animals) that are combined.
A wide panoply of techniques have been developed and successfully tested in a
range of regions that are based on this perspective (Pretty 2008). Integrated nutrient
management reconciles the need to fix nitrogen within farm systems with the import
of inorganic and organic sources of nutrients and the reduction of nutrient losses
Modern science combines with local knowledge in agroecological research. In Central America
4
for instance, the coffee groves grown under high-canopy trees were improved by the identification
of the optimal shade conditions minimizing the entire pest complex and maximizing the beneficial
microflora and fauna while maximizing yield and coffee quality (see Staver et al. 2001).
6 O. De Schutter
5
The 79% figure is for the 360 reliable yield comparisons from 198 projects. There was a wide
spread in results, with 25% of projects reporting a 100% increase or more.
6
Not all these projects, it should be added, comply fully with the principles of agroecology.
7
Such as improvements on cassava, for which NaCRRI developed locally-developed resistant vari-
eties in Uganda, or improvements on Tef in Ethiopia, where the Debre Zeit Agricultural Research
Centre developed a new variety, the Quncho.
8 O. De Schutter
300
250
Fertilizers and crude oil price index
200
150
50
0
2003/1 2004/1 2005/1 2006/1 2007/1 2008/1 '
own pest control, thus diminishing need of pesticides (Altieri and Nicholls 2004);
the availability of adapted seeds, planting materials and livestock breeds also pres-
ents multiple advantages, both for the farmer and to ensure the availability of the
required diversity of such materials in major crops such as maize, rice, millet, sor-
ghum, potato and cassava (UN Special Rapporteur on the right to food 2009). This
is particularly beneficial to small-scale farmers – especially women – with low or no
access to credit, and which have no capital, or whom fertilizer distribution systems
often do not reach, particularly since the private sector is unlikely to invest into the
most remote areas where communication routes are poor and where few economies
of scale can be achieved.
A study on agroforestry in Zambia which involved intercropping or rotation
between various trees and maize showed that the net benefit of agroforestry practices
is 44–58% superior to non-fertilised continuous maize production practice. And
while subsidised fertilised maize was the most financially profitable of all the soil
fertility management practices, given government’s 50% subsidy on fertiliser, the
difference in profitability between fertilised maize and agroforestry practices is
reduced sharply from 61% to 13% once the subsidy is accounted for in the computa-
tion. Even more importantly, agroforestry practices yielded higher returns per unit of
investment cost than continuous maize fields with or without fertiliser. Each unit of
money invested in agroforestry practices yielded returns ranging between 2.77 and
3.13 (i.e., a gain of between 1.77 and 2.13 per unit of money invested) in contrast
with 2.65 obtained through subsidised fertilised maize, and 1.77 through non-
subsidised fertilised maize. The return to labour per person-day was consistently
higher for agroforestry practices than for continuous maize practice. The study noted
that ‘in rural areas where road infrastructure is poor and transport costs of fertiliser
are high, agroforestry practices are most likely to outperform fertilised maize in
both absolute and relative profitability terms’ (Ajayi et al. 2009: 279, 283).
See Ajayi et al. 2009: 279 (research on agroforestry in Zambia does not support ‘the popular
8
In East Africa, this development was facilitated by the exchange of technology from Brazilian
9
Green Revolution approaches in the past have focused primarily on boosting cereal
crops (rice, wheat and maize) in order to avoid famines. However, these crops are
mainly a source of carbohydrates. They contain relatively little protein, and few of
the other nutrients essential for adequate diets. The shift from diversified cropping
systems to simplified cereal-based systems thus contributed to micronutrient malnu-
trition in many developing countries (Demment et al. 2003): of the over 80,000 plant
species available to humans, only three (maize, wheat and rice) supply the bulk of
our protein and energy needs (Frison et al. 2006). Nutritionists now increasingly
insist on the need for more diverse agro-ecosystems, in order to ensure a more diver-
sified nutrient output of the farming systems (Alloway 2008; DeClerck et al. 2011).
The diversity of species on farms managed following agroecological principles,
as well as in urban or peri-urban agriculture, is an important asset in this regard. For
example, it has been estimated that indigenous fruits contribute on average about
42% of the natural food-basket that rural households rely on in southern Africa
(Campbell et al. 1997). This not only is an important source of vitamins and other
micronutrients; it also may be critical for sustenance during lean seasons. And nutri-
tional diversity, allowed by increased diversity in the field, is of particular impor-
tance to children and women.
The agroforestry programme developed in Malawi protected farmers from crop failure
after droughts, thanks to the improved soil filtration it allowed (Akinnifesi et al.
2010). Indeed, on-farm experiments in Ethiopia, India, and the Netherlands have
demonstrated that the physical properties of soils on organic farms improved the
drought resistance of crops (Eyhord et al. 2007 ; Edwards 2007). A sixfold difference
was also measured in Brazil between infiltration rates under low-tillage agriculture
and traditional tillage. This allow rainfall to better recharge groundwater, and it
reduces the risks of flooding (Landers 2007). The soil’s infiltration capacity is also
maintained by the use of mulch cover, which protects the soil surface from tempera-
ture changes and minimizes soil evaporation (Kassam et al. 2009). In addition,
diversity of species and the diversification of farm activities that agroecological
approaches allow are a way to mitigate risks from extreme weather events, as well
as from the invasion of new pests, weeds and diseases, that will result from global
warming. Several agroecological approaches, such as cultivar mixtures, increase
crop heterogeneity and genetic diversity in cultivated fields. This improves crop
resistance to biotic and abiotic stresses In the Yunnan Province in China, after dis-
ease-susceptible rice varieties were planted in mixtures with resistant varieties,
yields improved by 89% and blast (a major disease in rice) was 94% less severe than
when they were grown in monoculture, leading farmers to abandon the use of fun-
gicidal sprays (Zhu et al. 2000).
Agroecology also puts agriculture on the path of sustainability, by delinking food
production from the reliance on fossil energy (oil and gas). And it contributes to miti-
gating climate change, both by increasing carbon sinks in soil organic matter and
above-ground biomass, and by avoiding carbon dioxide or other greenhouse gas emis-
sions from farms by reducing direct and indirect energy use. The IPCC has estimated
the global technical mitigation potential for agriculture at 5.5–6 Gt of CO2-equivalent
per year by 2030 (IPCC 2007: Sect. 8.4.3.). Most of this total (89%) can come from
carbon sequestration in soils, storing carbon as soil organic matter (humus); 9% from
methane reduction in rice production and livestock/manure management; and 2%
from nitrous oxide reduction from better cropland management (Hoffmann 2010: 11;
see generally on the mitigation potential of agriculture FAO 2009).
The discussion above points to the need for an urgent reorientation of agricultural
development towards systems that use fewer external inputs linked to fossil ener-
gies, and that use plants, trees and animals in combination, mimicking nature instead
of industrial processes at the field level. However, in moving towards more sustain-
able farming systems, time is the greatest limiting factor: whether or not we will
succeed will depend on our ability to learn faster from recent innovations and to
disseminate what works more widely.
Governments have a key role to play in this regard. Encouraging a shift towards
sustainable agriculture implies transition costs, since farmers must learn new
Agroecology, a Tool for the Realization of the Right to Food 13
techniques that move away from the current systems, which are both more specialized
and less adaptive, and have a lower innovation capacity (Pretty 2008). In order to
succeed in implementing such a transition, we should base the spread of agroecol-
ogy on the farmers themselves, its main beneficiaries, and encourage learning from
farmer to farmer, in farmer field schools or through farmers’ movements, as in the
Campesino-a-Campesino movement in Central America and Cuba (Degrande et al.
2006: 6; Holt-Giménez 2006; Rosset et al. 2011). Farmer field schools have been
shown to significantly reduce the amounts of pesticides use, as inputs are being
replaced by knowledge: large-scale studies from Indonesia, Vietnam and
Bangladesh recorded 35–92% reductions in insecticide use in rice, and 34–66%
reductions in pesticide use in combination with 4–14% better yields recorded in
cotton production in China, India and Pakistan (Van Den Berg and Jiggins 2007).
Farmer field schools are also empowering, helping farmers to organize them-
selves better, and they stimulate continued learning. The successful dissemination
of the push-pull strategy (PPS) in East Africa, promoted by the International
Centre for Insect Physiology and Ecology (ICIPE), rests in particular on the
demonstration fields managed by model farmers which attract visits of other
farmers during field days and on partnerships with national research systems in
Tanzania, Uganda, Ethiopia and other countries that made research and develop-
ment efforts to make the necessary adaptations such as choice of maize cultivars
(Amudavi et al. 2009: 226).
An improved dissemination of knowledge by horizontal means transforms the
nature of knowledge itself, which becomes the product of a network (Warner and
Kirschenmann 2007). It should encourage farmers, particularly small-scale farm-
ers living in the most remote areas and those on the most marginal soil, to identify
innovative solutions, working with experts towards a co-construction of knowl-
edge ensuring that advances will benefit them as a matter of priority, rather than
only benefiting the better-off producers (Uphoff 2002: 255). This is key for the
realization of the right to food. First, it enables public authorities to benefit from
the experience and insights of the farmers. Rather than treating smallholder farm-
ers as beneficiaries of aid, they should be seen as experts with knowledge that is
complementary to formalized expertise. Second, participation can ensure that
policies and programmes are truly responsive to the needs of vulnerable groups,
who will question projects that fail to improve their situation. Third, participation
empowers the poor – a vital step towards poverty alleviation, because lack of
power is a source of poverty, as marginal communities often receive less support
than the groups that are better connected to government. Poverty exacerbates this
lack of power, creating a vicious circle of further dis-empowerment. Fourth, poli-
cies that are co-designed with farmers have a high degree of legitimacy and thus
favor better planning of investment and production and better up-take by other
farmers (FAO-IIED 2008). Participation of food-insecure groups in the policies
that affect them should become a crucial element of all food security policies,
from policy design to the assessment of results to the decision on research priori-
ties. Improving the situation of millions of food-insecure peasants indeed cannot
be done without them.
14 O. De Schutter
Bibliography
Ajayi CO et al (2009) Labour inputs and financial profitability of conventional and agroforestry-
based soil fertility management practices in Zambia. Agrekon 48:246–292
Akande G, DieiOuadi Y (2010) Post-harvest losses in small-scale fisheries: case studies in five
sub-Saharan African countries. FAO Fisheries Technical Paper No 550
Akinnifesi FK et al (2010) Fertiliser trees for sustainable food security in the maize-based produc-
tion systems of East and Southern Africa. A review. Agron Sustain Dev 30(3):615–629
Alloway BJ (ed) (2008) Micronutrient deficiencies in global crop production. Springer Verlag,
Heidelberg
Alston J et al (2002) A meta-analysis of rates of return to agricultural R&D: research report 113,
IFPRI, Washington, DC
Altieri MA (1995) Agroecology: the science of sustainable agriculture, 2nd edn. Westview Press,
Boulder
Altieri MA (2002) Agroecology: the science of natural resource management for poor farmers in
marginal environments. Agric Ecosyst Environ 93:1–24
Altieri MA, Nicholls C (2004) Biodiversity and pest management in agroecosystems, 2nd edn.
CRC, Boca Raton
Amudavi DM et al (2009) Evaluation of farmers’ field days as a dissemination tool for push-pull
technology in Western Kenya. Crop Prot 28:225–235
Burney JA et al (2010) Greenhouse gas mitigation by agricultural intensification. Proc Natl Acad
Sci 107(26):12052–12057
Campbell B et al (1997) Local level valuation of Savannah resources: a case study from Zimbabwe.
Econ Bot 51:57–77
Christiaensen L, Demery L, Kuhl J (2011) The (evolving) role of agriculture in poverty reduction –
an empirical perspective. J Dev Eco 96:239–254. doi: 10.1016/j.jdeveco.2010.10.006
Cline WR (2007) Global warming and agriculture impact estimates by country. Center for Global
Development and the Peterson Institute for International Economics, Washington, DC
DeClerck FAJ et al (2011) Ecological approaches to human nutrition. Food Nutr Bull, 32 (suppl 1):
41S–50S
Degrande A et al (2006) Mechanisms for scaling-up tree domestication: how grassroots organisa-
tions become agents of change, ICRAF, Nairobi
Delgado C, Hopkins J, Kelly VA (1998), Agricultural growth linkages in sub-Saharan Africa,
IFPRI Research Report 107. International Food Policy Research Institute, Washington, DC
Demment MW et al (2003) Providing micronutrients through food based solutions: a key to human
and national development. J Nutr 133:3879–3885
Diop AM (2001) Management of organic inputs to increase food production in Senegal. In: Uphoff N
(ed) Agroecological innovations increasing food production with participatory development.
Earthscan, London
Edwards S (2007) The impact of compost use on crop yields in Tigray, Ethiopia. In: International
conference on organic agriculture and food security, FAO, Rome, 2–4 May 2007
Eyhord F et al (2007) The viability of cotton-based organic agriculture systems in India. Int J Agric
Sustain 5:25–38
FAO (United Nations Organisation for Food and Agriculture) (2006a) World agriculture, towards
2030/2050. FAO, Rome
FAO (United Nations Organisation for Food and Agriculture) (2006b) Livestock’s long shadow.
FAO, Rome
FAO (United Nations Organisation for Food and Agriculture) (2009) Food security and agricul-
tural mitigation in developing countries: options for capturing synergies, FAO, Rome
FAO (United Nations Organisation for Food and Agriculture) – IIED (International Institute for
Environment and Development) (2008) The right to food and access to natural resources –
using human rights arguments and mechanisms to improve resource access for the rural poor,
right to food study. FAO, Rome
Agroecology, a Tool for the Realization of the Right to Food 15
FAO (United Nations Organisation for Food and Agriculture) and Bioversity International,
Sustainable Agriculture and Rural Development (SARD) Policy Brief 11, 2007
Frison E et al (2006) Agricultural biodiversity, nutrition and health: making a difference to hunger
and nutrition in the developing world. Food Nutr Bull 27(2):167–179
Garrity DP et al (2010) Evergreen Agriculture: a robust approach to sustainable food security in
Africa. Food Secur 2:197–214
Gliessman S (2007) Agroecology: the ecology of sustainable food systems. CRC, Boca Raton
Hoffmann U (2010) Assuring food security in developing countries under the challenges of climate
change: key trade and development issues of a profound transformation of agriculture.
UNCTAD, Discussion Paper No. 201, November 2010
Holt-Giménez E (2002) Measuring farmers’ agroecological resistance after hurricane Mitch in
Nicaragua: a case study in participatory, sustainable land management impact monitoring.
Agric Ecosyst Environ 93(1–2):87–105
Holt-Giménez E (2006) Campesino a campesino: voices from Latin America’s farmer to farmer
movement for sustainable agriculture. Food First Books, Oakland
IAASTD (International Assessment of Agricultural Knowledge, Science and Technology for
Development) (2008) Summary for Decision Makers of the Global Report, April 2008,
Washington, DC
IPCC (Intergovernmental Panel on Climate Change) (2007) Climate change 2007: climate change
impacts, adaptation and vulnerability. Working group II contribution to the fourth assessment
report of the Intergovernmental Panel on Climate Change. Cambridge University Press,
Cambridge/New York
Kassam A et al (2009) The spread of conservation agriculture: justification, sustainability and
uptake. Int J Agric Sustain 7(4):292–320
Kasterine A, Vanzetti D (2010) The effectiveness, efficiency and equity of market-based and vol-
untary measures to mitigate greenhouse gas emissions from the agri-food sector. Trade and
Environment Review 2009/2010, UNCTAD, Geneva, pp 87–111
Keyzer MA et al (2005) Diet shifts towards meat and the effects on cereal use: can we feed the
animals in 2030? Ecol Econ 55(2):187–202
Khan A, Ahmed GJU, Magor NP, Salahuddin A (2005) Integrated rice-duck: a new farming system
for Bangladesh. In: Van Mele P, Ahmad S, Magor NP (eds) Innovations in rural extension: case
studies from Bangladesh, Cabi bioscience and IRRI. Cabi Publishing, Oxford, pp 243–256
Khan Z et al (2011) Push-pull technology: a conservation agriculture approach for integrated
management of insect pests, weeds and soil health in Africa. Int J Agr Sustain 9(1):162–170
Landers J (2007) Tropical crop-livestock systems in conservation agriculture: the Brazilian experi-
ence, integrated crop management, vol 5. FAO, Rome
Linyunga K et al (2004) Accelerating agroforestry adoption: a case of Mozambique, ICRAF-
agroforestry project. Paper presented at the IUFRO Congress, Rome, Italy, 12–15 July 2004
Lipton M (1977) Why poor people stay poor: a study of urban bias in world development. Maurice
Temple Smith, London
Neumann CG et al (2007) Meat supplementation improves growth, cognitive, and behavioral out-
comes in Kenyan children. J Nutr 137(4):1119–1123
Platform for Agrobiodiversity Research (2010) Climate Change project, Bioversity International
and The Christensen Fund, The use of agrobiodiversity by indigenous and traditional agricul-
tural communities in adapting to climate change – Synthesis paper
Pretty J (2008) Agricultural sustainability: concepts, principles and evidence. Phil Trans R Soc B
363(1491):447–465
Pretty J et al (2006) Resource-conserving agriculture increases yields in developing countries.
Environ Sci Technol 40(4):1114–1119
Pretty J et al (2011) Sustainable intensification in African agriculture. International Journal of
Agric Sustain pp 5–24. doi: 10.3763/ijas.2010.0583
Pye-Smith C (2008) Farming trees, banishing hunger. How an agroforestry programme is helping
smallholders in Malawi to grow more food and improve their livelihoods. World Agroforestry
Centre, Nairobi
16 O. De Schutter
Pye-Smith C (2010) A rural revival in Tanzania: how agroforestry is helping farmers to restore the
woodlands in Shinyanga region, ICRAF trees for change no. 7. World Agroforestry Centre,
Nairobi
Reardon T, Berdegué JA (2002) The rapid rise of supermarkets in Latin America. Challenges and
opportunities for development. Dev Policy Rev 20:317–334
Reardon T et al (2007) Supermarkets and horticultural development in Mexico : synthesis of find-
ings and recommendations to USAID and GOM. Report submitted by MSU to USAID/Mexico
and USDA/Washington, August 2007
Reardon T et al (2009) Agrifood industry transformation and small farmers in developing
countries. World Dev 37:1717–1727
Rosset P et al (2011) The Campesino to- Campesino agroecology movement of ANAP in Cuba.
J Peasant Stud 38(1):1–33
Sims B et al (2009) Agroforestry and conservation agriculture: complementary practices for
sustainable development. II World Congress of Agroforestry, Nairobi, Kenya, 23–28 August
2009
Smith P et al (2007) Agriculture. In: Metz et al (eds) Climate change 2007: mitigation, contribution
of WG III to the fourth assessment report of the intergovernmental panel on climate change.
Cambridge University Press, Cambridge and New York
Staver C et al (2001) Designing pestsuppressive multistrata perennial crop systems: shade-grown
coffee in Central America. Agrofor Syst 53:151–170
Stern N (2007) Stern review report on the economics of climate change. Cambridge University
Press, Cambridge
UN Special Rapporteur on the right to food, Report to the General Assembly (2009) Seed policies
and the right to food: enhancing agrobiodiversity, rewarding innovation, UN doc. A/64/170,
October 2009
UNCTAD (United Nations Conference on Trade and Development) (2009) World investment
report 2009. Transnational corporations, agricultural production and development
UNCTAD (United Nations Conference on Trade and Development) and UNEP (United Nations
Environmental Programme) (2008) Organic Agriculture and Food Security in Africa, UNEP-
UNCTAD Capacity Building Task Force on Trade, Environment and Development (UNCTAD/
DITC/TED/2007/15), United Nations, New York/Geneva
UNDP (United Nations Development Programme) (2007) Human development report 2007/2008.
Fighting climate change: human solidarity in a divided world
UNEP (United Nations Environmental Programme) (2005) Agroecology and the search for a truly
sustainable agriculture, Mexico
UNEP (United Nations Environmental Programme) (2009) The environmental food crisis. UNEP,
Nairobi
Uphoff N (2002) Institutional change and policy reforms. In: Uphoff N (ed) Agroecological inno-
vations increasing food production with participatory development. Earthscan Publications,
London
Van den Berg H, Jiggins J (2007) Investing in farmers. The impacts of farmer field schools in
relation to integrated pest management. World Dev 35(4):663–686
Warner KD, Kirschenmann F (2007) Agroecology in action: extending alternative agriculture
through social networks. MIT Press, Cambridge
Wezel A et al (2009a) A quantitative and qualitative historical analysis of the scientific discipline
of agroecology. Int J Agric Sustain 7(1):3–18
Wezel A et al (2009b) Agroecology as a science, a movement and a practice. A review. Agron
Sustain Dev 29:503–515
World Agroforestry Centre (2009) Creating an evergreen agriculture in Africa for food security
and environmental resilience. World Agroforestry Centre, Nairobi
World Bank (2007) Word development report 2008: agriculture for development. The World Bank,
Washington, DC
Zhu YY et al (2000) Genetic diversity and disease control in rice. Nature 406:718–722
Agroecology and the Food System
Abstract On a global scale agriculture and food will face key challenges of properly
feeding a population of nine billion individuals in 2050, while preserving the eco-
systems from which other services are also expected, such as bioenergy production,
biodiversity use and conservation, carbon storage and climate regulation. To develop
future sustainable agricultural production and food systems, agronomic, ecological,
economic and social challenges have to simultaneously be taken into account. The
framework of agroecology applied on the food system could be a useful concept to
support this development. Although the scale and dimension of scientific research
in agroecology has been enlarged in the last years towards the food system approach,
it is still difficult to outline clear concepts, new models and new methods that spec-
ify it. In using two contrasted research case studies, we evaluate benefits and chal-
lenges using the framework of agroecology applied on the food system.
The first case study illustrates research questions around water quality and man-
agement of shallow lakes with fish production, biodiversity of the lakes, agricultural
land use on the surrounding land, and local fish products and its marketing strate-
gies. It shows that research was initiated by an ecologist working at the lake scale,
but implementing quite quickly a systems approach in integrating the disciplines
ecology, agronomy, geography, socio-economy and sociology with a food systems
approach. The second case study illustrates research questions around organic wheat
production and food chain. It shows the evolution of a research program where
research objectives and methodology have been slowly turned from technical ques-
tions on nitrogen management of organic wheat, supported by agronomist, applied
at field scale, to overall agroecological questions around organic grain producers,
A. Wezel (*) • C. David
Department of Agroecosystems, Environment and Production,
ISARA Lyon (associated member of the University of Lyon), 23 rue Jean Baldassini,
69364 Lyon cedex 07, France
e-mail: wezel@isara.fr
1 Introduction
World agriculture and food provision will face key challenges of properly feeding a
population of nine billion individuals in 2050 where contrasted regional food avail-
ability will support important migration. Therefore, there is a crucial need to pre-
serve the environment and natural resources of agricultural land from which other
services are also expected: bioenergy production, biodiversity use and conservation,
carbon storage and climate regulation. Research on the world’s agricultural produc-
tion and food, to support the objective of sustainable development, has become the
subject of many studies and debates (FAO 2003; Agrimonde 2009). The framework
of agroecology applied on the food system may significantly support this sustain-
able development by considering simultaneously agronomic, ecological, economic
and social dimension at different scales.
Although agroecology as a scientific discipline exists already since many
decades, the food systems approach in agroecology has been developed only recently
(Wezel and Soldat 2009; Wezel and Jauneau 2011). Still it is difficult to outline clear
concepts, new models and new methods that specify this approach. Besides agro-
ecology as a scientific discipline, other interpretations such as agroecology as a
practice or as a movement are present (Wezel et al. 2009).
The scale and dimension of scientific research in agroecology has been enlarged
over the past 80 years from (1) the plot, field or animal scale to (2) the farm or agro-
ecosystem scale and finally in the last years to (3) the dimension of the food system
(Wezel and Soldat 2009). On the plot/field/animal scale, the aim of agroecological
Agroecology and the Food System 19
research is to develop new farming practices such as more efficient use of natural
resources, improved nutrient cycling, and enhancement of diversity and the health
of soils, crops and livestock. For instance, in crop production research focuses on
techniques to limit off-farm fertilisers, e.g. mixed crops, intercropping systems to
better use crop diversity and N fixation from legumes or to improve pest manage-
ment by using natural processes, e.g. allopathy or natural enemies for plant protec-
tion. In animal production, research investigates for example natural alternatives
like plant extracts to antibiotics or adaptation of animal densities and pasture rota-
tion to improve fodder quality and availability. At this scale, research does not really
consider interactions and implications of these techniques on the agroecosystem or
the environment at a larger scale.
The second major approach is the agroecosystem approach. Here, ongoing
research dominates the agroecosystem scale, including exchange with, and impact
on the surrounding environment. Agroecological analyses focuses on plant and
animal communities, food web interactions, and conservation biology in agricul-
tural landscapes and agroecosystems (Department of Crop Science, Section of
Agroecology, at the University of Göttingen 2008). Within the agroecosystem
approach the definitions and concepts might vary depending on the delimitation of
an agroecosystem. Sometimes, the farm is seen as equivalent to an agroecosystem
where the relations between farmers’ practices and natural resources are analysed
(Conway 1987). For others an agroecosystem is larger, that is, a local or regional
landscape where relations between different types of agriculture and the natural
resources of the landscape is investigated.
The most recent and broadest approach is the food systems approach. This
approach was firstly defined by Francis et al. (2003) as ‘the integrative study of
the ecology of the entire food systems, encompassing ecological, economic and
social dimensions, or more simply the ecology of food systems’. Gliessman
(2007) stated that the politics/policy dimension should also be included in this
definition, as the different political decisions and policies are an important issue
to be considered. This author defined agroecology as ‘the science of applying
ecological concepts and principles to the design and management of sustainable
food systems’. These two definitions are based on former definitions of Altieri
(1989, 1995, 2002).
During the beginning of the 2000s, several authors demand that agriculture has
to be analysed in a holistic manner. For example Robertson et al. (2004) demand
that agricultural research needs long-term, system-level research at multiple scales,
and that natural and social science must be better integrated. Gliessman (2007)
stated that ‘to recognise the influence of social, economic, cultural, and political
factors on agriculture, we must eventually shift our focus from sustainability of
agroecosystems to the sustainability of our food systems’. Nevertheless, it is still
difficult to outline clear concepts, new theoretical models, and new methods that
specify and translate these demands, and in particular the expanded definition of
agroecology of the food system, into concrete cases. In fact, very few papers are
given in the literature where agroecology concepts and theory are applied on the
food system, e.g. Francis and Rickerl (2004).
20 A. Wezel and C. David
This leads to the objectives of this paper. Two examples of actual research topics
will be presented and analysed in how they are placed within or in relation with the
food systems approach of agroecology. A particular question will be what distin-
guishes them from more disciplinary research approaches such as agronomy or
ecology, which research concepts are used and how the different research scales are
taken into consideration.
In the following, we will present the two case studies, the agroecosystems where
they have been carried out, the research objectives and the main research questions,
the methods used to analyse them, and the interaction between the different research
components and disciplines. A special emphasis will be laid on the historical evolu-
tion of the research objectives, which disciplines initiated the projects, and which
disciplines joined in thereafter. In a subsequent section their place within the agro-
ecology approach with the food system will be illustrated and discussed.
The research objectives of this case study were, first, to evaluate if shallow lake
management practices and agricultural practices in the surroundings favour high
biodiversity which can then be used for the promotion of local fish products, and,
secondly, if the agricultural and aquaculture practices at the same time can maintain
a sufficient level of fish production and preserve un acceptable water quality.
The Dombes region in south-eastern France, the study area, was formed by gla-
cial activity during the quaternary period (Avocat 1975). It is a plateau of about
1,000 km2 with long, fan-shaped morainic mounds, so-called drumlins. The average
altitude is about 280 m. The plateau is flanked by three fluvial valleys about
50–100 m below the plateau. During the late Würm glaciation, substantial amounts
of loess were mainly deposited in the depressions between the drumlins (Williams
2006). Post-glacial rain leached much of the loess creating decalcified clayey soils
in the depressions which induce water stagnation when soils are wet (Avocat 1975).
In the morainic areas, more sandy soils dominate. Annual precipitation varies
between 800 and 1,200 mm (Blanchet 1993; Bernard and Lebreton 2007). The his-
tory of the Dombes and its shallow lake system started in the thirteenth century
(Guichenon 1650 cited in Sceau 1980). The shallow lakes were created in smaller
depressions for the production of fish, and to drain surrounding loamy-clayey soils
to be able to crop cereals. The fish production activity expanded largely during the
medieval period because of the need to find fish at a time in which food prescrip-
tions were very strict. Today, the Dombes region is characterised by about 1,100
shallow lakes with about 12,000 ha, located in an agricultural area with pastures,
cropped fields and forests (Bernard and Lebreton 2007). The size of the shallow
lakes varies considerably from less than 1 ha up to one which is larger than 100 ha.
Average depth of the shallow lakes is about 1 m. The fish farming practiced in the
shallow lakes is oriented toward raising mainly carp, but also tench, roach and pike
Agroecology and the Food System 21
(Bernard and Lebreton 2007). It is based on an extensive system that alternates fish
farming and grain farming on the same unit of land. Shallow lakes are emptied every
year for fish harvesting, and then refilled. After 3–4 years, the shallow lakes are left
to dry up to be cultivated mainly with oats, maize or sorghum for 1 year; few are not
cultivated (Wezel et al. submitted). The water that fills the shallow lakes during the
wet phase comes either from a shallow lake situated at a higher elevation or from a
system of ditches which lead into the shallow lake and which collect rainwater from
the catchment.
The research presently carried out in the Dombes region touches different scales
and different disciplines. At the scale of a shallow lake, which is considered here as
the plot/field scale mentioned above, different physical-chemical water and sedi-
ment parameter are analysed for a selection of shallow lakes to evaluate the trophic
status and its changes during a year (ecology). This type of research was started
already a few years earlier, before other components were added to have a more
holistic approach. For the latter, species richness and diversity of phytoplankton,
marcophytes, macro-invertebrates, dragonflies and amphibians are additionally
investigated (ecology). Also data on annual fish harvest are collected from manag-
ers of the shallow lakes (socio-economy). Land use and biotopes within a 100 m
radius around the shallow lakes (field scale) and within the catchment of shallow
lakes (agroecosystems scale) are analysed by aerial photograph interpretation and
ground surveys (geography, landscape ecology). In addition, farmers are inter-
viewed about their agricultural practices such as fertilisation, nutrient management,
pesticide use and water drainage on the fields adjacent to the shallow lakes and in
the catchment (field scale; agronomy). Owners or managers of the shallow lakes are
questions concerning different fish production and lake management practices (lake/
field scale; socio-economy). Finally, an analysis is carried out to investigate the
network of stakeholder for processing, selling and marketing of the fish production,
and about the creation of a label of geographical denomination of origin for the fish
products (food system scale; sociology, socio-economy).
The different analyses carried out are used to evaluate either singular results of
the different parameters analysed, but also their complex interactions. Water quality
and sediment parameter are analysed to evaluate the trophic status of the shallow
lakes itself, but also how these parameters are influenced by land use around and
lake management practices. The richness and diversity of the different species
groups are evaluated in relation to the trophic status of the shallow lakes, but also in
relation to lake management as well as for agricultural practices and biotopes pres-
ent in the vicinity of lakes. The evaluation of the fish production is the most com-
plex as fish production is evaluated in relation to trophic status of shallow lakes,
which is additionally influenced by lake management practices and agricultural land
use around the lakes. In addition, the impact of several species groups such as phy-
toplankton, marcophytes, and macro-invertebrates, are evaluate in relation to fish
production because of being a source of feed for fish or being important for nutrient
turn-over in the water. Finally, it is evaluated if the existence of a certain biodiver-
sity (the species groups and the biotopes) can be valorised for the marketing of the
fish production, or more specifically for a product label, or even as being a quality
22 A. Wezel and C. David
Society Politics
Agroecosystem and
its natural resources
Plant Animal
production production
Environment Economy
Shallow lake
Mixed cropping-
agroecosystem
livestock
Fish agroecosystem
production
Wheat production,
Plant Animal N-fertilisation,
production production Crop rotation
Fig. 1 The general food systems approach of agroecology is illustrated above (From Wezel and
Soldat 2009) where agricultural production within an agroecosystem and the interactions and
influences from and to the environment, economy, society and politics are taken into account.
Below left, the case study of the shallow lake agroecosystem, and below right, the case study of
organic cereal farming, are illustrated with the respective key elements
indicator for the Dombes shallow lakes agroecosystem and its different types of
management and practices.
In this section we will show how this first case study can illustrate the theoretical
concept of Francis et al. (2003) for the food system approach in agroecology. The
agroecosystem of this case study consists of shallow lakes within a matrix of agri-
cultural land forests and (semi-)natural ecosystems (Fig. 1, below left). Three types
of production exist and interact in different ways: fish production in shallow lakes,
cropping of cereals, sun flowers and rape on fields as well as cattle and some sheep
production on pastures. These three types of production have different impacts on
the environment. The use of fertilisers and pesticides for plant production influences
to different degrees the water quality of shallow lakes (Vallod et al. 2008, Wezel
et al. submitted), and thus also fish production, but also different natural species in
and around the shallow lakes such as dragon flies, phytoplankton or macrophytes.
The impact strongly depends on where the different types of land use are located in
the agroecosystem, and how they are connected by ditches or drainage systems with
Agroecology and the Food System 23
the shallow lakes. In addition, it is necessary to know how farmers manage their
fields and pastures as well as their borders or the hedgerows in the agroecosystem.
This together with the knowledge about how fish producers mange their shallow
lakes is necessary to evaluate the impact on ecosystems such as reed, hedgerows,
thickets and grassland as well as selected species groups in the shallow lakes vicin-
ity. The management of the farmers and fish producers is influenced to different
degrees by regional, national and European regulations such as the EU Common
Agricultural Policy, the European Water Framework Directive and NATURA 2000,
thus these regulations have to be taken into account if modification of practices are
intended. In addition, the role of farmers and fish producer among other stakehold-
ers in the Dombes agroecosystem such as local politicians, mayors, conservationist
and different agricultural and fish associations and institutions has to be analysed to
anticipate reaction within the social structure of the Dombes region to proposed
changes or innovations. Finally, it is essential to identify the different stakeholders
of the fish food chain: from producers, collectors, processors, sellers to the con-
sumer. This analysis enable to evaluate how fish could be marketed in increasing or
assuring income by using different types of labels such as Geographical Denomination
of Origin, or a new local label indicating that with the traditional local fish produc-
tion the cultural landscape and/or biodiversity is preserved.
This case study illustrates the food system approach with research questions
around water quality and management of shallow lakes with fish production, biodi-
versity of the lakes, agricultural land use on the surrounding agricultural land, and
local fish products and its marketing strategies. It shows that research was initiated
by ecologist, but implementing quite quickly a systems approach in integrating the
disciplines ecology, agronomy, geography, socio-economy and social science with
an agroecosystems and food systems approach.
The research objectives of this case study were, first, to evaluate how nitrogen
management of organic wheat can be improved and how the farming system has to
be adapted to this, and, secondly, to analyse the organisation of organic grain pro-
ducers and the wheat-flour food chain.
The study area is located in south-eastern France where two closely located sub-
areas, the Diois and the Plain of Valence, were selected. The Diois is a hilly area
located along the Drome River, at the southern feet of the vast karst plateau of the
Vercors with an average altitude of 1,100 m. The altitude of the Diois ranges between
420 and 520 m with a mean annual temperature of 10.2°C (David et al. 2005a). In
this area, clayey and stony soils dominate, except along the Drome River where
cereals are produced on alluvial soils. Annual precipitation varies between 885 and
1,100 mm. The traditional farming system is characterized by a mixed production
of livestock with sheep and goats, arable crops and perennial crops such as aromatic
24 A. Wezel and C. David
plants, walnuts or grapes. Climatic conditions with cold winter and dry summer
limit strongly wheat performance.
The Plain of Valence is located at the confluence of the fertile Rhone, Drome and
Isere River valleys where loamy and sandy soils dominate. The altitude ranges between
150 and 250 m with a mean annual temperature of 11.4°C (David et al. 2005a). Annual
precipitation varies between 850 and 950 mm. The traditional farming system
mainly produces grains, sometimes in combination with other productions such as
poultry or field vegetables.
In the two districts, where the study areas are located, the development of the
organic sector (production and processors) in the last year has been one of the fast-
est growing in France with 8–10% of the usable agricultural area under organic
agriculture (Agence Bio 2008). In particular in the Diois area, an active organic sec-
tor around wine, grains and aromatic plants has developed since the beginning of
the 1990s.
As the Dombes example, this research project has been carried out at different
scales and by integrating different disciplines. The on-farm research program on
organic wheat started in 1993, and up to 1998 the objective was to improve the techni-
cal and economical performance of organic grain systems with a special emphasis on
organic wheat being the most important crop (Von Fragstein et al. 1997). This first
phase had been set up on 17 farms, first, to take into account a wider range of growing
conditions than is available on on-station experiments, secondly, to benefit from farm-
ers’ expert knowledge when research on organic grains systems was still very limited,
and, finally, to consider the entire farm system and its socio-economic parameters
(Lockeretz and Stopes 1999). Nitrogen and weed management were experimented on
more than 40 organic fields from 1993 to 1998 by testing various techniques and
equipment (field scale, agronomy) defined by experts to improve yield performance.
Different factors limiting organic crop production such as weed and pest infestation,
soil compaction or climatic conditions like water stress and hot temperatures could be
determined (field scale; agronomy) (David et al. 2005a; Casagrande et al. 2009). From
1998 to 2004, management of N fertilisation had also been studied under controlled
on-station conditions, to produce references for N nutrition of organic and low-input
wheat from organic N sources (David et al. 2004). This research also allowed develop-
ing a decision support system to manage N fertilisation of organic wheat (David et al.
2005b; David and Jeuffroy 2009) to improve grain yield and grain protein content. In
addition, it gave an early indication of whether this decision support system is likely
to be adopted by farmers (agronomy, sociology). During the second phase of the pro-
gram, research went beyond the restricted field scale analyses in integrating more
farm management aspects. A multivariate analysis of quantitative and qualitative data
such as grain yield, protein content, crop management and farming system manage-
ment from 97 organic farms located in the two districts demonstrated the incidence of
the farming systems, e.g. the presence or absence of livestock on the farm, the inci-
dence of crop management, e.g. cultivar, preceding crop, N fertilisation and weed
control, but also the incidence of soil and climatic conditions such as water deficit and
temperature on grain yield and protein content (field and agroecosystem scale; agron-
omy). Furthermore, interviews with farmers which were started in the first phase,
Agroecology and the Food System 25
enlarged in the second phase and which became up to present a key element of the
research program, enabled to study more completely the farm management (plot, farm
and food system scale; agronomy, economy and sociology). It could be concluded that
diversification of farm production and activities, off-farm employment and profes-
sional and social networking contributed significantly to farm viability (David et al.
2010). In parallel, the analysis of the wheat-flour food chain allowed to determine the
interactions between producers, collectors, processors and consumers (David and
Joud 2008). Also, a structured organic food chain supported by cooperatives and bak-
ers improved economic viability of farms.
The present research project now tries to integrate even more many different
scientific disciplines such as agronomy, food technology, economy, and sociology,
and to work simultaneously at different scales of the field, the farm and the food
system to consider a more holistic approach. Thus, the present research objectives
are to improve nitrogen supply by undersowing of leguminous species or use of
organic fertiliser and soil management for wheat production, but also flour process-
ing to improve baking quality, nutritional value and to avoid mycotoxin contamina-
tion. Further research questions are how local and regional processing, marketing,
distribution and selling enterprises in the region can be establish or better imple-
mented in the region in considering the increasing requirements from processors on
quality and safety of organic wheat as well as the demand from the regional and
national organic food market to decrease the variation of offer and quality as well as
to limit instability of prices? And last but nor least, how can the organic farmers be
better integrated in this food chain network, also considering the different support
payment systems on national and European level for organic agriculture?
As for the first case study, we also will illustrate the theoretical concept of Francis
et al. (2003) for the food system approach in agroecology with the organic farming
case study. The agroecosystems characteristics of the two subareas of this case study
strongly influences the farming systems but also the food system (Fig. 1, below
right). The Diois agroecosystem consists of limited areas with fertile soil in the
Drome Valley, where cereals are produced in a long term and diversified crop rota-
tion of 8–11 years, surrounded by large areas with low soil fertility occupied by
vineyards, lavender fields, permanent pastures and (semi-)natural ecosystems. The
agricultural productivity is limited in this area. In contrast, the high agricultural
diversity together with the Drome River and the adjacent mountains make it to a
beautiful landscape and give a strong value for tourism for which farmers produce
local food, vine and lavender as well as offering accommodation. Conversion to
organic production allowed maintaining economic value to low-input agricultural pro-
ductions like vine, grains and aromatic plants. Moreover, the organic development,
promoted by local authorities, supports the “natural” value of this area. The marketing
26 A. Wezel and C. David
of organic products such as grain, wine and aromatic plants, promoted by cooperatives
is associated with identity and origin, supported by traditional varieties and specific
products, for instance by the Clairette de Die, a famous sweet sparkling wine pro-
duced exclusively in this area.
As the agroecosystem of the Plain of Valence consists of a large fertile plain, yield
performance of dominating grain production is much higher, compared to the Diois.
Organic grain systems differ only slightly from conventional systems. Cropping sys-
tems are based on a balanced proportion of spring crops, mostly irrigated, such as
maize and soybean associated in the crop rotation of 4–6 years with winter cereals
such as wheat, barley or triticale. The organic grains are collected by conventional
cooperatives where a limited organic sector has been developed to answer farmers’
requirements. Tourism is very limited in the Plain of Valence area, thus direct selling,
provision with local food products or accommodation at farm are rare.
As shown above, the agroecosystems characteristics of the two subareas do not
only influence the farming systems but implicate also differences for the food system
(Fig. 1, below right). For instance, in the Diois, the wheat-flour-bread chain is essen-
tially based on small niche market for traditional organic bakers or organic retailers
looking for specific flavour obtained with ancient varieties, but also providing iden-
tity as originating from the area. On the contrary, the wheat-flour food chain in the
Plain of Valence is essentially based on standardised quality requirement, e.g. protein
content over the conventional threshold of 11.5 g per 100 g and no mycotoxin, applied
from mass distribution or enterprises (David and Joud 2008). Nevertheless, on-going
research clearly needs to demonstrate the incidence of crop management, in particu-
lar N fertilisation, interaction with environmental conditions soil and climate via
wheat flour quality to local, regional or national marketing and selling networks. In
this relation from the field to the food chain scale, farmers’ management goals, their
economic situation and their receptivity for innovations, e.g. reduced tillage or under-
sowing of leguminous species, as well as regional, national and European agricul-
tural policy framework have to be taken into consideration.
This case study illustrates research questions around organic wheat production
and food chain in a study area in south-eastern France. It also shows the evolution
of a research program since 1993 where research objectives and methodology have
been slowly turned from technical questions on nitrogen management of organic
wheat, supported by agronomist, applied at field scale, to overall agroecological
questions around organic grain producers, raised by economists, sociologists,
agronomists and food technologists, focussing on the wheat-flour food chain,
applied at farm and food system scales.
c oncepts and approaches should be valorised, and new one should be developed. We
will start with existing concepts, than coming to new potential ones.
In general, the concepts of holism with a systemic approach including different
scales and interdisciplinarity exist already, so they can already be the basis for
research and analyses for agroecology of the food system. The two case studies
presented above show how analyses and evaluations from the field/plot, the farm/
agroecosystem, and the food system scale can be used to orient research towards a
system approach. Nonetheless, it is essential to emphasize on the up-scaling meth-
ods to relate research questions from the field/plot to the food system. The two
research examples clearly demonstrate the value of interdisciplinary research com-
bining agronomy, ecology, social sciences, socio-economy, but also food technol-
ogy. If we really intend to establish sustainable agricultural systems, it is essential
to focus research questions around a food product, or more generally around an
agricultural commodity, and to analyse the different scales with an interdisciplin-
ary perspective. Two types of research approaches seem possible, a bottom-up and
a top-down approach. The bottom-up approach would be for example to analyse
the incidence of innovative fertilisation management for crop performance and for
farm management, but also to anticipate what type of impact this would have on
the agroecosystem and the food quality (Le Bail and Meynard 2003). Which analy-
ses or what type of investigations have to be considered to evaluate their potential
impacts? The top-down approach could also be applied. For example if a local or
regional food label want to be created for better marketing, specific requirement
along the food chain, but also by specific values or ‘capitals’ from the agroecosys-
tem have to be taken into account. Consequently, the analyses have to be related to
the social systems and networks as well as to the agroecosystem itself to know for
instance if it is a particular cultural landscape which preserves certain species or
certain ecosystems, and thus if this information could be used for the promotion of
the product.
In general, different theoretical models have been developed to conceptualise the
complex relationships of how agroecosystems exist in the intersection between
nature and society (Gliessman 2007). The models presented focus on sustainable
agroecosystem and influences from ecological, socio-economic, and technological
factors (Hernandéz Xolocotzi 1977, cited in Gliessman 2007), the relation of agro-
ecosystems to certain resources, called ‘capitals’ such as human, social, natural, and
financial capital (Flora 2001), and the interactions among social and ecological
components of sustainable agroecosystems (Gliessman 2007). Although some of
the factors, capitals, or components are related in different ways to the food system,
the food systems approach is not explicitly integrated within the models.
Other possible theoretical approach could be the holon approach of Bland and
Bell (2007). Due to the need to tackle the problems of boundaries, e.g. scales, sys-
tem limits, or actors, and change, e.g. time or evolutions and adaptations, that are
evident for all agroecological research questions, they argue that agroecologists
need to take into account how intentionalities, e.g. research objectives, seek to create
holons, an intentional entity, that persist amid the ever changing contexts, and how
boundaries can be recognized based on how intentionalities draw and act upon them.
28 A. Wezel and C. David
Although the basis and the historical origin of agroecology are founded in the two
disciplines agronomy and ecology, the present scientific discipline agroecology and
its approach to the food system seems to be the most promising research framework
Agroecology and the Food System 29
Food system
sociology, anthropology, geography, socioe-conomy, ecology,
agronomy
Farm, Agroecosystem
Scale agronomy, ecology, geography, (anthropology,
sociology)
Field
agronomy, zoology,
ecology, crop
physiology
Agroecological complexity
Fig. 2 Agroecological complexity for research with different scale approaches of agroecology.
The increasing scales used for the farm/agroecosystem and the food system approach of agroecol-
ogy demand considering an increasing number of disciplines to deal with increasing complexity of
research questions. Agronomy and ecology are the basic disciplines for all scale approaches. The
disciplines in brackets are so far only integrated in certain cases at the farm/agroecosystem scale
research methods from different disciplines, and applying them to different scales,
a concept for agroecological analyses of the food system already exists. Nevertheless,
our examples also show that they remain to a certain degree incomplete. For exam-
ple among key social factors in food systems sustainability such as equitability,
sustainable diet patterns, control of population growth, and self-sufficiency and
bioregionalism, as proposed by Gliessman (2007), only bioregionalism was consid-
ered in the Dombes example. We could add more factors to that list which we think
as important to be included in food systems analyses such as energy consumption,
transport, or food quality, but probably we should also accept that is unrealistic to
demand now that every potential parameter or factor has to be included in the analy-
ses. In practice it is evident that it is not that easy to carry out such type of necessary
research as it will be seldom financed in its totality, but rather as research projects
which analyse only parts of it. In addition, interdisciplinarity is a keyword com-
monly used everywhere today in the scientific research community, but being really
implemented in only rarer cases.
It is also indispensable to integrate the stakeholders from the different food sys-
tem networks. With this a broader vision of the problems and a better identification
of potential solutions are achievable. Consequently, a more client-oriented research
will be implemented. Nevertheless, it should not be forgotten that integrating
researchers and food system stakeholders in a common process is often a tricky
thing as it demands a lot of efforts to find a common language and understanding. It
also often slows down the starting phase of the research projects as so many things
have to be taken into account, e.g. identification of stakeholders, common work-
shops or meetings, agreeing on terms and definitions.
Prerequisite three demands that already during the construction of an agroeco-
logical research project and the establishment of the research hypothesis, potential
environmental, economic or social impacts or problems of the expected results have
to be anticipated. For example, the intention to test different levels of liquid manure
application to the shallow lakes to increase fish production, as in case study 1,
should be first evaluated in respect to an increased nutrient status in the water which
might have a negative impact on nearby rivers when shallow lakes are emptied once
a year. If negative impacts seem to be possible, then the research approach should
be adapted and modified. Anticipating potential impacts at the field scale is of course
probably easier than at the agroecosystem scale.
Our fourth prerequisite for agroecology of the food system is that recommenda-
tions from agroecological research have to be impact assessment-driven for the dif-
ferent scales. That means that results obtained at a certain scale should be evaluated
in respect to their potential impacts at other scales. For example, before recom-
mending a certain amount of N fertilisation for organic wheat, as it proved to
increase significantly yields or baking quality, it has to be evaluated if these N inputs
might create N leaching and drinking water contamination in the watershed in cer-
tain periods of the year, or if the necessary organic fertilisers, or the grains of under-
sown leguminous species, are not available on the regional market or are too
expensive or to energy demanding during production.
Agroecology and the Food System 31
We are aware that the four prerequisites for agroecology of the food system
approach are not that easy to be completely fulfilled for all research programs.
Nevertheless, we are sure that if the food system approach is already taken into
account during the design of a research project, and be it only during reflections at
an initial stage of the project, it will substantially improve the quality of agricultural
research in the future, and thus contributing in search for more sustainable food
systems.
In this paper we focused on agroecology and the food system from a scientific
research perspective, but as mentioned before, a strong link of agroecology and the
food systems has also been established in recent years with a development and
movement perspective (e.g. Cruces 1996; Caporal and Costabeber 2000; Altieri
2002; Sevilla Guzmán 2002; Altieri and Nicholls 2008; Brandenburg 2008). The
main topics in these and other papers are rural development, built on local social and
cultural values, which provides food sovereignty and food security for small farm-
ers in developing countries. Based on local and traditional knowledge, low-input
alternative agricultural systems are favoured.
6 Conclusion
From the experience of the two research programs we can state that without the
holistic/systems approach of agroecology and the food system, the different research
topics would have been treated in a restricted, more disciplinary way, and only at
lower scales. In using the food system approach, the indispensable interdisciplinary
research is carried out automatically by integrating other disciplines such as sociol-
ogy, socio-economy and geography to the two basic disciplines agronomy and ecol-
ogy. These two case studies also show that in combining already existing research
methods from different disciplines, and applying them to different scales, a concept
for agroecological analyses of the food system already exists. Nevertheless, our
case studies also show that they remain to a certain degree incomplete. Other impor-
tant factors such as such as energy consumption or food quality could have been
included, but probably we should also accept that is unrealistic to demand now that
every potential parameter or factor has to be included in a food system analysis.
We finally conclude that four prerequisites are necessary for the agroecology of
the food system approach: ex-ante impact anticipation of expected results when
starting research, multi-scale and interdisciplinary research as well as scale related
impact assessment of proposed recommendations. We assume that in considering
these four prerequisites, quality of agricultural research will substantially improve
in the in the future, and thus contributing in search for more sustainable food
systems.
References
Abstract The need for both Competitiveness and Sustainability, the two primary
overarching goals of EU policy, present the agri-food sector with a unique set of
formidable challenges and uncertainties. These point to the need for development of
new, quality-focused models for agriculture and food production that are sustain-
ably-competitive. The design criteria for the concept are outlined and developed
within the context of an agronomic model for multifunctional, grass-based cattle
production systems. This model highlights the importance of harnessing the benefits
of functional biodiversity within two key epicenters of the system in order to realise
both agronomic and environmental – and hence economic – advantage. Whilst
much of the knowledge needed to implement the described model already exists, the
functionality of biologically complex rumen and pasture processes within the two
key system epicenters, represent the two main pillars of an innovation-driven
research programme that is needed to provide fundamental new knowledge neces-
sary to underpin practical development of the model.
Optimisation of rumen function is a primary determinant of feed conversion
efficiency, animal health and performance, and product quality (milk and meat), and
can contribute to minimisation of greenhouse gas (GHG) emissions. These strategic
1 Introduction
1.1 Policy Development
A number of recent strategic initiatives have recognised the need for a radical
transformation of agricultural systems to meet wider needs. At EU level, a series of
detailed Foresight studies of agri-food futures have been conducted under the aus-
pices of the Standing Committee for Agricultural Research (SCAR). The first major
output of these initiatives highlighted the dependency of current production systems
on high inputs of declining natural resources, including land, fossil fuels and water,
and in the face of increasing global food demands highlighted the unpredictable
effects of climate change and the ongoing loss of biodiversity and ecosystem integrity
(FEG I 2007). This report identified the vulnerability of current production systems
to climate shock, energy crisis and food crisis, and the need for greater cooperation
with nature. A follow-up report identified and highlighted the deficiencies of
increasing reliance on technological solutions subject to the profit motives of
commercial organisations operating within globalised international markets. It
concluded that the resilience of food supply systems was rapidly deteriorating as
a consequence of insufficient innovation in alternative systems development (FEG
II 2008).
In seeking to address the needs of global agriculture, the Royal Society in the
UK developed a perspective for a sustainable intensification of agriculture (Royal
Society 2009). This sought to identify strategies for an increase in the global pro-
duction of food crops to meet the needs of an expanding human population, whilst
protecting global ecosystem integrity and remaining natural environments.
Focusing on the socio-economic dimensions of agriculture, Friz and Schiefer
(2008) outlined a framework for development of sustainable food networks at a
more local level. Meanwhile in the US, innovative cooperative structures have
become the focus of what is termed Agriculture of the Middle (Gray 2009; AOTM
2010). This represents a systematic attempt to develop an alternative strategy for
the economic survival of many medium sized farmers that is midway between
increasingly industrialised scales of food production, and the comparative niche
opportunities provided by organic production systems. It also represents a wel-
come diversification in models for food production strategy that theoretically can
do much to enhance the resilience of the wider food supply system. By having a
particular regard for the maintenance of production systems that underpin local
economies, it clearly has relevance for agriculture-based economies in Europe
(MackenWalsh 2010).
In this chapter, we develop the concept of Sustainably-Competitive Agriculture,
with particular regard to livestock production systems. Through this model, we
argue that a holistic integration of scientific knowledge across agronomic and envi-
ronmental fields can better reconcile the increasing conflicts between industrialised
food production, and growing sustainability concerns. We also draw attention to the
need for a fundamental change of mind set in terms of policy development and
infrastructural supports in order to achieve this ambition.
Development of a Sustainably-Competitive Agriculture 39
culture’ is needed (Boody and DeVore 2006). Many of the current problems of
unsustainability in agricultural systems stem from a failure to recognise this crucial
fact. Thus, in designing new systems of food production, particular attention needs
to be given to the central importance of, and the advantages provided by the local
environment (Fig. 1). For Europe to capitalise fully on its rich heritage of natural
and cultural resources, the agricultural sector must also address the daunting chal-
lenge of protecting and maintaining environmental quality, which is intimately
linked to regional economic viability (Boyle 2009). Purvis et al. (2009a) provide
details of a recently developed methodology designed to identify local agri-environ-
mental priorities, and evaluate policy options designed to ameliorate the negative
effects of prevailing farm systems. However, much of the knowledge necessary to
develop innovative, new farm production systems to achieve such aims already
exists. What is lacking is firstly an economic framework that correctly recognises
the wider potential of such systems; and secondly, a coherent and integrative
approach to their development and validation.
To address the growing international concern with climate change, immediate
urgency needs to be given to the adoption of more energy efficient agriculture, and
in particular to ameliorating the effects of greenhouse gas (GHG) emissions from
ruminant livestock production (Johnson and Johnson 1995; US EPA 2006). The
protection of biodiversity is also a major environmental concern that brings with it
important international obligations (CBD 1993; Brussaard et al. 2010). A signifi-
cant proportion of habitats within the European landscape is created by farming,
42 G. Purvis et al.
and the ongoing process of agricultural intensification across much of Europe has
resulted in a significant loss of associated biodiversity (McLaughlin and Mineau
1995; Duelli 1997; Donald et al. 2001; Vickery et al. 2001; Hoffmann and Greef
2003; DeHeer et al. 2005). The most effective approach to addressing biodiversity
loss through agricultural policy is a matter of considerable debate. There are two
proposed models; an integrated model that advocates the enhancement of heteroge-
neity within farming systems to create a landscape matrix that facilitates population
connectivity (Benton et al. 2003; Donald and Evans 2006); and a land-sparing
model that proposes the separate designation of specified refuge areas for biodiver-
sity protection, in order to avoid compromising the competitiveness of farm systems
(Green et al. 2005; Kleijn et al. 2009). Given the deeply embedded land manage-
ment role of agriculture within the modern European landscape and the relative
scarcity of true wilderness areas, the concept of sustainably-competitive agriculture
is clearly more compatible with an integrated, heterogeneous landscape strategy. In
resolving many of the biodiversity concerns within agro-ecosystems, however, an
absolute priority must be given to the functional relevance of biodiversity, and in
agricultural research a particular emphasis is required on the role of biodiversity
components that improve the efficiency of production processes (Büchs 2003). The
resulting systems would then be much more likely to benefit other aspects of biodi-
versity conservation and nature protection within the farmed landscape.
A lower dependence on the use of concentrate feedstuffs derived from potential
human food crops makes pasture-based cattle production systems inherently more
environmentally sustainable than feedlot systems (e.g. see Shah 2009). However,
the drive to global competitiveness has led to greatly increased intensification of
pasture management and consequential environmental damage (Aguir 2005;
Bouwman et al 2005; McDowell 2008). The intensification of grassland manage-
ment, which is especially evident on dairy (Shalloo et al. 2004; O’Neill and Mathews
2001; Dillon et al. 2008) and grass-based beef finishing farms (Crosson et al. 2007),
is likely to exacerbate GHG emissions from pasture-based ruminant production
(Pinares-Patino et al. 2009). Increasing fertiliser inputs and stocking rates also
impact directly on key soil processes. Studies using stable N isotopes have shown
that these effects include a marked reduction in the efficiency of atmospheric nitro-
gen fixation by pasture legumes under conditions of increased inorganic fertiliser
use (Purvis et al. 2009b). Additionally, the loss of nutrient inputs from intensified
grassland systems to the wider environment is excessive (Ball and Ryden 1984;
Ledgard et al. 1999). In Europe, this has contributed significantly to the need for
increasing levels of environmental control, notably the Nitrates Directive (91/676/
EEC), Water Quality (2000/60/EC), and imminent Soils Framework Directives.
Optimum animal health and welfare are also of key importance in the development
of sustainably-competitive agricultural systems (Downey et al. 2008). As shown in
Development of a Sustainably-Competitive Agriculture 43
The progressive lengthening of the food supply chain and the lack of transparency
and understanding of its detailed workings are inevitable consequences of increased
44 G. Purvis et al.
globalisation in agriculture, and have major implications for food safety, security,
and ethics, as well as future energy demands. Arguably this issue is one of the greatest
challenges for European agri-food production (Barcos 2001), and is of growing
public concern (Safefood 2009). The largest and most economically damaging
events affecting European agri-food industries and wider rural economies over
recent decades have been widespread outbreaks of animal diseases in cattle (BSE,
Foot and Mouth Disease, Blue Tongue), pigs (Classical Swine Fever) and poultry
(Avian Influenza). In addition to animal diseases, there have been numerous other
food scares, resulting from the discovery of banned substances in animal feedstuffs
(e.g. dioxins), and chemical contaminants such as melamine in food products.
Multiple causative factors are responsible for the widespread nature of these food
safety problems, including reduced EU import controls. However, the unsustainable
lengthening of the food supply chain is an important underlying cause (Downey
2006). As the food supply chain lengthens, the sharing of knowledge, mutual under-
standing and trust between farmers, food processors, retailers and consumers declines
and ultimately ceases. Currently, what is generally referred to as the food supply
chain is not in fact a chain. Rather, it comprises a series of virtually independent
components, each primarily concerned with its own profit maximisation. Despite the
introduction of stricter controls on animal feedstuffs and the implementation of new
food safety policies and regulations (Ilbery et al. 2000), the absence of reliable trans-
parency and accountability in international markets seriously undermines consumer
confidence. As a result, food safety and country of origin now feature among the top
concerns of consumers (FSAI 2007; Safefood 2009). This strongly underlines the
market potential for value-added products of impeccable production standards, with
the highest safety and quality, and demonstrable authenticity.
Consistency is the most critical determinant of food product quality. The plane of
animal nutrition is a primary determinant of the consistency and storage stability of
dairy products (Downey and Doyle 2007). Dietary factors also affect the quality and
nutritional value of meat (Dunshea et al. 2005). Accordingly, in developing new
farm production systems, attention needs to be given to employing feeding strate-
gies designed to meet livestock energy requirements, while controlling feed costs.
Again, this requires particular attention to optimising the nutritional performance of
cattle, otherwise, the composition and processing characteristics of milk and meat
may be seriously impaired. In developing such systems, opportunities exist to
improve the quality and safety of livestock products through the use of dietary
manipulations designed to improve their nutritional value and reduce associated
human health hazards, such as pathogen contamination (McGee et al. 2001).
Opportunities also exist to enhance human health by raising levels of potentially
important health-promoting ingredients in milk and other livestock products through
the use of appropriate livestock feeding strategies. For example, milk with enhanced
Development of a Sustainably-Competitive Agriculture 45
levels of conjugated linoleic acids and vaccenic acid that can protect against some
cancers may be produced by pasture-grazing (Coakley et al. 2007), or through other
strategic dietary manipulations (Shingfield et al. 2005).
Cattle and other domesticated ruminants can convert bulky cellulose-based vegetation
into valuable high protein food products without directly competing for human food
crops (Oltjen and Beckett 1996). Geo-climatic circumstances in several regions of
NW Europe are well suited to capitalising on this ability through pasture-based rumi-
nant production. In such systems, the production process depends on the functional-
ity of two key epicentres, namely rumen function and pasture function. Understanding
the role of functional biodiversity within these inter-dependent epicentres is essential
in optimising the ecological and agronomic efficiency of the system (Fig. 2).
Feed conversion efficiency and animal health. The rumen is central to the conversion
of fibre-rich feed into milk and meat, and accounts for over 80% of total digestion
within the alimentary canal. It is the principal site of fibre digestion and its functional-
ity is the primary determinant of feed conversion efficiency (Beever and Doyle 2007),
and key to reducing the incidence of production related diseases (Beever 2006). The
predominant health and performance issue is the control of acid production and conse-
quential acidosis in the rumen, which can be most adverse when lactic acid is produced
following the ingestion of feedstuffs high in sugar and/or starch content. For optimal
efficiency, the rumen contents require gentle and constant mixing, together with strong
bouts of cud chewing, which aids long-fibre breakdown. Optimal microbial fermenta-
tion of fibre requires a stable pH of at least 6 (Mould et al. 1983). However, conversion
of fibre to volatile fatty acids, which supply a very significant proportion of the energy
used by the cow (see Box 1), leads to reduction of the rumen pH. If the ingested feed
contains a suitable proportion of fibre, repeated rumination events involve both further
cud chewing to facilitate physical maceration of larger fibre particles and the secretion
and addition of significant amounts of saliva containing bicarbonates and phosphates,
which buffer and maintain a suitable rumen pH. In this event, the effects of a transient
Development of a Sustainably-Competitive Agriculture 47
fall in rumen pH following initial feed ingestion are likely to be minimal. However, if
the ingested substrate lacks the appropriate fibre content and contains relatively large
amounts of simpler nutrients, rumination is reduced and sustained periods of sub-opti-
mally low rumen acidity will occur with important and undesirable consequences.
Most notably, as the rumen pH level drops the functionality of fibre-digesting bacteria
is reduced, and the rumen microbial population shifts towards aggressive utilisers of
48 G. Purvis et al.
starch and sugars. Starch in particular is much more rapidly digested producing lactic
acid, which is more acidic than volatile fatty acids and so rumen pH declines further.
This inevitably impacts negatively on feed conversion efficiency.
Dairy systems. High levels of starch-rich feeds in the diet are a prime cause of
rumen acidosis and impaired rumen function in dairy cattle (Krause and Oetzel
2005). In particular, feeding large amounts of cereals in discrete meals at each milk-
ing can have a dramatic effect on rumen pH. Sustained acidity below pH 6 leads to
sub-acute ruminal acidosis, which may persist resulting in acute ruminal acidosis
below pH 5.5 (Bramley et al. 2006; Beauchemin 2007). In severe cases, the rumen
wall may become ulcerated, allowing microbial toxins to pass into the systemic
circulation, subsequently leading to liver abscesses, or inflamed lamina causing
laminitis, a common nutritionally-induced lameness. Compromised foot health has
both welfare and economic consequences, whilst compromised liver function
impacts negatively on feed intake and feed conversion efficiency. Cows suffering
from rumen acidosis tend to have exaggerated hindgut digestion and this can lead to
the discharge of manures of inconsistent and frequently highly fluid composition.
Low rumen pH levels can also occur in grass fed cows, driven by a relative lack of
fibre and high levels of easily digestible sugars in high input ryegrass swards (Wales
and Doyle 2003). In Australia, cows grazing lush, “high quality” pastures had rumen
pH levels below 6 for more than 75% of the day (Williams et al. 2005).
The growing incidence of production diseases in virtually all major dairying
countries has important implications for research in bovine health management.
There is a pressing need to develop and refine intelligence gathering for the manage-
ment of dairy herd health. In particular, systems need to be developed that allow
collation of information on herd genetic composition, health and husbandry practice,
and integration of these data with centralised databases containing, for example,
milk production and fertility statistics. Disease prevention, in its broadest sense is
no longer the sole preserve of veterinarians and addressing the challenge of dairy
herd health will require the adoption of an interdisciplinary partnership approach,
involving the farmer, veterinarian, nutritional advisor and animal breeding consul-
tant (Le Blanc et al. 2006). There is an increasing need to place significant emphasis
on dissemination of knowledge, training, motivation and the encouragement of
fundamental attitudinal changes to disease prevention within the dairy industry.
Whether or not individual farmers implement an optimal disease management
strategy is frequently determined by an “intention-behaviour deficit” (Sneihotta
et al. 2005). While most farmers would agree on the importance of animal health
and welfare, many still fail to act on appropriate advice. There is therefore also a
need to engage with social scientists and to use methodologies such as action
research and behavioural economics, to ensure farmer understanding of the impor-
tance and economic relevance of consumer perceptions regarding animal health and
welfare. Only then will the concept of a value-adding approach be truly realisable.
Beef systems. In beef production, greater attention needs to be given to meeting the
nutritional needs of pasture-based suckler cows. This could lead to significant improve-
ments in a number of performance indices, including the number of live calves born,
Development of a Sustainably-Competitive Agriculture 49
and the mean weight of reared calves at weaning. In many situations the breeding win-
dow is too long with spring-calving extending to 18 weeks, as recently shown by
EBLEX data from the UK. If optimum nutrition can be achieved, and given an average
oestrus period of 21 days, a calving period of not more than 9 weeks can be realistically
targeted. To achieve improved and consistent rates of weight gain in beef cattle, feed
conversion efficiency will need to be improved. As more grain is used for the produc-
tion of conventional and novel human foods (such as corn sweeteners), and potentially
for fuels, less grain will be available for direct feeding to ruminants. Conversely, how-
ever, increased industrialised processing of grains is likely to provide significant
amounts of co-products suitable for feeding to ruminant livestock (e.g. distillers grains).
Including such products in rations for beef cattle could significantly reduce total feed
costs/kg weight gain for growing and finishing livestock, as well as providing a produc-
tive and environmentally acceptable use for such materials. However, their use will
need to be carefully balanced in a feeding regime that ensures optimum dietary fibre.
The needs of high fibre-based bovine nutrition can be met in two ways. Firstly, by
provision of additional fibre in carefully balanced rations (Yang and Beauchemin 2005;
Humphries et al. 2010). Alternatively, within the context of the pasture-based model
depicted in Fig. 2, optimum rumen function may be achievable by the provision of
pastures with the required levels of structural digestible fibre for the grazing animal. As
well as improving rumen function and animal performance through the provision of
greater amounts of digestible fibre, there is evidence that a more varied, species-rich
forage would benefit other aspects of animal health and welfare (Villalba et al. 2010).
In addition to improving the diet, health and performance of the grazing animal,
optimising pasture function provides an essential means to address and reduce the
adverse consequences of intensive grassland husbandry practices. As outlined in
Sect. 2, the prevailing emphasis on price competitiveness within a context of appar-
ently in-exhaustible supplies of “cheap” fertilisers, has increasingly driven produc-
ers to intensified pasture management. This involves widespread use of short-duration
single species grass leys containing perennial ryegrass (Lolium perenne), or less
persistent Italian ryegrass (Lolium multiflorum) cultivars bred for maximum pro-
ductivity under conditions of high nutrient input. However, in conditions of limited
or reduced nutrient input, such cultivars may perform less well than many other
potential forage species. Many of the negative effects associated with prevailing,
intensive grass production systems may be addressed by adoption of forage species
mixes better adapted to, and capable of yielding optimally, under more variable
conditions with less intensive inputs. A large body of knowledge derived from both
theoretical and empirical studies, indicates that use of low-input, species diverse
pastures could also achieve other important ecological benefits.
Efficient use of nutrient inputs. Reduction in fertiliser use in grassland farming over
the last decade (e.g. Lalor et al. 2010) reflects increasing input costs and regulation
of nutrient usage. To deal with these constraints and achieve sustainable competi-
tiveness, a shift will be needed in grassland husbandry away from the use of highly
selected ryegrass monocultures that persist and yield optimally only under condi-
tions of high nitrogen input. A major objective for grassland management must be
an increased efficiency of nutrient recovery from animal manures, and improved
utilisation of inorganic fertiliser inputs. This can be achieved by an improved utili-
sation of the functional system benefits provided by botanical sward diversity and
closely related elements of soil biodiversity such as mycorrhizal fungi (van der
Heijden et al. 2006) and soil nematodes (De Deyn et al. 2003), which respond posi-
tively to the extensification of grassland management. Such biodiversity compo-
nents of pasture function are likely to contribute significantly to the efficiency of
nutrient retention and supply, and to soil carbon sequestration. Stable isotope trac-
ers and modeling techniques provide a means to study the benefits of low-input,
species-rich pasture systems in limiting nutrient losses to soil water and the atmo-
sphere (see Hoekstra et al. 2010). The ecological advantages of low input, mixed
species pastures in terms of their more efficient use of plant nutrients (N and P) and
reduction of losses to the wider environment is a key component of the model
depicted in Fig. 2.
Benefits for farmland biodiversity. The wider impact of grassland farming on the
conservation of biodiversity within the farmed landscape was the primary focus of
a recently completed study funded by the Irish Environmental Protection Agency
(Purvis et al. 2009b). Using pre-existing grass husbandry experiments and extensive
surveys on commercial farms, this project documented clearly negative impacts of
intensified grassland nutrient inputs on floral and faunal biodiversity at both indi-
vidual field and landscape scales. A key conclusion of the study was the urgent need
to establish dedicated, long-term and large-scale grassland systems research to
quantify the specific agronomic and ecological merits of low input, mixed species
pastures. However, one of the less expected findings of this study, was that within
the wider farmed landscape, dairy farming has important beneficial and ecologi-
cally distinct effects on some aspects of biodiversity compared with less intensive
forms of grass-based livestock farming. In particular, dairy farms were found to
support significantly enhanced breeding bird populations compared with drystock
farms (McMahon et al. 2010).
Such a finding is a likely consequence of an observed greater availability of
invertebrate food (albeit of reduced taxon diversity) that was associated with the
relatively higher nutrient levels and stocking rates on dairy pastures, compared with
less intensively managed pastures on drystock farms. This observation, however, is
also very likely to be related to the fact that all surveyed farms (both dairy and
drystock) were typically relatively small, and both farm types retained a similar
prevalence of permanent field boundaries amounting to over 12 linear km of tradi-
tional hedgerows per km2. Such an extensive network of high quality bird habitat is
unusual within European farmland. Accordingly, Irish dairy farming may represent
52 G. Purvis et al.
The model outlined in Fig. 2, highlights the urgent need to address climate change,
and in particular concerns regarding the output of greenhouse gases (GHGs) from
ruminant livestock systems. Manipulation of grass-based forages, particularly with
regard to the intensity of nitrogenous fertiliser inputs and the maintenance of opti-
mum fibre content, may have important benefits in reducing the loss of NH4 and N20
from animal excreta (Külling et al. 2003; Ambus et al. 2007). Methane production is
an inherent consequence of ruminant digestion, currently estimated to be as high as
700 g of methane per kg of edible beef produced when taking full account of the
methane costs of the suckler cow. Clearly, this is a situation that needs to be targeted
for serious reduction. Shifting rumen fermentation from the production of acetate
and butyrate to the production of propionate would provide a sink for hydrogen, and
thus simultaneously reduce its conversion to methane and improve feed conversion
efficiency. A wide range of dietary modification strategies to limit methanogenesis is
currently being investigated (Martin et al. 2009). The use of feed additives has yet to
gain commercial success, but even if this could be achieved, such additives would
have little practical application in pasture-based systems (Waghorn and Clark 2006).
However, improving pasture feed conversion efficiency and raising daily weight gain
offers a potentially feasible opportunity to reduce emissions. In vitro studies suggest
that plants with a range of naturally occurring secondary plant products, including
hydrolysable and condensed tannins and saponins (Bhatta et al. 2009; Sirohi et al.
2009), might be beneficially incorporated into a multi-species pasture strategy. The
combined influence of pasture husbandry and rumen function on GHG emissions,
including rumen methanogenesis and nitrous oxide and ammonia emissions from
animal excreta are important components of the model elaborated in Fig. 2.
Optimisation of pasture management to ensure more efficient rumen func
tion and assimilation of energy from a pasture-based diet, and the reduction of
methanogenesis in the rumen, may be compatible and mutually achievable goals
Development of a Sustainably-Competitive Agriculture 53
(Morgavi et al. 2010); but this remains to be substantiated. However, GHG emis-
sions in pasture-based livestock systems can be mitigated to a significant extent
through the carbon sequestration potential of grasslands. This potential is greatly
enhanced by avoiding many of the practices associated with intensive pasture man-
agement (Davidson et al. 1995; Soussana et al. 2010), such as frequent soil cultiva-
tion in short-term ley-pasture farming, and the high intensity of nutrient inputs
needed to maintain the productivity of single-species swards. Grass-husbandry
based on the use of long-term, low input multi-species pastures can potentially make
a significant contribution to the carbon balance of the entire system, and so the influ-
ence of pasture composition and grassland husbandry practice on carbon sequestra-
tion is a vital focus of the elaborated model (Fig. 2).
Life Cycle Analysis (LCA) provides a means to integrate and quantify the multi-
dimensional performance of production systems (Cederberg and Mattsson 2000;
Haas et al. 2001; Thomassen and De Boer 2005). Using LCA, it has been shown that
intensification of grassland management reduces the ecological efficiency of grass-
based dairy farming (Bassett-Mens et al. 2007), which can be improved by reducing
dependency on imported concentrate feeds, and excessive nutrient inputs (Thomassen
et al. 2008), which are both inefficient and costly. LCA can effectively be used to
evaluate the total, multi-dimensional performance of the model illustrated in Fig. 2.
When combined with holistic economic analysis, the development and optimisation
of this model could permit governments to deal with climate change by facilitating
strategic planning towards a sustainable low-carbon economy, rather than adopting
the more expensive and less effective contrivance of purchasing carbon credits
(Styles and Jones 2008).
markers available are: volatile fatty acid and vitamin profiles influenced by forage
intake, as well as stable isotope ratios reflecting both the vegetation diet and local
environmental factors, including the underlying geology, soil type and climatic con-
ditions under which the animal was reared (Smith et al. 2008; Prache 2009). In
grass-based livestock systems, authentication systems can be extended to include
reconstruction of an animal’s life history prior to slaughter using markers in archival
tissues, such as hoof and hair (Schmidt et al. 2005; Harrison et al. 2007).
4.1 Innovation-Driven Research
As detailed above, much of the knowledge required to begin the practical develop-
ment of a sustainably-competitive grass-based cattle production systems already
exists. However, the complex biological processes involved in optimising both
rumen and pasture functions need to be further elucidated (Bocquier and González-
García 2010). These constitute the two main pillars of the innovation-driven research
programme required to underpin system development. The overarching generic
objectives that need to be prioritised in framing research programmes for such sys-
tems are outlined in Table 1.
However, the generation of new knowledge in agri-food systems is all too often
undertaken by investment in short-term projects that seek to ‘unpick’ and exploit the
functionality of individual components within the wider system. Knowledge derived
by this reductionist approach has a fractal and probably infinite structure that can
rapidly lead to “information overload” (Gallagher and Appenzeller 1999). As
objectives, interests and particularly the outputs from different research frontiers
become increasingly isolated in an ever-expanding scientific literature1, a situation
has been created where practical integration of research outputs into farm systems
development is significantly more difficult (Buhler et al. 2002). The development of
sustainably-competitive systems requires a more holistic approach that seeks to
integrate and harness the use of new understanding and technologies, including
where necessary molecular biology and genetic modification. Such integration
needs to complement and facilitate the harnessing of the complex processes that
characterise natural systems. In contrast to exploitative use of fragmentary knowl-
edge, such an approach would do much to encourage a wider acceptance of new
technologies (Arntzen et al. 2003), and ensure that European agriculture benefits
from technical innovation.
1
For an essay on the limitations of reductionism in the bio-medical sciences, see Ahn et al. (2006),
and for an early example of its deficiencies in agriculture that is very relevant to the grass-based
ruminant model, see Smil (2001).
Development of a Sustainably-Competitive Agriculture 55
4.3 Organisational Structures
Public good concerns are inherently multi-dimensional, and relate to such crucial
strategic areas as policy formation, climate change, energy supply, food safety, animal
welfare and wider environmental concerns. Agriculture, like other natural resource
based industries, is critically dependent on concerted public good funding as the only
realistic means to ensure effective support for longer-term systems development.2 The
concept of sustainably-competitive agriculture is closely compatible with the
European model of multifunctional agriculture (OECD 2001). Only dedicated public
good funding can ensure the necessary transition from the predominantly production/
output bias of the former EU Common Agricultural Policy (CAP), and support the
development of more consumer/society-orientated, multifunctional agri-food models
2
For an illustrative account of the limitations of the open-innovations, market-lead model in sup-
plying the support necessary for holistic systems development, see Toleubayev et al. (2010).
Development of a Sustainably-Competitive Agriculture 57
that meet the considerable challenges facing rural economies and the wider issues of
food supply in Europe in the twenty-first century. Key to achieving this goal will be
the deployment of an appropriate proportion of the budget for the Common
Agricultural Policy to ensure the development and widespread adoption of the value-
adding concept of Sustainably-Competitive Regional Agri-Food Systems.
5 Conclusion
References
Aguiar MR (2005) Biodiversity in grasslands: current changes and future scenarios. In: Reynolds
SG, Frame J (eds) Grasslands: developments opportunities perspectives. Science Publishers in
association with the Food and Agriculture Organisation of the United Nations (FAO), Enfield,
pp 261–281
58 G. Purvis et al.
Ahn AC, Tewari M, Poon C-S, Philips RS (2006) The limits of reductionism in medicine: could sys-
tems biology offer an alternative? PLoS Med 3(6):709–713. doi:10.1371/journal.pmed.0030208
Ambus P, Petersen SO, Soussana J-F (2007) Short-term carbon and nitrogen cycling in urine
patches assessed by combined carbon-13 and nitrogen-15 labelling. Agric Ecosyst Environ
121:84–92. doi:10.1016/j.agee.2006.12.007
AOTM (2010) Agriculture of the middle web page. Available at. http://WWW.agofthemiddle.org/
archives/2004/08/key_documents.html. Accessed 17 Sept 2010
Arntzen CJ, Coghlan A, Johnson B, Peacock J, Rodemeyer M (2003) GM crops: science, politics
and communication. Nat Rev Genet 4:839–843. doi:10.1038/nrg1185
Ball PR, Ryden JC (1984) Nitrogen relationships in intensively managed temperate grasslands.
Plant Soil 76:23–33. doi:10.1007/BF02205564
Barcos LO (2001) Recent developments in animal identification and the traceability of animal
products in international trade. Revue Scientifique et Technique de L’Office International des
Epizooties 20:640–651
Barrett HR, Ilbery B, Browne AW, Binns T (1999) Globalisation and the changing networks of
food supply: the importation of fresh horticultural produce from Kenya into the UK. Trans Inst
Br Geogr 24:159–174. doi:10.1111/j.0020-2754.1999.00159.x
Barry TN (1998) The feeding value of chicory (Cichorium intybus) for ruminant livestock. J Agric
Sci 131:251–257. doi:10.1017/S002185969800584X
Bassett-Mens C, van der Werf H, and Bertaglia M (2007) Life cycle assessment of farming systems. In:
Cleveland CJ (ed) Encyclopedia of earth. Environmental Information Coalition, National Council
for Science and the Environment, Washington, D.C. Published 10 July 2007. Available at. http://
www.eoearth.org/article/Life_cycle_assessment_of_farming_systems. Accessed 19 Mar 2010
Beauchemin KA (2007) Ruminal acidosis in dairy cows: balancing physically effective fiber with
starch availability. Florida ruminant nutrition symposium, Gainesville, USA, pp 16–27
Beever DE (1993) Rumen function. In: Forbes JM, France J (eds) Quantitative aspects of ruminant
digestion and metabolism. CAB International, Wallingford, pp 187–215
Beever DE (2006) The impact of controlled nutrition during the dry period on dairy cow health, fertil-
ity and performance. Anim Reprod Sci 96:212–226. doi:10.1016/j.anireprosci.2006.08.002
Beever DE, Doyle PT (2007) Feed conversion efficiency; an important determinant of dairy farm
profitability. Aust J Exp Agric 47(6):645–657. doi:10.1071/EA06048
Beever DE and Thorp C (1996) Advances in the understanding of factors influencing the nutritive
value of legumes. In: Legumes in sustainable farming systems. British Grassland Society
Occasional symposium, Reading, pp 194–207
Benton TG, Vickery JA, Wilson JD (2003) Farmland biodiversity: is habitat heterogeneity the key?
Trends Ecol Evol 18:182–188. doi:10.1016/S0169-5347(03)00011-9
Berendse F (1983) Interspecific competition and niche differentiation between Plantago lanceolata
and Anthoxanthum odoratum in a natural hayfield. J Ecol 71:379–390
Bhatta R, Uyeno Y, Tajima K, Takenaka A, Yabumoto Y, Nonaka I, Enishi O, Kurihara M (2009)
Difference in the nature of tannins on in vitro ruminal methane and volatile fatty acid production
and on methanogenic archaea and protozoal populations. J Dairy Sci 92:5512–5522.
doi:10.3168/jds.2008-1441
BHC (Bovine HapMap Consortium) (2009) Genome-wide survey of SNP variation uncovers the
genetic structure of cattle breeds. Science 324:528–532. doi:10.1126/science.1167936
Bocquier F, Gonzalez-Garcia E (2010) Sustainability of ruminant agriculture in the new context:
feeding strategies and features of animal adaptability into the necessary holistic approach.
Animal 4(7):1258–1273. doi:10.1017/S1751731110001023
Boody GY, Devore B (2006) Redesigning agriculture. Bioscience 56(10):839–845. doi:10.1641/
0006-3568(2006) 56[839:RA]2.0.CO;2
Bouwman AF, Van der Hoek KW, Soenario I (2005) Exploring changes in world ruminant produc-
tion systems. Agric Syst 84(2):121–153. doi:10.1016/j.agsy.2004.05.006
Boyle G (2009) The Irish agricultural rural landscape. In: The Irish landscape 2009. Published
papers from the 2009 Irish landscape conference, The Heritage Council of Ireland, Killkenny,
Ireland, pp 100–110
Development of a Sustainably-Competitive Agriculture 59
Bramley E, Lean LJ, Fulkerson WJ, Stevenson MA, Rablee AR, Costa ND (2006) The definition
of acidosis in dairy herds predominantly fed on pasture and concentrates. J Dairy Sci 91:308–321.
doi:10.3168/jds.2006-601
Bruinsma J (2003) World agriculture: towards 2015/2030. An FAO perspective. Earthscan, London,
432 pp
Brussaard L, Caron P, Campbell B, Lipper L, Mainka S, Rabbinge R, Babin D, Pulleman M (2010)
Reconciling biodiversity conservation and food security: scientific challenges for a new agri-
culture. Curr Opin Environ Sustain 2:34–42. doi:10.1016/j.cosust.2010.03.007
Büchs W (2003) Biodiversity and agricultural indicators – general scopes and skills with special refer-
ence to the habitat level. Agric Ecosyst Environ 98:35–78. doi:10.1016/S0167-8809(03)00070-7
Buhler W, Morse S, Arthur E, Bolton S, Mann J (2002) Science, agriculture and research: a
compromised participation? Earthscan Publications Ltd., London, 220 pp
Caldeira MC, Ryel RJ, Lawton JH, Pereira JS (2001) Mechanisms of positive biodiversity-production
relationships: insights provided by 13C analysis in experimental Mediterranean grassland plots.
Ecol Lett 4:439–443. doi:10.1046/j.1461-0248.2001.00238.x
CBD (Convention on Biological Diversity) (1993) Text of the convention on biological diversity.
Available at. http://www.cbd.int/convention/convention.shtml. Accessed 10 June 2010
Cederberg C, Mattsson B (2000) Life cycle assessment of milk production – a comparison of con-
ventional and organic farming. J Clean Prod 8:49–60. doi:10.1016/S0959-6526(99)00311-X
Chesson P (2000) General theory of competitive coexistence in spatially-varying environments.
Theor Popul Biol 58:211–237. doi:10.1006/tpbi.2000.1486
Clauss M, Hume ID, Hummel J (2010) Evolutionary adaptations of ruminants and their potential rele-
vance for modern production systems. Animal 4(7):993–1007. doi:10.1017/S1751731110000388
Coakley M, Barrett E, Murphy JJ, Ross RP, Devery R, Stanton C (2007) Cheese manufacture with
milk with elevated conjugated linoleic acid levels caused by dietary manipulation. J Dairy Sci
90:2919–2927. doi:10.3168/jds.2006-584
Crosson P, Rotz CA, O’Kiely P, O’Mara FP, Wallace M, Schulte RPO (2007) Modeling the nitrogen
and phosphorus inputs and outputs of financially optimal Irish beef production systems. Appl
Eng Agric 23(3):369–377
Culleton N, Barry P, Sheehy J (2002) Grass/clover mixtures. In: Culleton N, Barry P, Fox R, Schulte R,
Finn J (eds) Principles of successful organic farming. Teagasc, Dublin, pp 21–24
Davidson EA, Nepstad DC, Klink C, Trumbore SE (1995) Pasture soils as a carbon sink. Nature
376:472–473. doi:10.1038/376472a0
De Deyn GB, Raaijmakers CE, Zoomer HR, Berg MP, de Ruiter PC, Verhoef HA, Bezemer TM,
van der Putten WH (2003) Soil invertebrate fauna enhances grassland succession and diversity.
Nature 422:711–713. doi:10.1038/nature01548 Letter
DeHeer M, Kapos V, ten Brink BJE (2005) Biodiversity trends in Europe: development and testing
of a species trend indicator for evaluating progress towards the 2010 target. Phil Trans Roy Soc
London B 360:297–308. doi:10.1098/rstb.2004.1587
Dennis MJ (1998) Recent developments in food authentication. Analyst 123:151R–156R.
doi:10.1039/A802892C
Dillon P, Hennessy T, Shalloo L, Thorne F, Horan B (2008) Future outlook for the Irish dairy indus-
try; a study of international competitiveness, influence of international trade reform and require-
ment for change. Int J Dairy Technol 61(1):16–29. doi:10.1111/j.1471-0307.2008.00374.x
Donald PF, Evans AD (2006) Habitat connectivity and the matrix restoration: the wider implications
of agri-environmental schemes. J Appl Ecol 43:209–218. doi:10.1111/j.1365-2664.2006.01146.x
Donald PF, Green RE, Heath MF (2001) Agricultural intensification and the collapse of Europe’s
farmland bird populations. Proc Roy Soc London B 268:25–29. doi:10.1098/rspb.2000.1325
Downey L (2006) EU agri-food industries & rural economies by 2025 – towards a knowledge bio-
economy – research & knowledge transfer systems. Report prepared for European Commission,
Brussels, 41 pp. Available at. http://ec.europa.eu/research/agriculture/scar/pdf/scar_foresight_
rural_economy_en.pdf. Accessed 30 June 2010
Downey L, Doyle PT (2007) Cow nutrition and dairy product manufacture – implications of
seasonal pasture-based milk production systems. Aust J Dairy Technol 62:3–11
60 G. Purvis et al.
Haas G, Wetterich F, Kopke U (2001) Comparing intensive, extensive and organic grassland farming
in southern Germany by process life cycle assessment. Agric Ecosyst Environ 83:43–53.
doi:10.1016/S0167-8809(00)00160-2
Harrington KC, Thatcher A, Kemp PD (2006) Mineral composition and nutritive value of some
common pasture weeds. N Z Plant Prot 59:261–265
Harrison SM, Zazzo A, Bahar B, Monahan FJ, Moloney AP, Scrimgeour CM, Schmidt O (2007)
Using hooves for high-resolution isotopic reconstruction of bovine dietary history. Rapid
Commun Mass Spectrom 21(4):479–486. doi:10.1002/rcm.2861
Haskins C (2003) Rural delivery review: a report on the delivery of government policies in rural
England. Department For Environment, Food and Rural Affairs, London, 170 pp. Available at.
http://www.defra.gov.uk/rural/documents/policy/ruraldelivery/haskins_full_report.pdf.
Accessed 12 Mar 2010
Hector A, Schmid B, Beierkuhnlein C, Caldeira MC, Diemer M, Dimitrakopoulos PG, Finn JA,
Freitas H, Giller PS, Good J, Harris R, Högberg P, Huss-Danell K, Joshi J, Jumpponen A, Körner
C, Leadley PW, Moreau M, Minns A, Mulder CPH, O’Donovan G, Otway SJ, Pereira JS, Prinz
A, Read DJ, Scherer-Lorenzen M, Schultze E-D, Siamantziouras A-SD, Spehn EM, Terry AC,
Troumbis AY, Woodward FI, Yachi S, Lawton JH (1999) Plant diversity and productivity experi-
ments in European grasslands. Science 286:1123–1127. doi:10.1126/science.286.5442.1123
Hobson PN, Stewart CS (eds) (1997) The rumen microbial ecosystem, 2nd edn. Chapman & Hall,
London, 719 pp
Hoekstra NJ, Lalor STJ, Richards KG, O’Hea N, Lanigan GJ, Dyckmans J, Schulte RPO, Schulte
O (2010) Slurry 15NH4-N recovery in herbage and soil: effects of application method and timing.
Plant Soil 330:357–368. doi:10.1007/s11104-009-0210-z
Hoffmann J, Greef JM (2003) Mosaic indicators – theoretical approach for the development of
indicators for species diversity in agricultural landscapes. Agric Ecosyst Environ 98:387–394.
doi:10.1016/S0167-8809(03)00098-7
Hooper DU (1998) The role of complementarity and ecosystem responses to variation in plant
diversity. Ecology 79:704–719. doi:10.1890/0012-9658(1998) 079[0704:TROCAC]2.0.CO;2
Hooper DU, Chapin FS, Ewel JJ, Hector A, Inchausti P, Lavorel S, Lawton JH, Lodge DM, Loreau
M, Naeem S, Schmid B, Setälä H, Symstad AJ, Vandermeer J, Wardle DA (2005) Effects of
biodiversity on ecosystem functioning: a consensus of current knowledge. Ecol Monogr 75:3–35.
doi:10.1890/04-0922
Howden MS, Soussana J-F, Tubiello FN, Chhetri N, Dunlop M, Meinke H (2007) Adapting
agriculture to climate change. Proc Natl Acad Sci 104(50):19691–19696. doi:10.1073/
pnas.0701424104
Huhtanen P, Ahvenjarvi S, Weisbjerg MR, Norgaard P (2006) Digestion and passage of fibre in
ruminants. In: Sejrsen K, Hvelplund T, Nielsen MO (eds) Ruminant physiology: digestion,
metabolism and impact of gene expression, immunology and stress. Wageningen Academic
Publishers, Wageningen, pp 87–135
Humphries DJ, Reynolds CK, Beever DE (2010) Adding straw to a total mixed ration and the
method of straw inclusion affects production and eating behaviour of lactating dairy cows. In:
Advances in animal biosciences. Food, feed, energy and fibre from land – a vision for 2020, p 95.
Proceedings of the British Society of Animal Science and the Agricultural Research Forum, Annual
conference, Belfast, 12–14 April 2010. Cambridge University Press, ISBN 978-0-906562-67-3.
Available at. http://www.bsas.org.uk/downloads/annlproc/pdf2010/pdf2010.pdf. Accessed
17 Nov 2010
Ilbery B, Kneafsey M (1998) Product and place: promoting quality products and services in
the lagging regions of the European Union. Eur Urban Reg Stud 5:329–341.
doi:10.1177/096977649800500404
Ilbery B, Kneafsey M (1999) Niche markets and regional speciality food products in Europe:
towards a research agenda. Environ Plann A 31(12):2207–2222. doi:10.1068/a312207
Ilbery B, Kneafsey M, Bamford M (2000) Protecting and promoting regional speciality food and drink
products in the European Union. Outlook Agr 29:31–37. doi:10.5367/000000000101293022
Johnson KA, Johnson DE (1995) Methane emissions from cattle. J Anim Sci 73:2483–2492
62 G. Purvis et al.
Kleijn D, Kohler F, Baldi A, Batary P, Concepcion ED, Clough Y, Diaz M, Gabriel D, Holzschuh
A, Knop E, Kovacs A, Marshall EJP, Tscharntke T, Verhulst J (2009) On the relationship
between farmland biodiversity and land-use intensity in Europe. Proc Roy Soc London B
276:903–909. doi:10.1098/rspb.2008.1509
Knaus W (2009) Dairy cows trapped between performance demands and adaptability. J Sci Food
Agric 89:1107–1114. doi:10.1002/jsfa.3575
Knops JMH, Tilman D, Haddad NM, Naeem S, Mitchell CE, Haarstad J, Ritchie ME, Howe
KM, Reich PB, Siemann E, Groth J (1999) Effects of plant species richness on invasion
dynamics, disease outbreaks, insect abundances and diversity. Ecol Lett 2:286–293.
doi:10.1046/j.1461-0248.1999.00083.x
Krause KM, Oetzel G (2005) Inducing subacute ruminal acidosis in lactating dairy cows. J Dairy
Sci 88:3633–3639. doi:10.3168/jds.S0022-0302(05)73048-4
Külling DR, Menzi I, Sutter F, Lischer P, Kreuzer M (2003) Ammonia, nitrous oxide and methane
emissions from differently stored dairy manure derived from grass- and hay-based rations. Nutr
Cycl Agroecosys 65:13–22. doi:10.1023/A:1021857122265
Lalor STJ, Coulter BS, Quinlan G, Connolly L (2010) A survey of fertilizer use in Ireland from
2004–2008 for grassland and arable crops. Teagasc Project Report (RMIS 5943), Teagasc,
Carlow. 89 pp
Le Blanc SJ, Lissemore KD, Kelton DF, Duffield TF, Leslie KE (2006) Major advances in disease
prevention in dairy cattle. J Dairy Sci 89:1267–1279. doi:10.3168/jds.S0022-0302(06)72195-6
LEAF (2010) Linking Environment and Farming – organisation web page. Available at. http://
www.leafuk.org/leafuk/. Accessed 12 Mar 2010
Ledgard SF, Steele KW (1992) Biological nitrogen fixation in mixed legume/grass pastures. Plant
Soil 141:137–153. doi:10.1007/BF00011314
Ledgard SF, Penno JW, Sprosen MS (1999) Nitrogen inputs and losses from clover/grass pastures
grazed by dairy cows, as affected by nitrogen fertilizer application. J Agric Sci 132(2):215–225.
doi:10.1017/S002185969800625X
Leng RA (1993) Quantitative ruminant nutrition – a green science. Aust J Agric Res 44:363–380
MackenWalsh A (2010) Agriculture, rural development and potential for a ‘Middle Agriculture’ in
Ireland. Teagasc Rural Economy Research Centre, Working paper series, WP-RE-04,
March 2010. Available at. http://www.agresearch.teagasc.ie/rerc/workingpapers.asp. Accessed
17 June 2010
Martin C, Morgavi DP, Doreau M (2009) Methane mitigation in ruminants: from microbe to the
farm scale. Animal 4:351–365. doi:10.1017/S1751731109990620
McDowell RW (2008) Environmental impacts of pasture farming. CABI Publishing, Wallingford,
283 pp
McEntire JC, Arens S, Bernstein M, Bugusu B, Busta FF, Cole M, Davis A, Fisher W, Geisert S,
Jensen H, Kenah B, Lloyd B, Mejia C, Miller B, Mills R, Newsome R, Osho K, Prince G,
Scholl S, Sutton D, Welt B, Ohlhorst S (2010) Traceability (product tracing) in food systems:
an IFT report submitted to the FDA, volume 1: technical aspects and recommendations. Comp
Rev Food Sci Food Saf 9:92–158. doi:10.1111/j.1541-4337.2009.00097.x
McGee P, Bolton DJ, Sheridan JJ, Earley B, Leonard N (2001) The survival of Escherichia coli
0157:H7 in slurry from cattle fed different diets. Lett Appl Microbiol 32:152–155.
doi:10.1046/j.1472-765x.2001.00877.x
McLaughlin A, Mineau O (1995) The impact of agricultural practices on biodiversity. Agric
Ecosyst Environ 55(3):201–212. doi:10.1016/0167-8809(95)00609-V
McMahon BJ, Helden AJ, Anderson A, Sheridan H, Kinsella A, Purvis G (2010) Interactions
between livestock farming systems and biodiversity in South-East Ireland. Agric Ecosyst
Environ 139:232–238. doi:10.1016/j.agee.2010.08.008
Mee JF (2004) Temporal trends in reproductive performance in Irish dairy herds and associated
risk factors. Ir Vet J 57:158
Mertens DR (2005) Rate and extent of digestion. In: Dijkstra J, Forbes JM, France J (eds)
Quantitative aspects of ruminant digestion and metabolism, 2nd edn. CABI Publishing,
Wallingford, pp 13–48
Development of a Sustainably-Competitive Agriculture 63
Monahan FJ, Moloney AP, Downey G, Dunne PG, Schmidt O, Harrison SM (2010) Authenticity
and traceability of grassland production and products. In: Schnyder H, Isselstein J, Taube F,
Schellberg J, Wachendorf M, Herrmann A, Gierus M, Auerswald K, Wrage N, Hopkins A
(eds.) Grassland in a changing world. Grassland science in Europe, vol 15. Mecke Druck und
Verlag, Duderstadt, pp 410–444. ISBN 978-3-86944-021-7
Morgavi DP, Forano E, Martin C, Newbold CJ (2010) Microbial ecosystem and methanogenesis in
ruminants. Animal 4(7):1024–1036. doi:10.1017/S1751731110000546
Mould FL, Orskov ER, Mann SO (1983) Associative effects of mixed feeds. 1. Effects of type
and level of supplementation and the influence of the rumen fluid pH on cellulolysis in vivo
and dry matter digestion of various roughages. Anim Feed Sci Technol 10:15–30.
doi:10.1016/0377-8401(83)90003-2
Mulligan FJ, Doherty ML (2008) Production diseases in the transition cow. Vet J 176:3–9.
doi:10.1016/j.tvjl.2007.12.018
Newman Turner F (1955) Fertility pastures. Herbal leys as the basis for soil fertility and animal
health. Faber and Faber Ltd, London
O’Connor EE, Li RW, Baldwin RL, Li C (2010) Gene expression in the digestive tissues of rumi-
nants and their relationships with feeding and digestive processes. Animal 4(7):993–1007.
doi:10.1017/S1751731109991285
O’Neill S, Mathews A (2001) Technical change and efficiency in Irish agriculture. Econ Soc Rev
32(3):263–284
OECD (Organisation for Economic Co-operation and Development) (2001) Multifunctionality:
towards an analytical framework. OECD, Paris, 28 pp. Available at. http://www.oecd.org/
dataoecd/43/31/1894469.pdf. Accessed 17 June 2010
Oltjen JW, Beckett JL (1996) Role of ruminant livestock in sustainable agricultural systems.
J Anim Sci 74:1406–1409
Pinares-Patino CS, Waghorn GC, Hegarty RS, Hoskin SO (2009) Effects of intensification of
pastoral farming systems on greenhouse gas emissions in New Zealand. N Z Vet J 57(5):
252–269
Prache S (2009) Diet authentication in sheep from composition of animal tissues and products.
Rev Bras Zootecn 38:362–370 (supl. especial)
Purvis G, Louwagie G, Northey G, Mortimer S, Park J, Mauchline A, Finn J, Primdahl J, Vejre H,
Vesterager J-P, Knickel K, Kasperczyk N, Balázs K, Vlahos G, Christopoulos S, Peltola J
(2009a) Conceptual development of a harmonised method for tracking change and evaluating
policy in the agri-environment: the agri-environmental footprint index. J Environ Sci Policy
12:321–337. doi:10.1016/j.envsci.2009.01.005
Purvis G, Anderson A, Baars J-R, Bolger T, Breen J, Connolly J, Curry JP, Doherty P, Doyle M,
Finn J, Geijzendorffer I, Helden A, Kelly-Quinn M, Kennedy T, McDondald J, McMahon BJ,
Miksche D, Santorum V, Schmidt O, Sheehan C, Sheridan H (2009b) Ag-Biota: monitoring,
functional significance and management for the maintenance and economic utilisation of bio-
diversity in the intensively farmed landscape. STRIVE summary report series no. 21.
Environmental Protection Agency, Wexford, Ireland; 64 pp. Available at. http://www.epa.ie/
downloads/pubs/research/biodiversity/name,25860,en.html. Accessed 22 Mar 2010
Rees M, Condit R, Crawley MJ, Pacala SW, Tilman D (2001) Long-term studies of vegetation
dynamics. Science 293:650–655. doi:10.1126/science.1062586
RELU (2010) Rural Economy and Land Use Programme web page. Available at. http://www.relu.
ac.uk/. Accessed 12 Mar 2010
Royal Society (2009) Reaping the benefits: science and the sustainable intensification of agricul-
ture. The Royal Society, London, October 2009, 73 pp. Available at. http://royalsociety.org/
reapingthebenefits/. Accessed 10 Nov 2010
Safefood (2009) Where does our food come from? Consumer focused review. Safefood, Cork,
Ireland; 90 pp. Available at. http://www.safefood.eu/en/Publication/Research-reports/Where-
does-our-food-come-from/. Accessed 16 June 2010
Sanderson MA, Labreveux M, Hall MH, Elwinger GF (2003) Nutritive value of chicory and
English plantain forage. Crop Sci 43:1797–1804. doi:10.2135/cropsci2003.1797
64 G. Purvis et al.
Schmidt O, Quilter JM, Bahar B, Moloney AP, Scrimgeour CM, Begley IS, Monahan FJ (2005)
Inferring the origin and dietary history of beef from C, N and S stable isotope ratio analysis.
Food Chem 91:545–549. doi:10.1016/j.foodchem.2004.08.036
Shah A (2009) Global issues: beef. Available at. http://globalissues.org/article/240/beef. Updated:
01 Jan 2009, Accessed 18 Mar 2010
Shalloo L, Dillon P, Rath M, Wallace M (2004) Description and validation of the Moorepark dairy
system model. J Dairy Sci 87:1945–1959. doi:10.3168/jds.S0022-0302(04)73353-6
Sheridan H, Glynn E, Culleton N, O’Donovan G (2003) Responses of experimental grassland field
margin communities to reduced fertiliser application. Tearmann 3:77–86
Sheridan H, Finn JA, Culleton N, O’Donovan G (2008) Plant and invertebrate diversity in grass-
land field margins. Agric Ecosyst Environ 123:225–232. doi:10.1016/j.agee.2007.07.001
Shingfield KJ, Reynolds CK, Lupoli B, Toivonen V, Yurawecz MP, Delmonte P, Griinari JM,
Grandison AS, Beever DE (2005) Effect of forage type and proportion of concentrate in the diet
on milk fatty acid composition in cows fed sunflower oil and fish oil. Anim Sci 80:225–238.
doi:10.1079/ASC41820225
Shmida A, Ellner S (1984) Coexistence of plant species with similar niches. Vegetatio 58:29–55
Sirohi SK, Pandey N, Goel N, Singh B, Mohini M, Pandey P, Chaudhry PP (2009) Microbial activity
and ruminal methanogenesis as affected by secondary plant metabolites in different plant
extracts. Int J Environ Sci Eng 1:52–58
Smil V (2001) Enriching the Earth: Fritz Haber, Carl Bosch and the transformation of world food
production. Massachusetts Institute of Technology Press, Cambridge, 338 pp
Smith GC, Pendell DL, Tatum JD, Belk KE, Sofos JN (2008) Review: post-slaughter traceability.
Meat Sci 80:66–74. doi:10.1016/j.meatsci.2008.05.024
Sneihotta FF, Scholz U, Schwarzer R (2005) Bridging the intention-behaviour gap: planning, self-
efficacy and action control in the adoption and maintenance of physical exercise. Psychol
Health 20(2):143–160. doi:10.1080/08870440512331317670
Soussana JF, Tallec T, Blanfort V (2010) Mitigating the greenhouse gas balance of ruminant
production systems through carbon sequestration in grasslands. Animal 4:334–350.
doi:10.1017/S1751731109990784
Spehn EM, Hector A, Joshi J, Scherer-Lorenzen M, Schmid B, Bazeley-White E, Beierkuhnlein C,
Caldeira MC, Diemer M, Dimitrakopoulos PG, Finn JA, Freitas H, Giller PS, Good J, Harris R,
Högberg P, Huss-Danell K, Jumpponen A, Koricheva J, Leadley PW, Loreau M, Minns A,
Mulder CPH, O’Donovan G, Otway SJ, Palmborg C, Pereira JS, Pfisterer AB, Prinz A, Read
DJ, Schulze E-D, Siamantziouras A-SD, Terry AC, Troumbis AY, Woodward FI, Yachi S,
Lawton JH (2005) Ecosystem effects of biodiversity manipulation in European grasslands.
Ecol Monogr 75:37–63. doi:10.1890/03-4101
Steinfeld H, Gerber P, Wassendaar T, Castel V, Rosales M, De Haan C (2006) Livestock’s long
shadow: environmental issues and options. Food & Agriculture Research Organisation of the
United Nations, Rome, 390 pp
Styles D, Jones MB (2008) Life-cycle environmental and economic impacts of energy-crop fuel-
chains: an integrated assessment of potential GHG avoidance in Ireland. Environ Sci Policy
11:294–306. doi:10.1016/j.envsci.2008.01.004
Tallowin JRB, Jefferson RG (1999) Hay production from lowland semi-natural grasslands: a
review of implications for ruminant livestock systems. Grass Forage Sci 54:99–115.
doi:10.1046/j.1365-2494.1999.00171.x
Thomassen MA, de Boer IJM (2005) Evaluation of indicators to assess the environmental
impact of dairy production systems. Agric Ecosyst Environ 111:185–199. doi:10.1016/j.
agee.2005.06.013
Thomassen MA, van Calker KJ, Smits MCJ, Iepema GL, de Boer IJM (2008) Life cycle assess-
ment of conventional and organic milk production in the Netherlands. Agric Syst 96:95–107.
doi:10.1016/j.agsy.2007.06.001
Thórhallsdóttir TE (1990) The dynamics of a grassland community: a simultaneous investigation
of spatial and temporal heterogeneity at various scales. J Ecol 78:884–908
Tilman D, Downing JA (1994) Biodiversity and stability in grasslands. Nature 367:363–365.
doi:10.1038/367363a0
Development of a Sustainably-Competitive Agriculture 65
J. Webb (*)
AEA, Gemini Building, Harwell Business Centre, Didcot, Oxfordshire, OX11 0QR, UK
e-mail: J.Webb@aeat.co.uk
S.G. Sommer
Department of Chemical Engineering, Biotechnology and Environmental Technology,
Faculty of Engineering, University of Southern Denmark,
Campusvej 55, 5230 Odense, Denmark
T. Kupper
Swiss College of Agriculture, Laenggasse 85, CH-3052 Zollikofen, Switzerland
K. Groenestein
Animal Sciences Group, Wageningen University and Research Centre,
P.O. Box 17NL-6700, AA Wageningen, The Netherlands
N.J. Hutchings
Department of Agroecology and Environment, Research Centre Foulum, Blichers Allé,
Postbox 50DK-8830, Tjele, Denmark
B. Eurich-Menden
Association for Technology and Structures in Agriculture (KTBL),
Bartningstrasse 49, 64289 Darmstadt, Germany
L. Rodhe
JTI – Swedish Institute of Agricultural and Environmental Engineering,
Box 7033SE-750 07 Uppsala, Sweden
T.H. Misselbrook
North Wyke Research, Okehampton, Devon, EX20 2SB, UK
B. Amon
Department of Sustainable Agricultural Systems, Division of Agricultural Engineering,
University of Natural Resources and Applied Life Sciences,
Peter-Jordan-Strasse 82, A-1190 Vienna, Austria
losses of N from livestock excreta and manures are as gaseous emissions. These
emissions are in the form of ammonia (NH3), nitrous oxide (N2O) and methane
(CH4). Ammonia forms particles in the atmosphere which reduce visibility and
may also harm human health, and when deposited to land NH3 causes nutrient
enrichment of soil. Nitrous oxide and CH4 contribute significantly to global
warming and N2O can also cause the breakdown of the protective ozone layer in
the upper atmosphere. We established a database of emissions from solid
manures. Statistical analysis provided new information, focussing on developing
emission factors, emission algorithms and also new understanding of emission
patterns from solid manure.
The review found that housing systems with deep litter emit more NH3 than tied
stalls. This is likely to be because the emitting surface area in a tied stall is smaller.
Laying hens emit more NH3 than broilers and reduced-emission housing systems
for poultry, including the aviary system, can reduce NH3 emissions by between
50% and 80%. The greatest N2O-N emissions from buildings housing livestock
were also from deep litter systems, but the amount of N2O-N was smaller than that
of NH3-N by a factor of 15. Air exchange and temperature increase induced by
aerobic decomposition during manure storage may greatly increase NH3 emission.
Emissions of 0.25–0.30 of the total-N have been recorded from pig and cattle
manure heaps undergoing aerobic decomposition. Increased density of manure
during storage significantly decreased temperatures in manure heaps. Storing solid
manures at high density also reduces air exchange which with the low temperature
limits the formation and transfer of NH3 to the surface layers of the heap, reducing
emissions. Most N2O emission estimates from cattle and pig manure have been
between 0.001 and 0.009 of total-N. Emission of N2O from poultry manure tends
to be small. Average unabated NH3 emissions following application of manure
were 0.79, 0.63 and 0.40 of total ammoniacal-N (TAN) from cattle, pig and poul-
try manure respectively. The smaller emission from poultry manure is expected as
hydrolysis of uric acid to urea may take many months and is often incomplete even
after application, hence limiting the potential for NH3 emission. Manure incorpo-
ration within 4 h after application reduced emission on average by 32%, 92% and
85% for cattle, pig and poultry manure respectively. Reductions following incor-
poration within 24 h or more after application were 20%, 56% and 50% for cattle,
pigs and poultry, respectively. Incorporation by disc or harrow reduced NH3 emis-
sions less than incorporation by plough. Emissions of N2O following the applica-
tion of cattle manure were 0.12 of TAN without incorporation after application
and 0.073 TAN with incorporation after application. Conversely, emissions fol-
lowing application of pig and poultry manures were 0.003 and 0.001 TAN respec-
tively without and 0.035 and 0.089 TAN respectively with incorporation after
application.
1 Introduction
Traditionally livestock manures, along with deposits of excreta during grazing, clover
and green manures, were the only sources of crop nutrients in addition to those
already in the soil. Organic manures arising from livestock production (liquid slurries,
litter-based farmyard manures (FYM) and poultry manures) applied to agricultural
land remain valuable sources of most major plant nutrients and organic matter.
Careful recycling to land allows their nutrient value to be used to enhance crop
growth and maintain or improve soil fertility, which will usually result in large
savings in the use of inorganic fertilizers.
Oenema et al. (2007) estimated that in 2000 total N excretion by livestock in the
EU-27 was c. 10,400 kt. About 65% of the total N excreted was collected from build-
ings housing livestock and stored for some time prior to application to agricultural
land. Almost 30% of the N excreted in buildings was lost from those buildings or dur-
ing storage; approximately 19% via emissions of ammonia (NH3), 7% via emissions
of other N gases, and 4% via leaching and run-off. A further 19% of the N excreted
in housed livestock systems was estimated to be lost via NH3 emissions following the
application of the manure to land. The results indicate that only c. 52% of the N
excreted in livestock was potentially recycled as a plant nutrient. Since the greatest
losses of N from livestock excreta and manures are as gaseous emissions an improved
understanding of these is essential to increasing the proportion of excretal-N that may
be effectively recovered by growing crops. Of the gases released from manures, NH3
is usually emitted in the largest amounts. Ammonia is a reactive gas, and may be
removed from the atmosphere by being absorbed by land and water surfaces (dry
deposition) (Aneja et al. 2001). Most of the NH3 is removed from the atmosphere in
this way, leading to most of it being deposited close to where it was emitted. However,
some NH3 may reach higher levels in the atmosphere and be transported long dis-
tances before being deposited in rainfall or snow (wet deposition) (Aneja et al. 2001).
When deposited to land NH3 causes nutrient enrichment of soil, changing the balance
of plant life, in extreme cases leading to the replacement of valuable conservation
plant with weeds (Bouwman and Van Vuuren 1999; Heil and Diemont 1983; Pitcairn
et al. 1998). Ammonia will react with oxides of sulphur and nitrogen in the atmo-
sphere (Renard et al. 2004), forming particles (aerosols) which reduce visibility
(Graedel and Crutzen 1993) and may also harm human health (Brunekreef and
Holgate 2002). In aerosol form NH3 may be transported longer distances before depo-
sition, so NH3 emissions from one country may be deposited in another.
Although nitrous oxide (N2O) is usually emitted in only small amounts it contrib-
utes significantly to global warming (Bouwman 1990), with each molecule of N2O
having a warming potential of 298 molecules of carbon dioxide (CO2) (IPCC 2006).
Nitrous oxide can also cause the breakdown of the protective ozone layer in the
upper atmosphere (Crutzen 1981). Methane (CH4) is also emitted from manure
(Chadwick 2005) and contributes to global warming. Each molecule having a warming
70 J. Webb et al.
2.1 Introduction
Solid manure is produced when livestock are provided with litter, usually cereal
straw but also other absorbent materials, which makes the resultant manure stack-
able. The term also refers to stackable manure from poultry, with or without litter.
There is a wide range of housing systems for various livestock categories, in which
solid manure is stored for widely varying periods of time. Solid manure is therefore
any manure that is not slurry and hence otherwise hard to define.
We considered that to provide representative data that could be sensibly analy-
sed, the number of data (n) should be larger than 1 and there should be data from
more than one country. For which reason we excluded French data from buildings
housing turkeys and Dutch data on suckler cows. In addition, the number of animals
per measurement should be greater than 10 for cattle and pigs, and greater than 50
for poultry, otherwise scaling up to practical farm size may not be reliable. This
restriction excluded 11 trials with beef from the UK with four animals in a windtun-
nel (‘polytunnel’) and four French trials with three fattening pigs. Finally, daily
measurements should last for at least 24 h. For example, this restriction excluded
two French trials with broilers with measurements of 2 h per day.
Groenestein (2006) summarized the factors affecting emissions of NH3, N2O and
CH4 from buildings housing pigs. These factors are given in Table 1. Because this
analysis aims to identify the processes giving rise to gaseous emissions, the results
72 J. Webb et al.
Table 1 Key factors affecting emission of NH3, N2O and CH4 from pig houses
NH3 N2O CH4
Animal-related factors
Age/liveweight + + +
Amount and composition of feed + + +
Water use – 0 0
Environment-relating factors
Housing configuration +/− +/− +/−
Air velocity over emitting surface + 0 0
Temperature of inside air + + +
Temperature of outside air + + +
Factors related to slurry/litter mixture
C/N ratio – + +
O2 concentration + +/− –
Surface area + 0 0
Maturity of litter/slurry mixture 0 + +
pHa + 6 7
Temperature of the slurry/litter + + +
NH4+ concentration + + –
Volatile Solids concentration 0 0 +
Drymatter content 0 0 –
Adapted from Aarnink (1997), Monteny (2000)
a
Values in columns indicate optima
+ indicates a positive correlation, − indicates a negative correlation and 0 indicates no relevant
effect
are also applicable to emissions from buildings housing cattle and poultry. It is clear
that all these factors are of importance when explaining differences among measure-
ments and that these factors are mutually dependent. As indicated earlier, differences
among emissions from different systems for fattening pigs arise from animal-related
factors, such as weight, and environmental factors such as air temperature. Also men-
tioned are factors related to the characteristics of the emitting substance, in this case
solid manure. A particularly important aspect is manure management: type of litter;
amount of litter; amount of area covered by litter; depth of the litter bed; removal
frequency; frequency of addition of fresh litter etc. (Groenestein et al. 2009).
2.2 System Boundaries
The system for managing solid livestock manure is here considered to start with
buildings housing the livestock, continue to manure storage and end with field
application. Material enters the livestock buildings as live animals, animal feed,
bedding and water for drinking and washing. Gases considered are NH3, N2O and
CH4 which leave the system when they escape to the free atmosphere. Manure solids
Emissions of Ammonia, Nitrous Oxide and Methane During the Management... 73
and liquids lost in addition to the gaseous emissions, via uncaptured runoff from
housing or storage, are also considered to have left the system, but are not consid-
ered here. Manures arising from feedlots are not included in this review.
The processes driving NH3, N2O and CH4 emissions from solid manure are briefly
described here; more comprehensive descriptions can be found in Sommer et al.
(2006) and Vavlin et al. (1998). The purpose here is to describe the physical and
chemical conditions that determine the emission of each of these three gases. The
occurrence of these conditions depends on the design and management of the solid
manure management system, as described in subsequent sections.
Carbon (C) and nitrogen (N) enter the solid manure management system in the
organic form, as urea and other low molecular weight compounds in urine, or as
more complex organic compounds in faeces, bedding and spilt animal feed. In the
case of the C and N compounds in urine, decomposition generally occurs quite
rapidly, primarily via enzyme-promoted hydrolysis, resulting in the formation of
bicarbonate ions (HCO3−), carbon dioxide (CO2) and ammonium (NH4+). The
decomposition of the more complex organic compounds is a slower process, brought
about by microbial degradation and resulting in the formation of microbial biomass,
CH4, H2O, CO2 and NH4+. The extent to which the different gases are produced
depends on aerobicity, pH, C:N ratio, dry matter content and other conditions
reported in Table 1.
Nitrous oxide can be produced in two ways. Firstly, the process of microbial
nitrification of NH4+ to nitrate (NO3−) involves the formation of a number of inter-
mediate compounds, including hydroxylamine (NH4OH) and nitrite (NO2−). If the
concentration of oxygen is low, a proportion of the NH4OH is not oxidised to NO2−
and is instead emitted as N2O. Secondly, if nitrification proceeds fully to (NO3−) and
then the oxygen (O2) concentration falls or the NO3− is transported to an area where
O2 concentration is low, micro-organisms will use the NO3– as an oxygen source.
Complete microbial denitrification results in the release of N2, with NO2, NO and
N2O as intermediate products. However, if the conditions are not fully anaerobic,
the denitrification may not be complete and nitric oxide (NO) and N2O can be
released.
denitrificationNO3 − → NO 2 − → NO → N 2 O → N 2
74 J. Webb et al.
The solubilities of N2O and CH4 in water are moderate (c. 60 mL of N2O/100 mL of
water) and relatively small (c. 5 mL of CH4/100 mL of water), respectively, and
consequently, these gases are largely expelled from the manure. In contrast, the
solubility of NH3 in water is particularly large and so the emission of this gas
depends on a range of conditions. The liquid in manure in animal housing, manure
storage or in field-applied manure can be considered a dilute aqueous solution of
NH3. At a number of locations within the manure management system, this solution
forms a surface with surrounding air e.g., on the floor of livestock buildings, within
the matrix of deep litter in a manure heap. The NH3 in the layer of air immediately
adjacent to the manure solution is in dynamic equilibrium with the NH3 in the
manure solution. The concentration of the NH3 in this adjacent air layer is deter-
mined by the concentration of NH3 in the surface layers of the solution and its tem-
perature, as described in Henry’s Law. The concentration of NH3 in the solution is
itself determined by the concentration of NH4+, the temperature and the pH, as
described by the dissociation equation for NH4+ (Muck and Steenhuis 1982). The
concentration of NH4+ can decrease over time via emission, uptake and immobilisa-
tion by micro-organisms or nitrification, or dilution if water is added. Alternatively,
it can increase if new NH4+ is added via the hydrolysis of urea or mineralization of
N in organic matter, or if water is lost by evaporation. The emission of NH3 from
this layer of air adjacent to the manure surface is dependent on its surface area and
the rate at which NH3 is transported out of the layer. This transport is driven by
turbulent diffusion or advection. This turbulent diffusion and/or advection is deter-
mined by the extent to which the design and management of animal housing, manure
storage or field-applied manure modifies the flow of ambient air.
It is possible that in moving from the bulk of the liquid phase towards the free
atmosphere, the gases can undergo further transformation. If N2O passes through an
area of greater anaerobic microbial activity, it may be reduced to N2. Conversely, if
CH4 passes through an area of aerobic activity, it may be oxidised to CO2. Finally, if
NH3 passes through an area where the micro-organisms are starved of N, the NH3
may be assimilated into microbial biomass.
In the following sections, the system for managing solid animal manures covered
by this review is defined.
Data from experiments from various European countries measuring emissions from
housing systems with solid manure were studied. None of the systems discussed
here had outdoor areas which the stock could access. Table 2 gives the number of
available datasets for each livestock category and their country of origin. Apart from
those using fattening pigs and cattle very few studies measured emissions of N2O or
CH4. Details on data handling are discussed in subsequent paragraphs.
Emissions of Ammonia, Nitrous Oxide and Methane During the Management... 75
Table 2 Experiments on gaseous emissions (NH3, N2O, CH4) from housing of livestock: livestock
category; total number of experiments (n); countries and the number of animals involved in the
experiments
Livestock Category n Countries Number of animals
Cattle Dairy 10 NL, AT, UK 12–90
Beef 16 AT, UK 4–99
Suckler cows 1 NL 49
Pigs Piglets 3 UK, BE 40–294
Fattening pigs 35 NL, UK, FR, BE, DE 3–873
Dry sows 10 NL, UK 366–250
Poultry Laying hens 44 NL, IT, UK 740–60,000
Broilers 33 NL, IT, UK, IE, FR 66–48,000
Turkey 2 FR 3,000–4,200
AT Austria, BE Belgium, DE Germany, DK Denmark, FR France, IE Ireland, IT Italy, NL
Netherlands, UK United Kingdom
Table 3 Variation of system factors between trials with the different housing systems for cattle
System factor Dairy Beef
Amount of straw, kg a−1 1,250–3,500 –
Amount of littered surface, % 60–85 100
Type of litter Long straw, chopped straw Long straw
Initial live weight, kg – 200–640
Air temperature inside, °C 3–21 10–18
% of total floor area within buildings
2.5 Ammonia
2.5.1 Cattle
Two dairy systems could be distinguished: tied stalls and deep litter systems. The
measurements originated from a limited number of countries (UK and NL for dairy
on deep litter, AT for dairy in tied stalls). The four AT datasets from tied stalls were
all from the same experimental setting with forced ventilation and 1,000 kg straw
per year. The main reported differences for the deep litter systems are listed in
Table 3.
The data from buildings housing beef cattle varied between four straw flow
systems in the same experimental unit (AT) and a commercial deep litter system
(UK). The mean NH3-N emission is given in Fig. 1. The data suggest greater NH3-N
emission from dairy on deep litter than from beef, which is plausible because dairy
cattle are bigger than beef cattle, require more feed and hence excrete more N.
Secondly the data suggest that deep litter systems emit more NH3-N than from tied
stalls which is also plausible because the emitting surface area in a tied stall is
smaller.
76 J. Webb et al.
2 1000
20
10 1 500
0 0 0
Dairy Dairy Beef Dairy Dairy Beef Dairy Dairy Beef
deep litter tied stalls n=5 deep litter tied stalls deep litter tied stalls
n=8 n=4 n=8 n=4 n=5 n=8 n=4 n=5
Fig. 1 Mean emission of ammonia-N from cattle housing with solid manure with standard devia-
tion and number of measurements (n). The data suggest that deep litter systems emit more NH3-N
than tied stalls. This is likely to be because the emitting surface area in a tied stall is smaller. Mean
nitrous oxide-N emission from Dutch dairy deep litter systems, Austrian tied stalls for dairy and
Austrian straw flow systems for beef with standard deviation and number of measurements (n).
The greatest N2O-N emissions were from the deep litter system, but the amount of N2O-N was
smaller than that of NH3-N by a factor of 15. Mean methane emission from Dutch dairy deep litter
systems, Austrian tied stalls for dairy and Austrian straw flow systems for beef with standard
deviation and number of measurements (n). The large emission from buildings housing dairy cattle
on deep litter may be due to the anaerobic conditions induced by compaction caused by animals
walking on the mixture of straw and excreta
Peat as litter may reduce NH3 emissions from both buildings and stores. The
properties of peat are beneficial as peat has a high water-binding capacity, low pH
and above all, the ability to chemically bind NH3. A study by Kemppainen (1987)
showed that peat (sphagnum peat) absorbs 0.027 kg kg–1 NH3 per unit mass of DM
at 0.70 water content. Karlsson and Jeppsson (1995) found a reduction of 90% of
NH3 emissions during storage with 0.60 peat (weight DM) in straw beds with young
cattle compared to only straw in the bedding. However, as peat is a limited natural
resource in most areas of Europe, this approach is not considered further in the
analysis.
2.5.2 Pigs
The main reported differences observed among the systems in pig housing are listed
in Table 4. For piglets and dry sows only a few factors were reported. Ventilation
rate was often not reported because houses were mainly naturally ventilated. Mean
NH3 emissions from pig houses and standard deviations are presented in Fig. 2. The
above factors were not found to be conclusive in determining the differences in NH3
emission and no reduced-emission systems could be identified. Although not sig-
nificant, piglets emit the least and sows the most NH3 per animal place, which would
be expected. The data available do not allow emissions to be expressed as a propor-
tion of N or TAN excreted since N excretion was not reported.
Emissions of Ammonia, Nitrous Oxide and Methane During the Management... 77
Table 4 Variation of system factors between trials with the different housing systems for pigs
System factor Fattening pigs Piglets Dry sows
Surface area per animal, m 2
0.6–2.6 – –
Amount of litter,% surface 25–100 100 –
Amount of litter, kg a−1 per place 36–395 – –
Type of litter Straw, saw dust Straw, saw dust straw
Litter management None; removal of part of – –
slurry; mixing; addition
of water
Initial live weight, kg 18–55 7.7– 12 –
End live weight, kg 90–146 – –
Air temperature inside, °C 6.3– 22.7 – –
25 25
20 20
15 15
10 10
5 5
0 0
Piglets Fatteners Dry sows N2O CH4
n=3 n=33 n=10 n=20 n=12
Fig. 2 Mean emission of ammonia-N from pig housing with solid manure with standard deviation
and number of measurements (n). Although not significant, piglets emit the least and sows the
most NH3 per animal place, which would be expected given the sizes of the livestock
2.5.3 Poultry
All broiler systems had fully littered floors. Differences were reported due to
differences in litter treatment intended to mitigate NH3 emission. This was the case
in four studies, in two of which the litter was belt-dried continuously with an air
flow, while in the other two litter was first heated and later in the growing period
cooled by means of a cooling/heating system in the concrete floor. All four reduced-
emission systems were Dutch.
The differences among systems for laying hens mainly arose because laying hens
were housed in basically three different kinds of housing systems:
1. Floor housing: layers live on a fully- or partly-slatted floor with litter and no
restriction of movement;
78 J. Webb et al.
Table 5 Variation of system factors between trials with the different housing systems for broilers
and laying hens
System factor Broiler Laying hen
Surface area per animal, m2 0.04–0.15 0.05–0.5
Amount of litter, % surface 100 0–100
Amount of litter, kg a−1 per 0.2–10 –
place
Type of litter straw, sawdust, rice husks, wood Wood shavings, sand,
shavings, wood chips sawdust
Litter management None, drying, cooling None, removal, drying and
removal
End live weight, kg 2–4 –
Air temperature inside, °C n.m. 16–26
Ventilation rate, m3 h−1 per 1–12 1–9
place
2. Aviary housing: floor housing with litter, but with extra living space by levels or
tiers, usually wired (tiers with wired floor aviary systems). Underneath the wired
floors, belts are installed to collect the droppings. The laying hens are not
restricted in movement, even between tiers.
3. Battery cages: laying hens are kept in cages with restriction of movement and
without litter. Usually there are several tiers and underneath belts are installed to
collect the droppings.
The main reported differences among the systems for broilers and laying hens are
summarized in Table 5. It shows that apart from litter management, ventilation rate
differed among trials. For laying hens inside temperature was different and for broil-
ers live weight at the end of the production cycle varied from 2 to 4 kg among coun-
tries. Inside air temperature was often not measured with broilers, but most countries
started with a temperature of 31–32°C and decreased gradually to 18–22°C.
Figure 3 presents the mean and standard deviation of NH3 emissions from broiler
and layer housing. It shows that buildings housing laying hens emit more NH3 than
buildings housing broilers and that reduced-emission systems, including the aviary
systems, can reduce NH3 emissions by between 50% and 80%. Within the
floor-housing system and the batteries, traditional and reduced-NH3 emission sys-
tems could be distinguished based mainly on litter management (drying and fre-
quent removal of manure). The aviary system also removed part of the dried litter
daily by belt and was therefore also a reduced-emission system. However, litter
management appears a major factor, although because of the large variations, differ-
ences were not always significant.
While measurements from conventional layer housing systems were available
from three countries, measurements from the floor system and the aviary were only
reported from the Netherlands and may not be representative of absolute emissions in
other countries. Nevertheless, these results provide a useful comparison of NH3 emis-
sions from three housing systems based on several experiments. We concluded that
the relative differences may be applicable to those systems used in other countries.
Emissions of Ammonia, Nitrous Oxide and Methane During the Management... 79
NH3 emission,
g N d-1animal place-1
1.0
0.8
0.6
0.4
0.2
0.0
Laying hen Laying hen Laying hen Laying hen Laying hen Broiler Broiler
floor floor, low aviary battery battery, low floor floor, low
n=9 emission n=4 n=1 emission n=29 emission
n=14 n=16 n=4
Fig. 3 Mean emission of ammonia-N from poultry houses with standard deviation and number
of measurements (n). The data show that laying hens emit more NH3 than broilers and that
reduced-emission systems, including the aviary systems, can reduce NH3 emissions by between
50% and 80%
2.6 Nitrous Oxide
Data were available for cattle and pigs but none for poultry.
2.6.1 Cattle
Figure 1 gives the N2O-N emission from five Dutch deep litter trials in two different
commercial housing systems, from tied stalls and from beef with a straw-flow sys-
tem. The UK studies did not measure greenhouse gas emissions. In the tied stall and
straw-flow systems, the manure is only stored for a short time in the house and
hence there is little opportunity for it to become compacted by the cattle. Consequently
the manure is likely to remain aerobic and so few N2O emissions would be expected.
The greatest N2O-N emissions were from the deep litter system, but the amount of
N2O-N was smaller than that of NH3-N (Fig. 1) by a factor of 15.
2.6.2 Pigs
Nitrous oxide was only measured in buildings housing fattening pigs in the
Netherlands, Germany and Belgium (n = 20). The average emission was 2.7 g d−1
N2O-N per animal place (stdev = 2.5) (Fig. 2). This is somewhat more than emitted
80 J. Webb et al.
from cattle manure, despite the much greater TAN excretion of cattle (Fig. 1). This
suggests a more aerobic environment in deep litter with pigs. Nevertheless, emis-
sions of N2O-N were still a factor of 3 less than emissions of NH3-N.
2.7 Methane
2.7.1 Cattle
Figure 1 shows the CH4-C emission from the same housing systems from which
N2O-N was measured. Methane emission from dairy cattle was less from the tied
stall than the deep litter system because of the short storage time and the straw flow
system. The emission from the tied stall system is in the range to be expected from
enteric fermentation, suggesting that the manure was a minimal source. The CH4
from the deep litter system is c. six times greater and suggests that the slurry/litter
mixture was mainly stored under anaerobic conditions. This is in agreement with
the relatively small emission of N2O-N compared with NH3-N, and with the N2O-N
from the deep litter systems for pigs. The large CH4 emission from buildings hous-
ing dairy cattle on deep litter could be explained by the anaerobic conditions induced
by compaction caused by animals walking on the mixture of straw and excreta.
Emissions expressed as CO2-equivalents for CH4 from the deep litter bed are much
larger than emissions from N2O expressed as CO2 equivalent.
2.7.2 Pigs
produced in deeper anaerobic layers of the litter bed in buildings housing pigs is
oxidised in the surface layer, due to aeration by the rooting and foraging behaviour
of the pigs. Cattle do not aerate the top layer of the bed by rooting and foraging so
this effect is absent from the deep litter beds in dairy houses.
3.1 Introduction
Addition of straw, or other bedding material with a large C:N ratio, to livestock
housing will not only increase manure porosity but may also increase the amount of
degradable-C and induce immobilization of mineral-N, transforming inorganic- to
organic-N (Kirchmann and Witter 1989). During storage of farmyard manure the
reverse process may occur and some UK studies (Chadwick 2005; Williams et al.
2003; Sagoo et al. 2006), which carried out a mass balance of total and organic N at
the beginning and end of a storage period, indicated net mineralization of up to 0.30
of the initial organic N content of the heap. Using 15N labelling, Thomsen and
Olesen (2000) were able to show that gaseous N losses from faecal and straw frac-
tions of farmyard manure (as compared with urine) became progressively more
important with duration of storage, indicating that mineralization occurring during
the storage period made this previously unavailable organic-N available for gaseous
emission. Mineralization was greater in aerobically stored (i.e. actively composted)
than anaerobically stored farmyard manure (Thomsen and Olesen 2000). Self-
heating will occur in most heaps containing porous manure with access of air to the
sides of the heap. In general aerobic decomposition, increasing temperatures up to
70–80°C, will take place in pig faeces and in heaps of cattle manure with daily straw
addition rates greater than 2.5 kg straw per head of livestock (Sommer et al. 2006).
Further mineralization and immobilization will change the organic N and TAN
pools, which will affect emission from the stored manure.
The data provided in this study show that temperatures in manure heaps decrease
significantly with increased density of the manure (Fig. 4). Density and water con-
tent also affect air transport in the heap (Poulsen and Moldrup 2007), and conse-
quently affect aerobic microbial activity that is the source of heating. Self-heating
may be reduced by covering the heap with tarpaulin (Hansen et al. 2007), reducing
air transfer to the heap interior. Thus, increasing manure density or effective cover-
age of the manure reduces the transfer of oxygen to the interior of the heap and
thereby reduces heap temperature. A high density may be a consequence of high
water content, a low content of bedding material like straw or wood chips, or due to
deliberate compaction of the animal manure.
In stored solid manure, the air exchange and temperature increase induced by
aerobic decomposition may greatly influence NH3, N2O and CH4 emission, as
illustrated in Figs. 5 and 6. Deep litter from pig and cattle housing and pig manure
with a large proportion of straw will decompose aerobically, because of the high
82 J. Webb et al.
Fig. 4 Temperatures in livestock manure heaps. The open symbols are data from experiments
where the heaps were covered with PVC sheets or surrounded by walls. The data show that tem-
peratures in manure heaps decrease significantly with increased density of the manure. (a) all data
used for the linear regression and (b) data from densities > 0.5 Mg m−3 have been omitted from the
data analysis. (a) T(D)=88 − 86*D, r 2 = 0.75 , (b) T(D)= 78 − 57*D, r 2 = 0.41
a b c
Ammonia emission, Ammonia emission, Ammonia emission,
% of Total N % of TAN ln(% of TAN)
50 300 5
250 4
40
200
30 3
150
2
20 100
50 1
10
0
0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Heap density, Mg m-3 Heap density, Mg m-3 Heap density, Mg m-3
Fig. 5 Ammonia emission from livestock manure heaps related to% total-N content of the manure
(a),% of total ammoniacal-N (TAN) (b) and ln (% of TAN) (c). In figure B(b), the encircled sym-
bols are data from experiments with high straw amendments or sheeted but still exhibited high
temperature. In figure (c), the encircled symbols are from experiments where the manure was
compressed to some extent or covered efficiently. The data indicate air exchange and temperature
increase induced by aerobic decomposition may greatly increase NH3 emission. Reducing access
by air through compacting, covering or otherwise storing manure heaps at high density reduces
NH3 emission during storage. F(D) = 6.5 − 7.6*D, r 2 = 0.49
permeability of the organic material and the presence of large amounts of degradable
C. In contrast, temperature in high bulk density farmyard manure from cattle will
not often increase (Forshell 1993). Manure from open beef feedlots is often so dry
that aerobic decomposition will not occur without the addition of water. The gaseous
Emissions of Ammonia, Nitrous Oxide and Methane During the Management... 83
1.0
0.5
0.0
0.0 0.2 0.4 0.6 0.8 1.0
Density, Mg m-3
emission from stored solid manure will therefore reflect the variety in manure
composition. For example, the addition of water to dry manure heaps will enhance
aerobic decomposition, but aerobic decomposition may be decreased if the water
content is increased to the extent that air exchange through the heap is reduced
(Poulsen and Moldrup 2007).
The tables and figures presented in this section contain emission estimates from the
references given in Table 6. The number of data in the datasets for each pollutant is
shown in Tables 7–9.
3.3 Ammonia
Mean NH3 emissions for different livestock and solid manure types from the data
reviewed in this study are given in Table 7 and, although subject to large variation,
indicate that emission from pig farmyard manure tends to be greater than from other
livestock and solid manure types.
The emission of NH3 from stored solid manure is controlled by TAN concentra-
tion, pH, air flow through the heap and temperature in the heap. Measured TAN
proportions in solid manures (10–90% tile) have been reported as between 0.008
and 0.18 of N (cattle) and 0.024 and 0.42 (pigs). Ammonia emission is also affected
by the cation exchange capacity (CEC) of the manure and formation of ammonium
crystals (Sommer et al. 2006). Data reviewed for this study show that reducing
84 J. Webb et al.
Table 6 Data presented in figures and tables below are collected from the following reports and
articles
Emission measured
NH3 N2O CH4 Treatment
Sommer and Dahl (1999) X X X Cattle deep litter; untreated, compacted and
mixed
Osada et al. (2001) x x x Cattle deep litter; untreated
Sagoo et al. (2006) X X Cattle FYM, straw added at increasing rates
Pig; FYM
Williams et al. (2003) x Cattle FYM.
Pig FYM
Nicholson et al. (2002) X Poultry manure; wood shavings with and
without tarpaulin cover
Mosquera et al. (2005a) X X Cattle FYM
Mosquera et al. (2005b) X X Deep litter
Groot Koerkamp and x Poultry manure; wood shavings
Kroodsma (2000)
Espagnol et al. (2006) x x x Pig manure deep litter; heaps turned and
unturned
Fukumoto et al. (2003) x x Pig manure; wood shavings
Szanto et al. (2007) x x x Pig deep litter; rich in straw
Chadwick (2005) x x x Cattle FYM, covered with tarpaulin and
uncovered
Amon et al. (1998) x x x Cattle FYM – from tied stall
Amon et al. (2001) x x x Cattle FYM-tied stall; fleece sheet covering
Groot Koerkamp and x Layers manure from belt; some wood
Kroodsma (2000) shavings
Sommer (2001) x x x Cattle deep litter; compacted, cut manure,
covered with plastic (polyvinyl chloride),
untreated
FYM farmyard manure
The greater sources of data are designated X, other sources are designated x
of the initial N during composting of poultry manure while losses during composting
of other animal manure ranged from 0.21 to 0.77 (Martins and Dewes 1992). Amon
et al. (2001) found that composting farmyard manure emitted less N2O and CH4, but
more NH3, compared with anaerobically-stacked farmyard manure.
Cattle farmyard manure with only a small amount of straw has a high density and
C:N ratio and does not decompose aerobically. Consequently, NH3 emission from
cattle FYM is generally less than from heaps of pig farmyard manure, which often
will be aerobic and start to decompose aerobically. However, the studies reviewed
here provide very little information about the source and characterisation of manures,
so the reasons for the differences in emissions between cattle and pig farmyard
manure cannot be attributed with certainty.
From manure heaps undergoing aerobic decomposition emissions of 0.25–0.30 of
the total-N in stored pig manure and cattle deep litter have been recorded (Petersen
et al. 1998; Karlsson and Jeppson 1995). Smaller NH3 emissions in the range 0.01–0.10
of TAN have also been measured in studies where the low emission was partly due to
rain reducing the emission potential of the manure by leaching surface layer TAN
(Amon et al. 2001; Chadwick 2005) and partly due to the composition of the manure.
Surface concentration of TAN is important as e.g. addition of fresh manure on the heap
creates a new outer surface from which emission can occur, thus NH3 emission will
peak soon after each addition of manure to the heap (Muck et al. 1984).
3.4 Nitrous Oxide
Significant N2O production takes place during storage (Table 8) due to nitrification
and subsequent denitrification, as also shown by Yamulki (2006) and Hansen et al.
(2007). Nitrification in passively aerated heaps is a consequence of the porous nature
of manure in the surface layer, allowing O2 to diffuse into the manure. Addition of
straw litter may also serve as a conduit for O2 and the oxygenation of the manure
(Sommer and Møller 2000). Therefore, NO2− and NO3− are found in the surface lay-
ers of most heaps, and in consequence emissions of N2O have been measured from
dung heaps (Amon et al. 2001; Berges and Crutzen 1996; Groenestein and Van
Faassen 1996; Petersen et al. 1998; Chadwick 2005). Nitrous oxide emissions
increase with increasing manure density (Fig. 6), which may be due to an increased
number and volume of sites with relatively low oxygen content from which N2O
emissions can occur. Groenestein and van Faassen (1996) provided the following
explanation: NO and N2O are intermediate products of anaerobic denitrification and
therefore are expected to be emitted when O2 pressure increases (Burton et al. 1993;
Poth and Focht 1985). However, factors that reduce oxygen pressure in the bed can
also increase N2O production. According to Poth and Focht (1985) this is caused by
reduction of NO2− to NO rather than through the nitrification by an aerobic process,
and they defined it as nitrifier denitrification. This is in agreement with Burton and
Turner (2003), who found production of N2O from pig manure without production
of NO3− and NO2−. This occurred during aerobic treatment after the addition of
manure, when O2 consumption tripled within minutes. The laboratory study of
Emissions of Ammonia, Nitrous Oxide and Methane During the Management... 87
Groenestein and van Faassen (1996) confirmed the findings of Poth and Focht
(1985) and Burton et al. (1993).
Hansen et al. (2007) measured N2O emission of 0.05 of total-N from a heap con-
taining organic solids from separated slurry. This emission was reduced to less than
0.001 of total N by covering the heap, thereby reducing air flow into the heap reduc-
ing the temperature significantly. In addition to reducing the temperature, covering
also reduced the O2 content of the manure which reduced nitrification to an
insignificant amount. The same effect of covering manure heaps was shown in the
study of Chadwick (2005). The use of 5 kg of straw per livestock unit per day in the
manure reduced N2O emission significantly by increasing porosity and thereby
reducing anaerobic spots in the heap compared with using 2.5 kg per livestock unit
per day (Amon 1999; Sommer and Møller 2000).
Table 8 presents data from the relatively few studies that have examined N2O
emission from manure heaps. The experimental conditions varied greatly, i.e. the
heaps included in the study had variable surface:volume ratios, with gradients of O2
and temperature that varied with time and manure properties (Petersen et al. 1998).
The emissions vary considerably but, due to the limited number of studies available,
it has not been worthwhile quantifying the effect of the major factors controlling
them. This is because there are relatively few data available and the main control-
ling factors are confounded within the studies. Most emission estimates from heaps
with cattle deep litter, straw amended cattle manure or untreated cattle and pig
manure have been between 0.001 and 0.009 of total-N (Table 8) as shown in Sommer
(2001), Petersen et al. (1998) and Yamulki (2006). From pig deep litter heaps emis-
sions as great as 0.098 of total-N have been measured. Emission of N2O from poul-
try manure tends to be small.
3.5 Methane
No relation between manure heap density and CH4 emission was found in the current
study, which could be due to the small number of available data. Although CH4 emis-
sion occurs only under locally anaerobic conditions, the relationship with the aero-
bicity of the whole stack is not straightforward. Aerobic decomposition in straw-rich
loosely-packed heaps of solid manure leads to both high temperatures and anaerobic
hotspots, so CH4 emission occurs, even though the stack is largely aerobic (Hellmann
et al. 1997). On the other hand, if an air-tight cover is put over the heap, thereby pre-
venting aerobic microbial activity and the associated increase in temperature, CH4
emissions will be reduced, even though the stack is largely anaerobic. Efficient cov-
ering reduced CH4 emissions from a heap of a dry matter-rich separated slurry frac-
tion from 0.035 to 0.0017 of the initial C content (Hansen et al. 2007). The balance
between aerobic and anaerobic turnover is critical. If the heap is not covered effi-
ciently, or if the compaction is not enough to prevent all air flow into the heap, then
CH4 emissions may be enhanced (Amon 1999; Sommer 2001). Thus loosely-packed
pig manure emitted five times more CH4 than cattle farmyard manure, probably due
to a greater gas exchange and higher temperature in the manure (Husted 1994).
88 J. Webb et al.
Chadwick (2005) reported CH4 emissions varied from 0.005 to 0.097 of the ini-
tial carbon content. The greatest and least emissions were from manure stored in
compacted and PVC-covered heaps, respectively (Table 9). Frequent turning can be
used to reduce anaerobic zones in the heap. In one study this technique reduced CH4
emissions to about 0.005 of the initial C content (Amon et al. 2001, 2006).
In contrast to the relatively sparse data available for livestock housing and manure
storage, the quantity of data available for field-applied solid manure was sufficient
to support a more detailed statistical analysis. The relevant characteristics and
chemical composition of the manures investigated, the experimental design and the
resulting emissions were surveyed. The survey yielded a total of 35 studies includ-
ing 292 datasets on NH3, 57 on N2O and 11 on CH4 (Table 10), with most of the
datasets originating from mid or northern Europe. Two thirds of the manures inves-
tigated were stored before application (average duration 175 days), the remainder
were applied directly from the livestock building.
Manure composition was in the expected range (up to 20% N in dry matter and
up to 80% of total-N as TAN and <1.0% of total-N as nitrate) (Table 11). Differences
were likely to depend on housing systems, feeding regimes, litter materials, amounts
of litter, duration of storage and conditions during storage.
4.1.1 Experimental Conditions
The studies were carried out between 1990 and 2007, mainly during spring, summer and
autumn (n = 66, 52 and 106, respectively), while 12 studies spanned all four seasons.
Table 10 Number of datasets on emission of ammonia (NH3), nitrous oxide (N2O) and methane
(CH4) following application of solid manures to land, per livestock category
Livestock category NH3 N2O CH4
Dairy cattle 49 4 0
Beef cattle 62 29 9
Fattening pigs 85 18 1
Broilers 38 2 0
Laying hens 42 4 1
Suckler cows 13
Other livestock categoriesa 3
Total 292 57 11
a
1 for turkeys, 2 for a mixture of horse, pig and poultry manure
Emissions of Ammonia, Nitrous Oxide and Methane During the Management... 89
Table 11 Composition of the investigated manuresa, expressed as: dry matter (d.m.),% of fresh weight; volatile
solids (v.s.),% of d.m.; total nitrogen (Ntot)% of d.m., total ammoniacal nitrogen, (TAN),% of total-N; nitrate,%
of Ntot; phosphorus, (P),% of d.m.; potash (K),% of d.m.; pH; C;N for dairy cattle, beef cattle, fattening pigs,
broilers and laying hens
d.m. v.s. Ntot TAN Nitrate P K C
% % d.m. % d.m. % Ntot % Ntot % d.m. % d.m. % d.m. pH C/N
Dairy cattle (total number of datasets: n = 53)
n 36 31 53 36 4 23 19 0 22 8
Average 20 72 2.7 18 0.29 0.6 3.4 – 8.4 14
Median 19 77 2.5 17 0.29 0.5 2.9 – 8.4 14
Minimum 15 41 0.3 1.6 0.17 0.2 0.5 – 7.4 12
Maximum 40 86 20.0 38 0.40 1.0 8.8 – 8.9 16
Standard deviation 5 14 3.6 8.8 0.14 0.2 1.8 – 0.4 1.5
Beef cattle (total number of datasets: n = 69)
n 47 0 56 69 7 9 9 6 27 6
Average 20 – 2.6 8.2 0.02 0.6 2.7 15 8.2 17
Median 18 – 2.6 7.2 0.01 0.7 2.4 11 8.3 16
Minimum 15 – 0.4 0.0 0.00 0.5 1.8 7 7.7 13
Maximum 42 – 5.9 39 0.08 0.8 4.6 38 9.2 21
Standard deviation 5.6 – 1.3 8.4 0.03 0.1 0.8 12 0.4 3.2
Fattening pigs (total number of datasets: n = 93)
n 87 4 87 87 7 5 5 7 30 7
Average 25 55 2.9 19 0.02 3.3 2.8 17 8.2 10
Median 22 59 3.0 17 0.03 4.3 2.6 10 8.3 10
Minimum 17 0.0 0.6 0.8 0.00 1.3 2.4 7 6.7 9
Maximum 64 81 6.2 54 0.03 4.6 3.7 37 8.8 12
Standard deviation 7 32 0.9 16 0.01 1.5 0.5 13 0.5 1.3
Broilers (total number of datasets: n = 38)
n 38 8 38 38 0 16 16 6 29 8
Average 63 71 4.4 30 – 1.7 3.4 30 8.6 13
Median 65 69 4.1 32 – 1.5 3.5 22 8.7 8.5
Minimum 40 67 1.1 9.0 – 1.1 2.4 16 6.5 6.4
Maximum 93 80 6.6 49 – 3.8 3.9 72 8.9 32
Standard deviation 13 4.9 1.4 13.0 – 0.7 0.5 21 0.5 9.0
Laying hens (total number of datasets: n = 44)
n 36 17 36 36 0 13 13 8 27 8
Average 52 70 4.6 36 – 2.3 3.0 16 7.9 7.7
Median 44 72 4.9 31 – 2.1 2.7 11 8.3 6.1
Minimum 21 61 1.4 2.9 – 1.5 2.2 6.3 6.4 3.4
Maximum 90 80 6.7 78 – 3.6 4.2 33 9.2 19
Standard deviation 22 5.6 1.5 23 – 0.8 0.9 11 0.9 5.1
n for all livestock cat 244 60 270 266 18 66 62 27 135 37
a
Data were obtained from: Akiyama and Tsuruta (2003); Amon et al. (2001); Asteraki et al. (1998); Bode
(1990); Bruins and Hol (1990); Bruins and Huijsmans (1989); Chadwick et al. (2000); Chambers et al. (1997);
Hansen (2004); Hol (1992); Karlsson and Salomon (2002); Kosch (2003); Malgeryd (1996, 1998); Mazzotta
et al. (2003); Menzi et al. (1997a, b); Misselbrook et al. (2005a, b); Mulder (1992a, b); Mulder and Hol (1993);
Mulder and Huijsmans (1994); Regione Emilia-Romagna (2004, 2006, 2007); Rochette et al. (2008); Rodhe
and Karlsson (2002); Rodhe et al. (1996); Sagoo et al. (2006, 2007); Sannö et al. (2003); Thorman et al. (2007);
Webb et al. (2004, 2006); Williams et al. (2003)
90 J. Webb et al.
Mean temperatures during measurements ranged between 11°C and 13°C, which
can be considered as typical for mid European climates (Flechard et al. 2007).
Information on weather conditions was available from 141 datasets. For 67 datasets,
dry weather was recorded and for 74 datasets rain events were reported or rainy
weather prevailed.
The majority of NH3 measurements were made using wind tunnels (n = 171).
Micrometeorological methods (n = 47) and the N balance (n = 10) approach were
also used. Chamber methods (n = 77) were used for measuring both NH3 and N2O:
dynamic chambers for NH3, and closed chambers for N2O. The average duration of
measurements ranged between 96 and 362 h, N2O measurements were made for
longer (between 2 and 12 months).
Application rates were adjusted according to the N requirements of the crops,
and thus within the range of usual agricultural practice. Manures were applied onto
bare soil, stubbles and grass. Manures from pigs and poultry were mostly applied
onto stubbles while manures from cattle were predominantly spread onto grass.
The objective of most studies was to investigate factors influencing emissions after
manure spreading, i.e.: manure incorporation and the time delay before incorporation
(33 experiments); the conditions under which manure was stored before application
(9 experiments); the type of machine used for incorporation (8 experiments); the
amount of litter material (5 experiments); the influence of covering the manure during
storage (3 experiments); the influence of rain after application and of turning the
manure heaps during storage (2 experiments each); the water content of the manure;
the compaction of manure during storage; the application rate and the soil type
(1 experiment each), on subsequent emissions.
Thirty datasets reported NH3 emissions >1.50 of TAN applied. Fifteen of the
manures used in these studies had TAN contents <0.10 total-N or TAN contents of
the manures were not available. These apparently anomalous emissions were likely
due to the difficulty of taking accurate subsamples of farmyard manure (Webb et al.
2004), falsely low TAN contents due to analytical problems or large NH3 losses during
handling or storage of the samples (Misselbrook et al. 2005a). In addition, there
could also have been problems achieving an even spatial distribution of solid manure
on the plots. We therefore decided to exclude these datasets from the statistical
evaluation. The other 15 datasets with >1.50 TAN which exhibited TAN concentra-
tions in the manure reaching at least half of the standard UK book value, which is
10% of total-N (Anon 2000), were retained for the statistical evaluation but the
emissions were limited to 1.50 TAN. This was our estimate of the potential maxi-
mum emission arising from volatilization of all the TAN in manure at application
Emissions of Ammonia, Nitrous Oxide and Methane During the Management... 91
Génermont and Cellier (1997) concluded that emission rates measured by enclo-
sures covering small areas (wind tunnels, dynamic chambers) modify environmen-
tal conditions (wind speed, temperature, rain) in a way that will tend to lead to an
overestimation of NH3 emissions at the beginning of the measurement period (due
to advection) compared with emissions measured over larger areas e.g. by microme-
teorological methods. In addition, combined effects of the small surface area sam-
pled and the high spatial variability of the emissions mean that results of enclosure
studies have to be interpreted with caution. In general, they are considered as unsuit-
able for developing absolute values for NH3 emissions. For determining absolute
NH3 fluxes, micrometeorological methods are the most suitable because they are
non intrusive. However, they require larger plots and are difficult to replicate, except
for the integrated horizontal flux technique (Shah et al. 2006) and the equilibrium
concentration technique, developed at the Swedish Institute of Agricultural and
Environmental Engineering (JTI), Sweden (Svensson 1994). However, enclosures
covering small areas are appropriate to measure relative emissions in order to com-
pare the relative effect of influencing factors or the effectiveness of different mitiga-
tion measures. Pain et al. (1991) assessed the incorporation of pig slurry using both
a micrometeorological technique and wind tunnels. In those experiments abatement
from incorporation by plough, as estimated using wind tunnels, was c. 5% more
effective than in the experiment in which NH3 emissions were measured by the
meteorological method. Webb et al. (2004) concluded that wind tunnels were an
appropriate method to estimate the abatement efficiency of manure incorporation
techniques.
Nitrous oxide emissions may also be measured using micrometeorological meth-
ods and by closed chambers. As for NH3 emissions, micrometeorological methods
are considered to be optimal because of minimal disturbance of environmental
conditions. However, they are limited to large fields and certain meteorological con-
ditions (Pape et al. 2009). In all the studies reviewed here, N2O emissions following
application were measured using closed chambers. Studies comparing both meth-
ods reported good agreement (Christensen et al. 1996; Laville et al. 1999) and we
concluded that the results were not systematically biased by the measuring method.
However, N2O emissions following manure application were reported to occur over
30–60 days (Wulf et al. 2002; Rochette et al. 2008). The average duration of mea-
surement for the studies reviewed was 13–18 days, which might lead to an underes-
timation of emissions.
Spreading technique (one- and two-step spreaders, finer scattering) did not influence
NH3 emissions, but greater application rates increased the proportion of N lost as
NH3 (Rodhe et al. 1996). Climatic conditions such as air temperature, saturation defi-
cit of the air, irradiation, wind speed and rainfall may influence emissions. Misselbrook
et al. (2005a) did not find a relationship between total NH3 losses and temperature for
solid manure applications. Losses would be expected to increase with increasing
temperature. However, crusting of the surface layer of manure at higher temperatures
may reduce emissions. For solid manures, rainfall was identified as the parameter
with most influence on NH3 emissions, due to NH4–N leaching from manure to the
soil, where it will be less susceptible to volatilization (Misselbrook et al. 2005a).
Sommer and Christensen (1990) found that irrigation with more than 20 mm reduced
total NH3 emission to less than half of the emission from untreated solid pig manure.
Rodhe et al. (1996) found a reduction of 30% of NH3 emissions with 20 mm irriga-
tion directly after spreading of semi-solid manure and less reduction for applied solid
manure. On the other hand, regular wetting prevents the manure from drying and
might enhance mineralization, prolonging NH3 release (Misselbrook et al. 2005a)
and also potentially increasing emissions of N2O. Chambers et al. (1997) found emis-
sion increased following rain events of 13 mm about 5 days after application and
16 mm about 8 days after manure application. Gordon and Schuepp (1994) reported
that rainfall events of approximately 1 mm h−1 suppressed NH3 fluxes on subsequent
days after spreading of pig manure. Ammonia losses immediately after field applica-
tion appeared to be slightly enhanced by watering, although the effects of the total N
applied were dominant (Gordon and Schuepp 1994).
Numerous studies have shown that N2O production increases with temperature
(Dobbie et al. 1998; Smith et al. 2003). While no influence of soil type on NH3 emis-
sions from solid manure has been demonstrated to date, N2O emissions from agricul-
tural soils were found to be greater from fine- than from coarse-textured soils. This is
likely to be driven by the lower redox potentials of fine-textured soils and greater
resistance to O2 diffusion (Rochette et al. 2008). Nitrous oxide production can increase
with increasing soil moisture (Dobbie et al. 1998; Smith et al. 2003). Rochette et al.
(2008) reported that periods of greater emissions following manure and fertilizer-N
application corresponded with the period when soil mineral N contents were greatest
and water-filled pore space (WFPS) was greater than 0.5 m3 m−3. Increasing soil mois-
ture and decreasing temperatures (e.g. over the winter period) are expected to favour
the reduction of any N2O produced to N2 (Firestone and Davidson 1989).
4.3 Ammonia
a b c
Ammonia emission, Ammonia emission, Ammonia emission,
% of TAN % of TAN % of TAN
140 140 140
120 30 4 120 120
4
4
100 100 18 100
27 5 20
80 19 80 19 80 8
7 1
60 60 60 3
5 6
13
40 40 6 40 8
4 3
20 20 20
1
0 0 0
Long Short Long Short Long Short Long Short Long Short Long Short
Wind tunnel Other methods Wind tunnel Other methods Wind tunnel Other methods
Fig. 7 Ammonia emissions from cattle (a), pig (b) and poultry (c) manure according to the mea-
suring method (wind tunnel and other methods) and the duration of measurement (long: duration
of measurement more than 120 h; short: up to 120 h) no incorporation (light grey column on the
left) or incorporation (dark grey column on the right) after spreading. The columns give the aver-
age and the bars the standard error. The numbers over the bars indicate the number of datasets.
Consistently greater emissions were reported using wind tunnels, suggesting an overestimation of
emissions with this method. Average unabated NH3 emissions following application of cattle
manure were 0.79 TAN, from pig manure 0.63 TAN and from poultry manure 0.40 TAN. Source
of the data: see footnote of Table 11
emissions (Table 12). Consistently greater emissions were reported using wind tun-
nels, suggesting an overestimation of emissions with this method. Short duration of
measurement (i.e. less than 120 h) produced smaller emissions, implying that NH3
emissions may continue for more than 5 days after application. The different mea-
suring methods exhibited mean NH3 emissions without incorporation after applica-
tion between 0.62 and 1.11 TAN for cattle manure. Emissions were less for pig
manure (0.41–0.76 TAN) and poultry manure (0.36–0.73 TAN) than for cattle
manure. It has to be noted however that the number of datasets differ for the live-
stock categories, measuring methods and incorporation. The incorporation of
manure significantly reduced emissions. The reduction due to incorporation was
independent of the measuring method but differed among livestock categories. On
average, emissions were 17%, 48% and 10% less with incorporation of manure for
cattle, pigs and poultry, respectively. However, these figures do not take into account
factors influencing emissions that were not included in the statistical analysis. A more
precise quantification of the effect of manure incorporation is given below.
We considered an appropriate estimate of unabated NH3 emissions from cattle
manure could be obtained from measurements made over more than 120 h, exclud-
ing those made using wind tunnels. This gave an average emission of 0.79 kg kg−1 N
(related to TAN) (Fig. 7a), albeit from only four datasets. The same approach esti-
mated unabated emissions from pig manure as 0.63 TAN (Fig. 7b). This figure can
be considered as relatively robust due to the comparatively large number of datasets
Emissions of Ammonia, Nitrous Oxide and Methane During the Management... 95
Table 12 Results of the analysis of variance testing the influence of livestock category, measuring
method and manure incorporation as well as their two-way interactions on ammonia emissions
(% TAN)
Square Df F-value Significance
Livestock category 56775 2 27.36 p < 0.001
Measurement method 53140 3 17.07 p < 0.001
Incorporation 15186 1 14.63 p < 0.001
Animal: Measurement 15647 6 2.51 p < 0.05
Animal: Incorp 7085 2 3.42 p < 0.05
Measurement: Incorp 332 3 0.11 ns
Residuals 204429 197
Data in the table are type-II sums of squares, degrees of freedom, F ratios and significance levels
for each effect in the model
(n = 19). Unabated NH3 emission following application of poultry manure was 0.40
TAN (n = 6; Fig. 7c). This smaller emission factor for poultry manure is expected as
hydrolysis of uric acid to urea may take many months during storage and is often
incomplete even after application, hence limiting the potential for NH3 emission
(Kroodsma et al. 1988).
Other factors potentially influencing NH3 emissions after spreading which could
not be included in the statistical evaluation are the amount and type of litter, storage
time of manure before spreading, the interval of incorporation after spreading, rate
of application, the machine used for spreading or incorporation and wetting of the
manure after application due to rain.
The available datasets did not allow us to determine any influence of litter type
on emissions after application since the same material is used for almost all manures
(e.g. straw for cattle and pigs, wood shavings for broilers). In the two studies where
the influence of different amounts of litter in the manure was investigated, emissions
tended to increase with an increasing amount of litter. For manure from fattening
pigs, a similar trend was less clear. We did not consider it appropriate to quantify the
effect of the amount of litter based on these results.
Emissions tended to be less from cattle, pig and layer (belt removed) manures that
had been stored than from fresh manure (Asteraki et al. 1998; Sagoo et al. 2006;
Hansen 2004; Karlsson and Salomon 2002; Regione Emilia-Romagna 2007). Hansen
(2004) reported that storage reduces the potential for NH3 volatilization following
spreading despite the increase in pH during storage. This is likely to be due to a
decrease in the amount of TAN in the manure during storage. Emissions after land
spreading of broiler manure, stored in the open air, were less than from manure stored
in a heap sheeted with a plastic cover. This was due to more TAN remaining in the
sheet-stored manure (Sagoo et al. 2007). For pig farmyard manure, the effect of
sheeting was less clear. One experiment (Sagoo et al. 2006) reported NH3 emission
to be less from sheeted manure (0.37 TAN) compared with conventionally stored
farmyard manure (0.65 TAN). In a second experiment, the opposite was observed.
Webb et al. (2004) investigated whether compaction of manure during storage might
lead to enhanced emissions after spreading. Compacted manures contained more
96 J. Webb et al.
Table 13 Reduction of ammonia emissions after application with incorporation of solid manure
from beef cattle, fattening pigs, broilers and laying hens in% of emissions measured without incor-
poration (in brackets: number of datasets)
Incorporation after
<4 h 4 h ³24 h Tool used for
Livestock category Emission reduction% incorporation
Dairy cattle – 63 (2) 38 (2) Harrow
Beef cattle – 58 (3) 20 (4) Plough
Beef cattle – – 9 (1) Harrow
Fattening pigs 92 (4) 64 (9) 63 (8) Plough
Fattening pigs – 61 (5) 37 (5) Disc
Broilers – 81 (2) 77 (2) Plough
Broilers – 53 (2) 24 (2) Disc
Broilers – 44 (1) – Harrow
Laying hens 97 (1) – – Mouldboard plough
Laying hens 83 (1) – – Chisel plough
Laying hens 82 (1) – – Rotary cultivator
Laying hens 79 (2) – – Harrow
TAN but less total-N. There was no significant effect of the storage method on emis-
sions following spreading cattle farmyard manure in the first experiment while the
emissions of NH3 were greater from the compacted manure in the second one. Losses
of NH3 from pig farmyard manure were unaffected by storage treatment. Turning pig
manure heaps twice during storage reduced emissions after surface spreading (Sagoo
et al. 2006). Turning has been shown to increase NH3 emissions from stored cattle
farmyard manure (Amon et al. 2001; Parkinson et al. 2004), hence the depletion of
TAN during storage might be expected to reduce emissions after spreading.
Increased emissions after wetting were observed for studies with pig and poultry
manures. For the latter, wetting increases hydrolysis of uric acid to NH4+ which can
then volatilize as NH3. However, reduced emissions due to wetting occurred in one
study on manure from cattle and two on laying hens as well.
In most cases, incorporation within 4 h after application reduced emission more
than incorporation over longer intervals (i.e. average reduction of 32%, 92% and 85%
for incorporation of less than 4 h and 20%, 56% and 50% for incorporation within
24 h or more after application for cattle, pigs and poultry, respectively) (Table 13).
Incorporation by disc or harrow reduced NH3 emissions less than incorporation by
plough, although all machines used for incorporation achieved some mitigation.
These findings are consistent with other studies (e.g. Webb et al. 2004; Sagoo et al.
2007). Webb et al. (2004) suggested that incorporation of pig farmyard manure can
reduce NH3 emissions by c. 90%, 60% and 30% for immediate, within 4 h and within
24 h incorporation, respectively. For incorporation of cattle farmyard manure within
4 h, a reduction of c. 50% was achieved (Webb et al. 2004). The results of Sagoo et al.
(2007) indicate that rapid soil incorporation reduced emissions by 15–87% compared
with surface spreading. In contrast, Nicholson et al. (2002) concluded that the soil
incorporation of solid manure from pigs had little effect on NH3 emissions.
Emissions of Ammonia, Nitrous Oxide and Methane During the Management... 97
20 11
5
15
10
10
8
5
6 1
0
Cattle Pig Poultry
Fig. 8 Nitrous oxide emissions of cattle, pigs and poultry according to incorporation (light grey
column on the left) or no incorporation (dark grey column on the right) after spreading of manure.
The columns give the average and the bars the standard error. The numbers over the bars indicate
the number of datasets. Emissions of N2O following the application of cattle manure were 0.12 of
TAN without incorporation after application and 0.073 TAN with incorporation after application.
Emissions of N2O following application of pig and poultry manures were 0.003 and 0.001 TAN
respectively without and 0.035 and 0.089 TAN respectively with incorporation after application.
However, data variability was large. Source of the data: see footnote of Table 11. TAN total ammo-
niacal nitrogen
4.4 Nitrous Oxide
We decided within the Eager group to report TAN based emission factors. Although
reporting N2O emissions as a proportion of total-N is more usual, for this section of
the review, we prefer to employ the same emission factors for both NH3 and N2O.
Emissions of N2O following the application of cattle manure were 0.12 of TAN
without incorporation after application and 0.073 TAN with incorporation after
application (Fig. 8). Emissions following application of pig and poultry manures
were 0.003 and 0.001 TAN respectively without and 0.035 and 0.089 TAN respec-
tively with incorporation after application. It has to be noted that data variability
was large and the results were influenced by a few datasets with emissions of >0.20
TAN from manures with TAN contents much less than average. Chadwick et al.
(1999) found N2O emissions from solid manure of 0.059 TAN. Gregorich et al.
(2005) reported data for solid manure from cattle similar to those presented here.
In contrast, Loro et al. (1997) observed greater emissions (26.5 kg ha−1 N, applica-
tion rate: 600 kg ha−1 N) from solid beef manure.
98 J. Webb et al.
Table 14 Results of the analysis of variance testing the influence of livestock category, manure
incorporation and their interaction on nitrous oxide emissions (% TAN, log-transformed). Data in
the table are type-II sums of squares, degrees of freedom, F ratios and significance levels for each
effect in the model. TAN total ammoniacal nitrogen
Square Df F-value Significance
Livestock category 31.878 2 3.4759 p < 0.05
Incorporation 0.192 1 0.0419 ns
Animal:Incorp 51.742 2 5.6418 p < 0.01
Residuals 160.49 35
Cabrera et al. (1994) reported emissions from poultry manure obtained in a
laboratory study between 0.002 and 0.028 of the N applied. This complies with the
range found in the present study (0.005–0.014 Ntot).
Nitrous oxide emissions decreased in the order cattle > pigs > poultry with
statistically significant differences among the livestock categories (Table 14). In
general, the effect of incorporation of the manure was not statistically significant.
However, interactions between incorporation and livestock categories occurred.
Incorporation of cattle manure induced a significant reduction of N2O emissions
while the opposite was observed for pig and poultry manure. The results of Webb
et al. (2004) and Thorman et al. (2007) suggest that incorporation does not increase
emissions. In contrast, Gregorich et al. (2005) found greater N2O emissions when
manure was ploughed into the soil in autumn than if it was left on the surface.
4.5 Methane
Literature data on CH4 emissions released from manures following application are
scarce. In the studies reported, emissions of CH4 following application were mea-
sured using closed chambers. The duration of measurement was between 1 and
3 weeks. Methane emissions were reported to occur mainly in the first 2 days after
application of liquid or solid products obtained from screw press separation of cattle
slurry (Fangueiro et al. 2008). It can thus be expected that the duration of measure-
ment of these studies sufficiently reflect total emissions.
Emissions of Ammonia, Nitrous Oxide and Methane During the Management... 99
Table 15 Ammonia emission factors for solid manure used in national inventories, related to TAN
excreted (%). TAN total ammoniacal nitrogen
Model Dairy cattle Beef cattle Finishing pigs Broilers Layers
Switzerland deep litter 18.3 18.3 15.7 20 50
Switzerland, production 18.3 18.3 –a – –
of solid and liquid
manure
Denmark 10.0 36.0 35.7
UK 22.9 22.9 25.0 8.1 19.2
Germany 19.7 28.4 20.0 52.9
Netherlands 16.9 20.0 32.1
Mean 18.9 26.7 28.2 35.0
a
Systems with production of solid and liquid manure produce negligible amount of solid manure in
Switzerland. Therefore, they are not accounted for in the Swiss emission model
In the nine experiments with beef cattle manure, an average CH4 emission of
8 mg m−2 C was measured. While the amount of CH4 released from poultry manure
measured in one study was in a similar range to that for cattle (3 mg m−2 C), emis-
sions from pig farmyard manure were considerably greater (239 mg m−2 C).
Fangueiro et al. (2008) reported CH4 emissions of 55 mg m−2 C from the solid frac-
tion separated cattle slurry measured over 42 days which are comparable with the
present datasets.
Table 15 presents emission factors for NH3-N emissions from buildings housing
livestock used in the different national inventories expressed as the proportion of
TAN excreted. As indicated in the present paper, the emission factors vary considerably,
not only due to variations in NH3-N emission, but also due to variations in the
proportions of TAN excreted. The dataset analysed here did not provide enough
data to calculate emissions based on TAN. From Fig. 2 the mean NH3-N emission
factor for fattening pigs can be calculated as c. 10 g d−1 per pig.This equates to a
mean annual emission factor for fattening pigs of 0.267 N (as indicated by
Table 15).
With respect to the strategy we outlined in the introduction, we conclude that the
empirical data are not sufficient to support a recommendation for emission factors.
When characterising gaseous emissions from the main housing systems, animal
category and litter management are major aspects because these define the composi-
tion of the emitting substance. As can be seen from the results described above,
despite the numerous measurements, the variation is quite large. As far as the data
allow, the differences between the main systems were described. However, while
100 J. Webb et al.
the theoretical implications are clear (Table 1), the quantitative impacts on emis-
sions are not sufficiently defined to parameterize systems. For slurry systems, the
main parameters like air temperature, air velocity, urea concentration, NH3 concen-
tration and pH are known and NH3-N emission can be modelled (Monteny 2000;
Aarnink 1997). The microbial ecosystem in solid manure housing systems and the
quantitative impact on emissions needs more consideration. One of our intentions in
this review was to describe how different approaches to management of solid
manures in buildings and during storage might influence subsequent emissions.
However, it has not been easy to draw firm conclusions from these studies which,
for the most part, were unrelated. Ideally, experiments would make measurements
of gaseous emissions from the same batches of manure within buildings, stores and
following application to land. In this way the impacts of differences among systems
at the earlier stages of manure management on subsequent emissions could be dem-
onstrated unequivocally. However, to carry out such studies in parallel, using repli-
cate buildings and stores, in order to make measurements from different treatments
under the same weather conditions, would be very costly. But, if comparisons are
made in sequence, using the same facilities, adapted for the different manure
management systems, then replication is by time, and temperature, wind speed and
other environmental factors may differ and introduce confounding with the treat-
ments, especially during application, making analysis of the results problematic. It
would also be useful to incorporate N- and TAN-excretion calculations based on
feed intake into measuring protocols. This would enable expression of results in a
form which makes results from different studies easier to compare and also make it
easier to incorporate the data into N- and TAN-flow models. However one must bear
in mind that for an individual batch of manure, the relation between TAN and NH3
emission is also related to the concentration of TAN. If a lot of litter is used, then
even if large amounts of TAN are produced, the concentration of TAN in the manure
may be low, resulting in a little NH3 emission per mass unit of manure.
5.2 Land Application
Acknowledgements The authors wish to acknowledge support from: the Federal Office for the
Environment (Switzerland), Danish Council for Strategic Research (DSF) under the research pro-
gram “Strategic Research in Sustainable Energy and Environment” to the project “Clean and envi-
ronmentally friendly animal waste technologies for fertilizer and energy production (Cleanwaste)”;
the Dutch Ministry of agriculture, nature and food quality. We thank Laura Valli of CRPA (Italy)
and Melynda Hassouna (INRA) for providing data for the study. We also thank Sabine Guesewell
(Swiss College of Agriculture) for the statistical evaluation and Harald Menzi for discussion dur-
ing preparation of the paper.
References
Aarnink AJA (1997) Ammonia emission from houses for growing pigs as affected by pen design,
indoor climate and behaviour. Thesis Wageningen University, IMAG DLO-report 97–03, ISBN
90-5406-151-0, Wageningen, 175 pp
Akiyama H, Tsuruta H (2003) Nitrous oxide, nitric oxide, and nitrogen dioxide fluxes from soils
after manure and urea application. J Environ Qual 32:423–431
Amon B (1999) NH3-, N2O- und CH4-Emissionen aus der Festmistanbindehaltung für Milchvieh
– Stall – Lagerung – Ausbringung. Dissertation. Forschungsbericht Agrartechnik 331.
Universität für Bodenkultur, Institut für Land-, Umwelt und Energietechnik, Wien
Amon B, Amon T, Boxberger J, Alt C (2001) Emissions of NH3, N2O and CH4 from dairy cows
housed in a farmyard manure tying stall (housing, manure storage, manure spreading). Nutr
Cycl Agroecosyst 60:103–113
102 J. Webb et al.
Groot Koerkamp PWG, Kroodsma W (2000) Environmental benefits of the burning of poultry
manure. IMAG report 2000–2004
Hansen MN (2004) Influence of storage of deep litter manure on ammonia loss and uniformity of
mass and nutrient distribution following land spreading. Biosyst Eng 87:99–107
Hansen MN, Henriksen K, Sommer SG (2007) Observations of production and emission of green-
house gases and ammonia during storage of solids separated from pig slurry: effects of covering.
Atmos Environ 40:4172–4181
Hansen RC, Keener HM, Hoitink HAJ (1989) Poultry manure composting. An exploratory study.
Trans ASAE 32:2151–2158
Heil GW, Diemont WH (1983) Raised nutrient levels change heathland into grassland. Vegetation
53:113–120
Hellmann B, Zelles L, Palojärvi A, Bai Q (1997) Emission of climate-relevant trace gases and suc-
cession of microbial communities during open-windrow composting. Appl Environ Microbol
63:1011–1018
Hol JMG (1992) Research on the ammonia emission after application of manure: solid, liquid
manure. DLO Report 34506–42000
Hutchings NJ, Sommer SG, Andersen JM, Asman WAH (2001) A detailed ammonia emission
inventory for Denmark. Atmos Environ 35:1959–1968
Husted S (1994) Seasonal variation in methane emission from stored slurry and solid manures.
J Environ Qual 23:585–592
IPCC (2006) Chapter 11: N2O emissions from managed soils, and CO2 emissions from lime and
urea application. 2006 IPCC guidelines for national greenhouse gas inventories. Volume 4:
Agriculture, forestry and other land use
Karlsson S, Salomon E (2002) Deep litter manure to spring cereals – manure properties and ammo-
nia emissions. Poster presented at the 10th international conference of the FAO European
System of Cooperative Research Networks in Agriculture (ESCORENA) – Recycling of
Agricultural, Municipal and Industrial Residues in Agriculture Network (RAMIRAN), Strbske
Pleso, High Tatras, 14–18 May 2002. Report (paper) in Conference Proceedings
Karlsson S, Jeppson KH (1995) Djupströbädd i stall och mellanlager (Deep litter in livestock
buildings and field storage). JTI Report 204, Swedish Institute of Agricultural Eng., Ultuna
Kemppainen E (1987) Ammonia binding capacity of peat, straw, sawdust and cutter shavings.
Annales Agriculturae Fenniae 26:89–94
Kirchmann H, Lundvall A (1993) Relationship between N immobilization and volatile fatty acids
in soil after application of pig and cattle slurry. Biol Fert Soils 15:161–164
Kirchmann H, Witter E (1989) Ammonia volatilization during aerobic and anaerobic manure
decomposition. Plant Soil 115:35–41
Kosch R (2003) Einfluss der Festmistaufbereitung und –anwendung auf die Stickstoffflüsse im
ökologisch wirtschaftenden Futterbaubetrieb. PhD thesis, Göttinger Agrarwissenschaftliche
Beiträge, Band 12, 108 pp (in German)
Kroodsma W, Scholtens R, Huis J (1988) Ammonia emission from poultry housing systems. In:
Nielsen VC, Voorburg JH, L’Hermite P (eds) Volatile emissions from livestock farming and
sewage operations. Elsevier Applied Science, London/New York, pp 152–161
Kupper T, Bonjour C, Achermann B, Rihm B, Zaucker F, Nyfeler-Brunner A, Leuenberger C,
Menzi H (2010) Ammonia emissions for Switzerland: revised calculation 1990 to 2007.
Previsions until 2020. Report in German with summary in English. Bundesamt für Umwelt
(BAFU), Abteilung Luftreinhaltung und NIS, Sektion Luftqualität, 3003 Bern. pp 79. http://
www.agrammon.ch/documents-to-download/ (Oct 2010)
Laville P, Jambert C, Cellier P, Delmas R (1999) Nitrous oxide fluxes from a fertilised maize crop
using micrometeorological and chamber methods. Agr Forest Meteorol 96:19–38
Loro PJ, Bergstrom DW, Beauchamp EG (1997) Intensity and duration of denitrification following
application of manure and fertilizer to soil. J Environ Qual 26:706–713
Malgeryd J (1996) Åtgärder för att minska ammoniakemissionerna vid spridning av stallgödsel.
JTI-rapport Lantbruk & Industri nr 229, Jordbrukstekniska institutet, Uppsala (in Swedish)
Emissions of Ammonia, Nitrous Oxide and Methane During the Management... 105
Malgeryd J (1998) Technical measures to reduce ammonia losses after spreading of animal manure.
Nutr Cycl Agroecosys 51:51–57
Martins O, Dewes T (1992) Loss of nitrogenous compounds during composting of animal wastes.
Bioresour Technol 42:103–111
Mazzotta V, Bonazzi G, Fabbri C, Valli L (2003) Ammonia and greenhouse gas emission of poul-
try farms: emission factors and reduction techniques. ENEA, Rome, 42 pp (in Italian)
Menzi H, Katz P, Frick R, Fahrni M, Keller M (1997a) Ammonia emissions following the applica-
tion of solid manure to grassland. In: Jarvis SC, Pain BF (eds) Gaseous nitrogen emissions
from grasslands. CAB International, Wallingford, pp 265–274
Menzi H, Keller M, Katz P, Fahrni M, Neftel A (1997b) Ammoniakverluste nach der Anwendung
von Mist. Agrarforschung 4:328–331 (in German)
Misselbrook TH, Nicholson FA, Chambers BJ (2005a) Predicting ammonia losses following the
application of livestock manure to land. Bioresour Technol 96:159–168
Misselbrook TH, Nicholson FA, Chambers BJ, Johnson RA (2005b) Measuring ammonia
emissions from land applied manure: an intercomparison of commonly used samplers and
techniques. Environ Pollut 135:389–397
Monteny GJ (2000) Modelling of ammonia emissions from dairy cow houses. Thesis Wageningen
University, Wageningen 156 pp. ISBN 90-5808-348-9
Mosquera J, Hol JMG, Hofschreuder P (2005a) Gaseous emission from dairy cattle farm (spruits
family). Storage of manure outside the animal house. J. Agrotechnologie and food innovations
report 556
Mosquera J, Hofschreuder P, Hol JMG (2005b) Research on the emission of a natural ventilated
animal house for dairy cattle: storage of manure outside the animal house. Agrotechnologie
and food innovations report 325
Muck RE, Guest RW, Richards BK (1984) Effects of manure storage design on nitrogen conserva-
tion. Agr Wastes 10:205–220
Muck RE, Steenhuis TS (1982) Nitrogen losses from manure storages. Agr Wastes 4:41–54
Mulder EM (1992a) Research on the ammonia emission after application of manure: ammonia
emission after application of deep litter and FYM on bare soil. DLO Report 34506-4100b
Mulder EM (1992b) Research on the ammonia emission after application of manure: ammonia
emission after application of deep litter on grass. DLO Report 34506-4100a
Mulder EM, Hol JMG (1993) Tunnel research on the application of manure: dried chicken manure
and chicken manure chips on bare soil. DLO Report 34506–6800
Mulder EM, Huijsmans JFM (1994) Reduction of ammonia emission after application of manure:
overview measurements DLO 1990–1993. ISSN: 0926–7085
Nicholson FA, Smith KA, Chambers BJ (2002) Defra project WA0712, Management techniques
to minimise ammonia losses during storage and land spreading of poultry manure. Final report
to Defra, London. ADAS Gleadthorpe Research Centre. Mansfield, Notts. NG20 9PF pp 22
Oenema O, Oudendag D, Velthof GL (2007) Nutrient losses from manure management in the
European Union. Livest Sci 112:261–272
Osada T, Sommer SG, Dahl P, Rom HB (2001) Gaseous emission and changes in nutrient compo-
sition during deep litter composting. Acta Agric Scandin Sect B Soil Plant Sci 51:137–142
Pain BF, Phillips VR, Huijsmans JFM, Klarenbeek JV (1991) Anglo-Dutch experiments on odour
and ammonia emissions following the spreading of piggery wastes on arable land. Research
Report 88–2, IMAG, Wageningen, 28 pp
Pape L, Ammann C, Nyfeler-Brunner A, Spirig C, Hens K, Meixner FX (2009) An automated
dynamic chamber system for surface exchange measurement of non-reactive and reactive trace
gases of grassland ecosystems. Biogeosciences 6:405–429
Parkinson R, Gibbs P, Burchett S, Misselbrook T (2004) Effect of turning regime and seasonal
weather conditions on nitrogen and phosphorus losses during aerobic composting of cattle
manure. Bioresour Technol 91:171–178
Petersen SO, Lind AM, Sommer SG (1998) Nitrogen and organic matter losses during storage of
cattle and pig manure. J Agr Sci 130:69–79
106 J. Webb et al.
Petersen SO, Amon B, Gattinger A (2005) Methane oxidation in slurry storage surface crusts.
J Environ Qual 34:455–461
Pitcairn CER, Leith ID, Sheppard LJ, Sutton MA, Fowler D, Munro RC, Tang S, Wilson D (1998)
The relationship between nitrogen deposition, species composition and foliar N concentrations
in woodland flora in the vicinity of intensive livestock farms. Environ Pollut 102(S1):41–48,
Nitrogen Special Issue
Poth M, Focht DD (1985) N-15 kinetic-analysis of N2O production by nitrosomonas-europaea –
and examination of nitrifier denitrification. Appl Environ Microb 49:1134–1141
Poulsen T, Moldrup P (2007) Air permeability of compost as related to bulk density and volumetric
air content. Waste Manag Res 25:343–351
Regione Emilia-Romagna (2004) Best available techniques for the reduction of the emissions from
livestock production. Final technical report (in Italian)
Regione Emilia-Romagna (2006) Poultry farms for meat production: emissions prevention and
reduction with respect of animal welfare. Final technical report (in Italian)
Regione Emilia-Romagna (2007) Innovative techniques for measurements and Best Available
Techniques (BAT) for the reduction of the emissions in the livestock farms. Final technical
report (in Italian)
Reidy B, Dämmgen U, Döhler H, Eurich-Menden B, van Evert FK, Hutchings NJ, Luesink HH,
Menzi H, Misselbrook TH, Monteny G-J, Webb J (2007) Comparison of models used for
national agricultural ammonia emission inventories in Europe: liquid manure systems. Atmos
Environ 42:3452–3464
Reidy B, Rhim B, Menzi H (2008) A new Swiss inventory of ammonia emissions from agriculture
based on a survey on farm and manure management and farm-specific model calculations.
Atmos Environ 42:3266–3276
Reidy B, Webb J, Monteny G-J, Misselbrook TH, Menzi H, Luesink HH, Hutchings NJ, Eurich-
Menden B, Döhler H, Dämmgen U (2009) Comparison of models used for national agricultural
ammonia emission inventories in Europe: litter-based manure systems. Atmos Environ
43:1632–1640
Renard JJ, Calidonna SE, Henley MV (2004) Fate of ammonia in the atmosphere – a review for
applicability to hazardous releases. J Hazard Mater 108:29–60
Rochette P, Angers DA, Chantigny MH, Gagnon B, Bertrand N (2008) N2O fluxes in soils of
contrasting textures fertilized with liquid and solid dairy cattle manures. Can J Soil Sci
88:175–187
Rohde L, Karlsson S (2002) Ammonia emissions from broiler manure – influence of storage and
spreading method. Biosyst Eng 82:455–462
Rodhe L, Salomon E, Rammer C (1996) Spreading of farmyard manure to ley with different meth-
ods. Yield and silage quality. Swed J Agr Res 26:43–51
Sagoo E, Williams JR, Chambers BJ, Chadwick DR (2006) Defra project WA0716, management
techniques to minimise ammonia emissions from solid manures. Final report to Defra, London.
ADAS Gleadthorpe Research Centre. Mansfield, Notts. NG20 9PF pp 35
Sagoo E, Williams JR, Chambers BJ, Boyles LO, Matthews R, Chadwick DR (2007) Integrated
management practices to minimise losses and maximise the crop nitrogen value of broiler litter.
Biosyst Eng 97:512–519
Sannö J-O, Cederberg C, Gustafsson G, Hultgren J, Jeppsson K-H, Nadeau E (2003) LIFE ammo-
nia. Sustainable milk production through reduction of on-farm ammonia losses. Report no. 5,
Department of Animal Environment and Health, Swedish University of agricultural Sciences
(In Swedish, English summary)
Shah SB, Westerman PW, Arogo J (2006) Measuring ammonia concentrations and emissions from
agricultural land and liquid surfaces: a review. J Air Waste Manag Assoc 56:945–960
Smith KA, Ball T, Conen F, Dobbie KE, Massheder J, Rey A (2003) Exchange of greenhouse
gases between soil and atmosphere: interactions of soil physical factors and biological pro-
cesses. Eur J Soil Sci 54:779–791
Sommer SG (2001) Effect of composting on nutrient loss and nitrogen availability of cattle deep
litter. Eur J Agron 14:123–133
Emissions of Ammonia, Nitrous Oxide and Methane During the Management... 107
Sommer SG, Christensen BT (1990) NH3 emission from solid manure and raw, fermented and
separated slurry after surface application, injection, incorporation into the soil and irrigation.
Tidsskr Planteavl 94:407–417 (in Danish)
Sommer SG, Dahl P (1999) Emission of ammonia, nitrous oxide, methane and carbon dioxide
during composting of deep litter. J Agr Eng 74:145–153
Sommer SG, Hutchings NJ (2001) Ammonia emission from field applied manure and its reduc-
tion—invited paper. Eur J Agron 15:1–15
Sommer S-G, Møller HB (2000) Emission of greenhouse gases during composting of deep litter
from pig production - effect of straw content. J Agr Sci 134:327–335
Sommer SG, Zhang GQ, Bannink A, Chadwick D, Hutchings NJ, Misselbrook T, Menzi H, Ji-Qin
N, Oenema O, Webb J, Monteny G-J (2006) Algorithms determining ammonia emission from
livestock houses and manure stores. Adv Agron 89:261–335
Svensson L (1994) A new dynamic chamber technique for measuring ammonia emissions from
land-spread manure and fertilizers. Act Agric Scand Sec B – Plant Soil Sci 44:35–46
Szanto GL, Hamelers HVM, Rulkens WH, Veeken AHM (2007) NH3, N2O and CH4 emissions
during passively aerated composting of straw-rich pig manure. Bioresour Technol
98:2659–2670
Tam NFY, Tiquia SM (1999) Nitrogen transformation during co-composting of spent pig manure,
sawdust litter and sludge under forced-aerated system. Environ Technol 20:259–267
Thomsen IK, Olesen JE (2000) C and N mineralization of composted and anaerobically stored
ruminant manure in differently textured soils. J Agr Sci 135:151–159
Thorman RE, Chadwick DR, Harrison R, Boyles LO, Matthews R (2007) The effect on N2O emis-
sions of storage conditions and rapid incorporation of pig and cattle farmyard manure into
tillage land. Biosyst Eng 97:501–511
UNECE (1999) Protocol to the 1979 convention on long-range transboundary air pollution to abate
acidification, eutrophication and ground-level ozone. United Nations Economic Commission
for Europe (UNECE), Geneva
Van Evert F, van der Meer H, Berge H, Rutgers B, Schut T, Ketelaars J (2003) FARMMIN: modeling
crop-livestock nutrient flows. Agron. Abstr. 2003, ASA/CSSA/SSSA, Madison
Vavilin VA, Lokshina LY, Rytov SV, Kotsyurbenko OR, Nozhevnikova AN (1998) Modelling low-
temperature methane production from cattle manure by an acclimated microbial community.
Bioresour Technol 63:159–171
Veeken AHM, de Wilde V, Szanto G, Hamelers HVM (2002) Passively aerated composting of
straw-rich organic pig manure. In: Insam H, Riddech N (eds) Microbiology of composting.
Springer, Berlin, pp 607–621
Webb J, Anthony S, Yamulki S (2006) Validating the Mavis model for optimizing incorporation
of litter-based manures to reduce ammonia emissions. Trans Am Soc Agr Biol Eng
49:1905–1913
Webb J, Misselbrook TH (2004) A mass-flow model of ammonia emissions from UK livestock
production. Atmos Environ 38:2163–2176
Webb J, Chadwick D, Ellis S (2004) Emissions of ammonia and nitrous oxide following incorporation
into the soil of farmyard manures stored at different densities. Nutr Cycl Agroecosyst
70:67–76
Williams JR, Chambers BJ, Chadwick DR, Balsdon SL (2003) Defra project WA0632, Ammonia
fluxes within solid and liquid manure management systems. Final report to Defra, London.
ADAS Gleadthorpe Research Centre. Mansfield, Notts. NG20 9PF, pp 33
Witter E, Lopez-Real J (1988) Nitrogen losses during the composting of sewage sludges, and the
effectiveness of clay soil, zeolite, and compost in adsorbing the volatilized ammonia. Biol
Wastes 23:279–294
Wulf S, Maeting M, Clemens J (2002) Application technique and slurry co-fermentation effects on
ammonia, nitrous oxide, and methane emissions after spreading: II. Greenhouse gas emissions.
J Environ Qual 31:1795–1801
Yamulki S (2006) Effect of straw addition on nitrous oxide and methane emissions from stored
farmyard manures. Agr Ecosyst Environ 112:140–145
Communication in the Rhizosphere, a Target
for Pest Management
Abstract The industrial agriculture has given rise to an excessive use and misuse
of agrochemicals causing environmental pollution. Therefore, it is urgent to find
alternatives that are more environmentally friendly than chemical fertilizers and
pesticides for disease control. The key to achieve successful biological control strat-
egies is the knowledge of the ecological interactions that occur belowground. The
rhizosphere constitutes a very dynamic environment harbouring the plant roots and
many organisms. Plants communicate and interact with those organisms through the
production and release of a large variety of secondary metabolites into the rhizo-
sphere. Thus, they use these metabolites to defend themselves against soil-borne
pathogens, which can adversely affect plant growth and fitness, but also to establish
mutualistic associations with beneficial soil microorganisms. However, despite the
importance of these plant-organism interactions the mechanisms regulating them
remain largely unknown.
We review here chemical communication that takes place in the rhizosphere
between plants and other soil organisms, and the potential use of this molecular
dialogue for developing new biological control strategies against deleterious organ-
isms. We focus on the knowledge of the root parasitic weed germination stimulants –
strigolactones – to develop more efficient control methods against this pest.
Finally, we illustrate this with an exciting example: the use of the mutualistic
arbuscular mycorrhizal symbiosis for controlling root parasitic weeds by reducing
the production of strigolactones in the host plant.
Abbreviations
AM arbuscular mycorrhiza
AHL N-acyl homoserine lactone
PGPF plant growth promoting fungi
PGPR plant growth promoting rhizobacteria
QS Quorum sensing
1 Introduction
Plants are living organisms that continuous and reciprocally communicate with
other organisms in their environment. However, unlike animals plants cannot
speak, see, listen or run away, and therefore they largely rely on chemicals as sig-
nalling molecules to perceive environmental changes and survive. Thus, plants use
flower colour and volatiles to attract pollinators, use chemicals to defend them-
selves against enemies such as pathogens and herbivores, but they also use signal-
ling molecules to establish mutualistic beneficial associations with certain
microorganisms such as bacteria and fungi (Fig. 1). Microorganisms can affect
plant growth and development, change nutrients dynamics, susceptibility to dis-
ease, tolerance to heavy metals, and can help plants in the degradation of xenobiot-
ics (Morgan et al. 2005). As a result, these plant-microorganism interactions have
considerable potential for biotechnological exploitation. A nice example of this
complex and precisely regulated signalling takes place underground, where plants
use the roots to communicate and interact with other organisms in the so-called
rhizosphere.
The term rhizosphere derives from the Greek words rhiza, which means root, and
sphere, meaning field of influence (Morgan et al. 2005). The rhizosphere is the nar-
row soil zone surrounding plant roots that contains a wide range of organisms and
is highly influenced by the roots, the root exudates and by local edaphic factors
(Bais et al. 2006; Badri et al. 2009). Originally, the root system was thought only to
provide anchorage and uptake of nutrients and water. However, it has been shown
that roots are chemical factories that mediates numerous underground interactions
Communication in the Rhizosphere, a Target for Pest Management 111
Fig. 1 Plant interactions with other organisms. Positive and negative interactions occurring
aboveground and belowground in the rhizosphere. Yellow arrows indicate root exudates (Adapted
from Pozo and Azcón-Aguilar 2007)
(Badri et al. 2009). Plants produce and exude through the roots a large variety of
chemicals including sugars, amino acids, fatty acids, enzymes, plant growth regulators
and secondary metabolites into the rhizosphere some of which are used to commu-
nicate with their environment (Siegler 1998; Bertin et al. 2003; Bais et al. 2006).
Moreover, the release of root exudates together with decaying plant material provides
carbon sources for the heterotrophic soil biota. On the other hand, microbial activity
in the rhizosphere affects rooting patterns and the supply of available nutrients to
plants, thereby modifying the quantity and quality of root exudates (Barea et al.
2005). Of special interest in this rhizosphere communication are the so-called
secondary metabolites, which received this name because of their presumed secondary
importance in plant growth and survival (Siegler 1998). These metabolites include
compounds from different biosynthetic origins and have been shown to be of eco-
logical significance because they are important signals in several mutualistic and
pathogenic plant-organism interactions (Estabrook and Yoder 1998; Siegler 1998;
Bertin et al. 2003; Bais et al. 2006).
112 J.A. López-Ráez et al.
In the rhizosphere some of the most complex chemical, physical and biological
interactions between plant roots and other organisms occur influencing plant fitness.
Among these relationships we can find root-root, root-microbe and root-insect
interactions. Many of these interactions have a neutral effect on the plant. However,
the rhizosphere is also a playground for beneficial microorganisms establishing
mutualistic associations with plants, and a battlefield for soil-borne pathogens which
establish parasitic interactions (Raaijmakers et al. 2009).
2.1 Parasitic Interactions
As mentioned above, the rhizosphere is not only the playground for mutualistic
associations, but also a battlefield where parasitic interactions between plants and
soil-borne pathogens take place (Raaijmakers et al. 2009). In most agricultural eco-
systems, these negative interactions are economically important as they cause
important limitations in the production of marketable yield. It has long been under-
stood that the development of disease symptoms is not solely determined by the
pathogen responsible, but is also dependent on the complex interrelationship
between host, pathogen and prevailing environmental conditions. Negative interactions
with plant roots include pathogenesis by bacteria, true fungi or oomycetes, inverte-
brate herbivory and parasitism between plants (Agrios 2005; Bais et al. 2006).
Among them, fungi and oomycetes, nematodes and parasitic plants are major players
in the rhizosphere exerting a serious threat to world agricultural production.
Comparatively, fewer bacteria are considered as soil-borne plant pathogens, with
some exceptions such as Ralstonia solanacearum (causing bacterial wilt of tomato),
the enteric phytopathogen Erwinia carotovora, responsible of the bacterial soft rot,
and Agrobacterium tumefaciens, the causal agent of crown gall disease (Hirsch
et al. 2003; Genin and Boucher 2004; Badri et al. 2009).
pathogenic fungi include the genera Fusarium spp, Verticillium spp and Rhizoctonia
solani, which affect crops such as barley, wheat, maize, potato and tomato all over
the world (Priest and Campbell 2003; Garcia et al. 2006).
The oomycetes include a unique group of biotrophic and hemibiotrophic plant
pathogens that gain their nutrients from living cells, and are considered as non-
true fungi. Indeed, although they are physiologically and morphologically simi-
lar to fungi they belong to different phylogenetical groups. The oomycetes are
phylogenetically more closely related to brown algae than to fungi and, in contrast
to fungi, they contain cellulose in their cell wall instead of chitin (Raaijmakers
et al. 2009). However, despite being only distantly related to fungi, the oomy-
cetes have developed very similar infection strategies. These pathogens estab-
lish intimate relations with their hosts by forming an organ called haustorium,
which is used to obtain nutrients from the plant, redirecting host metabolism
and suppressing host defences. The oomycetes include some of the most destruc-
tive plant pathogens worldwide, particularly in the genera Phytophthora and
Phytium, that affect important crops such as potato, tomato, lettuce and soybean
(Raaijmakers et al. 2009).
2.1.2 Nematodes
Nematodes are small and complex worm-like eukaryotic invertebrates that rank
among the most numerous animals on the planet (Perry and Moens 2006). Most
nematodes in soil are free-living and consume bacteria, fungi and other nematodes,
but some can also parasitize plant roots being important crop pests in agricultural
ecosystems. Some feed on the outside of the root (ectoparasites), some penetrate
and move inside the root (endoparasites), and some set up a feeding site in the inte-
rior of the root and remain there for reproduction (sedentary endoparasites). Upon
infection, nematodes cause important changes in root cells in order to complete
their life cycle. Although the parasitism is rarely fatal for the infected plant, there
are substantial consequences of the interaction such as stunted growth, chlorosis and
poor yields. The most economically important groups of nematodes are the seden-
tary endoparasites, which include the genera Meloidogyne (root-knot nematodes)
and Heterodera and Globodera (cyst nematodes). They are particularly important
in tropical and subtropical regions (Bird and Kaloshian 2003; Williamson and
Gleason 2003).
Root-knot nematodes are obligate biotrophic pathogens found in all temperate
and tropical areas that have evolved strategies for infesting thousands of plant species
such as cereals, tomato, potato and tobacco (Caillaud et al. 2008). These root patho-
gens must locate and penetrate a root, migrate into the vascular cylinder and estab-
lish a permanent feeding site, known as giant cells. Unlike root-knot nematodes,
cyst nematodes are only able to infect a few plant species, principally soybean and
potato, and are more destructive as they migrate and travel intracellularly through
the root (Fuller et al. 2008). In both cases, these events are accompanied by exten-
sive signalling between the nematode and the host.
114 J.A. López-Ráez et al.
Parasitic plant
Strigolactone
O O O O O O O O O O
O O O O O O O O O O O O O O
O O O O O O O O O O O O O O O O O O O O O
O O O O O O O O O O O O O O O O O O O O O O O O O O O O
O O O
O O O O O O O O O
O O O O O O O O O O O O O O O O O O O O O O O O O
O O
O O
O O O O O O O O O O O O O O O O O
O O O O O O O O O
O O O
O O O O O O O O O O O O
O O O O O O O O O O
O O O O O O O O
O O O O O O O O O O O O O O O
O O O O O O O O O O O O
Fig. 2 Life cycle of root parasitic plants. (a) Seeds are buried in the soil and perceive the germination
stimulants exuded by the roots of the host plant, strigolactones, and germinate. (b) The germinated
seeds form a haustorium by which they attach to the host root, establishing a xylem-xylem connection.
(c) The parasitic plant develops, and the shoots emerge from the soil. There is areduction of host
growth. (d) Parasitic plant flowering and crop yield reduction. (e) Production of mature seeds that
end up in a new generation of seeds in the soil (Redrawn from Sun et al. 2007)
Root parasitic plants of the family Orobancheaceae, including the Striga, Orobanche
and Phelipanche genera are some of the most damaging agricultural pests, causing
large crop losses. These obligate root parasites attach to the roots of many plant spe-
cies and acquire nutrients and water from their host through a specialized organ
called haustorium (Estabrook and Yoder 1998; Bouwmeester et al. 2003). Striga is
a hemiparasite, which means that it obtains nutrients from its host but it can also
perform its own photosynthesis. It infects important crops such as maize, sorghum,
pearl millet, finger millet and upland rice, causing devastating losses in cereal yields
in Africa (Gressel et al. 2004). On the other hand, the holoparasitic (lacking chloro-
phyll and being completely dependent on their host) Orobanche and Phelipanche
spp. affect important agricultural crops in more temperate climates such as southern
Europe, Central Asia and the Mediterranean area parasitizing legumes, tobacco,
crucifers, sunflower and tomato (Joel et al. 2007).
Although root parasitic plants parasitize different hosts in different parts of the
world, their lifecycles are very similar and involve germination in response to a root
host stimulus, radicle growth towards the host root, and attachment and penetration
through the haustorium (Fig. 2). Upon vascular connection, the parasitic plant
obtains nutrients and water from the host plant, negatively affecting plant fitness and
crop yield. After emergence from the soil, parasitic plants will flower and produce
new ripe seeds that are shattered increasing the seed bank (Fig. 2) (Bouwmeester
et al. 2003; López-Ráez et al. 2009). Parasitic weeds are difficult to control
because most of their life cycle occurs underground and therefore new control strat-
egies that focus on the initial steps in the host-parasite interaction are required
(López-Ráez et al. 2009).
Communication in the Rhizosphere, a Target for Pest Management 115
The rhizosphere generally helps the plant by maintaining the recycling of nutrients,
providing resistance to diseases and to improve tolerance to toxic compounds. When
plants lack essential mineral elements, such as phosphorous or nitrogen, symbiotic
relationships can be beneficial and promote plant growth. Thus, plants biologically
interact with other organisms to establish mutualistic associations which rely on a
mutual fitness benefit. Mutualism is very ancient, indeed is thought to have driven
the evolution of much of the biological diversity present today (Thompson 2005).
In addition, mutualism plays a key role in ecology being very important for the
correct functioning of the terrestrial ecosystem. Microorganisms that positively
affect plant growth and health include the plant growth-promoting rhizobacteria
(PGPR) and plant growth-promoting fungi (PGPF), the nitrogen-fixing Rhizobium
bacteria (rhizobia), and the mycorrhizal fungi (mycorrhiza). The PGPR are non-
symbiotic beneficial rhizosphere bacteria that are known to participate in many
important ecosystem processes, such as nitrogen fixation, nutrient cycling, seedling
growth, phytohormone production, and biological control of plant pathogens (Barea
et al. 2005; Raaijmakers et al. 2009). The most commonly genera described as including
PGPR are Pseudomonas and Bacillus. The PGPF include rhizospheric non-symbiotic
beneficial fungi from the Deuteromycetes, e.g. Trichoderma, Gliocladium and non-
pathogenic Fusarium oxysporum (Raaijmakers et al. 2009). These ubiquitous soil
fungi are effective in controlling a broad range of phytopathogenic fungi by competi-
tion, antibiosis and mycoparasitism (Raaijmakers et al. 2009).
Other beneficial microorganisms, the endophytes, establish mutualistic symbio-
sis with plants by colonizing the root tissues and promote plant growth and plant
protection (Barea et al. 2005). Although new endophytic microbes which colonize
roots and promote plant growth are being found such as the fungus Piriformospora
indica (Varma et al. 1999), the best studied examples of rhizosphere mutualism are
those established with rhizobia bacteria and mycorrhizal fungi.
2.2.1 Rhizobia
Rhizobia are free-living soil bacteria which colonize plant roots (endosymbionts)
establishing a mutualistic relationship with most of the plant legume species world-
wide (Sprent 2009). The two partners cooperate in a nitrogen-fixing symbiosis of
major ecological importance because in many environments nitrogen limits plant
growth (Masson-Boivin et al. 2009). Legume-rhizobia symbiosis is a classic exam-
ple of mutualism, where rhizobia supply ammonia (NH4+) or amino acids to the
plant and in return receive organic acids (principally malate and succinate) as a
carbon and energy source, proteins and sufficient oxygen to facilitate the fixation
process (Fig. 3a). Fixed nitrogen is a limiting nutrient in most environments, with
the main reserve of nitrogen in the biosphere being the molecular nitrogen in the
atmosphere. Molecular nitrogen cannot be directly assimilated by plants, but it
116 J.A. López-Ráez et al.
Rhizobia Flavonoid
Nodule
. . .
. . . . . . . . .
. .
. . . . . . . .
Nod factor
1 2 3
Strigolactone Mycelium
O O . O O
O O
O O
OO O O O OO O O O O O O O
O O OO O O O OO O
. . . .
. OO O . OO O . OO O . OO O
OO O OO O
O O O O O O O O O O O O O O O O
. . . .
OO O OO O OO O OO O OO O OO O OO O OO O
O O . O O . . .
. . . . . . . .
OO O OO O
1 2 3 4
becomes available through the biological nitrogen fixation process that only some
prokaryotic cells (diazotrophs), including rhizobia, have developed (Masson-Boivin
et al. 2009).
In rhizobial plants, nitrogen fixation takes place in special organs known as
nodules. On the roots of host plants, principally in the root hairs, rhizobia colonize
Communication in the Rhizosphere, a Target for Pest Management 117
2.2.2 Mycorrhiza
some mycorrhizal fungi can access forms of nitrogen and phosphorous that are not
available to non-mycorrhizal plants, for example when bound in organic forms
(Morgan et al. 2005). Thus, AM symbiosis contributes to global phosphate and
carbon cycling and influences primary productivity in terrestrial ecosystems (Fitter
2005). Besides improving the nutritional status, the symbiosis enables the plant to
perform better under stressful conditions (Pozo and Azcón-Aguilar 2007; Parniske
2008). Therefore, AM symbiosis plays a crucial role in agriculture and natural
ecosystems.
In summary, the rhizosphere is an environment influenced by the plant root
exudates where both pathogenic and beneficial interactions between plant and other
organisms constitute a major influential force on plant growth and fitness, soil quality
and ecosystem dynamics.
All the different interactions reported above are based on molecular communica-
tion occurring belowground. Plants produce and release enormous amounts of
chemicals into the rhizosphere through their roots in order to communicate and
interact with their environment. Root exudates can be divided into two classes of
compounds: high-molecular weight such as polysaccharides and proteins, and low-
molecular weight compounds including amino acids, organic acids, sugars, pheno-
lics, and other secondary metabolites (Bais et al. 2006). Although the functions of
most of the compounds present in root exudates have not been determined so far, it
has been determined that several of them are essential to establish plant interac-
tions with other organisms in the rhizosphere. Equally, chemical signals secreted
by the rhizospheric organisms are also involved in early steps of host recognition
and colonization, and necessary for the establishment of the association. These
signalling molecules are important in both negative and positive interactions (Bais
et al. 2006).
3.2.1 Communication in Nodulation
fungi hyphal growth, differentiation and root colonization (Steinkellner et al. 2007).
Besides flavonoids, the strigolactones, a recently described new class of plant
hormones regulating plant architecture (Gomez-Roldan et al. 2008; Umehara et al.
2008; Koltai et al. 2010; Ruyter-Spira et al. 2011), have been shown to be crucial for
a successful root colonization by the AM fungi (Akiyama et al. 2005). Interestingly,
strigolactones are present in the root exudates of a wide range of plants and trigger
a response only in AM fungi, not in other beneficial fungal species such as
Trichoderma and Piriformospora (Steinkellner et al. 2007).
AM fungi depend entirely on their plant host to complete their life cycle (Fig. 3b).
As for the rhizobia-legume association, AM symbiosis establishment and function-
ing also require a high degree of coordination between the two partners (Paszkowski
2006; Hause et al. 2007; Requena et al. 2007). The AM fungi-plant host molecular
dialogue starts in the rhizosphere with the production of strigolactones by the host
plant that induce hyphal branching in germinating spores of AM fungi (Akiyama
et al. 2005; Besserer et al. 2006; Parniske 2008). Spores of AM fungi can germinate
spontaneously and undergo an initial asymbiotic stage of hyphal germ tube growth,
which is limited by the amount of carbon storage in the spore. If a partner is nearby,
the hyphal germ tube grows and ramifies intensively through the soil towards the
host root (Bouwmeester et al. 2007). It has been suggested that these signalling
molecules, later known as strigolactones, may also act as the chemoattractant that
directs the growth of the AM hyphae to the roots (Sbrana and Giovannetti 2005).
Once the host-derived strigolactones are perceived by the fungus, it engages its
catabolic metabolism which results in hyphal branching that will increase the prob-
ability to contact the root and establish symbiosis. Similarly to the nodulation
process, it has been proposed that a Myc factor analogous to the rhizobial Nod factor
and produced by the metabolic active fungus, induces molecular responses in the
host root required for a successful AM fungal colonization (Fig. 3b) (Kosuta et al.
2003; Bucher et al. 2009). The chemical nature of the elusive Myc factor, has
remained unknown for a long time. However, it has been recently shown to have
structural similarities with rhizobial Nod factors (Maillet et al. 2011).
Despite the importance of strigolactones in the initiation of AM symbiosis, it is
unknown whether they also play a role in subsequent steps of the symbiosis. Since
strigolactones are considered plant hormones and are ubiquitous in plants, it is
tempting to speculate about their involvement in other plant-microorganism interac-
tions in the rhizosphere. Indeed, it has been recently shown that strigolactones
positively affect nodulation, although their effect was not due to an effect on the
bacteria (Soto et al. 2010). Probably, this just represent the tip of the iceberg of
biological roles for the strigolactones, showing the biological and ecological importance
of these signalling compounds.
Thus, plants form associations – either beneficial or detrimental – with other
organisms in the rhizosphere. Interestingly, most of these interactions are facilitated
by a molecular dialogue between the host and the symbionts through chemical cues,
which are crucial for the establishment of these belowground associations. However,
although some of these signalling molecules have been identified there are still
many other unknown factors involved.
122 J.A. López-Ráez et al.
Strigolactones have been recognized as a new class of plant hormones that inhibits
shoot branching and hence controls above ground architecture (Gomez-Roldan
et al. 2008; Umehara et al. 2008). More recently, it has been suggested that they
also affect root growth and root hair elongation (Koltai et al. 2010; Ruyter-
Spira et al. 2011), which shows they are even more important components in the
Communication in the Rhizosphere, a Target for Pest Management 123
r egulation of plant architecture than already postulated. Long before the discovery of
their function as plant hormones, the strigolactones were described as germination
stimulants for the seeds of root parasitic plants Striga, Orobanche and Phelipanche
spp (Cook et al. 1972; Bouwmeester et al. 2003) (see Sect. 2.1.3). They are pro-
duced and exuded into the rhizosphere by plants in very low amounts, can stimulate
the germination of these parasitic plants in nano- and pico-molar concentrations,
and are instable in a watery environment and in alkaline soils (Bouwmeester et al.
2007; Yoneyama et al. 2009; Zwanenburg et al. 2009). Strigolactones are derived
from the carotenoids (Matusova et al. 2005; López-Ráez et al. 2008a) and all the
strigolactones characterized so far are remarkably similar, showing a similar chemical
structure (Fig. 4) (Rani et al. 2008; Yoneyama et al. 2009; Zwanenburg et al. 2009).
The structural core of the molecules consists of a tricyclic lactone (the ABC-rings)
connected via an enol ether bridge to a butyrolactone group (the D-ring). It has been
suggested that the biological activity of the strigolactones resides in the enol ether
bridge, which can be rapidly cleavage in an aqueous and/or alkaline environment
(Yoneyama et al. 2009; Zwanenburg et al. 2009; Akiyama et al. 2010).
An intriguing question was why plants would produce compounds that have such
negative consequences (parasitiation by parasitic plants) for the plants themselves.
The answer to this question came only few years ago when Akiyama and co-workers
demonstrated that these secondary metabolites are involved in signalling between
plants and mutualistic AM fungi (Akiyama et al. 2005). We now know that under
nutrient deficient conditions plants increase the production of strigolactones to
attract AM fungi and establish a mutualistic relationship, but the parasitic weeds
have evolved a mechanism by which they can abuse this ‘cry for help’ plant signal
to establish a negative interaction (Bouwmeester et al. 2007) (Fig. 4). The ability to
develop AM symbiosis is of great advantage to plants and this, therefore, likely
explains why strigolactones are secreted by plants despite the possibility of being
abused by root parasitic plants.
Again, a better understanding about how strigolactone signalling is regulated and
the possible specificity of different strigolactones seems crucial to further evaluate
their importance in the plant-parasitic plant and plant-AM fungus interactions and
favor one against another.
As mentioned in Sect. 2.1.3, root parasitic plants are a serious threat to agriculture
causing enormous crop losses worldwide. One of the reasons of their devastating
effect is that these parasitic weeds are difficult to control because most of their life-
cycle occurs underground (Fig. 2). This fact makes the diagnosis of infection diffi-
cult and normally only after irreversible damage has already been caused to the
crop. To date, a wide number of approaches such as hand weeding, crop rotation,
sanitation, fumigation, solarization and improvement of soil fertility are being used
to control root parasites without the desirable success (Joel et al. 2007; Rispail et al.
124 J.A. López-Ráez et al.
O O
C
A B
O O O
OH D
AM fungi Orobancheaceae
MUTUALISTIC INTERACTION PARASITIC INTERACTION
Fig. 4 Underground communication between plants, arbuscular mycorrhizal (AM) fungi and
parasitic plants. Plants produce and release strigolactones into the rhizosphere to communicate
with AM fungi in order to establish a mutualistic association. As a response, AM fungi release the
so-called Myc factors which are recognized by the host plant. However, strigolactones can be
abused by root parasitic plants of the family Orobancheaceae as an indicator of host presence,
resulting in seed germination and establishment of a parasitic interaction. Similarly to the AM
signal (Myc factor), it has been suggested that, in response to the strigolactones, the germinating
parasitic seeds would produce Par factors (Modified from Bouwmeester et al. 2007)
2007; Scholes and Press 2008), and the most efficient control method – fumigation –
is environmentally hazardous. Therefore, new methods for a more effective control
against these agricultural pests are required. Since the root parasites affect their host
from the moment they attach and exert the greatest damage prior to emergence (Joel
et al. 2007; Scholes and Press 2008), the development of more effective control
strategies should focus on the initial steps in the host-parasite interaction. Particularly
on the germination of the parasitic weed seed stage, which is trigged by the strigolac-
tones (Sun et al. 2007; López-Ráez et al. 2009). In this sense, two general approaches
to control root parasitic plants may be envisaged: through enhanced or reduced seed
germination.
Communication in the Rhizosphere, a Target for Pest Management 125
This strategy consists in the use of non-host plant species that produce germination
stimulants – strigolactones -, inducing suicidal germination of the parasite’ seeds.
Once germinated, the seeds cannot survive without a suitable host, hence causing a
reduction in the parasite seed bank (Zwanenburg et al. 2009). These trap and catch
crops can be resistant in a later stage of the parasite lifecycle – trap crops – or
harvested before the seeds of the parasite are shed – catch crops – (Bouwmeester
et al. 2003; Sun et al. 2007). The effectiveness of catch and trap crops could be
increased by the selection of cultivars overproducing germination stimulants (breeding)
or through molecular engineering of such overproduction. The latter can potentially
be achieved by overexpression of the rate-limiting enzymes from the strigolactone
biosynthetic pathway such as CCD7 or CCD8. In addition to the suicidal germination
induced by these catch and trap crops with enhanced production of strigolactones,
they could favour arbuscular mycorrhizal colonization in the host plant, with the
corresponding benefits on plant growth, fitness and yield.
An alternative strategy to controlling root parasitic plant infestation through the induc-
tion of suicidal germination is the use of synthetic germination stimulants. In this
sense, the application at very low concentrations of the strigolactone analogues GR24,
GR7 and Nijmegen-1 to Striga-infested soils resulted in reduction in the seed popula-
tion (Johnson et al. 1976; Wigchert et al. 1999). However, one of the limitations of this
approach is that these synthetic germination stimulants are rather unstable in the soil.
Therefore, more stable compounds or suitable formulations should be developed in
order to overcome these stability problems and increase their effectiveness.
Another approach to avoid root parasitic weed infection is based on the opposite
strategy, aimed at reducing seed germination. However, since strigolactones are also
AM hyphal branching factors and are involved in plant architecture, the conse-
quences for the AM fungal community in the soil and possible unwanted side-effects
on plant architecture should be carefully evaluated before following this approach.
6.2.1 Soil Fertilization
6.2.2 Chemical Inhibitors
Strigolactones are derived from the carotenoids (Matusova et al. 2005; López-Ráez
et al. 2008a). Therefore, herbicides that inhibit carotenoid biosynthesis such as
fluridone, norflurazon, clomazone and amitrole could be used in very low concen-
trations as a tool to reduce strigolactone production and ultimately parasitic seed
infection (López-Ráez et al. 2009; Jamil et al. 2010). Indeed, it was observed that
application of these inhibitors at concentrations that do not cause chlorophyll
bleaching to maize, sorghum, cowpea, rice and tomato strongly reduces strigolac-
tone production and in vitro germination of Striga hermonthica and Phelipanche
ramosa seeds by the exudates of the treated plants (Matusova et al. 2005; López-
Ráez et al. 2008a; Jamil et al. 2010). These results show that treatments with such
herbicides may be an effective and relatively cheap method to reduce parasitic
weed infestation in the field either alone or in combination with other control
strategies.
6.2.4 Genetic Engineering
Molecular biology techniques targeting one or more of the rate-limiting genes from
the strigolactone biosynthetic pathway could be another approach to reduce strigolac-
tone biosynthesis. Indeed, ccd7 and ccd8 mutants of several plant species show a
reduced production of strigolactones (Gomez-Roldan et al. 2008; Umehara et al.
2008). Moreover, genetic engineering using RNAi technology on CCD7 and CCD8
genes induced a significant reduction on strigolactones in tomato, which correlated
with a reduction in the germinating activity of P. ramosa seeds (Vogel et al. 2010;
Kohlen, López-Ráez and Bouwmeester, unpublished). Therefore, molecular engi-
neering may be an important and efficient component of a long-term strategy for
parasitic weed control. However, further research is required to completely charac-
terize the biosynthetic pathway of strigolactones in order to select appropriate target
genes with temporal or inducible promoters.
The fact that the strigolactones play a dual role in the rhizosphere as signalling mol-
ecules for both AM fungi and root parasitic plants (Fig. 4), and that AM symbiosis
greatly benefits plant fitness make the strigolactones a suitable candidate to develop
environmentally friendly biological control methods against parasitic weeds. Indeed,
it was shown that AM fungal inoculation of maize and sorghum led to a reduction
in Striga hermonthica infection in the field (Lendzemo et al. 2005), and it was pro-
posed that this reduced infection was caused, at least partially, by a reduction in the
production of strigolactones in the mycorrhizal plants (Lendzemo et al. 2007; Sun
et al. 2008) (Fig. 5). A similar effect was observed in pea, where AM colonization
reduced seed germination of Orobanche and Phelipanche species (Fernández-
Aparicio et al. 2010). We have recently shown that AM symbiosis in tomato also
leads to a reduction in the germination stimulatory activity of tomato exudates for
seeds of the parasite P. ramosa, and have analytically demonstrated that this reduction
is caused by a reduction in the production of strigolactones (López-Ráez et al.
2011). Moreover, we have also observed that this reduction requires a fully estab-
lished mycorrhizal association (López-Ráez et al. 2011). The results with maize,
sorghum, pea (although not analytically supported) and tomato suggest that the
reduction in strigolactone exudation induced by AM symbiosis is conserved across
the plant kingdom. As AM fungi colonize roots of most agricultural and horticul-
tural species and are widely distributed around the globe, this environmentally
friendly biocontrol strategy can potentially be used in the majority of economically
important crops that suffer from these root parasites worldwide. Thus, mycorrhizal
128 J.A. López-Ráez et al.
- AM + AM
O O
O O
O O O O O O O
O O O O O O O
O O O O O O
O O O O O O O O
O O
O O O O O
O O O
O O O O O
O O
O O O O O
O O O
O O O
Fig. 5 Effect of arbuscular mycorrhizal (AM) symbiosis on root parasitic plant control. Under low
phosphorous conditions plants produce an increased amount of strigolactones. These signalling
molecules act as germination stimulants of root parasitic plant seeds (left). Upon mycorrhizal colo-
nization, plants reduce the production of strigolactones thus reducing parasitic plant infection, and
consequently diminishing the deleterious effect of these weeds on plant fitness and yield (right)
7 Conclusion
Chemicals fertilizers and pesticides are used to prevent, mitigate or control plant
diseases. However, the environmental pollution caused by excessive use and misuse
of agrochemicals has led to public concerns about the use of these chemicals in
agriculture. Therefore, there is a need to find more environmentally friendly alterna-
tives for disease control. The key to achieve successful biological control is the
knowledge on plant interactions in an ecological context. We emphasize here the
importance of the chemical communication that occurs in the rhizosphere between
Communication in the Rhizosphere, a Target for Pest Management 129
plants and other organisms, and the potential use of this molecular dialogue as a
target to control soil-borne pathogens and pests. An interesting example is the use
of the mutualistic AM symbiosis for controlling root parasitic plant infection by
reducing the production of strigolactones by the host plant. This example illustrates
the suitability of approaches based on the knowledge of the biological system to
target. Further research will expand our knowledge on what is going on under-
ground, and the information generated will help us decipher the regulation of chem-
ical communication in the rhizosphere and may result in the development of new
biocontrol strategies against soil pests.
References
Caillaud MC, Dubreuil G, Quentin M, Perfus-Barbeoch L, Lecornte P, Engler JD, Abad P, Rosso
MN, Favery B (2008) Root-knot nematodes manipulate plant cell functions during a compati-
ble interaction. J Plant Physiol 165:104–113
Cook CE, Whichard LP, Wall ME, Egley GH, Coggon P, Luhan PA, McPhail AT (1972) Germination
stimulants. 2. The structure of strigol, a potent seed germination stimulant for witchweed
(Striga lutea Lour.). J Am Chem Soc 94:6198–6199
Delgado JA (2002) Quantifying the loss mechanisms of nitrogen. J Soil Water Conserv
57:389–398
Ejeta G (2007) Breeding for Striga resistance in sorghum: exploitation of an intricate host-parasite
biology. Crop Sci 47:S216–227
Estabrook EM, Yoder JI (1998) Plant-plant communications: rhizosphere signaling between para-
sitic angiosperms and their hosts. Plant Physiol 116:1–7
Faure D, Vereecke D, Leveau JHJ (2009) Molecular communication in the rhizosphere. Plant Soil
321:279–303
Fernández-Aparicio M, García-Garrido JM, Ocampo JA, Rubiales D (2010) Colonisation of field
pea roots by arbuscular mycorrhizal fungi reduces Orobanche and Phelipanche species seed
germination. Weed Res 50:262–268
Fitter AH (2005) Darkness visible: reflections on underground ecology. J Ecol 93:231–243
Fuller VL, Lilley CJ, Urwin PE (2008) Nematode resistance. New Phytol 180:27–44
Garcia VG, Onco MAP, Susan VR (2006) Review. Biology and systematics of the form genus
Rhizoctonia. Span J Agric Res 4:55–79
Garg N, Geetanjali (2007) Symbiotic nitrogen fixation in legume nodules: process and signaling.
A review. Agron Sustain Dev 27:59–68
Genin S, Boucher C (2004) Lessons learned from the genome analysis of Ralstonia solanacearum.
Annu Rev Phytopathol 42:107–134
Gomez-Roldan V, Fermas S, Brewer PB, Puech-Pagés V, Dun EA, Pillot JP, Letisse F, Matusova R,
Danoun S, Portais JC, Bouwmeester H, Bécard G, Beveridge CA, Rameau C, Rochange SF
(2008) Strigolactone inhibition of shoot branching. Nature 455:189–194
Gressel J, Hanafi A, Head G, Marasas W, Obilana AB, Ochanda J, Souissi T, Tzotzos G (2004)
Major heretofore intractable biotic constraints to African food security that may be amenable
to novel biotechnological solutions. Crop Prot 23:661–689
Harrison MJ (2005) Signaling in the arbuscular mycorrhizal symbiosis. Annu Rev Microbiol
59:19–42
Hause B, Mrosk C, Isayenkov S, Strack D (2007) Jasmonates in arbuscular mycorrhizal interac-
tions. Phytochemistry 68:101–110
Hirsch AM, Bauer WD, Bird DM, Cullimore J, Tyler B, Yoder JI (2003) Molecular signals and
receptors - controlling rhizosphere interactions between plants and other organisms. Ecology
84:858–868
Horiuchi J, Prithiviraj B, Bais HP, Kimball BA, Vivanco JM (2005) Soil nematodes mediate posi-
tive interactions between legume plants and rhizobium bacteria. Planta 222:848–857
Jain R, Foy CL (1992) Nutrient effects on parasitism and germination of Egyptian broomrape
(Orobanche aegyptiaca). Weed Technol 6:269–275
Jamil M, Charnikhova T, Verstappen F, Bouwmeester H (2010) Carotenoid inhibitors reduce
strigolactone production and Striga hermonthica infection in rice. Arch Biochem Biophys
504:123–131
Joel DM, Hershenhom Y, Eizenberg H, Aly R, Ejeta G, Rich JP, Ransom JK, Sauerborn J, Rubiales D
(2007) Biology and management of weedy root parasites. Hortic Rev 33:267–349
Johnson AW, Roseberry G, Parker C (1976) A novel approach to Striga and Orobanche control
using synthetic germination stimulants. Weed Res 16:223–227
Karandashov V, Bucher M (2005) Symbiotic phosphate transport in arbuscular mycorrhizas.
Trends Plant Sci 10:22–29
Koltai H, Dor E, Hershenhorn J, Joel DM, Weininger S, Lekalla S, Shealtiel H, Bhattacharya C,
Eliahu E, Resnick N, Barg R, Kapulnik Y (2010) Strigolactones’ effect on root growth and root-
hair elongation may be mediated by auxin-efflux carriers. J Plant Growth Regul 29:129–136
Communication in the Rhizosphere, a Target for Pest Management 131
Kosuta S, Chabaud M, Lougnon G, Gough C, Denarie J, Barker DG, Becard G (2003) A diffusible
factor from arbuscular mycorrhizal fungi induces symbiosis-specific MtENOD11 expression in
roots of Medicago truncatula. Plant Physiol 131:952–962
Lendzemo VW, Kuyper TW, Kropff MJ, van Ast A (2005) Field inoculation with arbuscular myc-
orrhizal fungi reduces Striga hermonthica performance on cereal crops and has the potential to
contribute to integrated Striga management. Field Crops Res 91:51–61
Lendzemo VW, Kuyper TW, Matusova R, Bouwmeester HJ, van Ast A (2007) Colonization by
arbuscular mycorrhizal fungi of sorghum leads to reduced germination and subsequent attach-
ment and emergence of Striga hermonthica. Plant Signal Behav 2:58–62
López-Ráez JA, Charnikhova T, Gómez-Roldán V, Matusova R, Kohlen W, De Vos R, Verstappen
F, Puech-Pages V, Bécard G, Mulder P, Bouwmeester H (2008a) Tomato strigolactones are
derived from carotenoids and their biosynthesis is promoted by phosphate starvation. New
Phytol 178:863–874
López-Ráez JA, Charnikhova T, Mulder P, Kohlen W, Bino R, Levin I, Bouwmeester H (2008b)
Susceptibility of the tomato mutant high pigment-2 (hp-2dg) to Orobanche spp infection.
J AgricFood Chem 56:6326–6332
López-Ráez JA, Matusova R, Cardoso C, Jamil M, Charnikhova T, Kohlen W, Ruyter-Spira C,
Verstappen F, Bouwmeester H (2009) Strigolactones: ecological significance and use as a target
for parasitic plant control. Pest Manag Sci 64:471–477
López-Ráez JA, Charnikhova T, Fernández I, Bouwmeester H, Pozo MJ (2011) Arbuscular
mycorhizal symbiosis decreases strigolactone production in tomato. J Plant Physiol
168:294–297
Maillet F, Poinsot V, Andre O, Puech-Pages V, Haouy A, Gueunier M, Cromer L, Giraudet D,
Formey D, Niebel A, Martinez EA, Driguez H, Becard G, Denarie J (2011) Fungal lipochitoo-
ligosaccharide symbiotic signals in arbuscular mycorrhiza. Nature 469:58–63
Masson-Boivin C, Giraud E, Perret X, Batut J (2009) Establishing nitrogen-fixing symbiosis with
legumes: how many rhizobium recipes? Trends Microbiol 17:458–466
Matusova R, Rani K, Verstappen FWA, Franssen MCR, Beale MH, Bouwmeester HJ (2005) The
strigolactone germination stimulants of the plant-parasitic Striga and Orobanche spp. are
derived from the carotenoid pathway. Plant Physiol 139: 920–934
Morgan JAW, Bending GD, White PJ (2005) Biological costs and benefits to plant-microbe inter-
actions in the rhizosphere. J Exp Bot 56:1729–1739
Nagahashi G, Douds DD (2004) Isolated root caps, border cells, and mucilage from host roots
stimulate hyphal branching of the arbuscular mycorrhizal fungus, Gigaspora gigantea. Mycol
Res 108:1079–1088
Otten W, Gilligan CA (2006) Soil structure and soil-borne diseases: using epidemiological con-
cepts to scale from fungal spread to plant epidemics. Eur J Soil Sci 57:26–37
Parniske M (2008) Arbuscular mycorrhiza: the mother of plant root endosymbioses. Nat Rev
Microbiol 6:763–775
Paszkowski U (2006) A journey through signaling in arbuscular mycorrhizal symbioses 2006.
New Phytol 172:35–46
Perret X, Staehelin C, Broughton WJ (2000) Molecular basis of symbiotic promiscuity. Microbiol
Mol Biol Rev 64:180–201
Perry RN, Moens M (2006) Plant nematology. CABI publishing, London
Pozo MJ, Azcón-Aguilar C (2007) Unravelling mycorrhiza-induced resistance. Curr Opin Plant
Biol 10:393–398
Priest FG, Campbell I (2003) Brewing microbiology. Kluwer, New York
Raaijmakers JM, Paulitz TC, Steinberg C, Alabouvette C, Moenne-Loccoz Y (2009) The rhizo-
sphere: a playground and battlefield for soilborne pathogens and beneficial microorganisms.
Plant Soil 321:341–361
Raghothama KG (2000) Phosphate transport and signaling. Curr Opin Plant Biol 3:182–187
Rani K, Zwanenburg B, Sugimoto Y, Yoneyama K, Bouwmeester HJ (2008) Biosynthetic consid-
erations could assist the structure elucidation of host plant produced rhizosphere signalling
132 J.A. López-Ráez et al.
compounds (strigolactones) for arbuscular mycorrhizal fungi and parasitic plants. Plant Physiol
Biochem 46:617–626
Reddy PM, Rendon-Anaya M, de los Dolores Soto del Rio M (2007) Flavonoids as signaling
molecules and regulators of root nodule development. Dyn Soil Dyn Plant 1:83–94
Requena N, Serrano E, Ocon A, Breuninger M (2007) Plant signals and fungal perception during
arbuscular mycorrhiza establishment. Phytochemistry 68:33–40
Rispail N, Dita MA, Gonzalez-Verdejo C, Perez-de-Luque A, Castillejo MA, Prats E, Roman B,
Jorrin J, Rubiales D (2007) Plant resistance to parasitic plants: molecular approaches to an old
foe. New Phytol 173:703–711
Ruyter-Spira C, Kohlen W, Charnikhova T, van Zeij A, van Bezouwen L, de Ruijter N, Cardoso C,
López-Ráez JA, Matusova R, Bours R, Verstappen F, Bouwmeester H (2011) Physiological
effects of the synthetic strigolactone analogue GR24 on root system architecture in Arabidopsis:
Another below-ground role of strigolactones? Plant Physiol 155:721–734
Sbrana C, Giovannetti M (2005) Chemotropism in the arbuscular mycorrhizal fungus Glomus
mosseae. Mycorrhiza 15:539–545
Schenk H, Driessen RAJ, de Gelder R, Goubitz K, Nieboer H, Bruggemann-Rotgans IEM,
Diepenhorst P (1999) Elucidation of the structure of Solanoeclepin A, a natural hatching factor
of potato and tomato cyst nematodes, by single-crystal x-ray diffraction. Croatica Chemica
Acta 72:593–606
Scholes JD, Press MC (2008) Striga infestation of cereal crops - an unsolved problem in resource
limited agriculture. Curr Opin Plant Biol 11:180–186
Siegler DS (1998) Plant secondary metabolism. Kluwer, Boston
Smith SE, Read DJ (2008) Mycorrhizal symbiosis, 3rd edn. Academic, London
Smith SE, Barker SJ, Zhu YG (2006) Fast moves in arbuscular mycorrhizal symbiotic signalling.
Trends Plant Sci 11:369–371
Soto MJ, Fernandez-Aparicio M, Castellanos-Morales V, Garcia-Garrido JM, Ocampo JA, Delgado
MJ, Vierheilig H (2010) First indications for the involvement of strigolactones on nodule
formation in alfalfa (Medicago sativa). Soil Biol Biochem 42:383–385
Sprent JI (2009) Legume nodulation. A global perspective. Wiley-Blackwell, Chichester
Steinkellner S, Lendzemo V, Langer I, Schweiger P, Khaosaad T, Toussaint JP, Vierheilig H (2007)
Flavonoids and strigolactones in root exudates as signals in symbiotic and pathogenic plant-
fungus interactions. Molecules 12:1290–1306
Sun Z, Matusova R, Bouwmeester H (2007) Germination of Striga and chemical signaling
involved: a target for control methods. In: Gressel J, Ejeta G (eds) Integrating new technologies
for Striga control: towards ending the witch-hunt. World Scientific, Nairobi, pp 47–60
Sun Z, Hans J, Walter MH, Matusova R, Beekwilder J, Verstappen FWA, Ming Z, van Echtelt E,
Strack D, Bisseling T, Bouwmeester HJ (2008) Cloning and characterisation of a maize caro-
tenoid cleavage dioxygenase (ZmCCD1) and its involvement in the biosynthesis of apocarote-
noids with various roles in mutualistic and parasitic interactions. Planta 228:789–801
Thompson JN (2005) Coevolution: the geographic mosaic of coevolutionary arms races. Curr Biol
15:R992–R994
Umehara M, Hanada A, Yoshida S, Akiyama K, Arite T, Takeda-Kamiya N, Magome H, Kamiya Y,
Shirasu K, Yoneyama K, Kyozuka J, Yamaguchi S (2008) Inhibition of shoot branching by new
terpenoid plant hormones. Nature 455:195–200
Varma A, Verma S, Sudha, Sahay N, Bütehorn B, Franken P (1999) Piriformospora indica, a cul-
tivable plant-growth-promoting root endophyte. Appl Environ Microbiol 65:2741–2744
Vogel JT, Walter MH, Giavalisco P, Lytovchenko A, Kohlen W, Charnikhova T, Simkin AJ, Goulet C,
Strack D, Bouwmeester HJ, Fernie AR, Klee HJ (2010) SlCCD7 controls strigolactone biosyn-
thesis, shoot branching and mycorrhiza-induced apocarotenoid formation in tomato. Plant J
61:300–311
Weerasinghe RR, Bird DM, Allen NS (2005) Root-knot nematodes and bacterial Nod factors
elicit common signal transduction events in Lotus japonicus. Proc Natl Acad Sci U S A
102:3147–3152
Communication in the Rhizosphere, a Target for Pest Management 133
Weir TL, Park SW, Vivanco JM (2004) Biochemical and physiological mechanisms mediated by
allelochemicals. Curr Opin Plant Biol 7:472–479
Wigchert SCM, Kuiper E, Boelhouwer GJ, Nefkens GHL, Verkleij JAC, Zwanenburg B (1999)
Dose-response of seeds of the parasitic weeds Striga and Orobanche toward the synthetic
germination stimulants GR24 and Nijmegen 1. J Agric Food Chem 47:1705–1710
Williamson VM, Gleason CA (2003) Plant-nematode interactions. Curr Opin Plant Biol
6:327–333
Yoneyama K, Takeuchi Y, Yokota T (2001) Production of clover broomrape seed germination
stimulants by red clover requires nitrate but it inhibited by phosphate and ammonium. Physiol
Plant 112:25–30
Yoneyama K, Yoneyama K, Takeuchi Y, Sekimoto H (2007) Phosphorus deficiency in red clover
promotes exudation of orobanchol, the signal for mycorrhizal symbionts and germination stim-
ulant for root parasites. Planta 225:1031–1038
Yoneyama K, Xie XN, Sekimoto H, Takeuchi Y, Ogasawara S, Akiyama K, Hayashi H, Yoneyama K
(2008) Strigolactones, host recognition signals for root parasitic plants and arbuscular mycor-
rhizal fungi, from Fabaceae plants. New Phytol 179:484–494
Yoneyama K, Xie X, Yoneyama K, Takeuchi Y (2009) Strigolactones: structures and biological
activities. Pest Manag Sci 65:467–470
Zwanenburg B, Mwakaboko AS, Reizelman A, Anilkumar G, Sethumadhavan D (2009) Structure
and function of natural and synthetic signalling molecules in parasitic weed germination. Pest
Manag Sci 65:478–491
A Novel Land-Energy Use Indicator
for Energy Crops
Abstract The growth of the bioenergy field raises a myriad of problems, including
the selection of the most appropriate crops and cropping systems, the trade-off
between land to be allocated for bioenergy and for food production, the appraisal of
the agro-energy systems sustainability in their economic, social and ecological
aspects. A correct approach to such multifarious problems requires unbiased and
transparent procedures, based on accepted common protocols and metrics, permitting
to objectively compare and rank all the possible solutions. This chapter focuses on
the evaluation of resource inputs to energy crops, in one attempt to contribute to
clarify the existing confusion in terms and appraisal methods and to offer a tool for
supporting the correct evaluation of contrasting crops and farming systems. Currently,
energy use is analyzed mainly in terms of difference between output and input, of
ratio between output and input, of annual energy input per unit of surface, and of
energy input per specific crop yield. Here the criticism to all such “uni-dimensional”
indicators is illustrated, and a novel indicator, combining land and energy use in
crop systems and potentially including more aspects - is proposed. This novel,
bi-dimensional “Land and Energy Use Indicator” (LEUI) and its advantages vis-à-vis
uni-dimensional indicators are demonstrated with specific examples in the comparison
of four energy crops. By evidencing the difference with other indicators, it is also
demonstrated how this indicator avoids misleading conclusions in the comparison of
organic and non-organic farming systems. It is suggested that its adoption can reduce
the room for intended or unintended misinformation.
E.G. Koukios
Bioresource Technology Unit, National Technical University, Athens, Greece
V. Sardo (*)
Department of Agricultural Engineering, University of Catania, Catania, Italy
e-mail: sardov@unict.it
1 Introduction
The growing concern for the environmental and social problems linked to bioenergy
and biofuel crops has triggered the sprouting of researches, theories, simulation
models and guidelines aimed at optimizing the choices and supporting the strive for
sustainability, which has resulted in a considerable advancement of knowledge and
in a better awareness by operators. According to Reijnders (2006) “The sustainable
use of biomass is defined as a type of use that can be continued indefinitely, without
an increase in negative impact due to pollution, while maintaining natural resources
and beneficial functions of living nature relevant to humankind over millions of
years, i.e., the common lifespan of a mammalian species.” The list of factors affect-
ing the sustainability of bioenergy applications is a long one, including a group
preserving the stock of vital natural resources, such as soil, soil organic matter,
nutrients, consumption of fossil fuels, and water; and another group of factors
maintaining key natural cycles and ecosystem services, such as the mobilization of
elements, impact on climate, land use, biodiversity, economy and social acceptance
(Reijnders 2006).
Due to such a quantity of intervening factors many shadows remain even in basi-
cally important issues: one example is given by the passionate debate between those
maintaining that the mineral energy required to produce one unit of bioethanol or
biodiesel exceeds the amount of useful energy produced and is even “a crime against
humanity”, because it reduces available food (e.g., Pimentel 2001, 2003; Pimentel
and Patzek 2005; Pimentel et al. 2007; Ziegler 2007) and those insisting on the need
for producing bioenergy to improve the environment and reduce greenhouse gas
emissions (e.g. Graboski 2002; Shapouri et al. 2002; Schmer et al. 2008; USDE
2009; Aljama 2010). One further issue for debate is the extent to which organic
agriculture principles should be accepted for sustainable biomass production, in the
light of its supporters’ claims of top sustainability (International Network for
Sustainable Energy–Europe 2006; Muller and Davis 2009), categorically denied by
others (Trewavas 2004; Wu and Sardo 2010).
Reasons for such discrepancies in views include the inconsistency in procedures
and metrics used by the diverse researchers, as pointed out by Bertilsson et al.
(2008), and frequently also strongly biased approaches, even in high profile institu-
tions, such as the Food and Agriculture Organization of the United Nations (FAO),
and the British Ministry of Agriculture, Fisheries and Food (MAFF) and Department
for Environment, Food and Rural Affairs (DEFRA), as demonstrated below in
Sect. 4.2 of this paper.
As advocated in a brochure issued by the Royal Society (2008), “[a]dditional
sustainability metrics need to be agreed to guide developments in the supply chain,
including energy efficiency, amount of fossil energy used, cost per unit of energy and
environmental impacts such as local air and water pollution”. Any attempt aimed
at supplying “additional sustainability metrics”, contributing to improve the procedure
for an objective evaluation of alternative options and reducing the risk of misrepre-
sentations seems therefore of some interest.
A Novel Land-Energy Use Indicator for Energy Crops 137
With the ongoing diffusion of biomass crops “competition may arise between different
land use systems for food, feed, biomass production, and nature protection and
landscape conservation, as well as between the production of different biofuel feed-
stocks” and therefore “the choice of the best suited energy crop is crucial for the
development of strategies that allow for the highest land use efficiency, substitution
of fossil energies and the reduction of GHG emissions” (Boehmel et al. 2008).
In a 2009 ATTRA publication Holly Hill wondered: “One issue that affects
reliable comparison is how to account for the potential yield differences between
systems. Should energy consumption be measured per unit of land area, per unit of
economic activity or per unit of produce?” (Hill 2009). In this section, some met-
rics commonly used to give an answer to such questions are briefly commented
upon; an excellent, thorough overview can be found in Appendix A of Spitzley and
Keolian (2004).
Indicators based on the difference between energy output and energy input basi-
cally include Net Energy Gain (NEG), Net Energy Value (NEV), and Primary Net
Energy Yield (PNEY); they are useful in the evaluation of energy crops, but have
not much sense when applied to food crops. Even less useful are the Net Energy
Ratio (NER) or the Energy Use Efficiency (EUE), namely the ratio of the total
system energy output to total energy input (e.g., MAFF 2000; FAO 2002; Boehmel
et al. 2008): a convincing criticism of this type of indicators can be found in
Farrel et al. (2006).
Expressing energy use in terms of annual energy input per unit of surface
(EI, in MJ/ha.year; e.g., MAFF 2000; FAO 2002; Lillywhite et al. 2007; Gomiero
et al. 2008) is practically meaningless, because extremely low values of input,
even approaching zero, can be easily achieved by neglecting or even omitting the
agricultural practices, to the extent that a false impression of superb achievements
can be conveyed in those cases when the only energy input -other than solar
energy- is the one required to pick the scanty fruits spontaneously offered by
undomesticated plants.
In the same way, expressing energy use in terms of energy input per unit of crop
yield (EI, in MJ/t) can have the effect of deceiving the readers, as was the case with
MAFF (2000) and later, on a larger scale, with Azeez and Hewlett (2008) with the
unfortunate endorsement by FAO (Ziesemer 2007) and DEFRA (2008), as illus-
trated below (see Sect. 4.2). An indicator based simply on energy input per unit of
yield can in fact be used to suggest positive results, namely that a lower specific
energy is required, whenever some saving in energy is obtained at the cost of a
reduction in production, as shown in the examples in Tables 1 and 3 below.
As Thorup-Kristensen et al. comment: “Even though the amount of energy pro-
duced per kJ of energy used may be better in the organic systems, the higher produc-
tivity of the conventional systems means that conventional systems tend to have a
higher net energy production per hectare. The significance of the area used for crop
production is another open question when comparing different production systems.
138 E.G. Koukios and V. Sardo
While the organic systems may have the highest productivity per amount of invested
energy, they have a lower production per area. What is most important here invest-
ment of energy or area? Our area for crop production is not unlimited, and the extra
land we need for organic food production could be used for other purposes” (Thorup-
Kristensen et al. 2008). The same concept is illustrated by Bertilsson et al. (2008):
“Energy use per unit yield expresses system efficiency, but the term is insufficient to
evaluate the energy characteristics of agricultural systems [omissis]. Lower yields in
the organic systems, and consequently lower energy production per unit area, mean
that more land is required to produce the same amount of energy. This greater land
requirement in organic production must be considered in energy balances”
y MJ
LEUI = ha * *
t t
As LEUI expresses the combined land and energy burden required by crop systems,
the best crop system is the one with the lowest LEUI value. For instance (Table 1)
if we compare three systems A, B and C, yielding 10, 5 and 1 t/ha of biomass,
respectively, with a specific energy input EI (in MJ/t) of 10000/10 = 1000 in system
A, 5000/5 = 1000 in system B, and 500/1 = 500 in system C, we find that the indica-
tor EI (MJ/t) does not permit to appreciate any difference between systems A and B,
and even denounces a better performance (i.e., a lower EI) in system C, failing to
take into due account the reduction in crop productivity, and thus we shall absurdly
conclude that the performance of system C is largely superior. Similarly, if the spe-
cific energy input is referred to the surface area (in MJ/ha*y), system C appears far
better than the others. In conclusion, system C seems largely preferable under both
A Novel Land-Energy Use Indicator for Energy Crops 139
Fig. 1 Graphical representation of the three systems’ “iso-burden” curves LEUI = Land and
Energy Use Indicator, corresponding to the areas between the abscissa and the dashed lines of the
three systems
criteria because it uses “less energy per unit area and per unit of output”, according
to DEFRA’s flawed criteria (Shepherd et al. 2003), echoing MAFF’s (2000) misrep-
resentation. However, if the yearly land input (ha*y/t) as well as the energy input
(MJ/t) are simultaneously taken into account through the proposed LEUI, in the
case of system A we obtain the value of 100, whereas in system B the value is 200
and in system C rises to 500, which denounces the worse global performance in
B and C because of their higher combined resources use. The principle is graphi-
cally illustrated in Fig. 1, reporting for the three ideal systems the land and energy
“iso-burden” curves –they could also be named “iso-productivity” or “indifference”
curves- along which constant LEUI values are located.
Assuming that land and energy inputs can be freely inter-changed -which is true
within some limits: e.g., by applying more fertilizer or water the same yield can be
obtained with less land, and vice versa- the diagram shows for every system how
one input will change in response to the other’s changes when moving along the
curves. This permits to find the trade-offs between land and energy input best fitting
any specific conditions. For instance, in system A 100 MJ/t rather than 1,000 MJ/t
of energy will be sufficient if the used land moves from 0.1 to 1.0 ha*y/t (LEUI
value remaining unvaried); conversely, in system C 1,000 MJ/t will be required
rather than 500 to reduce the land input from 1 to 0.5 ha*y/t.
The areas included between the abscissa and the dashed lines at the lower limit
of the single systems convey a visual representation of the environmental burden, in
140 E.G. Koukios and V. Sardo
terms of specific land and energy use, imposed by the particular system and
expressed by LEUI; of course a larger area denounces more inputs and therefore
indicates a less favorable solution.
The proposed indicator could be useful for ranking different energy crops, for
identifying the most suitable land/energy input combinations under a constant LEUI,
or comparing different farming technologies implying different LEUI values.
The principle of LEUI can be also extended to formulate multi-dimensional, com-
plex indicators, which can assist in the rationally based quest for the most sustainable
solutions, e.g. by considering also the other factors listed by Reijnders (2006), such as
the greenhouse gas emissions, the impact on biodiversity, the water consumption etc.,
and permitting to attribute diverse weights to the various dimensions (e.g. Matute and
Gupta 2007; Gómez-Limón and Sanchez-Fernandez 2010). In the proposed bi-dimen-
sional LEUI different weights can be attributed to land and energy inputs.
In order to demonstrate the practical use of LEUI, we will apply it in two specific
cases, one referring to the ranking of different energy crops, and one comparing
organic to non-organic farming technologies. In these examples the same weight
has been assigned to the inputs “energy” and “land”.
Data from a paper by Boehmel et al. (2008) were elaborated in order to jointly
appreciate land and energy aspects. Out of the six crops analyzed in the paper only
four, namely willow, miscanthus, switchgrass and energy maize, were considered
for comparison because data referring to two crop rotation systems were not easy to
handle due to the presence of co-products.
The experimental plan of the research was rather complex and included three
levels of nitrogen fertilization for each crop: here only the treatment labeled “N1”
with intermediate amounts of nitrogen was selected.
Some simple data manipulation was necessary to obtain the value of dry matter
yield (DMY) and specific Energy Input (MJ/t) of the four crops, since they were
both implicitly reported. DMY, necessary to express land input, was obtained by
dividing the Primary Energy Yield (PEY) from their table 6 by the lower heating
values in Table 3, while the energy input was obtained by subtracting the Primary
Net Energy Yield (PNEY) from the PEY.
The elaboration permitted to rank the four crops according to the values of five
indicators, i.e., annual land and energy input per metric tonne, PNEY, Energy Use
Efficiency – namely output/input ratio (EUE), and LEUI, as shown in Table 2.
A Novel Land-Energy Use Indicator for Energy Crops 141
Table 2 Ranking energy crops according to different indicators (From Boehmel et al. 2008)a
Crop Land input (ha*y/t) Energy input (MJ/t) PNEY (GJ/ha) EUE LEUI
Willow 0.0747 (3) 224(1) 243 (3) 78 (1) 16.7(1)
Miscanthus 0.0670(2) 537(3) 255 (2) 32 (3) 36.0(3)
Switchgrass 0.0924 (4) 463(2) 193 (4) 38 (2) 42.8(4)
Energy maize 0.0546 (1) 656(4) 342 (1) 29 (4) 35.8(2)
PNEY Primary Net Energy Yield, EUE Energy Use Efficiency, LEUI Land and Energy Use
Indicator
a
Within brackets the crop ranking according to the indicators
Striking dissimilarities in the ranking according to the various indicators are evi-
dent, particularly in the case of energy maize, and LEUI-based rankings result in
some way intermediate, thanks to the very nature of this indicator. It is therefore
reasonable to assume that LEUI-based assessments can assist for more balanced
decision processes.
In Fig. 2 the possibility is shown of finding a trade-off between land and energy
input for the four crops, moving along the iso-burden curves, thus maintaining
constant values of LEUI. The dashed lines correspond to the land and energy input
data reported in Table 2; again, the surface of the rectangles formed by the dashed
lines and the coordinates defines the LEUI values, which in this example are highest
for switchgrass and lowest for willow.
While the need for producing biomass in sustainable ways is evident (e.g. Schlegel
and Kaphengst 2007; Ceotto 2008; van Dam et al. 2008; ISCC 2009), organic
farming enthusiasts claim that only the adoption of their “philosophy” permits to
142 E.G. Koukios and V. Sardo
achieve the highest sustainability (e.g. Kotschi and Műller-Sämann 2004; Azeez
2009), and go so far as to suggest that for agricultural products economic support
should be confined to “solid and liquid biomass” complying with the rules of
organic farming and certified by IFOAM, the International Federation of Organic
Movements (INFORSE 2006). On the other hand, it is contended that such claims
are unfounded at least with reference to greenhouse gas emissions (e.g. Tuomisto
et al. 2009), carbon sequestration and soil fertility improvement (Bergström et al.
2008) and, above all, energy balance and land productivity, as we shall try to
demonstrate.
In an MAFF report aimed at modeling energy use in agriculture, energy inputs to
a number of conventionally and organically grown crops were compared, in terms
of MJ/ha and MJ/t, with the organic systems resulting more energy efficient than the
conventional: “[o]rganically grown crops have a lower energy input per unit area
than conventional crops, largely because of lower fertiliser and pesticide inputs”
(MAFF 2000). Organic crops fared better also in terms of energy input per unit
output (MJ/t).
The report gave evidence to the higher “Energy Ratio” (e.g. the energy output/
input ratio) in organic production, which is a rather useless, deceiving indicator,
since an extremely high energy ratio can be easily achieved by simply reducing
inputs, just picking naturally produced yields. In the case of pre-agriculture hunter-
gatherers, energy ratios approached infinity – neglecting solar energy – but at the
same time the land surface requirement in the wild was enormous. Bertilsson et al.
(2008) aptly write: “the calculation of output/input ratio is a poor measure for
system comparisons as it only expresses the efficiency and not the total or net
energy production”. The higher land input typically required by organic farming
was not given the due relevance in the MAFF report and as a consequence the real
effects on the overall performance of the systems were not highlighted. In conclu-
sion, the false impression was conveyed to the reader that organic systems are
“more efficient”.
In 2006 Williams and co-workers released a comprehensive report on environ-
mental burdens depending on agricultural and horticultural activities, where land and
energy inputs were defined for a number of commodities, with the aim of modelling
and comparing the burdens involved in their production (Williams et al. 2006). The
burdens in the case of non-organic and organic production systems were compared.
Unlike MAFF (2000), the authors correctly emphasized the considerably higher
land input in organic farming: “Land use was always higher in organic systems
(with lower yields and overheads for fertility building and cover crops), ranging
from 65% more for milk and meat to 160% for potatoes and 200% more for
bread wheat”.
The list of land and energy inputs resulting from the elaboration of their data
revised in 2009 (available at www.agrilca.org) for selected agricultural products is
reported in Table 3.
In almost all the cases organic systems required “less energy per unit area and
per unit of output”, thus confirming earlier MAFF (2000) and DEFRA (Shepherd
et al. 2003) claims, but also required more land per tonne of crop yield.
A Novel Land-Energy Use Indicator for Energy Crops 143
In 2007 an FAO report was released (Ziesemer 2007), copying data published
only later by Azeez and Hewlett (2008); the figures of MAFF (2000) and Williams
et al. (2006) were selectively picked to support the author’s claim that “[b]ecause
of its reduced energy inputs, organic agriculture is the ideal production method for
biofuels” (p. 20) and the conclusion that “[t]ypically, organic agriculture uses 30 to
50 percent less energy in production than comparable non-organic agriculture”
(p. 23). Possible energy savings were illustrated for the auspicious event that all
agriculture in the UK would become organic, but the parallel larger land input
required by organic farming was not mentioned.
Azeez and Hewlett for the Soil Association (2008) were quick to side this
approach –actually their own brainchild, to which the FAO had been a loudspeaker-
claiming that the figures by MAFF (2000) and Williams et al. (2006) demonstrated
that “UK organic farming uses around 26% less energy per tonne of output on
average”. Along the same reasoning as Ziesemer (2007), they revealed that if the
entire agricultural production in the UK went organic, the total savings in energy
could be 27.51%, but unfortunately they too forgot to mention that UK agricultural
land should simultaneously increase over twofold.
144 E.G. Koukios and V. Sardo
In 2008 DEFRA issued a report titled “The Contribution That Organic Farming
Makes in Supplying Public Goods”, where a table based on data from MAFF (2000)
and Williams et al. (2006) illustrated, once again, the possible percentage-wise
savings, in terms of energy use per tonne, when moving from non-organic to organic
systems. Their comment was: “Not surprisingly, there are many reliable life cycle
assessments from the UK and abroad that have found organic farming to be more
energy efficient that it’s [sic] non-organic counterpart” and “The research shows
organic production to be significantly more energy efficient per tonne of food pro-
duced in eleven out of the fifteen sectors examined ”. Once again, the authors were
oblivious of the larger land inputs required by organic farming.
The simple inspection of Table 3 shows indeed that energy inputs in terms of MJ/ha
and MJ/t are lower with organic technology, but at the same time the combination of
energy and land inputs through the adoption of LEUI highlights the combined impact
of the two environmental burdens, remarkably lower in the case of non-organic farm-
ing, thus evidencing the high risk of adopting the less sustainable organic systems.
The same exercise was done on other papers comparing organic and non-organic
farming (e.g., Reganold et al. 2001; Jørgensen et al. 2005; Gündoğmus 2006;
Pimentel 2006; Kaltsas et al. 2007; Guzmán and Alonso 2008), always with identical
results: although the use of EI (MJ/t) and EI (MJ/ha) as well as the Energy Use
Efficiency or Energy Productivity indicators alone may suggest that better results are
achieved with organic farming, the use of LEUI, after adjusting – when necessary –
the energy input data for human labour and organic manure (Wu et al. 2011) shows
that the opposite is in fact true.
5 Conclusion
The use of LEUI permits to fill a major gap in the quest for a rationally based trade-
off in the decision making process in the agricultural activity, i.e. the one between
land requirements and energy inputs.
Although its adoption can lead to rather counter-intuitive results when compar-
ing various alternative energy crops and cropping systems, its indications are more
objective, comprehensive and soundly based than those resulting from uni-dimen-
sional indicators.
When used to assess the comparative value of organic vs. non-organic farming
systems, LEUI makes apparent the vast superiority of the latter in terms of land and
energy efficiency, evidencing how organic farming is not a solution in the quest for
sustainability.
Overall, it is clear that the adoption of bi-dimensional LEUI permits the correction
of the incomplete description given by the use of uni-dimensional indicators, and
thus gives more balanced information reducing the room for intended or unintended
misinformation.
In conclusion, LEUI seems to deserve a place as a decision support tool in the
toolkit of the biomass policy and decision makers.
A Novel Land-Energy Use Indicator for Energy Crops 145
References
Aljama HAA (2010) Is ethanol fuel a smart choice? Pennsylvania State University. Available at.
www.greeningofoil.com
Azeez G (2009) Soil carbon and organic farming (Soil Association publ.) – Available at. www.
soilassociation.org/climate.aspx
Azeez GSE, Hewlett KL (2008) The comparative energy efficiency of organic farming. Presented
at the 16th IFOAM World Congress, Modena, Italy, 16–20 June 2008. Available at. http://
orgprints.org/view/projects/conference.html
Bergström L, Kirschmann H, Thorvaldsson G (2008) Widespread opinions about organic agriculture –
are they supported by scientific evidence? In: Kirchmann H, Bergström L (eds) Organic crop
production – ambitions and limitations. Springer Science + Business Media B.V, Dordrecht, pp
173–188
Bertilsson G, Kirschmann H, Bergström L (2008) Energy analysis of organic and conventional
agricultural systems. In: Kirchmann H, Bergström L (eds) Organic crop production – ambitions
and limitations. Springer Science + Business Media B.V, Dordrecht, pp 173–188
Boehmel C, Lewandowski I, Claupein W (2008) Comparing annual and perennial energy cropping
systems with different management intensities. Agric Syst 96:224–236. doi:10.1016/j.
agsy.2007.08.004
Ceotto E (2008) Grasslands for bioenergy production. A review. Agron Sustain Dev 28:47–55.
doi:10.1051/agro:2007034, available at: www.agronomy-journal.org
DEFRA, Department for Environment, Food and Rural Affairs (2008) The contribution that
organic farming makes in supplying public goods. Available at. www.defra.gov.uk-Defra,UK-
Farming-Organic Food and Farming
FAO, Scialabba NE, Hattam C (eds) (2002) Organic agriculture, environment and food security,
FAO environment and natural resources management series 4. Food And Organizations of the
United Nations, Rome. ISBN 9251048193
Farrell AE, Plevin RJ, Turner BT, Jones AD, O’Hare M, Kammen DM (2006) Ethanol can contrib-
ute to energy and environmental goals – renewable and appropriate energy laboratory. Available
at. http://rael.berkeley.edu
Gómez-Limón JA, Sanchez-Fernandez G (2010) Empirical evaluation of agricultural sustainability
using composite indicators. Ecol Econ 69:1062–1075. doi:10.1016/j.ecolecon.2009.11.027
Gomiero T, Paoletti MG, Pimentel D (2008) Energy and environmental issues in organic and con-
ventional agriculture. Critical Rev Plant Sci 27:239–254. doi:10.1080/07352680802225456
Graboski MS (2002) Fossil energy use in the manufacture of corn ethanol. Prepared for the
National Corn Growers Association, August 2008
Gündoğmus E (2006) Energy use on organic farming: a comparative analysis on organic versus
conventional apricot production on small holdings in Turkey. Energy Convers Manage
47(2006):3351–3359
Guzmán GI, Alonso AM (2008) A comparison of energy use in conventional and organic olive oil
production in Spain. Agric Syst 98:167–176
Hill H (2009) Comparing energy use in conventional and organic cropping systems, ATTRA.
Available at. www.attra.ncat.org/attra-pub/croppingsystems.html
INFORSE, International Network for Sustainable Energy, Europe (2006) Criteria for sustainable
use of biomass including biofuels- version 15 July 2006. Available at. www.inforse.org/
europe
ISCC, International Sustainability & Carbon Certification (2009) System basics for the certifica-
tion of sustainable biomass and bioenergy – ISCC 201 System Basics. Available at. http://
www.iscc-system.org/documents/certification/basics/index_eng.html
Jørgensen U, Dalgaard T, Kristensen ES (2005) Biomass energy in organic faming – the potential
role of short rotation coppice. Biomass Bioenerg 28:237–248
Kaltsas AM, Mamolos AP, Tsatsarelis CA, Nanos GD, Kalburtji KL (2007) Energy budget in
organic and conventional olive groves. Agric Ecosyst Environ 122:243–251
146 E.G. Koukios and V. Sardo
Kotschi J, Műller-Sämann K (2004) The role of organic agriculture in mitigating climate change
– a scoping study. Available at. www.ifoam.org
Lillywhite R, Chandler D, Grant W, Lewis K, Firth C, Schmutz U, Halpin D (2007) Environmental
footprint and sustainability of horticulture (including Potatoes) – a comparison with other
agricultural sectors. Final report produced for DEFRA
MAFF, Ministry of Agriculture, Fisheries and Food (2000) Energy use in organic farming systems
(OF0182). Available at. http://orgprints.org/8169
Matute J, Gupta AP (2007) Data quality and indicators. Am J Agr Biol Sci 2(1):23–30, ISSN
1557-4989
Muller A, Davis JS (2009) The potential of organic agriculture. Available at. http://orgprints.
org/16507/
Pimentel D (2001) The limits of biomass utilization. In: Meyers RA (ed) Encyclopedia of physical
science and technology, vol 2, 3rd edn. Academic Press, San Diego
Pimentel D (2003) Ethanol fuels: energy balance, economics, and environmental impacts are
negative. Nat Resour Res 12(2):127–134, June 2003
Pimentel, D. (2006) Impacts of organic farming on the efficiency of energy use in agriculture – The
Organic Centre. Available at. http://organic.insightd.net/reportfiles/ENERGY_SSR.pdf
Pimentel D, Patzek TW (2005) Ethanol production using corn, switchgrass, and wood; biodiesel
production using soybean and sunflower. Nat Resour Res 14(1):65–76. doi:10.1007/s11053-
005-4679-8, March 2005
Pimentel D, Patzek TW, Cecil G (2007) Ethanol production: energy, economic, and environmental
losses. Rev Environ Contam Toxicol 189:25–41
Reganold JP, Jerry D, Glover JP, Andrews PK, Hinman HR (2001) Sustainability of three apple
production systems. Nature 410(6831):926–930, April 2001
Reijnders L (2006) Conditions for the sustainability of biomass based fuel use. Energy Policy
34:863–876
Royal Society (2008) Sustainable biofuels: prospects and challenges – Royal Society Policy
Document 01/08 – ISBN 978 0 85403 662 2
Schlegel S, Kaphengst T (2007) European union policy on bioenergy and the role of sustainability
criteria and certification systems. J Agric Food Ind Org 5(2), Article 7. doi: 10.2202/1542-
0485.1193. Available at. http://www.bepress.com/jafio/vol5/iss2/art7
Schmer MR, Vogel KP, Mitchell RB, Perrin RK (2008) Net energy of cellulosic ethanol from switchgrass.
Natl Acad Sci USA 105:464–469, available at www.pnas.org_cgi_doi_10.1073_pnas.0704767105
Shapouri H, Duffield JA, Wang M (2002) The energy balance of corn ethanol: an update. U.S.
Department of Agriculture, Office of the Chief Economist, Office of Energy Policy and New
Uses, Agricultural Economic Report No. 814
Shepherd M, Pearce B, Cormack B, Philipps L, Cuttle S, Bhogal A, Costigan P, Unwin R (2003)
An assessment of the environmental impacts of organic farming – a review for Defra-funded
project OF0405
Spitzley DV, Keolian GA (2004) Life cycle environmental and economic assessment of willow
biomass electricity: a comparison with other renewable and non-renewable sources – Center
for Sustainable Systems, Report No. CSS04-05R, University of Michigan, Ann Arbor,
Michigan, 25 March 2004 (revised February 10, 2005)
Thorup-Kristensen K, Brennan M, Halberg N, Cooper J, Lampkin N, Niggli U (2008) Resource
efficiency of organic and low input systems in comparison to intensive agriculture. Presented
at the 16th IFOAM World Congress, Modena, Italy, 16–20 June 2008. Available at. www.
orgprints.org/13352
Trewavas A (2004) A critical assessment of organic farming-and-food assertions with particular
respect to the UK and the potential environmental benefits of no-till agriculture. Crop Prot
23:757–781
Tuomisto HL, Hodge ID, Riordan P, MacDonald DW (2009) Assessing the environmental impacts
of contrasting farming systems. Asp Appl Biol 93:167–172
U.S. Department of Energy (2009) Ethanol myths and facts. Available at. http://www1.eere.energy.
gov/biomass/ethanol_myths_facts.html
A Novel Land-Energy Use Indicator for Energy Crops 147
van Dam J, Junginger M, Faaij A, Jürgens I, Best G, Fritsche U (2008) Overview of recent
developments in sustainable biomass certification. Biomass Bioenerg 32:749–780.
doi:10.1016/j.biombioe.2008.01.018
Williams AG, Audsley E, Sandars DL (2006) Determining the environmental burdens and resource
use in the production of agricultural and horticultural commodities. Main Report. Defra
Research Project IS0205. Cranfield University and Defra, Bedford. Available at. www.silsoe.
cranfield.ac.uk and www.defra.gov.uk
Wu JY, Sardo V (2010) Sustainable vs organic agriculture – a review. In: Lichtfouse E (ed.) Sociology,
organic farming, climate change and soil science, sustainable agriculture review 3. Springer
Science + Business Media BV, Dordrecht/Heidelberg/London/New York. doi:10.1007/978-90-
481-3333-8_3 –
Wu JY, Martinov M, Sardo VI (2011) Human labour and green manure – two overlooked factors
for energy analysis in agriculture. In: Lichtfouse E (ed.) Genetics, biofuels and local farming
systems. Sustain Agric Rev 7:215–229. doi 10.1007/978-94-007-1521-9_7
Ziegler J (2007) UN Special Rapporteur – BBS news (27 October 2007)
Ziesemer J (2007) Energy use in organic food system – Natural Resources Management and
Environment Department, Food and Agriculture Organization of the United Nations. Available
at. www.fao.org./docs/
Conventional, Organic and Conservation
Agriculture: Production and Environmental
Impact
Jens B. Aune
have shown that nitrogen and greenhouse gas emission are less in conservation
agriculture as compared to conventional and organic agriculture. The non-use of
pesticides is the major environmental advantages of organic agriculture.
It appears from this review that conservation agriculture is the approach that can
best deliver on the production and environmental objectives of agriculture.
1 Introduction
The main role of agriculture is to produce food for a growing population. However,
this production has to be achieved in an environmentally friendly way that minimizes
the external effects of agriculture related to the emission of green house gases, the
release of nitrogen and phosphorous to the environment and the use and accumula-
tion of harmful pesticides in nature. Agriculture will also need to adapt to climate
change including more extreme weather events. In principle, there are three path-
ways for agricultural development: conventional agriculture (CO), organic agricul-
ture (OA) and conservation agriculture (CA). These pathways have different
approaches for addressing the above issues. This paper will assess how the different
pathways perform in relation to fulfilling the objectives of producing sufficient food
and preserving the environment. The differences between the pathways are sum-
marised in Table 1.
Conventional agriculture (CO) is characterized in high income countries and in
most parts of Asia and America by ploughing, nutrient supply through organic and
mineral fertiliser, limited use crop rotations and the use of synthetic chemicals to
control weeds, pest and diseases. Integrated Pest Management (IPM) is used to a
limited extent. Conventional agriculture in Sub-Saharan Africa is a subsistence ori-
ented type of agriculture characterized by ploughing or hoe cultivation and very low
use of external input like mineral fertiliser and pesticides. Yields are often very low
and nutrient recycling is limited (Fig. 1).
Organic agriculture (OA) is characterized by no use of mineral fertilisers and
synthetic pesticides. Soil fertility is instead maintained through the use of organic
Fig. 1 Conventional agriculture with ploughing causing wind erosion (Photo by cfu Zambia)
fertiliser and biological nitrogen fixation. Pests and diseases are controlled by use of
resistant varieties, crop rotation and natural enemies. This is a more regulated type
of agriculture as the production is certified. Organic agriculture is based on the
principles of health, environment, fairness and care (IFOAM 2009) and has a very
strong ideological underpinning.
Conservation agriculture (CA) can be characterized as direct sowing without any
tillage, complete soil cover and crop rotations (Hobbs et al. 2000). Conservation
agriculture therefore has an opposite approach to tillage, residue management and
crop rotation than conventional agriculture. Mineral fertilisers are permitted in con-
servation agriculture. No certification system has been developed for conservation
agriculture. Conservation agriculture is a system that tries to mimic a natural
ecosystem by minimizing soil disturbance (Fig. 2).
Certified organic agriculture was by the end of 2007 practiced on 32 million
hectares (IFOAM 2009) whereas the area of conservation agriculture (no tillage
systems) is above 100 million hectares (Derpch and Friedrich 2009). Conservation
agriculture is widely practiced in South America and in the USA.
This objective of this review paper is to assess how the different agricultural
pathways affect food production and the environment in temperate as well as in
tropical areas. Limited data are available to assess the environmental consequences
of the pathways in the tropics. Results from temperate areas are therefore used to
analyse the environmental consequences of the different pathways.
152 J.B. Aune
Fig. 2 Conservation agriculture with ripping and retention of crop residues as mulching (Photo by
cfu Zambia)
Currently there are more than one billion people that suffer from hunger and the
number is on the increase (Fan 2010). World production of food will have to increase
by 70% from 2009 to 2050 in order to provide sufficient food for the population
(FAO 2009). Most of this production increase will have to take place in low-income
countries as most of the population growth will occur here. A vital criterion for
assessing the different pathways will therefore be how they contribute to increased
agricultural productivity.
Assessing productivity of conventional, organic and conservation agriculture is a
complicated issue. Productivity of these systems cannot be assessed just by study-
ing productivity at the plot level, but must also be based on analyzing the pathways
in a system perspective. Productivity analysis will therefore be based on yield
extrapolation from historic yield levels, trends in yield levels in countries with dif-
ferent degrees of intensity in agricultural production, productivity without mineral
fertiliser, trends in long-term trials and nutrient balances. General development
trends such as population growth, growth in income, changes in diet and urbaniza-
tion will in addition influence the need for growth in agricultural production.
Conventional, Organic and Conservation Agriculture: Production and Environmental... 153
2.1 Assessment of Yields
There are different views on how the different pathways can contribute to global
food production. Kirchmann et al. 2008a, argue that yields in organic agriculture is
25–50% lower than conventional agriculture depending on availability of manure.
This result is based on official yield data in organic and conventional farms in
Sweden and Finland and on analyzing experiments comparing organic agriculture
and conventional agriculture. A 21-year rotation in Switzerland comparing organic
and conventional farming showed that yields of the organically grown crops were
20% lower than the yields of the conventionally grown crops (Mäder et al. 2002).
Long-term trials in Norway comparing conventional agriculture (ploughing), con-
servation tillage and organic farming showed that yield levels of cereals were similar
in conventional and conservation tillage, but yield levels were 55–60% lower in
organic farming (Korsaeth 2008). A survey of farmers in south-Asia rice-wheat
system showed that yields were equal or higher in fields of zero tillage farmers
compared to in conventional tillage farmers (Erenstein et al. 2008). Yields can be
similar in organic agriculture as in conventional agriculture, but that depends on
sufficient access to organic manure. It is very difficult to produce sufficient manure
on the farm unless farmers have access to large pasture areas. Access to manure is
therefore a key limitation in organic agriculture.
However, comparison of yields under organic and conventional agriculture has
also showed that it is possible to produce enough food with organic agriculture and
that nitrogen fixation can provide adequate nitrogen supply (Badgley et al. 2007).
The paper has, however, been criticized by Connor (2008) and Kirchmann et al.
(2008b) on the grounds that the comparisons undertaken between conventional agri-
culture and organic agriculture are not valid because the assessment for developing
countries were made between plots that did not receive any fertiliser (conventional
agriculture) with plots that received organic fertiliser (organic agriculture). This
gives misleading results as fertilisers are generally applied in conventional agricul-
ture. The study by Badgley et al. (2007) also failed to recognize the increasing com-
petition for organic fertiliser as organic agriculture expands. Furthermore, the study
underestimated the amount of land that has to be sacrificed for growing N-fixing
crops in order to provide sufficient nitrogen.
At the global level, it has been calculated that the type of agriculture that existed
around the year 1900 could provide food for about three billion people (Smil 2001).
This agriculture was similar to organic agriculture as its external input was very low.
However, based on the per capita food supply and including the changed food
consumption habits of 1995, this 1900-type of agriculture can presently only supply
food for about 2.4 billion people. This way of estimating future agricultural productiv-
ity may both underestimate and overestimate agriculture productivity. Underestimation
may occur due to technological and biological advances in organic agriculture that
have come about during the last century. On the other hand, overestimation can result
because of nutrient depletion that often takes place in agricultural systems that do not
receive any mineral fertiliser like in Sub-Saharan Africa (Smaling et al. 1997).
154 J.B. Aune
Plant nutrients supply is a key difference between the agricultural pathways. FAO
calculated that by the mid 1990s mineral fertiliser supplied between 44 and 51% of
nitrogen taken up by crops and this share may increase to 84% in the years to come
(Smil 2001; Fresco 2003). Organic fertiliser, organic recycling and irrigation water
supply about 30–35% of the global crop nitrogen supply in agriculture while the
remaining part is released from soil organic matter.
Nutrient mining must be considered as one of the primary causes of low produc-
tivity in Africa (Sanchez et al. 1997). Net losses of nutrient for N, P, and K have
been found to be respectively 22, 2.5 and 15 kg ha−1 year−1 (Smaling et al. 1997).
These losses occur mainly as a result of nutrient export via harvested products
and soil erosion and these losses must be replenished through nutrient inputs.
Sub-Saharan Africa only uses 2% of the mineral fertiliser that is used globally
(Bellarby et al. 2008).
The importance of fertiliser can be assessed by studying how yields and fertiliser
use have developed over the years in different regions of the world. In Sub-Saharan
Africa and South Asia, cereal yields were below 1 Mg ha−1 in 1960. Yields in 2005
in Sub-Saharan Africa were still below 1 Mg ha−1 whereas yields in South Asia were
about 2.5 Mg ha−1 in 2005 (FAOstat, Morris et al. 2007). Fertiliser use in this period
has remained below 10 kg nutrients ha−1 in sub-Saharan Africa whereas in South
Asia fertiliser use has increased to about 100 kg nutrients ha−1. In East and South
East–Asia cereal yields increased from 1.6 Mg ha−1 in 1960 to 3.7 Mg ha−1 in 2005.
The corresponding fertiliser increase in this period was from 0.01 to about 0.1 Mg
nutrients ha−1. Fertiliser use has been assessed to have contributed 50% of the yield
increase in Asia (Morris et al. 2007).
Conventional, Organic and Conservation Agriculture: Production and Environmental... 155
The first rains are often used for ploughing in conventional and organic agriculture
while in conservation agriculture it is possible to use the first rains for direct sowing
or using planting basins that have been established in the dry season. Earlier sowing
makes it possible for the crops to escape drought and in some cases also pests and
diseases.
Establishment of a permanent soil cover through retention of crop residues on
the soil surface is a challenge for development of conservation agriculture in low–
income countries because crop residues are used for so many other purposes like
fodder, fuel and building material. If farmers are to retain increased amounts of crop
residues they must be provided with alternative sources of fodder, fuel and building
material.
It appears from the studies reviewed that conservation agriculture is more
efficient in building soil organic matter than organic agriculture and conventional
agriculture.
Agricultural soils can both act as a source and a sink of greenhouse gas. Soil acts as
a sink by sequestering carbon in soil and vegetation while emissions of greenhouse
gas from agriculture occur in the form of N2O (nitrous oxide), CH4 (methane) and
CO2. The emissions of CH4 and N2O account for about 10–12% of the total emis-
sions of greenhouse gas in CO2 equivalents (Smith et al. 2007). Methane contributes
54% of the emissions from agriculture and the rest is N2O.
According the IPCC report 2007, deforestation account for about 17% of global
greenhouse gas emissions and expansion of agricultural land is the main cause for
deforestation (Baker et al. 2007). Higher yields in conventional and conservation
agriculture reduce the need to expand the cultivation area into forest and pasture
land. Since yields in OA are 25–50% lower than in conventional agriculture
(Kirchmann et al. 2008a), the land requirements are 50–100% higher. In reality the
land requirements are likely to be higher, because the best land is already taken for
agricultural production. A large study from England and Wales reported that land
requirements increased between 60% and 200% for the different crops when chang-
ing from conventional to organic agriculture (Williams et al. 2006). Agricultural
land requirements in India would be twice as high if the intensification of agricul-
ture through the green revolution had not taken place (Waggoner 1997).
The effect of the different pathways can therefore not be studied by looking at
greenhouse gas emission per hectare and per ton of product produced, but the land
requirements of the different pathways are of equal importance.
Fertiliser can contribute to both increased and reduced greenhouse gas emis-
sions. Increased emissions are related to the release of CO2 and N2O from the pro-
duction and use of mineral fertilisers and reduced emissions can occur if farmers
choose to increase productivity of existing land rather than clearing forests. The
greenhouse gas emissions from the production of mineral fertilisers in the form of
158 J.B. Aune
CO2 and N2O account for about 0.8% of the world’s total emissions of greenhouse
gas (Bellarby et al. 2008) whereas soil N2O from mineral fertiliser represents about
1.2% of the world’s emissions of greenhouse gas (Brentrup 2009). The production
and use of mineral fertiliser therefore represents about 2% of the total emissions of
greenhouse gas. Improved new technologies in the production of fertiliser can
reduce the N2O emission from the production of fertiliser by about 70–90% by
using a de-N2O catalyst (Yara 2007). This technology is now gradually being
introduced in existing and new fertiliser plants.
The effect of the different pathways for agricultural development on the emission
of greenhouse gas has only been measured in temperate agricultural systems. The
global warming potential of conventional, organic and no-tillage agriculture was
compared in an 8-year study including all the greenhouse gas on different plots in the
mid-west United States (Robertson et al. 2000). None of the three systems were able
to mitigate climate change, but no-tillage had lower CO2 emissions than the other
systems. The no-tillage-system, organic system and conventional tillage system had
emissions corresponding to 14, 41 and 114 g CO2 m−2 year−1 (CO2 equivalents)
respectively. Plantation of poplar was able to sequester 105 g CO2 m−2 year−1.
Greenhouse gas emissions from organic and non-organic farming have been
studied in England and Wales (Williams et al. 2006). The results showed that emis-
sions were generally slightly lower for organically produced crops, but emissions
from livestock production were clearly higher in organic production. For wheat,
oilseed rape and potatoes, the emissions were respectively 2%, 4% and 8% higher
in non-organic whereas for poultry, eggs and milk the emissions were 46%, 26%
and 16% higher in organic.
Conservation agriculture appears to have lower emission than organic and con-
servation agriculture because of the lower land-use requirements and the ability of
conservation agriculture to build soil organic carbon.
agriculture (reduced tillage and catch crops) and organic agriculture systems were
compared shows that the organic arable systems have nearly three times as much
nitrogen loss to the environment per energy unit food produced as a conservation
agriculture system (Korsaeth 2008). Arable conservation agriculture performed better
due to higher yield and less leaching of nitrogen. Conventional arable agriculture
also has 50% more nitrogen emissions per kg food energy produced than conserva-
tion agriculture. Danish results showed that nitrogen leaching from organic arable
farms was similar to conventional arable farms (Knutsen et al. 2006). Results from
the UK studying nitrogen loss from organic and conventional farms also showed
higher nitrogen losses (leaching) per kg grain in organic compared to conventional
systems (Stopes et al. 2002). When comparing conventional and organic dairy sys-
tems in the Norwegian long-term experiment, there were no differences in nitrogen
loss per produced unit of energy suitable for human consumption (Korsaeth 2008).
These results indicate that promoting organic agriculture for the purpose of reduc-
ing the amount of nitrogen load to the environment appears not to be an appropriate
approach. Both conventional and organic agriculture can have high nitrogen loss to
the environment. The lower nitrogen use efficiency in organic and conventional
systems compared to conservation agriculture systems in the Norwegian experi-
ments is also an indication of higher loss of nitrogen to the environment. This loss
of nitrogen will contribute to global warming (N2O emissions) and increasing the N
load to the environment.
The loss of nitrogen to the environmental also differ between animal-based and
crop- based systems. This effect is more important than whether the agricultural system
is conventional or organic. Animal based systems will have a higher loss of nitrogen
to the environment per kg of food produced because of nitrogen loss in fodder produc-
tion, in the conversion of fodder to animal products and in loss from manure (Korsaeth
2008). In crop systems up to 50% of the nitrogen is taken up by plants. In milk produc-
tion about 40% of the nitrogen is transferred to milk whereas for beef production only
5% of the nitrogen is transferred to meat (Smil 2002). In a study of different farming
systems in Norway including conventional arable production, conservation agricul-
ture, and organic and non-organic livestock systems, the livestock system had more
than double the loss of nitrogen to the environment per kg metabolisable energy com-
pared to the crop production systems (Korsaeth 2008). A high proportion of meat in
the diet will therefore increase the nitrogen load to the environment.
The results show that conservation agriculture has less loss of nitrogen to the
environment as compared to conventional agriculture and organic agriculture.
However, the losses will also depend on whether the production system is focused
on producing crop or livestock products.
Important soil quality parameters such as soil organic matter, nutrient content and
top-soil depth will also be affected by the choice of agricultural pathway.
160 J.B. Aune
Fig. 3 Burning of crop residues as often practiced in conventional agriculture decreases the
carbon input to the soil (Photo by cfu Zambia)
and temperatures (Buerkert et al. 2000). Research has shown that 1 Mg residue ha−1
is the minimum required to control soil erosion, while if the aim is improving soil
quality the amount of crop residues retained should be in the order of 3 Mg ha−1
(Wall 2009). However, this amount of residue is difficult to produce particularly
under dryland conditions where crop residue yields often are as low as 1 Mg ha−1.
The challenge is therefore to increase crop yields while at the same time retain the
crop residues in the field. Fertilisers will have a key role in order to produce suffi-
cient mulch in CA systems. Retention of crop residues in the field is however diffi-
cult, because the residues are used for other purposes such as fodder, fuel and
building material. In addition, free grazing of the animals is frequently practiced.
Developing conservation agriculture is therefore not only an agronomic challenge,
but calls for an integrated approach involving changes in land-use, livestock
management, energy and input supply and farmers’ institutions.
The nutrient budget is often negative in organic agriculture because the nutrient
outputs from the system will be higher than the inputs. In Sub-Saharan agriculture
low in-input agricultural systems were shown to have a negative nutrient balance
(Smaling et al. 1997).
Soil erosion rates will often be higher in conventional and organic agriculture
because ploughing is often practiced. Ploughing causes high erosion rates in all
agricultural areas with carbon emissions and eutrofication of lakes as end results.
Conservation agriculture is an effective way of controlling soil erosion as the no-till
system can reduce soil erosion rates up to 90% (Vlek and Tamene 2009). The ero-
sion rates are low in conservation agriculture because an undisturbed soil will be
more resistant to the erosive forces of rain and wind and because the mulch protects
the soil.
Conservation agriculture is efficient in improving soil quality because soil
organic carbon content is increased and erosion controlled. Farming systems using
the plough exposes the soil to soil erosion.
One of the major advantages of organic agriculture is the elimination of the use of
pesticides and organically produced food has been found to contain less residues of
pesticides (Baker et al. 2002). Use of pesticides is often high in conventional agri-
culture in order to control pest, diseases and weeds. Conservation agriculture also
uses pesticides, particularly to control weeds. The weed problems may increase
under conservation agriculture because ploughing is not used. However, the envi-
ronmental risks of using glyphosate which is the most commonly used herbicide in
conservation agriculture is limited because it is broken down by micro-organisms in
soil (Borggaard and Gimsing 2008). However, glyphosate resistant weeds have
started to appear particularly in fields where glyphosate is frequently used in crops
that have transgenic glyphosate –resistance (GRC) to tolerate spraying of glyphosate
(Glyphosate Ready Crops) (Powles 2008). The combination of glyphosate resistant
162 J.B. Aune
crops like soybean and maize and extensive use of glyphosate is particularly found
in conservation agriculture is USA and South America. It is a danger that conserva-
tion agriculture in these areas has become so reliant on the use of one herbicide.
However, the problems of glyphosate resistant crops can be overcome by using a
wider mix of herbicides and by giving more emphasis to controlling weeds by cul-
tivation methods. Integrated approaches to control pests are increasingly introduced
in conventional agriculture and conservation agriculture. Use of pesticides is par-
ticularly worrying in low-income countries because there is much less restriction on
pesticide use. A recent development is the use of the label “IPM foods” that signi-
fies low use of pesticides (Baker et al. 2002). This is food produced using Integrated
Pest Management, but use of mineral fertilisers is allowed.
The non-use of pesticides is the major environmental advantage of organic
agriculture. A risk in conservation agriculture is its dependence on the use of
glyphophate which have led to development of weeds resistance to glyphosate when
the herbicide is used frequently in crops with glyphosate resistance.
4 Conclusion
The main objectives of agriculture are to secure the production of sufficient and
nutritious food while at the same time protecting the environment. Conventional
agriculture, today’s dominant agricultural form of agriculture, is efficient in producing
food, but the environmental costs are high.
There are clear differences in the pressure that the different agricultural forms of
agriculture exert on the environment. Conventional and conservation agriculture
have higher yields resulting in less pressure on forest resources. The long-term
productivity of organic agriculture is questionable because the nutrient balance is
often negative.
The strength of conservation agriculture is to build soil organic carbon and reduce
soil erosion thereby making crop production more prepared to climate change.
Conservation agriculture has also lower greenhouse gas emissions and less release
of nitrogen to the environment than the other forms of agriculture. Organic agricul-
ture is better than conventional agriculture in terms of reducing greenhouse gas
emissions per hectare, but requires more land than the other forms of agriculture.
When comparing greenhouse gas emission per kg food produced, there a less clear
difference between organic and conventional agriculture. A problem with the type
of conservation agriculture practiced in the USA and South America is that it has
become so dependent on using glyphosate for weed control.
Conservation agriculture is the agricultural form of agriculture that can best
reconcile the interests of achieving sufficient production and preserving the envi-
ronment. However, conservation agriculture will need to take many forms depend-
ing on the variations in agro-ecological and socio-economical conditions across
the globe. There is therefore a need for continued research on conservation
agriculture.
Conventional, Organic and Conservation Agriculture: Production and Environmental... 163
References
Aune JB, Bationo A (2008) Agricultural intensification in the Sahel. The ladder approach. Agric
Syst 98:119–125
Badgley C, Moghtader J, Quinrero E, Zakem E, Chappel MH, Avilés-Vázquez K, Samulon A,
Perfecto I (2007) Organic agriculture and global food supply. Renew Agr Food Syst 22:86–108
Baker T et al (2007) Technical summary. In: Metz B, Davidson OR, Bosch PR, Dave R, Meyer LA
(eds) IPCC fourth assessment report. Climate change 2007. Mitigation of climate change.
Cambridge University Press, New York, pp 26–93
Baker BP, Benbrook CM, Groth EIII, Benbrook KL (2002) Pesticide residues in conventional,
IPM-grown and organic foods: insights from three U.S. data sets. Food Addit Contam
19:427–446
Bellarby J, Foerid B, Hastings A, Smith P (2008) Cool farming: climate impacts of agriculture and
mitigation potential. Greenpeace International, Amsterdam, 45 p
Borggaard OK, Gimsing AL (2008) Fate of glyphosphate in soil and the possibility of leaching to
ground and surface waters – a review. Pest Manag Sci 64:441–456
Brentrup F (2009) The impact of mineral fertilizers on the carbon footprint of crop production. The
proceeding of the international plant nutrition colloquium XVI, UC Davies, USA, 8 p
Buerkert A, Bationo A, Dossa K (2000) Mechanisms of residue mulch-induced cereal growth
increases in West Africa. Soil Sci Soc Am J 64:346–358
Connor DJ (2008) Organic agriculture cannot feed the world. Field Crops Res 106:187–190
Cordell D, White S (2008) The Australian story of phosphorus: sustainability implications of
global fertilizer scarcity for Australia. Discussion paper prepared for the national workshop on
the future of phosphorus, Sydney, 14 November 2008, Institute for Sustainable Futures,
University of Technology, Sydney, 13 p
Cordell D, Drangert J-A, White S (2009) The story of phosphorus: global food security and food
for thought. Glob Environ Change 19:292–305
Crews TE, Peoples MB (2004) Legumes versus fertilizer sources of nitrogen: ecological trade-offs
and human needs. Agric Ecosyst Environ 102:279–297
Derpch R (2005) The extent of conservation agriculture adaptation worldwide: implications and
impacts. Proceedings of the third world congress on conservation agriculture: linking production,
livelihoods and conservation, Nairobi, Kenya
Derpch R, Friedrich T (2009) Global overview of conservation agriculture adaptation. In: Lead
papers. 4th world congress on conservation agriculture, New Delhi, pp 429–438
Edmeades DC (2003) The long-term effects of manures and fertilisers on soil productivity and
quality: a review. Nutr Cycl Agroecosyst 66:165–180
Erenstein O, Farooq U, Malik RK, Sharif M (2008) On-farm impacts of zero tillage wheat in
South-Asia’s rice–wheat systems. Field Crops Res 105:240–252
Fan S (2010) Halving hunger: meeting the first millennium development goal through “business as
unusual”. International Food Policy Research Institute, Washington, DC, 17 p
FAO (2009) How to feed the world in 2050. http://www.fao.org/wsfs/forum2050/wsfs-background-
documents/issues-briefs/en/. Accessed 13 Oct 2010
Fresco,LO (2003) Fertiliser and the future. FAO spotlight. http://www.fao.org/ag/magazine/
0306sp1.htm. Accessed 20 Sept 2010
Gilbert N (2009) The disappearing nutrient. Nature 461:716–718
Gowing JW, Palmer M (2008) Sustainable agricultural development in sub-Saharan Africa: the
case of a paradigm shift in land husbandry. Soil Use Manage 24:92–99
Giller KE, Witter E, Corbeels M, Tittonell P (2009) Conservation agriculture and smallholder
farming in Africa: the heretics’ view. Field Crops Res 114:23–24
Graves A, Matthews R, Waldie K (2004) Low external input technologies for livelihood improve-
ments in subsistence agriculture. Adv Agron 82:473–555
Hobbs PR, Sayre K, Gupta R (2000) The role of conservation agriculture in sustainable agriculture.
Phil Trans R Soc B 363:543–555
164 J.B. Aune
Vanlauwe B, Giller KE (2006) Popular myths around soil fertility management in sub-Saharan
Africa. Agric Ecosyst Environ 116:34–46
Vlek PLG, Tamene L (2009) Conservation agriculture, why? In: Lead papers. Conference pro-
ceedings. 4th world congress on conservation agriculture, New Delhi, 4–7 February 2009,
pp 10–20
Waggoner PE (1997) How much land can ten billion people spare for nature? In: Ausubel JH,
Langford DH (eds) Technological trajectories and the human environment. National Acad
Press, Washington, DC, pp 56–73
Wall PC (2009) Strategies to overcome the competition for crop residues in Southern Africa: some
light in the end of the tunnel. In: Lead papers. Conference proceedings. 4th world congress on
CA, New Delhi, 4–7 February 2009, pp 65–70
Williams AG, Audsley E and Sandars DL (2006) Determining the environmental burdens and
resource use in the production of agricultural and horticultural commodities. Main Report.
Defra Research Project IS0205. Cranfield University and Defra, Bedford, 97 p
Yara (2007) Case 2007: Yara announces N2O reduction catalyst technology. http://www.yara.com/
about/history/2006-2007/n20_reduction_catalyst_technology.aspx. Accessed 20 Sept 2010
Zingore S, Manyame C, Nyamugafata P, Giller KE (2005) Long-term change in organic matter of
woodland soils cleared for arable cropping in Zimbabwe. Eur J Soil Sci 56:727–736
Improving Water Use Efficiency
for Sustainable Agriculture
Abstract Fresh water resources are becoming scarce and polluted while their
demands for agriculture, domestic, industrial, environmental and recreational uses
are on a continuous rise around the globe. Traditional ways to increase yield by
extending the area under cultivation, using high intensity of external inputs and
breeding for yield potential in high input agro-ecosystems offer limited possibilities
under limiting resource availability. Improved agricultural systems should ensure
high yields via an efficient and sustainable use of natural resources such as water.
This prospect has evoked calls for a “blue revolution” based on the core idea of
obtaining more crop per drop of water. This chapter presents approaches to improve
water use efficiency by better crop, soil and irrigation management, and analyses
underlying physiological and hydrological mechanisms. We found that most man-
agement measures contribute to better water use efficiency by improving water
availability to the crop while reducing unproductive water losses. The main effect of
crop, soil and irrigation management is an increase of the transpiration component
in relation to runoff, soil evaporation and drainage. Also the effect of deficit irriga-
tion methods is achieved partially by reducing stomatal conductance that results in
higher transpiration efficiency. Redistribution of water from soil evaporation to
plant transpiration is the key for better water use efficiency of residue management
and most measures in crop rotation design. Improved water use efficiency by better
A. Raza (*)
Nuclear Institute of Agriculture, Tando Jam, Hyderabad, Pakistan
e-mail: amir.raza@boku.ac.at
J.K. Friedel
Division of Organic Farming, Department of Sustainable Agricultural Systems,
University of Natural Resources and Life Sciences, Vienna, Austria
G. Bodner
Institute of Agronomy and Plant Breeding, Department of Applied Plant Sciences
and Plant Biotechnology, University of Natural Resources and Life Sciences,
Vienna, Austria
agronomy is achieved most effectively by an integral set of measures that are evalu-
ated over the whole crop rotation. Processes underlying most improvements of
water use efficiency in agronomy suggest that research should target plant water
uptake capacity. We conclude that an integral system approach and an interdisci-
plinary focus on possibilities for root system management are most promising for a
better water use and sustainable productivity in agriculture.
Keywords !GRONOMY s 7ATER USE EFlCIENCY s $ROUGHT TOLERANCE s 7ATER BALANCE
s 3OIL AND CROP MANAGEMENT s 2OOT WATER UPTAKE
1 Introduction
World population is projected to reach 9.4 billion by 2050 and 10 billion by 2100
(Fischer and Heilig 1997). Highest increase (3.5 billion) is expected to occur in
developing countries of South Asia and sub-Saharan Africa. Agriculture is confronted
with the challenge of feeding the rapidly growing population under a scenario of
decreasing land and water resources worldwide (Bossio and Geheb 2008). Global
estimates of food-insecure populations comprise 825 million (Lobell et al. 2008) to
850 million (Borlaug 2007), mainly in South and Southeast Asia and sub-Saharan
Africa. Contrary to United Nations’ Millennium Development Goals of cutting hun-
ger by half by 2015, the number of food-insecure populations in the world is likely
to grow (WWAP 2009).
Since the 1990s yields have not increased at the pace registered since the
1950s, while world population continues to rise (Araus et al. 2008). The “yield-gap”
(Röckström 2001) is expected to further aggravate due to climatic change impacts
such as extending soil degradation and higher frequency of droughts (IPCC 2007;
Bates et al. 2008; Trondalen 2008).
Globally, agriculture accounts for 80–90% of all freshwater used by humans, and
most of that is in crop production (Wallace 2000; Shiklomanov 2003; Morison et al.
2008). Still, water is the main abiotic stress limiting crop production in several
regions of the world (Araus et al. 2002; Ali and Talukder 2008). In 2030, 47% of the
world population will be living in areas of high water stress (WWAP 2009). Even
where water for irrigation is currently plentiful, there are increasing concerns about
future availability (Falkenmark 1997). The competition from industrial and urban uses
is increasing with demographic pressure and rapid industrialization (Gleick 2003;
Kondratyev et al. 2003; Johnson et al. 2001). The scarcity of fresh water is also
exacerbated by non-point and point source pollutions (Tilman et al. 2006), particu-
larly salinization of groundwater aquifers (UNEP 1996). Global water pollution is
on rise as every day two million tons of sewage and industrial and agricultural waste
are discharged into the world’s water (WWAP 2003). Seventy percent of untreated
industrial wastes in developing countries are disposed into water where they
contaminate the existing water supplies (UN-Water 2009). Mean nitrate levels
have risen globally by an estimated 36% in global water ways since 1990, with the
Improving Water Use Efficiency for Sustainable Agriculture 169
Table 1 Options for improving irrigation efficiency at a field level (Adapted from Wallace and
Batchelor 1997)
Improvement category Options
Agronomic 1. Crop management to enhance precipitation capture or reduce water
evaporation e.g., crop residues, conservation till, and plant spacing
2. Improved varieties
3. Advanced cropping strategies that maximize cropped area during
periods of lower water demands and/or periods when rainfall may
have greater likelihood of occurrence
Engineering 1. Irrigation systems that reduce application losses, improve distribution
uniformity, or both
2. Cropping systems that can enhance rainfall capture e.g., crop
residues, deep chiseling or paratilling, furrow diking, and dammer-
diker pitting
Management 1. Demand-based irrigation scheduling
2. Slight to moderate deficit irrigation to promote deeper soil water
extraction
3. Avoiding root zone salinity yield thresholds
4. Preventive equipment maintenance to reduce unexpected equipment
failures
Institutional 1. User participation in an irrigation district or scheme operation and
maintenance
2. Water pricing and legal incentives to reduce water use and penalties
for inefficient use
3. Training and educational opportunities for learning newer, advanced
techniques
most dramatic increase seen in Eastern Mediterranean and Africa, where nitrate
concentration has more than doubled (GEMS 2004).
Traditional approaches of yield maximization were based on (i) increase in area
under cultivation, (ii) high intensity of external inputs (fertilizer, irrigation) and
(iii) breeding for high yield potential in high input agroecosystems (“green revolution
varieties”) (Richards 2004; Waines and Ehdaie 2007).With decreasing land and water
resources, for the future these ways offer limited possibilities to satisfy the increasing
food demand. Improved agricultural production systems are required that ensure
high yield via an efficient and sustainable use of available natural resources. This
prospect has been evoked calls for a “blue revolution” (e.g. Lynch 2007; Finkel 2009)
based on the core idea of obtaining “more crop per drop” (UNIS 2000).
Improvements in agricultural water use can be achieved at several points along
the production chain, such as (1) the irrigation system (2) the proportion of water
attributed to plants use, and (3) the conversion of crop water consumption into yield
(Hsiao et al. 2007). Gravity driven irrigation systems can have efficiencies as low as
40%, being a main limiting factor for a productive water management (Howell 2001).
Better water use efficiency in field crop production can be achieved by adequate soil
and crop management measures. Wallace and Batchelor (1997) resumed four options
for enhancing water use efficiency in irrigated agriculture (Table 1) and pointed out
that focusing on only one category will likely be unsuccessful.
170 A. Raza et al.
Water use efficiency can be defined for different spatial and temporal scales and
according to the respective research focus (Passioura 2002, 2006). Table 2 gives
an overview of common definitions and scales where water use efficiency (WUE)
is studied.
Different integrative water use efficiency terms are often used interchangeably
in literature, e.g. transpiration efficiency, biomass water-use efficiency (WUEb;
e.g. Tambussi et al. 2007) and biomass water productivity (WUEb; e.g. Steduto
et al. 2007). Subscripts can be used to clearly indicate the relation of the numerator
to either biomass or yield.
Up scaling of water use efficiency from instantaneous leaf gas exchange to a time
integrated biomass or yield related parameter is complex and requires consideration
of relevant processes and environmental influences at the distinct scales (Steduto
et al. 2007). While intrinsic water use efficiency is largely controlled by stomatal
resistance, boundary layer effects can substantially affect the ratio of carbon to
water vapour fluxes at the leaf and canopy level when plant-atmosphere coupling is
imperfect (Jones 2004a; Passioura 2006).
At the whole plant level, transpiration efficiency of vegetative biomass under
given environmental conditions is a rather conservative measure (Steduto et al. 2007)
and mainly a function of the photosynthetic pathway. When targeting yield, the
Improving Water Use Efficiency for Sustainable Agriculture 171
Drought tolerance
Fig. 1 Mechanism of drought tolerance. Plants tolerate drought by using different mechanisms
including drought avoidance, dehydration tolerance and drought escape. These mechanisms are
governed by physiological processes and help plants to sustain growth and reproduction under
drought conditions (after Levitt 1972 and Jones 2004a)
where WU is plant water uptake, WUE is water use efficiency and HI is har-
vest index.
An extended model of overall water use efficiency across several scales was
proposed by Hsiao et al. (2007) to allow a stepwise analysis of all relevant efficien-
cies along the whole production chain. This conceptual model covers the efficiency
of the irrigation system, the efficiency of crop water use at the field scale and
the efficiency of assimilation and yield formation with a given amount of water.
In rain-fed agriculture Hsiao et al. (2007) introduced two soil management related
terms, being infiltration and rhizostorage efficiency. These terms again point to the
water balance concept as given in Eq. 2.
Equations 1–3 reveal the two relevant sides for a mechanistic analysis of agro-
nomic options to improve water use efficiency, being (i) physiological processes of
biomass production and drought tolerance of plants, and (ii) hydrological and soil
physical mechanisms of water dynamics.
Knowledge on relevant drought tolerance mechanisms is of high importance to
improve crop production in water limiting environments (see Farooq et al. 2009).
Figure 1 gives an overview of plant responses to drought in natural ecosystems
following Levitt (1972).
Most adaptations that have evolved in plant communities of dry ecosystems are
at the cost of reduced plant growth while ensuring reproductive survival. Comparing
two wheat cultivars differing in carbon isotope discrimination, Condon et al. (2004)
demonstrated that superior water use efficiency translated to better crop performance
only under high drought stress of soil water storage-driven environments. As shown
by Blum (2005), the potential agronomic use from a given mechanism of drought
tolerance depends on the characteristics of the drought environment (severity,
duration and timing of stress). He critically analyzed the breeding focus on water
use efficiency because drought tolerance traits improving plant water extraction and
leading to sustained stomata opening and assimilation might even result in lower
Improving Water Use Efficiency for Sustainable Agriculture 173
water use efficiency (Blum 2009). Therefore he suggests a shift to the concept of
effective water use which agrees to the conclusion of Jones (2004a) on the key
importance of and efficient use of available soil water in field crop production.
Affectivity of water use is considered in Eq. 3 in terms of the proportion of
transpiration in relation to the loss components in a water balance frame. In the
conceptual model of Hsiao et al. (2007) for dry land cropping, this uptake efficiency
would correspond to the combined effect of infiltration, rhizostorage, consumptive
and transpiration efficiencies.
An effective water use requires consideration of soil hydrological aspects
and their interaction with plant traits. In simplified way water use effects of
soil and plant parameters can be characterized by a relationship commonly used in
hydrological modelling (e.g. ŠimĬnek et al. 2008)
The definitions of water use efficiency as given in Table 2 imply that appropriate
methods have to be used for quantification at different scales. At the leaf scale,
water use efficiency is characterized by measurements of gas exchange and stomatal
conductance. The underlying methods of measuring CO2 and H2O fluxes are straight-
forward and several types of measurement devices are available.
A method relying on gas exchange physiology, but providing a time integrated
view of water use efficiency is carbon isotope discrimination (Farquhar and Richards
1984). Carbon isotope technique has been used to select genotypes possessing
174 A. Raza et al.
better water use efficiency (Johnson et al. 1990; Martin et al. 1999; Condon et al.
2004). Still the use of carbon isotope discrimination for crop improvement strongly
depends on the hydrological regime (Monneveux et al. 2005). It has been applied
most successfully to select adapted genotypes in storage driven and terminal drought
environments. This was explained by the conservative water use of cultivars with
high water use efficiency (low carbon isotope discrimination) ensuring sufficient
water availability at grain filling. Also their phenology was adapted to terminal
drought environments showing earlier flowering which is a characteristic drought
escape strategy (Condon et al. 2004). Under intermittent drought and potential yield
conditions, carbon isotope discrimination can also be negatively related to crop
performance.
A proper quantification of water use efficiency on the whole plant scale requires
an accurate measurement of the transpiration component. Frequently water rela-
tions are studied in pot experiments which allow a simple and precise measurement
of transpiration when withholding soil evaporation. Still care must be taken when
extrapolating results from pot experiments to the field due to (i) alterations of root
growth in the confined system and (ii) influences of pot size on water availability
and transpiration (Ray and Sinclair 1998).
In field studies, transpiration is mostly calculated via the water balance equation.
This however implies at least two uncertainties. First the other components of
the water balance (i.e. precipitation/irrigation, runoff, drainage, and change in
profile water content) have to be quantified accurately. While runoff can easily be
avoided by a proper site selection, the drainage component is very difficult to
measure. The most adequate instrument to determine all water balance components
are lysimeters. As they are not available in most cases, water use efficiency values are
frequently derived from measurements of change in profile water content only using
different water monitoring techniques and assuming zero drainage. We therefore
assume that differences in water use efficiency estimates found in literature often
derive from methodological difficulties of quantification of the water balance
components and errors originating in simplified assumptions.
Even with properly measured evapotranspiration, a further uncertainty arises from
the separation between soil evaporation and plant transpiration. Although there are
efforts to develop methods based on isotope composition (Hsieh et al. 1998), still
most studies rely on calculations based on Beer’s law and measurements of leaf area
index and radiation extinction coefficients (Brisson et al. 2006).
Due to difficulties in measurement, water use efficiency effects are frequently
evaluated using simulation models. Policy makers and water resource managers
have to deal with multitudinous scenarios of cropping systems, amounts, timing
and method of irrigation and fertilizer application for bringing improvement in water
use efficiency. Experimentation cannot address all scenarios, but accurate simulation
models may fill in the gap when appropriately parameterized and validated.
Different simulation models (e.g. AquaCrop, CropSyst, DSSAT, GOSSYM,
WOFOST) have been used to simulate yield and water use under a variety of
environmental, management and cropping regimes. Simulation of crop performance
in the FAO model, AquaCrop (Steduto et al. 2007) is based on a normalized
Improving Water Use Efficiency for Sustainable Agriculture 175
2 Better Agronomy
Table 3 Food and Agriculture Organization recommendations for practical measures to improve
agricultural water use efficiency in irrigated agriculture (FAO 1997)
Objective Measure
Enhancement of crop 1. Select most suitable and marketable crops for the region
growth 2. Use optimal timing for planting and harvesting
3. Use appropriate insect, parasite and disease control
4. Apply manures and green manures where possible and fertilize
effectively preferably by injecting the necessary nutrients into
the irrigation water
5. Use optimal tillage to avoid excessive cultivation
6. Practice soil conservation for long-term sustainability
7. Irrigate at high frequency and in the exact amounts needed to
prevent water deficits, taking account of weather conditions and
crop growth stage
8. Avoid progressive salinization by monitoring water-table
elevation and early signs of salt accumulation, and by
appropriate drainage
Conservation of water 9. Reduce direct evaporation during irrigation by avoiding midday
sprinkling. Minimize foliar interception by under-canopy, rather
than by overhead sprinkling
10. Reduce runoff and percolation losses due to over irrigation
11. Reduce evaporation from bare soil by mulching and by keeping
the inter-row strips dry
12. Reduce transpiration by weeds, keeping the inter-row strips dry
and applying weed control measures where needed
13. Reduce conveyance losses by lining channels or, preferably,
by using closed conduits
The following section will review the potential impact of crop, soil and irrigation
management practices as well as the mechanisms underlying their expected effects
on water use efficiency.
Crop management practices include decisions on sowing date, planting density, crop
rotation, phytosanitary measures and cultivar selection. These practices influence
agronomic water use efficiency by adapting the cropping system to the environmental
site conditions and providing optimum growth conditions for the single crop in order
to obtain maximum yield with available resources. Crop management practices
influence water use efficiency at the level of field crop stands, single plants and
physiological processes (Fig. 3). Beside crop husbandry, also management of
soil fertility by fertilization is considered here, although it strongly interacts
with soil management measures that are considered in Sect. 2.2.
Improving Water Use Efficiency for Sustainable Agriculture 177
Fig. 2 Effect of management practices on water use efficiency. Management practices can
improve water use efficiency by affecting yield and transpiration efficiency. The affectivity of any
management practice will depend on its interaction with environment
Sowing date of crops can significantly affect water use efficiency (Morrison and
Stewart 2002; Turner 2004; Gunasekera et al. 2006). Early sowing has frequently
been found to improve yield and water use efficiency (Gregory 2004), while yields
were reduced by delayed sowing (Oweis et al. 2000; Faraji et al. 2009).
In environments where water is the limiting factor, sowing date should adapt crop
growth and development to water availability (water storage, rainfall distribution)
within the restrictions imposed by other constraints (early droughts, frost, timing of
weed management). An appropriate sowing date can enhance early vigour of the crop
with better canopy cover of the soil surface. This reduces evaporation losses in favour
of transpiration (Tambussi et al. 2007). Increased water use efficiency of early sown
crops and winter-grown varieties is also related to the lower evaporative demand of
the atmosphere during part of the growing period (Purcell et al. 2003). Humphreys
et al. (2001) showed that early sowing of winter crops immediately after rice harvest
increased the water use efficiency of rice-based cropping systems by better use of
178 A. Raza et al.
Light
(e a -e )
i
(p a -p )
i
gs
CO2 H 2O
PROCESSES
Boundary layer resistance Source-sink relations Stomata conductance
Radiation interception Assimilate remobilization Mesophyll conductance
Inter-plant competition Disease resistance Photosynthetic capacity
MANAGEMENT MEASURES
Seeding date and method Crop type and cultivar selection Fertilization
Planting density Phytosanitary control Breeding
Crop rotation
Fig. 3 Measures and processes involved in regulation of water use efficiency. Management
measures positively affect physiological processes at single leaf scale. These effects are trans-
formed into better growth of individual plants with consequences of increase in overall water use
efficiency of crop stands
stored soil water and capture of winter rainfall instead of loosing it as runoff or deep
percolation. An appropriate sowing time of cereals also contributes to avoid summer
drought in Mediterranean climates, i.e. it benefits from a drought escape strategy
which ensures sufficient water supply for yield formation (Tambussi et al. 2007).
Using appropriate method of sowing can also help to improve water use efficiency.
Particularly sowing depth can influence early vigour and hence soil evaporation
(Ali and Talukder 2008). Deeper sowing combined with cultivars with longer
coleoptiles was found to increase growth vigour, yield and water use efficiency of
wheat in environments with early droughts as seedlings could make better use of
soil moisture (Rebetzke et al. 2007). Research in southern Queensland found that
water use of rice grown on beds was 32% less than when grown using conventional
permanent flood, while yields were maintained, resulting in a large increase in water
use efficiency (Borrell et al. 1997). Sowing of crops on precisely levelled fields can
also affect water use efficiency positively by ensuring uniform distribution of irriga-
tion water over the entire field and thereby ensure homogeneous and quick stand
establishment. Laser levelled fields exhibited 98.7% and 29.4% higher water use
efficiency as compared to unlevelled and traditionally levelled fields in case of
wheat. Use of laser land levelling surely increases grain yield and saves irrigation
water as compared to traditional method of sowing (Asif et al. 2003).
Improving Water Use Efficiency for Sustainable Agriculture 179
Sowing of crops with proper row spacing can also affect water use efficiency.
Karrou (1998) found that water use efficiency decreased with increasing row
spacing from 12 to 24 cm in wheat. Azam-Ali et al. (1984) on the contrary found
that increasing row spacing in pearl millet from 37.5 to 150 cm increased water use
efficiency for dry matter production from 2.1 to 4.7 kg m–3. It was due to the reason
that widely spaced plants used water more efficiently as compared to narrow and
medium spaced plants in this study. A major influence of row spacing is related to
soil evaporation that can be reduced by narrowing row distance (Chen et al. 2010).
High stand densities increase intra-plant competition. Therefore the effect of row
spacing on yield strongly depends on crop species, formation of yield components
and seasonal water availability. Ritchie and Basso (2008) for example showed that
modern cultivars of maize can be planted at higher densities as traditionally used,
thereby increasing yield and decreasing evaporation losses. Crops such a cereals
have high plasticity in plant architecture and yield components (Simane et al. 1993)
so that yield formation remains unaffected over a wide range of row spacing
(Gregory 2004).
The technique of seed priming has been shown to improve plant stands and
provide benefits in terms of earlier canopy closure and increased seed yield for a range
of crops such as wheat, maize, lentil, chickpea in rain fed as well as for irrigated
crops (Ali 2004; Rashid et al. 2002). Seed priming involves soaking seeds in
water for a specific period usually overnight, then surface dried and then sown.
This technique reduces the pre- or post-sowing irrigation needs, saves water and
increases the water use efficiency. Germination and water use efficiency of barley
was improved by 95% and 44%, respectively due to seed priming as compared to
unprimed seed (Ajouri et al. 2004).
the soil for subsequent crops in rotation (Gan et al. 2009). Effect of crop management
practices on water use efficiency is shown in Table 4. These values are indicated
here only to demonstrate the potential of a crop management practice on water use
efficiency and may vary greatly among regions as well as with application of sup-
porting soil and irrigation management practices.
Appropriate choice of crop sequence can improve water use efficiency by helping
to control diseases and weeds. Weeds compete for water and nutrient resources of the
main crops. Weeds can considerably decrease crop growth and water use efficiency
particularly in food legume crops which have slower initial growth than many cereals.
Weed control ensures that water stored in soil is used by the crops (Gregory 2004).
Also the efficiency of fallowing to increase water availability for the next season is
highly dependent on weed control (Gregory 2004). In lentil for example weed control
almost doubled dry matter production and water use efficiency (Cooper et al. 1987).
Control of pests and diseases by an appropriate crop rotation can be an efficient
way to increase yield and water use efficiency. Paul and Ayres (1984) for example
reported that plants infected with leaf rust showed reduced water use efficiency,
particularly under dry conditions.
Crop type and cultivar selection contributes to adapt the production system to
environmental growth conditions and it is fundamental for site specific optimization
of water use efficiency. Distinct response to water limiting conditions occurs due
to (i) different photosynthetic pathway and (ii) different energy requirements for
yield formation, as well as (iii) progress in breeding of adapted drought tolerant
varieties.
Plants with the C3 photosynthetic pathway are less efficient in water use than
plants with the C4 pathway, especially at higher temperatures and lower CO2
concentrations (Condon et al. 2004; Long 2006; Ali and Talukder 2008). In species
with C4 photosynthesis high photosynthetic rates can be associated with low sto-
matal conductance, leading to high water use efficiency (Cowan and Farquhar 1977;
Schulze and Hall 1982). In C4 plants carboxylation is carried out by an enzyme (PEP
carboxylase) with stronger affinity for CO2 than in C3 species (Rubisco), leading
to a lower intercellular CO2 concentration and thus a higher driving force gradient
182 A. Raza et al.
Table 5 Water use efficiency (kg m−3) of crops in the Mediterranean region. Values refer to
relationship between yield and evapotranspiration (After Katerji et al. 2008)
Crop Water use efficiency Reference
Wheat 0.5–9.4 Oweis (1997), Katerji et al. (2005b), Pala et al. (2007)
Corn 1.36–2.15 Karam et al. (2003), Dagdelen et al. (2006)
Sunflower 0.39–0.72 Marty et al. (1975), Katerji et al. (1996)
Soybean 0.39–0.77 Katerji et al. (2003), Karam et al. (2005)
Broad bean 0.45–1.37 Katerji et al. (2003), Katerji et al. (2005a)
Chickpea 0.4–0.98 Oweis et al. (2004), Katerji et al. (2005a)
Lentil 0.36–2.09 Katerji et al. (2003), Oweis (2004)
Cotton 0.61–1.3 Dagdelen et al. (2006), Karam et al. (2006)
Barley 1.46–2.78 Katerji et al. (2006)
Sorghum 0.67–1.59 Mastrorilli et al. (1995)
Potato 16.2–18.5 Katerji et al. (2003)
Sugar beet 6.6–7.0 Katerji et al. (2003)
Tomato 4.4–8.3 Katerji et al. (2003)
Grapes 16–18.1 Rana and Katerji (2007)
for CO2 uptake (Nobel 1991; Chaves et al. 2004). With rising atmospheric CO2
levels, it is likely that transpiration efficiency will increase in C3 crops. Except
for maize and sorghum, the world’s major food crops are C3 plants. Field experi-
ments with free-air CO2 enrichment have shown substantial improvement in
biomass, especially where water is limiting. With C4 crops such as maize and
sorghum, free-air CO2 enrichment experiments have shown negligible growth
responses to elevated CO2 (Passioura and Angus 2010). Some benefit of elevated
CO2 on C4 crops was shown in drought conditions due to reduced water use (Sun
et al. 2009). Following attempts to use conventional hybridization to get C3–C4
hybrids, some biotechnological advances to transformed C3 plants to acquire C4
characteristics have been reported (Matsuoka et al. 2001; Parry et al. 2005).
In relation to yield, water use efficiency decreases from cereals over legumes to
oil crops due to higher energy requirements in yield formation (Steduto et al. 2007;
Jones 2004a). High water use efficiencies are obtained in forage crops where the
entire aboveground portion of the plant is harvested. Higher water use efficiency for
forage crops when compared to seed crops is also related to lower non-productive
water losses through evaporation under their closed canopies (Hatfield et al. 2001).
Nielsen et al. (2005) found the highest average water use efficiency among forage
crops for forage pea (2.28 kg m–3 1), declining to 1.14 kg m–3 for corn silage (Nielsen
et al. 2005). Table 5 gives an overview of water use efficiencies of different crops
grown under Mediterranean conditions.
Water use efficiency varies between different genotypes of the same crop
(Hufstetler et al. 2007; Jaleel et al. 2008; Rajabi et al. 2009). Much effort has been
dedicated to breed for higher water use efficiency. Reynolds and Tuberosa (2008)
give an overview of breeding advances for improved productivity in drought-prone
environments. Following Passioura’ framework, most success was achieved via
higher harvest index (Condon et al. 2004). Only recently breeding efforts for enhanced
Improving Water Use Efficiency for Sustainable Agriculture 183
Yield
Water
No stress High stress
Fig. 4 Response of cultivars under water stress. Cultivars may vary in their response to water stress.
High water use efficiency under water stress can be due to increase in transpiration efficiency, low
stomatal conductance or high yield potential
water uptake capacity by targeting root parameters are reported (Yusuf Ali et al. 2005;
Kato et al. 2006; Gregory et al. 2009). Substantial progress therefore can be expected
in future from improved root systems as Waines and Ehdaie (2007) showed that
breeding of high yielding “green revolution” varieties has lead to small root systems
with low uptake capacity. Useful traits for improved drought tolerance depend on the
characteristics of the drought environment itself (van Ginkel et al. 1998). In relation
to water use efficiency, Condon et al. (2004) showed that wheat cultivars efficient in
water use and selected based on carbon isotope discrimination by reduced stomatal
conductance performed better and attained higher yields in stored-moisture envi-
ronment, than in environments where they have to rely upon in-season rainfall.
Genotypes where higher water use efficiency is related to photosynthetic capacity
(“capacity types”) and not to lower stomatal conductance (“conductance types”)
would result in sustainable yield improvements. Considering the typically erratic
nature of rainfall in dry areas with dry and wet years, Blum (2005, 2009) concluded
that sustainable optimization of yield should be obtained by maximising water uptake
efficiency rather than water use efficiency. Figure 4 gives an overview of expected
yield response to drought of cultivars from these different selection targets.
Relationships between nutrients and water use efficiency were first described by
Viets (1962). The roles of different nutrient elements are discussed by Marschner
(1995) and their effect on water use efficiency was reviewed by Davis (1994) and
Raven et al. (2004).
184 A. Raza et al.
Water availability and nutrient supply are interacting factors in determining crop
growth and crop water use efficiency. The efficiency of nutrients to increase yield
depends on water supply according to the law of optimum: For higher production,
the plant can make better use of the growth factor being in minimum, the more the
other growth factors are within the optimum (Claupein 1993). With increasing water
stress, nutrient availability as well as nutrient uptake capacity of the plant are
impaired and the marginal return in terms of yield increase per unit of applied nutrient
decreases (Ehlers and Goss 2003). Drought can limit nutrient availability due to
reduced mineralization of organic matter and lower transport of nutrients to the root.
Both, convective transport of non-adsorbing solutes (e.g. nitrate) as well as diffusive
transport of adsorbing nutrients (e.g. phosphate) is reduced with increasing water
shortage. Decreasing transpiration flux can cause nutrient deficiency in leaves due
to reduced xylem transport of dissolved nutrients from roots to the aboveground
plant parts (Alam 1999).
Nutrient uptake capacity is significantly influenced by root system parameters.
Root growth and root distribution are modified by nutrient availability and distribu-
tion in the soil (Hodge 2004). Plants respond to low nutrient availability by enhanced
root growth and root exudation. If water use efficiency is related to aboveground
biomass or yield, it can even decrease with increasing investment of assimilates and
energy into the root system (Raven et al. 2004).
The nutritional status of the crop influences stomatal response and water use
efficiency at leaf, whole plant and crop stand scale. Several physiological processes
relevant for water use efficiency are affected by nutrient deficiencies, such as
osmotic pressure, stomata regulation, photosynthesis and activity of nitrate reductase
in plant leaves (Hu and Schmidhalter 2005; Li et al. 2009).
At the whole plant and crop stand scale, the nutrient status influences growth
rate, leaf area and green leaf duration as well as assimilate partitioning (Davis 1994;
Gregory 2004). When relating water use efficiency to total evapotranspiration,
improvement by fertilizer input is obtained via increase in early canopy growth so that
it shades the surface and thereby reduces the proportion of soil evaporation on total
evapotranspiration (Schmidhalter and Studer 1998; Gregory 2004). Higher nutrient
availability leads to a different rate of increase in water use and crop yield. Early
studies already reported that improved nutrient status promoted yield more than
water use and therefore resulted in better water use efficiency (Power 1983; Ritchie
1983). Also Hatfield et al. (2001) consider fertilization as a principal measure to
improve plant growth and yield and thereby increase water use efficiency.
Nitrogen (N) management is one of the major factors to attain higher crop
productivity. Nitrogen effects have been described on gas exchange as well as inte-
grative agronomic water use efficiency. Positive effects of nitrogenous fertilizers
include increase in leaf area index, green crop duration and dry matter production
that ultimately lead to increase in water use efficiency (Latiri-Souki et al. 1998).
Up to 75% of leaf nitrogen is present in the chloroplasts, most of it in the
photosynthetic machinery which gives a positive relationship between light-saturated
rate of photosynthesis and leaf nitrogen concentration (Evans and Seemann 1989).
Leaf nitrogen is correlated with photosynthetic capacity by influencing Rubisco
Improving Water Use Efficiency for Sustainable Agriculture 185
activity and the capacity of electron transport. Although assimilation is not directly
proportional to leaf nitrogen, an enhanced photosynthetic capacity due to better
nitrogen-supply can results in higher transpiration efficiency at a given stomatal
conductance (Shangguan et al. 2000).
Nitrogen deficiency can reduce mesophyll conductance and to a lesser extent,
stomatal conductance (Jacob et al. 1995). Also Ciompi et al. (1996) related lower
gas-exchange water use efficiency of nitrogen-deficient sunflower leaves to a more
pronounced reduction of mesophyll activity compared to stomatal conductance.
Beside physiological processes, a main effect of nitrogen-deficiency on water use
efficiency is found on the whole plant and crop stand level. Restricted development
of nitrogen-deficient plants is usually due to a lower rate of leaf expansion rather
than to a decline in the rate of photosynthesis per unit leaf area (Sage and Pearcy
1987). Reduction in leaf expansion and leaf area under low nitrogen supply decreases
radiation interception and leads to higher evaporation losses (Davis 1994). Therefore
higher water use efficiency of well fertilized plants is mostly explained by a higher
proportion of transpiration in relation to total evapotranspiration. When water use
efficiency is related to yield, an additional advantage of nitrogen fertilization is
prolonged green leaf area duration and higher harvest index (e.g. Lawlor 2002).
However, ample nitrogen supply could also result in abundant vegetative growth
which may induce water shortages during yield formation as well as increased
lodging (Ehlers and Goss 2003).
The effect of nitrogen on root water uptake capacity is complex (Li et al. 2009).
Rational use of fertilizers can enhance root growth, while high levels of
nitrogen tend to reduce root penetration into the soil and restrict formation of fine roots
and root hairs, which could increase crop susceptibility to temporal water shortage.
Increased water use efficiency due to nitrogen fertilization was reported for grain
sorghum and maize by Varvel (1995) and Ogola et al. (2002). Higher water use
efficiency due to increased biomass production with improved nitrogen supply have
also been reported for wheat and corn by Campbell et al. (1992) and Varvel (1994),
respectively. A 25% increase in water use efficiency of chickpea has been reported
through application of nitrogen fertilizer (Bahavar et al. 2009). In the Sahel, water
use efficiency of Pearl millet was improved through the combination of nitrogen
management and increased plant densities (Payne 1997).
The efficiency of nitrogen management to improve water use efficiency is
influenced by environmental conditions. Under limited water supply, crop response
to higher dose of inorganic fertilizer is restricted (Hatfield et al. 2001). Under such
conditions, timing and dose of fertilizer application shall be adjusted based on
available soil moisture if positive effects of nitrogen application are to be fully
realized (Passioura 2006).
Phosphorus is required for several physiological processes including storage and
transfer of energy, photosynthesis, regulation of some enzymes, and transport of
carbohydrates (Hu and Schmidhalter 2005). Soils in arid Mediterranean areas as
well as large areas in the tropics suffer from low phosphate availability. Phosphorus
supply to the plant in these regions is further reduced by dry soil conditions that
lower diffusion rates to the roots (Simpson and Pinkerton 1989). Plant phosphorus
186 A. Raza et al.
uptake efficiency is strongly influenced by root traits (Lambers et al. 2006; Lynch
2007) as well as mycorrhization (Bolan 1991), while sufficient soil phosphorus can
enhance root growth, water uptake and water extraction from deep soil layers (Dang
1999). Payne et al. (1992) found an increase of transpiration efficiency at the whole
plant as well as the leaf scale. Increasing phosphorus availability resulted in stron-
ger increase in photosynthetic rate compared to transpiration rate. Phosphorus defi-
ciency was found to lower the level of light saturation which could explain observed
inhibition of photosynthetic rate (Payne et al. 1992). On the whole crop level, strong
effects of additional phosphorus supply on dry matter production and water use
efficiency, particularly under low water availability, have been reported for millet by
Brück et al. (2000). Kundu et al. (2008) showed increasing leaf area index and
higher water use efficiency of common bean with higher phosphorus supply.
Addition of phosphatic fertilizer has been reported to enhance water use efficiency
of different crops (Hatfield et al. 2001), such as pearl millet (Payne et al. 1992,
1995) and chickpea (Singh and Bhushan 1980).
The positive effect of potassium (K) on water stress tolerance is related to several
physiological processes (Pettigrew 2008). Potassium maintains the osmotic poten-
tial and turgor of the cells (Hsiao 1973) and regulates the stomatal functioning (Kant
and Kafkafi 2002; Benlloch-González et al. 2008). Potassium enhances photosyn-
thetic rate, yield and water use efficiency under stress conditions (Tiwari et al. 1998;
Egila et al. 2001; Umar and Moinuddin 2002). Improvement of potassium nutri-
tional status has also been found to protect plants against oxidative damage during
drought stress (Cakmak 2005).
Potassium promotes root growth of plants which in turn leads to a greater uptake
of nutrients and water by plants (Saxena 1985; Rama 1986). Gerardeaux et al.
(2010) described effects of potassium deficiency on cotton. Potassium stress during
vegetative development decreased plant dry matter production and leaf area,
increased dry matter partitioning to leaves and specific leaf weight. Severe deficiency
also reduced partitioning to roots and inhibited leaf photosynthetic rates.
Positive effect of potassium on drought tolerance include enhancement of deep
rooting, protection against tissue dehydration, optimization of stomatal opening and
closure resulting in better water use efficiency, detoxification of toxic oxygen radi-
cals, and improvement in translocation of photo assimilates (Römheld and Kirkby
2010). Higher application of potassium such as 125 and 200 kg ha–1 increased water
use efficiency of barley for dry matter production by 12% (Andersen et al. 1992).
He et al. (1999) conducted experiments to clarify the effects of water, nitrogenous
and potassium fertilizer and animal manures on water uee efficiency of potatoes.
The results showed that both fertilizer and water supply very significantly increased
water use efficiency. Application of farm yard manure and recommended doses of
NPK to soybean for three consecutive years increased seed yield and water use
efficiency by 103% and 76%, respectively, over the unfertilized control (Hati et al.
2006). Effect of fertilizers on water use efficiency is indicated in Table 6. These
values may vary among crops, regions and with other management practices and
shall be interpreted with great care.
Improving Water Use Efficiency for Sustainable Agriculture 187
Increased use of chemical fertilizer in dry land farming has doubled grain yields
and water use efficiency (Deng et al. 2006). Davis and Quick (1998) suggested
that cultivar selection for improved water use efficiency should be based on an
understanding of the role of nutrient management on photosynthetic rate, yield,
rooting characteristics, and transpiration. To optimize water use efficiency, cultivar
and nutrient management decisions have to be made together. Nutrient application
decisions for a given crop shall be made based on soil fertility tests and use of
balanced nutrition at appropriate time of crop growth can help to obtain better crop
yields and water use efficiency.
Fertilizer effects on water use efficiency are related to physiological leaf
processes, root system dynamics as well as radiation use within a field crop stand.
Nutrient supply and crop water status interact in determining the balance of dry
matter accumulation to transpiration losses. Most studies were made on nitrogen
fertilization. They suggest that high improvement could be expected at the level of
the crop stands by the common effect of better radiation use efficiency and reduced
soil evaporation due to enhanced leaf growth rate. Improved photosynthetic capacity
of plants with optimum nutrition status seems to contribute also to improve tran-
spiration efficiency. Under water stress, potassium is of particular importance for
maintenance of tissue water status, cell expansion and sustained water uptake from
the drying soil. Phosphorus is limiting growth in several arid and semi-arid regions
of the world, particularly in tropical ecosystems. Root properties are essential to
improve the phosphorus status of plants which in turn can lead to better water use
efficiency.
Appropriate crop management practices contribute to improve several components
of agronomic water use efficiency. Substantial increase of water use efficiency
by better crop management is documented by Xu and Zhao (2001) in north China
where water use efficiency improved threefold between 1949 and 1996. This was
due to a combined effect of water conservation facilities, better soil management,
extension of new crop varieties and a continuous increase in the use of nitrogen and
phosphorus fertilizers. Progress requires a combination of several crop management
practices. While improvement via better transpiration efficiency can be achieved by
breeding, crop type and cultivar selection as well as plant nutrition management,
reduction of evaporation, drainage and runoff losses can be obtained by proper
timing of crop establishment and improved root growth. Optimization of water use
efficiency on a system basis can be obtained by crop rotation practices that extended
188 A. Raza et al.
the time of soil coverage and crop growth avoiding prolonged fallow periods.
From the farmer’s prospective a monetary assessment of costs and benefits will
determine which set of management measures for improved water use efficiency
should be adopted.
Following Eq. 2, overall agricultural water use efficiency for a crop with given
transpiration efficiency (M/T) will only increase, if transpiration is maximized in
relation to unproductive water losses. While transpiration efficiency set the upper
limit, soil management determines whether water resources are allocated optimally
to sustain plant growth.
Figure 5 gives an overview of relevant soil physical and hydrological properties
that might be targeted by management measures to optimize the ratio of transpiration
to the sum of soil evaporation, runoff and drainage. Also plant traits influence these
hydrological processes as discussed in Sect. 2.1. The efficiency of soil management
also depends on non-manageable soil properties such as soil texture as shown by
Katerji and Mastorilli (2009) who found a general reduction in water use efficiency
on clay soils compared to loam soils.
Tillage operations can influence water use efficiency by (i) changing soil surface
properties, (ii) modifying soil hydraulic properties, and (iii) influencing root system
formation of crops (Fig. 5). Tillage therefore influences water dynamics and water
use efficiency via mechanical effect of the tillage implements, mulching effects
related to the amount of residues cover remaining on the soil surface, and biological
effects due to modified root system formation and soil microbiological activity.
All relevant components of the water balance framework of Gregory (2004) are
potentially influenced by these effects of tillage.
Soil surface roughness is higher under more intense tillage compared to minimum
and no-tillage (Lampurlanés and Cantero-Martínez 2006). Higher surface roughness
can reduce surface runoff by better storage of ponded water in the surface micro-relief.
However, Gómez and Nearing (2005) found only a minor effect of different surface
roughness on runoff. They also showed that increased surface roughness by higher
tillage intensity disappeared after the first rainfall.
Tillage can influence rainfall infiltration via changes of soil surface structure.
Barthés and Roose (2002) reported a significant reduction in surface runoff with
increased aggregate stability. After 24 years of conservation tillage, Zhang et al.
(2007c) found an increase of 52% in macro-aggregate stability and a 3.7 times higher
infiltration rate in no-tillage compared to conventional tillage which substantially
reduced runoff.
Most benefits of reduced tillage can be attributed to higher soil organic matter
and the effects of canopy and residue management that protect the soil surface
(Arriaga and Balkcom 2005). Canopy and mulch coverage protect the soil surface, pre-
venting crust formation and maintaining soil infiltration capacity (Armand et al. 2009).
Improving Water Use Efficiency for Sustainable Agriculture
Fig. 5 Effect of management measures on components of water balance. Modifications in soil surface properties, soil hydraulic properties and root and
rhizosphere properties induced by crop and soil management practices affect each component of water balance
189
190 A. Raza et al.
Zuazo and Pleguezuelo (2008) reviewed the effect of plant covers on soil-erosion
and runoff prevention. In average a surface cover of 50% resulted in a reduction of
runoff to only 10%. Particularly during intense rainfall runoff can be greatly reduced
with a good (>50%) residue cover (Silburn and Glanville 2002).
Also the higher organic matter content in the surface near soil layers under
conservation tillage is essential for an enhanced infiltration capacity and thereby
reduced runoff losses (Zhang et al. 2007c). Beside enhanced humus content, the
conservation of root and earthworm induced continuous biopores in no tillage
systems contributes to higher infiltration rates and reduction of runoff (Cresswell
and Kirkegaard 1995).
An essential tillage effect for improved water use efficiency is the reduction of
evaporation losses from the soil surface. Aase and Pikul (1995) sustained that
decreasing tillage intensity tends to improve water use efficiency because of
improved soil water availability through reduced evaporation losses. Evaporation
losses can be particularly high when rainfall is contributed by frequent small
events during the vegetation period (Sadras et al. 2003). In Mediterranean-type
environments, 30–60% of the seasonal evapotranspiration of wheat may be lost as
evaporation from the soil surface (Siddique et al. 1990). Evaporation losses are
affected by the water content of the soil surface. Therefore movement of moist soil
to the surface may result in higher losses in mouldboard plough systems (Ritchie
1971). Soil evaporation is influenced by the surface energy balance as well as water
transmission properties to the soil surface. Tillage intends to disrupt pore continuity
to the soil surface and thereby limit evaporation losses. In case of a fallow soil
surface, Moret et al. (2007) found a 20% higher soil evaporation from a no-tillage
soil compared to conventional tillage.
Mulching is regarded as one of the best ways to reduce soil evaporation (Steiner
1989; Li and Xiao 1992; Baumhardt and Jones 2002). Residues and mulches limit
evaporation by reducing soil temperature, preventing vapour diffusion, absorbing
water vapor on to mulch tissue, and reducing the wind speed gradient at the
soil–atmosphere interface (Greb 1966; Lagos et al. 2009). Crop residues extend
the duration of the first stage of soil drying and most effectively reduce soil evapo-
ration when the soil surface is wet. Unger et al. (1991) however reported that
cumulative evaporation from a residue covered soil may become similar to a
bare soil upon prolonged drying as the soil generally remains wetter in the upper
layers and therefore sustains water transport to the surface for longer time. Effect
of mulching on water use efficiency and components of water balance are presented
in Table 7. These may vary with residue cover, slope of land, rainfall intensity
and region.
Strudley et al. (2008) reviewed tillage effects on soil hydraulic properties. There
is no single trend how tillage influences soil hydraulic conductivity and both,
increase and decrease in saturated as well as unsaturated hydraulic conductivity
have been reported. This indicates a substantial influence of soil texture, crop
rotation as well as temporal effects on the measured values (Soracco et al. 2010).
Under reduced and no tillage system, an increase in soil water storage capacity
has been found in most studies. e.g. Fernandez-Ugalde et al. (2009) found 32.6%
Improving Water Use Efficiency for Sustainable Agriculture 191
Table 7 Effect of mulching on water use efficiency and components of water balance
Practice Effect (range) Reference
Mulching Reduction in runoff Carsky et al. (1998), Silburn and Glanville
(10–75%) (2002), Zuazo and Pleguezuelo (2008)
Reduction in evaporation Mellouli et al. (1998), Zhang et al. (2007b)
(11–36%)
Overall increase 10–45% Zhao et al. (1996), Zhang et al. (2002),
in WUE Sarkar et al. (2007), Zhang et al. (2007b)
Table 8 Effect of tillage practices on water use efficiency and components of water balance
Practice Effect (range) Reference
Conventional Tillage Reduction in evaporation Moret et al. (2007)
(1–20%)
Increase in infiltration Moreno et al. (1997), Lipiec
rates (35–61%) et al. (2005)
Increase in soil water Selvaraju and Ramaswami (1997),
storage (9–42%) Jin et al. (2007)
No tillage Increase in soil water Chen et al. (2005), Fernandez-Ugalde
storage (8–33%) et al. (2009), Wang et al. (2010)
Overall increase in WUE 17–30% Peterson and Westfall (2004),
Sarkar et al. (2007)
Reduced tillage Reduction in evaporation Lopez and Arrue (1997)
(1–19%)
Increase in soil water McHugh et al. (2007)
storage (15–24%)
Overall increase in WUE 7–30% Jin et al. (2009)
Dry matter
Evapotranspiration
Soil evaporation
Fig. 6 Relationship between evapotranspiration and dry matter production. Improvement of water use
efficiency can be achieved by reduced soil evaporation or higher transpiration efficiency. The impact
of soil management is on evaporation and other loss components of field water balance
are variable, ranging from no effect or even higher cumulative losses, to reductions
of 25–30%. Improved water use efficiency by 10–20% through reduced soil
evaporation and consequently increased water available for plant transpiration were
reported by Zhao et al. (1996) and Zhang et al. (2002). Improved water storage
capacity is often restricted to the upper soil layers where reduced tillage enhances
organic matter accumulation. Although moisture availability in upper layers can
be essential for crop growth when the root system is concentrated near the soil
surface, an enhanced root penetration to deep layer seems to be more effective to
increase plant water availability. Deep rooting crops have access to a higher soil
volume, effectively reduce drainage losses and can increase uptake of water as well
as mobile nutrients such as nitrate. All these effects will increase the affectivity of
water use by the crop and optimize yield under water limited conditions.
Most reported increases in water use efficiency by conservation tillage in
agronomic literature are based on evapotranspiration calculated via a water balance.
Frequently runoff and drainage are ignored and the ratio is given as biomass or yield
to total evapotranspiration. We therefore assume that the higher biomass or yield
values in these studies are mainly a result of water redistribution from soil evapo-
ration to productive plant use due to the protective effect of a mulch cover. This
effect is expressed in Fig. 6. Thus progress in tillage management will be obtained
from its hydrological effects on plant water availability, rather than changes in
transpiration efficiency.
194 A. Raza et al.
Globally 18% of the cultivated area is irrigated. About 40% of global food production
comes from irrigated agriculture and about 70% of all freshwater is used in agricul-
ture. Currently low efficiencies in irrigation systems would suggest high potential
for improvement in agricultural water use by better irrigation management (Hsiao
et al. 2007).
Introducing modern irrigation technology usually implies higher costs, which
must be compensated by sustainable yields, increases in water use efficiency with
resulting water savings. Sub surface drip irrigation is reported to have significantly
increased yield and WUE of many crops as revealed by 15 years of research in United
States (Ayars et al. 1999).Twenty-six percent increase in water use efficiency in cotton
was observed due to drip irrigation in comparison with check basin (surface flooding)
method of irrigation (Aujla et al. 2005). It was found from a study in California
that water use efficiency ranged from 60–85% for surface irrigation to 70–90% for
sprinkler irrigation and 88–90% for drip irrigation (Cooley et al. 2008). Irrigating
pepper with water pillow method – a novel irrigation method that combines drip
irrigation and mulching – at 11 days interval helped to obtain significantly higher
water use efficiency compared to conventional furrow irrigation (Gercek et al. 2009).
Potential water savings would be even higher if the technology switch were
combined with more precise irrigation scheduling and a partial shift from lower-value,
water-intensive crops to higher-value, more water-efficient crops (Cooley et al. 2008).
Measurement based irrigation scheduling is generally based on soil parameters such
as water content or pressure head. While plant based irrigation scheduling methods
would have the advantage to directly respond to a crop water stress parameter, they
are still limited by practical problems such as automatization (Jones 2004b).
Irrigation management increasingly focuses on more effective and rational uses
of limited water supplies with increasing water use efficiency (Marouelli et al. 2004;
Payero et al. 2009). Improved efficiency can be obtained by reducing drainage,
runoff and evaporation losses by using measurement or model assisted irrigation
scheduling (Pereira et al. 2002). Also supplemental irrigation at critical growth
stages has substantially improved irrigation efficiency (Oweis et al. 1999).
A proper timing of supplemental irrigation is critical for maximizing yield and
water use efficiency. Manipulation of pre- and post-flowering water use in crops can
be used to increase harvest index and by using methods of controlled irrigation the
optimized water use by stomata can lead to an increase in water use efficiency,
without a significant decrease in production and eventually with beneficial effects
on quality (Chaves and Oliveira 2004). Examples of some marked increase in water
use efficiency by supplemental irrigation are given by Deng et al. (2002), Oweis
et al. (2004) and Xue et al. (2006).
Several studies showed that optimizing irrigation not necessarily needs to provide
full crop water requirements (English and Raja 1996; Kirda 2002). Water use
efficiency can be increased if irrigation water is reduced and crop water deficit is
intentionally induced (Zwart and Bastiaanssen 2004). Studies on the effects of
limited irrigation on crop yield and water use efficiency show that crop yield can be
Improving Water Use Efficiency for Sustainable Agriculture 195
largely maintained and product quality can, in some cases, be improved while sub-
stantially reducing irrigation volume (Kang et al. 1992; Zhang and Oweis 1999;
Zhang et al. 1999). For example, Panda et al. (2004) evaluated the effect of different
irrigation methods on root zone soil moisture, growth, yield parameters, and water
use efficiency of corn and concluded that under water scarcity conditions irrigation
should be scheduled at 45% of the maximum allowable depletion of available soil
water to obtain high yield and high water use efficiency. When irrigation is above
the optimum, an excessive shoot growth can occur at the expense of roots and fruits
(Zhang 2004).
Thus, recent efforts in optimizing irrigation have studied practices that inten-
tionally induce slight water deficits to plants such as regulated deficit irrigation
and partial root zone drying. When water deficits start to build up, leaf stomatal
conductance usually decreases faster than carbon assimilation, leading to increased
transpiration efficiency (Chaves et al. 2004).
Regulated deficit irrigation involves the application of irrigation water below the
evapotranspiration requirements of crop. It tends to reduce or eliminate drainage
and helps to improve water use efficiency (Fereres and Soriano 2007). The basic
principle of regulated deficit irrigation is that water is withheld or reduced during a
period when vegetative growth is normally high and fruit growth is low. A normal
irrigation regime is resumed during the later period of rapid fruit growth. Successful
application of regulated deficit irrigation requires careful attention to the timing of
the water deficit period and to the degree of stress that is allowed to develop (Loveys
et al. 2004; Geerts and Raes 2009). This tactic helps to reduce vegetative growth
with little effect on fruit development. In fruit crops like peach, apple and pear
balance between vegetative and reproductive development is critical as excessive
vegetative vigour may result in mutual shading with consequences of long-term
fruitfulness. Knowledge about the phenology of vegetative and reproductive develop-
ment of fruit crops can be used for saving water through regulated deficit irrigation
(Chalmers et al. 1981, 1986). Application of regulated deficit irrigation has doubled
water use efficiency when compared with standard irrigation practice (Goodwin and
Boland 2002). These improvements are due to improved water use by reducing
unproductive losses, reduction in vegetative canopy size, and also due to reduced
leaf stomatal conductance during the regulated deficit irrigation period (Boland
et al. 1993). Effect of timing, method and scheduling of irrigation practices is
summarized in Table 9 to demonstrate the importance of irrigation management.
196 A. Raza et al.
on its environment and its application for improvement of water use efficiency still
remain the key concern in some parts of the world as adoption of technology is
constrained by cultural and societal issues.
Challenges for policy makers and extension staff are to ensure dissemination and
utilization of appropriate production technology packages to the end users. Use of
simulation models for decision support can be used to adapt available management
tools to local conditions. Still use of models for extension is restricted to developed
world. Data bases for model calibration and validation experiments are lacking for
many regions of the world, particularly developing countries. Capacity building and
technical training of scientists from developing countries for proper application of
simulation models is needed (Mathews and Stephens 2002).
Crop water use is likely to stay a main topic for research and practical agriculture,
and will probably even gain importance in future. Still there are large options for
improved water use efficiency that can contribute to narrow the “yield gap” that is
currently building up. Better knowledge of processes and effects across all scales,
from physiology to farming system design, will lay the grounds for better manage-
ment and broad adoption of measures for improved agricultural water use.
References
Aase JK, Pikul JL Jr (1995) Crop and soil response to long-term no-tillage practices in the Northern
Great Plains. Agron J 87:652–656
Abbate PE, Dardanelli JL, Cantarero MG, Maturano M, Melchiori RJM, Suero EE (2004) Climatic
and water availability effects on water-use efficiency in wheat. Crop Sci 44:474–483
Ajouri A, Asgedom H, Becker M (2004) Seed priming enhances germination and seedling growth
of barley under conditions of P and Zn deficiency. J Plant Nutr Soil Sci 16:630–636
Alam SM (1999) Nutrient uptake by plants under stress conditions. In: Pessarakli M (ed.) Handbook
of plant and crop stress. Marcel Dekker, New York, pp 285–314
Ali MO (2004) More grain from less rain, seed priming—a key technology of lentil production for
resource-poor farmers in dry areas. In: Proceedings of the 7th international symposium on
water, arsenic and environmental crisis in Bengal basin issues, impacts and strategies, held in
Dhaka, Dec 19–20
Ali MH, Talukder MSU (2008) Increasing water productivity in crop production—A synthesis.
Agr Water Manage 95:1201–1213. doi:10.1016/j.agwat.2008.06.008
Andersen MN, Jensen CR, Lösch R (1992) The interaction effects of potassium and drought
in field-grown barley. I. Yield, water use efficiency and growth. Acta Agr Scand Sect B
42(1):34–44. doi:10.1080/09064719209410197
Araus JL, Slafer GA, Reynolds MP, Royo C (2002) Plant breeding and drought in C3 cereals,
what should we breed for? Ann Bot 89:925–940. doi:10.1093/aob/mcf049
Araus JL, Slafer GA, Royo C, Serrert MD (2008) Breeding for yield potential and stress adaptation
in cereals. Cr Rev Plant Sci 27:377–412. doi:10.1080/07352680802467736
Armand R, Bockstaller C, Auzet A-V, Van Dijk P (2009) Runoff generation related to intra-field
soil surface characteristics variability: Application to conservation tillage context. Soil Tillage
Res 102:27–37
Arriaga F, Balkcom K (2005) Benefits of conservation tillage on rainfall and water management.
In: Proceedings of the 2005 Georgia water resources conference, The University of
Georgia, Athens, 25–27 April 2005. Hatcher KJ (ed.), Institute Ecology, The University of
Georgia, Athens
Improving Water Use Efficiency for Sustainable Agriculture 199
Asif M, Ahmed M, Gafoor A, Aslam Z (2003) Wheat productivity, land and water use efficiency
by traditional and laser land – leveling techniques. J Biol Sci 3:141–146
Aujla MS, Thind HS, Buttar GS (2005) Cotton yield and water use efficiency at various levels
of water and N through drip irrigation under two methods of planting. Agr Water Manage
71:167–179. doi:10.1016/j.agwat.2004.06.010, DOI:dx.doi.org
Ayars JE, Phene CJ, Hutmacher RB, Davis KR, Schoneman RA, Vail SS, Mead RM (1999)
Subsurface drip irrigation of row crops, a review of 15 years of research at the Water Management
Research Laboratory. Agr Water Manage 42:1–27. doi:10.1016/S0378-3774(99)00025-6,
DOI:dx.doi.org
Azam-Ali SN, Gregory PJ, Monteith JL (1984) Effects of planting density on water use and
productivity of pearl millet (Pennisetum typhoides). II. Water use, light interception and dry
matter production. Exp Agric 20:203–214
Bahavar N, Ebadi A, Tobeh A, Jamaati-E-Somarin S (2009) Effects of mineral nitrogen on water
use efficiency of chickpea (Cicer arietinum L.) under water deficit condition. Res J Environ Sci
3(3):332–338
Bai Y, Chen F, Li H, Chen H, He J, Wang Q, Tullberg JN, Gong Y (2008) Traffic and tillage effects
on wheat production on the Loess Plateau of China: 2. Soil physical properties. Aust J Soil Res
46:652–658
Barthès B, Roose E (2002) Aggregate stability as an indicator of soil susceptibility to runoff and
erosion; validation at several levels. Catena 47:133–149
Bates BC, Kundzewicz ZW, Wu S, Palutikof JP (2008) Climate change and water. Technical paper
of the Intergovernmental Panel on Climate Change, IPCC Secretariat, Geneva, pp 210
Baumhardt RL, Jones OR (2002) Residue management and tillage effects on soil-water storage
and grain yield of dryland wheat and sorghum for a clay loam in Texas. Soil Tillage Res
68(2):71–82. doi:10.1016/S0167-1987(02)00097-1, DOI:dx.doi.org
Bengough AG, Bransby MF, Hans J, McKenna SJ, Roberts TJ, Valentine TA (2006) Root responses
to soil physical conditions; growth dynamics from field to cell. J Exp Bot 57:437–447
Benlloch-González M, Arquero O, Fournier JM, Barranco D, Benlloch M (2008) K + starvation
inhibits water-stress-induced stomatal closure. J Plant Physiol 165:623–630. doi:10.1016/j.
jplph.2007.05.010
Blum A (2005) Drought resistance, water-use efficiency, and yield potential—are they compatible,
dissonant, or mutually exclusive? Aust J Agric Res 56:1159–1168
Blum A (2009) Effective use of water and not water-use efficiency is the target of crop yield
improvement under drought stress. Field Crops Res 112:119–123
Bodner G, Loiskandl W, Kaul HP (2007) Cover crop evapotranspiration under semi-arid conditions
using FAO dual crop coefficient method with water stress compensation. Agr Water Manage
93:85–98
Bolan NS (1991) A critical review on the role of mycorrhizal fungi in the uptake of phosphorus by
plants. Plant Soil 134:189–207. doi:10.1007/BF00012037
Boland AM, Mitchell PD, Jerie PH, Goodwin I (1993) The effect of regulated deficit irrigation on
tree water use and growth of peach. J Hort Sci 68:261–274
Borlaug N (2007) Feeding a hungry world. Science 318:359
Borrell A, Garside A, Fukai S (1997) Improving efficiency of water use for irrigated rice in a semi-arid
tropical environment. Field Crops Res 52:231–248. doi:10.1016/S0378-4290(97)00033-6,
DOI:dx.doi.org
Bossio D, Geheb K (2008) Conserving land, protecting water. International Water Management
Institute, Challenge Program on Water and Food, pp 320
Brisson N, Wery J, Boote K (2006) Fundamental concepts of crop models illustrated by a
comparative approach. In: Wallach D, Makowski D, Jones JW (eds.) Working with dynamic crop
models. Foundation, analysis, parameterization and applications. Elsevier, The Netherlands,
pp 257–280
Brück H, Payne WA, Sattelmacher B (2000) Effects of phosphorus and water supply on yield,
transpirational water-use efficiency, and carbon isotope discrimination of pearl millet. Crop Sci
40:120–125. doi:10.2135/cropsci2000.401120x
200 A. Raza et al.
Buttar GS, Aujla MS, Thind HS, Singh CJ, Saini KS (2007) Effect of timing of first and last
irrigation on the yield and water use efficiency in cotton. Agr Water Manage 89:236–242.
doi:10.1016/j.agwat.2007.01.011
Cakmak I (2005) The role of potassium in alleviating detrimental effects of abiotic stresses in
plants. J Plant Nutr Soil Sci 168:521–530. doi:10.1002/jpln.200420485521
Campbell CA, Zentner RP, McConkey BG, Selles F (1992) Effect of nitrogen and snow manage-
ment on efficiency of water use by spring wheat grown annually on zero-tillage. Can J Soil
Sci 72:271–279
Carsky JR, Hayashi Y, Tian G (1998) Benefits of mulching in the subhumid savanna zone: research
needs and technology targetting. Draft Resource and Crop Management Research Monograph.
IITA, Ibadan
Chalmers DJ (1986) Research and progress in cultural systems and management in temperate fruit
orchards. Acta Horticulturae 175:215–225
Chalmers DJ, Mitchell PD, van Heck L (1981) Control of peach tree growth and productivity by
regulated water supply, tree density and summer pruning. J Amer Soc Hort Sci 106:307–312
Chaves MM, Oliveira MM (2004) Mechanisms underlying plant resilience to water deficits: prospects
for water-saving agriculture. J Exp Bot 55(407):2365–2384. doi:10.1093/jxb/erh269
Chaves MM, OsoĒo J, Pereira JS (2004) Water use efficiency and photosynthesis. In: Bacon M (ed.)
Water use efficiency in plant biology. Blackwell, Oxford, pp 42–74
Chen Y, Cavers C, Tessier S, Monero F, Lobb D (2005) Short term tillage effects on soil cone index
and plant development in a poorly drained, heavy clay soil. Soil Tillage Res 82(2):161–171
Chen S, Zhang X, Sun H, Ren T, Wang Y (2010) Effects of winter wheat row spacing on
evapotranpsiration, grain yield and water use efficiency. Agr Water Manage 97:1126–1132.
doi:10.1016/j.agwat.2009.09.005
Ciompi S, Gentili E, Guidi L, Soldatini GF (1996) The effect of nitrogen deficiency on leaf gas
exchange and chlorophyll fluorescence parameters in sunflower. Plant Sci 118:177–184.
doi:10.1016/0168-9452(96)04442-1
Claupein W (1993) Stickstoffdüngung und chemischer Pflanzenschutz in einem Dauerfeldversuch
und die Ertragsgesetze von Liebig, Liebscher, Wollny und Mitscherlich. J Agron Crop Sci
171:102–113
Comstock JP (2002) Hydraulic and chemical signaling in the control of stomatal conductance and
transpiration. J Exp Bot 53:195–200
Condon AG, Richards RA, Rebetzke GJ, Farquhar GD (2004) Breeding for high water-use
efficiency. J Exp Bot 55:2447–2460. doi:10.1093/jxb/erh277
Cooley H, Christian-Smith J, Gleick PH (2008) More with less, agricultural water conservation
and efficiency in California. Oakland, Pacific Institute. www.pacinst.org/reports/more-with-
less-delta
Cooper PJM, Gregory PJ, Tully D, Harris HC (1987) Improving water use efficiency of annual
crops in the rainfed farming systems of West Asia and North Africa. Exp Agric 23:113–158
Cowan IR, Farquhar GD (1977) Stomatal function in relation to leaf metabolism and environment.
Symp Soc Exp Biol 31:471–505
Cresswell HP, Kirkegaard JA (1995) Subsoil amelioration by plant-roots – the process and the
evidence. Aust J Soil Res 33:221–239
Dagdelen N, Yılmaz E, Sezgin F, Gurbuz T (2006) Water-yield relation and water use efficiency of
cotton (Gossypium hirsutum L.) and second crop corn (Zea mays L.) in western Turkey. Agr
Water Manage 82(1–2):63–85
Dang TH (1999) Effects of fertilization on water use efficiency of winter wheat in arid highland.
Eco-Agric Res 7:28–31
Davies WJ, Bacon MA, Thompson DS, Sobeih W, Rodriguez L (2000) Regulation of leaf and fruit
growth in plants growing in drying soil: exploitation of the plants’ chemical signalling system
and hydraulic architecture to increase the efficiency of water use in agriculture. J Exp Bot
51:1617–1626
Davis JG (1994) Managing plant nutrients for optimum water use efficiency and water conservation.
Adv Agron 53:85–120
Improving Water Use Efficiency for Sustainable Agriculture 201
Davis JG, Quick JS (1998) Nutrient management, cultivar development, and selection strategies to
optimize water use efficiency. J Crop Prod 1:221–240. doi:10.1300/J144v01n02_09
De Wit CT (1958) Transpiration and crop yields. Verslagen van landbouwkundige onderzoekingen,
No. 64.4. Wageningen
Deng X, Shan L, Shinobu I (2002) High efficiency use of limited supplement water by dry land
spring wheat. Trans CSAE 18:84–91
Deng X, Shan L, Zhang H, Turner NC (2006) Improving agricultural water use efficiency in arid
and semiarid areas of China. Agr Water Manage 80:23–40. doi:10.1016/j.agwat.2005.07.021,
DOI:dx.doi.org
Diaz-Ambrona CH, Miniguez M (2001) Cereal–legume rotations in a Mediterranean environ-
ment, biomass and yield production. Field Crops Res 70:139–151. doi:10.1016/S0378-
4290(01)00132-0, DOI:dx.doi.org
Dordas CA, Sioulas C (2008) Safflower yield, chlorophyll content, photosynthesis, and water use
efficiency response to nitrogen fertilization under rain fed conditions. Ind Crop Prod 27:75–85.
doi:10.1016/j.indcrop. 2007.07.020
Dry PR, Loveys B, Düring H (2000) Partial drying of the rootzone of grape. II. Changes in the
pattern of root development. Vitis 39:9–12
Eapen D, Barroso ML, Ponce G, Campos ME, Cassab GI (2005) Hydrotropism: root growth
responses to water. Trends Plant Sci 10:44–50. doi:10.1016/j.tplants.2004.11.004
Egila JN, Davies FT Jr, Drew MC (2001) Effect of potassium on drought resistance of Hibiscus
rosa-sinensis cv. Leprechaun, plant growth, leaf macro and micronutrient content and root
longevity. Plant Soil 229:213–224
Ehlers W, Goss M (2003) Water dynamics in plant production. CABI Publishing, Wallingford,
pp 141–152
English MJ, Raja SN (1996) Perspectives on deficit irrigation. Agr Water Manage 32:1–14.
doi:10.1016/S0378-3774(96)01255-3, DOI:dx.doi.org
Evans JR, Seemann JR (1989) The allocation of protein N in the photosynthetic apparatus:
costs, consequences, and control. In: Briggs WR (ed.) Photosynthesis. Alan R Liss, New York,
pp 183–205
Evett SR, Tolk JA (2009) Introduction, Can water use efficiency be modeled well enough to impact
crop management? Agron J 101:423–425
Falkenmark M (1997) Meeting water requirements of an expanding world population. Phil T Roy
Lond Soc B 352:929–936. doi:10.1098/rstb.1997.0072
Fang Q, Mab L, Yuc Q, Ahuja LR, Malone RW, Hoogenboom G (2009) Irrigation strategies to
improve the water use efficiency of wheat–maize double cropping systems in North China
Plain. Agr Water Manage. doi:10.1016/j.agwat.2009.02.012, DOI:dx.doi.org
FAO (1997) Food and Agriculture Organization. http://www.fao.org/docrep/W3094E/w3094e04.
htm
Farahani HJ, Izzi G, Oweis TY (2009) Parameterization and evaluation of the AquaCrop model for
full and deficit irrigated cotton. Agron J 101:469–476. doi:10.2134/agronj2008.0182s
Faraji A, Latifi N, Soltani A, Rad AHS (2009) Seed yield and water use efficiency of canola
(Brassica napus L.) as affected by high temperature stress and supplemental irrigation. Agr
Water Manage 96:132–140. doi:10.1016/j.agwat.2008.07.014, DOI:dx.doi.org
Fare DC, Gilliam CG, Keever GJ (1993) Monitoring irrigation at container nurseries. Hortic
Technol 2:75–78
Farooq M, Wahid A, Kobayashi N, Fujita D, Basra SMA (2009) Plant drought stress: effects,
mechanisms and management. Agron Sustain Dev 29:185–212. doi:10.1051/agro:2008021
Farquhar GD, Richards RA (1984) Isotopic composition of plant carbon correlates with water-use
efficiency of wheat genotypes. Aust J Plant Physiol 11:539–552
Feddes RA, Raats PAC (2004) Parameterizing the soil-water-plant root system. In: Feddes RA,
de Rooij GH, van Dam JC (eds.) Unsaturated-zone modeling. Progress, challenges and
applications. Kluwer, Dordrecht, pp 95–144
Feddes RA, Bresler E, Neuman SP (1974) Field test of a modified numerical model for water
uptake by root systems. Water Resour Res 10:1199–1206
202 A. Raza et al.
Feng FX, Huang GB, Chai Q, Yu AZ (2010) Tillage and straw management impacts on soil
properties, root growth, and grain yield of winter wheat in northwestern China. Crop Sci
50:1465–1473. doi:10.2135/cropsci2008.10.0590
Fereres E, Soriano MA (2007) Deficit irrigation for reducing agricultural water use. J Exp Bot
58(2):147–159
Fernández-Ugalde O, Virto I, Descansa P, Imaz MJ, Enrique A, Karlen DL (2009) No-tillage
improvement of soil physical quality in calcareous, degradation-prone, semiarid soils. Soil
Tillage Res 106:29–35
Finkel E (2009) Making every drop count in the buildup to a blue revolution. Science 323:1004–1005.
doi:10.1126/science.323.5917.1004
Fischer G, Heilig GK (1997) Population momentum and the demand on land and water resources.
Phil Trans Roy Soc Lond B 352:869–889. doi:10.1098/rstb.1997.0067
Gan Y, Campbell CA, Liu L, Basnyat P, McDonald CL (2009) Water use and distribution profile
under pulse and oilseed crops in semiarid northern high latitude areas. Agr Water Manage
96:337–348. doi:10.1016/j.agwat.2008.08.012, DOI:dx.doi.org
Geerts S, Raes D (2009) Deficit irrigation as an on-farm strategy to maximize crop water produc-
tivity in dry areas. Agr Water Manage 96:175–1284. doi:10.1016/j.agwat.2009.04.009
GEMS (2004) Global environment monitoring system, United Nations Environment Programme/
Water Programme. State of water quality assessment reporting at global level (R. Robarts).
Presentation at the UN International Work Session on Water Statistics. http://unstats.un.org/
unsd/environment/waterstress_papers.htm. Accessed 27 July 2009
Gerardeaux E, Jordan-Meille L, Constantin J, Pellerin S, Dingkuhn M (2010) Changes in plant
morphology and dry matter partitioning caused by potassium deficiency in Gossypium
hirsutum (L.). Environ Exp Bot 67:451–459. doi:10.1016/j.envexpbot.2009.09.008
Gercek S, Comlekcioglu N, Dikilitas M (2009) Effectiveness of water pillow irrigation method on
yield and water use efficiency on hot pepper (Capsicum annuum L.). Sci Hortic 120(3):325–329.
doi:10.1016/j.scienta.2008.11.028, DOI:dx.doi.org
Gibson G, Radford BJ, Nielsen RGH (1992) Fallow management, soil water, plant-available soil
nitrogen and grain sorghum production in south west Queensland. Aust J Exp Agric 32:473–482.
doi:10.1071/EA9920473
Gleick PH (2003) Global fresh water resources. Science 302:1524–1528. doi:10.1126/science.
1089967
Gómez JA, Nearing MA (2005) Runoff and sediment losses from rough and smooth soil surfaces
in a laboratory experiment. Catena 59:253–266
Goodwin I, Boland AM (2002) Scheduling deficit irrigation of fruit trees for optimizing water use
efficiency. Water reports, FAO Publication number 22, Rome, pp 67–79
Greb BW (1966) Effect of surface-applied wheat straw on soil water losses by solar distillation.
Soil Sci Soc Am Proc 30:786–788
Gregory PJ (2004) Agronomic approaches to increasing water use efficiency. In: Bacon M (ed.)
Water use efficiency in plant biology. Blackwell, Oxford, pp 142–170
Gregory PJ, Bengough AG, Grinev D, Schmidt S, Thomas WTB, Wojciechowski T, Young IM
(2009) Root phenomics of crops: opportunities and challenges. Funct Plant Biol 36:922–929.
doi:10.1071/FP09150
Gu J, Li S, Gao H, Li M, Qin Q, Cheng K (2004) Effect of organic–inorganic fertilizers on the
water use efficiency of crops in dry land. Agr Res Arid Areas 22(1):142–145, 151 (In Chinese,
with English abstract)
Guinn G, Mauney JR, Fry KE (1981) Irrigation scheduling and plant population effects on growth,
bloom rates, boll abscission and yield of cotton. Agron J 73:529–534
Gunasekera CP, Martin LD, Siddique KHM, Walton GH (2006) Genotype by environment interactions
of Indian mustard (Brassica Iuncea L.) and canola (Brassica napus L.) in Mediterranean-type
environments. II. Oil and protein concentrations in seed. Eur J Agron 25:13–21
Hatfield JL, Sauer TJ, Prueger JH (2001) Managing soils to achieve greater water use efficiency: a
review. Agron J 93:271–280
Improving Water Use Efficiency for Sustainable Agriculture 203
Hati KM, Mandal KG, Misra AK, Ghosh PK, Bandyopadhyay KK (2006) Effect of inorganic
fertilizer and farmyard manure on soil physical properties, root distribution, and water-use
efficiency of soybean in Vertisols of central India. Biores Techonol 97(16):2182–2188
He H, Cheng GL, Zhao SW (1999) Effect of different water and fertilizer conditions on water use
efficiency of potato. Agr Res Arid Areas 17:59–66
Hinsinger P, Bengough AG, Vetterlein D, Young IM (2009) Rhizosphere: biophysics, biogeochemistry
and ecological relevance. Plant Soil 321:117–152. doi:10.1007/s11104-008-9885-9
Hodge A (2004) The plastic plant: root responses to heterogeneous supplies of nutrients.
New Phytol 162:9–24
Howell TA (2001) Enhancing water use efficiency in irrigated agriculture. Agron J 93:281–289
Hsiao TC (1973) Plant responses to water stress. Ann Rev Plant Physiol 24:519–570. doi:10.1146/
annurev.pp. 24.060173.002511
Hsiao TC, Steduto P, Fereres E (2007) A systematic and quantitative approach to improve water
use efficiency in agriculture. Irrig Sci 25:209–231. doi:10.1007/s00271-007-0063-2
Hsieh JCC, Chadwick OA, Kelly EF, Savin SM (1998) Oxygen isotopic composition of
soil water: quantifying evaporation and transpiration. Geoderma 82:269–293. doi:10.1016/
S0016-7061(97)00105-5
Hu Y, Schmidhalter U (2005) Drought and salinity: a comparison of their effects on mineral
nutrition of plants. J Plant Nurt Soil Sci 168:541–549
Hu SJ, Song YD, Zhou HF, Tian CY (2002) Experimental study on water use efficiency of cotton
in the Tarim River Basin. Agric Res Arid Areas 20:65–70
Hufstetler EV, Boerma HR, Carter TE Jr, Earl HJ (2007) Genotypic variation for three physio-
logical traits affecting drought tolerance in soybean. Crop Sci 47:25–35. doi:10.2135/
cropsci2006.04.0243
Humphreys E, Bhuiyan AM, Fattore A, Fawcett B, Smith D (2001). The benefits of winter crops
after rice harvest. Part 1: Results of field experiments. Part 2: Models to predict what will
happen in your situation. Part 3: What growers think about crops after rice. Farmers’ Newsl.
Large Area 157, pp 29–31, 36–42
IPCC (2007) Climate change, synthesis report. Contribution of working groups I, II and III to the
fourth assessment report of the Intergovernmental Panel on Climate Change. Pachauri RK,
Reisinger A (eds.). IPCC, Geneva
Islam N, Wallender WW, Mitchell J, Wicks S, Howitt RE (2006) A comprehensive experimental
study with mathematical modelling to investigate the effects of cropping practices on water
balance variables. Agr Water Manage 82:129–147
Ismail SM, Ozawa K, Khondaker NA (2008) Influence of single and multiple water application
timings on yield and water use efficiency in tomato (var. First power). Agr Water Manage
95:116–122. doi:10.1016/j.agwat.2007.09.006
Jacob J, Udayakumar M, Prasad TG (1995) Mesophyll conductance was inhibited more than
stomatal conductance in nitrogen deficient plants. Plant Physiol Biochem 17:55–61
Jaleel CA, Gopi R, Sankar B, Gomathinayagam M, Panneerselvam R (2008) Differential responses
in water use efficiency in two varieties of Catharanthus roseus under drought stress. C R Biol
331:42–47. doi:10.1016/j.crvi.2007.11.003, DOI:dx.doi.org
Jalota SK, Buttar GS, Sood A, Chahal GBS, Ray SS, Panigrahy S (2008) Effects of sowing date,
tillage and residue management on productivity of cotton (Gossypium hirsutum L.)–wheat
(Triticum aestivum L.) system in northwest India. Soil Tillage Res 99:76–83. doi:10.1016/j.
still.2008.01.005
Jin K, Cornelis WM, Schiettecatte W, Lu J, Yao Y, Wu H, Gabriels D, De Neve S, Cai D, Jin J,
Hartmann R (2007) Effects of different management practices on the soil–water balance
and crop yield for improved dryland farming in the Chinese Loess Plateau. Soil Tillage Res
96:131–144. doi:10.1016/j.still.2007.05.002
Jin H, Qingjie W, Hongwen L, Lijin L, Huanwen G (2009) Effect of alternative tillage and residue
cover on yield and water use efficiency in annual double cropping system in North China Plain.
Soil Tillage Res 104(1):198–205. doi:10.1016/j.still.2008.08.015, DOI:dx.doi.org
204 A. Raza et al.
Johnson DA, Asay KH, Tieszen LL, Ehleringer JR, Jefferson PG (1990) Carbon isotope
discrimination, potential in screening cool-season grasses for water-limited environments.
Crop Sci 30:338–343
Johnson N, Revenga C, Echeverria J (2001) Managing water for people and nature. Science
292:1071–1074
Jones H (2004a) What is water use efficiency? In: Bacon MA (ed.) Water use efficiency in plant
biology. Blackwell, Oxford, pp 27–41
Jones HG (2004b) Irrigation scheduling: advantages and pitfalls of plant- based methods. J Exp
Bot 55(407):2427–2436. doi:10.1093/jxb/erh213
Kang SZ, Liu XM, Xiong YZ (1992) Research on the model of water uptake by winter wheat roots.
Acta Univ Agric Boreali occidentalis 20:5–12
Kant S, Kafkafi U (2002) Potassium and abiotic stresses in plants. In: Pasricha NS, Bansal SK
(eds.) Role of potassium in nutrient management for sustainable crop production in India,
Potash Research Institute of India, Gurgaon.
Karam NS (1993) Overhead sprinkle strategies to reduce water and nitrogen loss from
container-growen plants. Ph.D. Dissertation. Virginia Polytechnic Institute and State University,
Blacksburg
Karam F, Breidy J, Stephan C, Rouphael J (2003) Evapotranspiration, yield and water use
efficiency of drip irrigated corn in the Bekaa Valley of Lebanon. Agr Water Manage
63(2):125–137
Karam F, Masaad R, Sfeir T, Mounzer O, Rouphael Y (2005) Evapotranspiration and seed yield of
field grown soybean under deficit irrigation conditions. Agr Water Manage 75:226–244
Karam F, Masaad R, Daccache A, Mounzer O, Rouphael Y (2006) Water use and lint yield response
of drip irrigated cotton to the length of irrigation season. Agric Water Manage 85:287–295
Karrou M (1998) Observations on effect of seeding pattern on water-use efficiency of durum
wheat in semi-arid areas of Morocco. Field Crops Res 59:175–179. doi:10.1016/S0378-
4290(98)00118-X, DOI:dx.doi.org
Katerji N, Mastrorilli M (2009) The effect of soil texture on the water use efficiency of irrigated
crops: results of a multi-year experiment carried out in the Mediterranean region. Eur J Agron
30:95–100. doi:0.1016/j.eja.2008.07.009
Katerji N, van Hoorn JW, Hamdy A, Karam F, Mastrorilli M (1996) Effect of salinity on water
stress, growth, and yield of maize and sunflower. Agr Water Manage 30:237–249
Katerji N, van Hoorn JW, Hamdy A, Mastrorilli M (2003) Salinity effect on crop development and
yield, analysis of salt tolerance according to several classification methods. Agr Water
Manage 62:37–66
Katerji N, van Hoorn JW, Hamdy A, Mastrorilli M, Oweis T (2005a) Salt tolerance analysis
of chickpea, faba bean and durum wheat varieties. I. Chickpea and faba bean. Agr Water
Manage 72:177–194
Katerji N, van Hoorn JW, Hamdy A, Mastrorilli M, Nachit MM, Oweis T (2005b) Salt tolerance
analysis of chickpea, faba bean and durum wheat varieties. II. Durum wheat. Agr Water Manage
72:195–207
Katerji N, van Hoorn JW, Hamdy A, Mastrorilli M, Fares C, Ceccarelli S, Grando S, Oweis T (2006)
Classification and salt tolerance analysis of barley varieties. Agr Water Manage 85:184–192
Katerji N, Mastrorilli M, Rana G (2008) Water use efficiency of crops cultivated in the Mediterranean
region: review and analysis. Eur J Agron 28:493–507. doi:10.1016/j.eja.2007.12.003
Kato Y, Abe J, Kamoshita A, Yamagishi J (2006) Genotypic variation in root growth angle in rice
(Oryza sativa L.) and its association with deep root development in upland fields with different
water regimes. Plant Soil 287:117–129
Kirda C (2002) Deficit irrigation scheduling based on plant growth stages showing water stress
tolerance. In Deficit irrigation practices. Water Rep. 22. FAO, Rome. pp 3–10
Kirda C, Topcu S, Cetin M, Dasgan HY, Kaman H, Topaloglu F, Derici MR, Ekici B
(2007) Prospects of partial root zone irrigation for increasing irrigation water use efficiency of
major crops in the Mediterranean region. Ann Appl Biol 150:281–291. doi:10.1111/
j.1744-7348.2007.00141.x
Improving Water Use Efficiency for Sustainable Agriculture 205
Kondratyev KY, Krapivin VF, Varotsos CA (2003) Global carbon cycle and climate change.
Springer, Berlin, p 388
Kundu M, Chakraborty PK, Mukherjee A, Sarkar S (2008) Influence of irrigation frequencies and
phosphate fertilization on actual evapotranspiration rate, yield and water use pattern of rajmash
(Phaseolus vulgaris L.). Agr Water Manage 95:383–390. doi:10.1016/j.agwat.2007.10.022
Lagos LO, Martin DL, Verma S, Suyker A, Irmak S (2009) Surface energy balance model of
transpiration from variable canopy cover and evaporation from residue-covered or bare-soil
systems. Irrig Sci 28:51–64. doi:10.1007/s00271-009-0181-0
Lambers H, Shane MW, Cramer MD, Pearse SJ, Veneklaas EJ (2006) Root structure and func-
tioning for efficient acquisition of phosphorus: matching morphological and physiological
traits. Ann Bot 98:693–713
Lampurlanés J, Cantero-Martínez C (2006) Hydraulic conductivity, residue cover and soil surface
roughness under different tillage systems in semiarid conditions. Soil Tillage Res 85:13–26
Larcher W (1994) Ökophysiologie der Pflanzen, 5th edn. Eugen Ulmer, Stuttgart
Latiri-Souki K, Nortcliff S, Lawlor DW (1998) Nitrogen fertilizer can increase dry matter, grain
production and radiation and water use efficiencies for durum wheat under semi-arid conditions.
Eur J Agron 9(1):21–34. doi:10.1016/S1161-0301(98)00022-7, DOI:dx.doi.org
Latta RA, Blacklow LJ, Cocks PS (2001) Comparative soil water, pasture production, and crop
yields in phase farming systems with lucerne and annual pasture in Western Australia. Aust
J Agric Res 52:295–303
Lawlor DW (2002) Carbon and nitrogen assimilation in relation to yield: mechanisms are the key
to understanding production systems. J Exp Bot 53:773–787
Leitner D, Klepsch S, Bodner G, Schnepf A (2010) A dynamic root system growth model based
on L-Systems. Plant Soil 332:177–192
Levitt J (1972) Responses of plants to environmental stresses. Academic, New York
Li S, Xiao L (1992) Distribution and management of drylands in the People’s Republic of China.
Adv Soil Sci 18:148–293
Li FR, Zhao SL, Geballe GT (2000) Water use patterns and agronomic performance for some
cropping systems with and without fallow crops in a semi-arid environment of Northwest
China. Agric Ecosyst Environ 79:129–142
Li Y, Wu L, Zhao L, Lu X, Fan Q, Zhang F (2007) Influence of continuous plastic film mulching
on yield, water use efficiency and soil properties of rice fields under non-flooding condition.
Soil Tillage Res 93:370–378. doi:10.1016/j.still.2006.05.010
Li SX, Wang ZH, Malhi SS, Li SQ, Gao YJ, Tian XH (2009) Nutrient and water management
effects on crop production, and nutrient and water use efficiency in dryland areas of China. Adv
Agron 102:223–265
Li F, Yu J, Nong M, Kang S, Zhang J (2010) Partial root-zone irrigation enhanced soil enzyme
activities and water use of maize under different ratios of inorganic to organic nitrogen fertilizers.
Agr Water Manage 97:231–239. doi:10.1016/j.agwat.2009.09.014
Lipiec J, Kus J, Słowinska-Jurkiewicz A, Nosalewicz A (2005) Soil porosity and water infiltration
as influenced by tillage methods. Soil Tillage Res 89:210–220
Liu HJ, Kang YH, Liu SP (2003) Regulation of field environmental condition by sprinkler irrigation
and its effect on water use efficiency of winter wheat. Trans Chin Soc Agric Eng 19:46–51
Lobell DB, Burke MB, Tebaldi C, Mastrandea MD, Falcon WP, Naylor RL (2008) Prioritizing
climate change adaptation needs for food security in 2030. Science 319:607–610. doi:10.1126/
science.1152339
Long SP (2006) C4 photosynthesis at low temperature. Plant Cell Environ 6:345–363.
doi:10.1111/j.1365-3040.1983.tb01267.x
Lopez MV, Arrue JL (1997) Growth, yield and water use efficiency of winter barley in response to
conservation tillage in a semi-arid region of Spain. Soil Tillage Res 44(1–2):35–54. doi:10.1016/
S0167-1987(97)00030-5, DOI:dx.doi.org
Loveys B, Ping L (2002) Plants response to water: new tools for vineyard irrigators. In: Dundon C,
Hamilton R, Johnstone R, Partridge S (eds.) ASVO Proceedings. Australian Society Viticulture
and Oenology, Victoria
206 A. Raza et al.
Loveys B, Stoll M, Davies WJ (2004) Physiological approaches to enhance water use efficiency in
agriculture: exploiting plant signalling in novel irrigation practice. In: Bacon M (ed.) Water use
efficiency in plant biology. Blackwell, Oxford, pp 113–141
Lynch JP (2007) Roots of the second green revolution. Aust J Bot 55:493–512
Machado S, Petrie S, Rhinhart K, Ramig RE (2008) Tillage effects on water use and grain yield of
winter wheat and green pea in rotation. Agron J 100:154–162. doi:10.2134/agrojnl2006.0218
Marouelli WA, Silva WLC, Moretti CL (2004) Production, quality and water use efficiency of
processing tomato as affected by the final irrigation timing. Hortic Bras 22(2):226–231
Marschner H (1995) Mineral nutrition of higher plants, 2nd edn. Academic, San Diego
Martin B, Tauer CG, Lin RK (1999) Carbon isotope discrimination as a tool to improve water use
efficiency in tomato. Crop Sci 39:1775–1783
Marty JR, Puech J, Maertens C, Blanchet R (1975) Etude expérimentale de la réponse de quelques
grandes cultures `a l’irrigation. C R Acad Agr 61:560–567
Mastrorilli M, Katerji N, Rana G (1995) Water efficiency and stress on grain sorghum at different
reproductive stages. Agr Water Manage 28:23–34
Mathews RB, Stephens W (2002) Crop –soil simulation models: applications in developing
countries. CABI publishing, Wallingford, pp 271
Matsuoka M, Furbank RT, Fukayama H, Miyao M (2001) Molecular engineering of C4 photo-
synthesis. Ann Rev Plant Physiol Plant Molecular Biol 52:297–314
McHugh OV, Steenhuis TS, Abebe B, Fernandes ECM (2007) Performance of in situ rainwater
conservation tillage techniques on dry spell mitigation and erosion control in the drought-prone
North Wello zone of the Ethiopian highlands. Soil Tillage Res 97:19–36. doi: 10.1016/j.
still.2007.08.002
Mellouli HJ, Hartmann R, Gabriels D, Cornelis WM (1998) The use of olive mill effluents
(‘margines’) as soil conditioner mulch to reduce evaporation losses. Soil Tillage Res 49:85–91
Monneveux P, Reynolds MP, Trethowan R, González-Santoyo H, Peña RJ, Zapata F (2005)
Relationship between grain yield and carbon isotope discrimination in bread wheat under four
water regimes. Eur J Agron 22:231–242. doi:10.1016/j.eja.2004.03.001
Moreno F, Pelegrin F, Fernandez JE, Murillo JM (1997) Soil physical properties, water depletion
and crop development under traditional and conservation tillage in southern Spain. Soil Tillage
Res 41:25–42
Moret D, Braud I, Arrúe JL (2007) Water balance simulation of a dryland soil during fallow under
conventional and conservation tillage in semiarid Aragon, Northeast Spain. Soil Till Res
92:251–263
Morison JIL, Baker NR, Mullineaux PM, Davies WJ (2008) Improving water use in crop production.
Phil T Roy Soc B 363:639–658. doi:10.1098/rstb.2007.2175
Morrison MJ, Stewart DW (2002) Heat stress during flowering in summer Brassica. Crop Sci
42:797–803
Nielsen DC, Unger PW, Miller PR (2005) Efficient water use in dry land cropping systems in the
great plains. Agron J 97:364–372
Nobel PS (1991) Physicochemical and environmental plant physiology. Academic, San Diego
Ogola JBO, Wheeler TR, Harris PM (2002) Effects of nitrogen and irrigation on water use
of maize crops. Field Crops Res 78(2–3):105–117. doi:10.1016/S0378-4290(02)00116-8,
DOI:dx.doi.org
Oweis T (1997) Supplemental irrigation. A highly efficient water use practice. ICARDA
Editions. pp 16
Oweis T (2004) Lentil production under supplemental irrigation in a Mediterranean environment.
Agr Water Manage 68:251–265
Oweis T, Hachum A, Kijne J (1999) Water harvesting and supplemental irrigation for improved
water use efficiency in dry areas. SWIM Paper 7, International Water Management Institute,
Colombo
Oweis T, Zhang H, Pala M (2000) Water use efficiency of rainfed and irrigation bread wheat in a
Mediterranean environment. Agron J 92:231–238
Improving Water Use Efficiency for Sustainable Agriculture 207
Oweis T, Hachum A, Pala M (2004) Water use efficiency of winter-sown chickpea under
supplemental irrigation in a mediterranean environment. Agr Water Manage 66:163–179.
doi:10.1016/j.agwat.2003.10.006, DOI:dx.doi.org
Pala M, Ryan J, Zhang M, Singh M, Harris HC (2007) Water-use efficiency of wheat-based rotation
systems in a Mediterranean environment. Agr Water Manage 93:136–144. doi:10.1016/j.
agwat.2007.07.001, DOI:dx.doi.org
Panda RK, Behera SK, Kashyap PS (2004) Effective management of irrigation water for maize
under stressed conditions. Agr Water Manage 66(3):181–203. doi:10.1016/j.agwat.2003.12.001,
DOI:dx.doi.org
Papastylianou I (1993) Productivity requirements of barley in rainfed Mediterranean conditions.
Eur J Agron 2:119–129
Parry MAJ, Flexas J, Medrano H (2005) Prospects for crop production under drought: research
priorities and future directions. Annals Appl Biol 147:211–226
Passioura J (1977) Grain yield, harvest index, and water use of wheat. J Aus Inst Agr Sci
43:117–121
Passioura JB (2002) Environmental biology and crop improvement. Funct Plant Biol 29:537–546
Passioura J (2006) Increasing crop productivity when water is scarce – From breeding to field
management. Agr Water Manage 80:176–196. doi:10.1016/j.agwat.2005.07.012, DOI:dx.doi.org
Passioura JB, Angus JF (2010) Improving productivity of crops in water-limited environments. In:
Sparks DL (ed.) Advances in agronomy, vol 106. Academic, Burlington, pp 37–75
Paul ND, Ayres PG (1984) Effects of rust and post-infection drought on photosynthesis, growth
and water relations in groundsel. Plant Pathol 33:561–569
Payero JO, Tarkalson DD, Irmak S, Davison D, Petersen JL (2009) Effect of timing of a deficit-
irrigation allocation on corn evapotranspiration, yield, water use efficiency and dry mass. Agr
Water Manage 96(10):1387–1397
Payne WA (1997) Managing yield and water use of Pearl millet in the Sahel. Agron J 89:481–490
Payne WA, Drew MC, Hossner LR, Lascano RJ, Onken AB, Wendt CW (1992) Soil phosphorus
availability and pearl millet water-use efficiency. Crop Sci 32:1010–1015
Payne WA, Hossner LR, Onken AB, Wendt CW (1995) Nitrogen and phosphorus uptake in pearl
millet and its relation to nutrient and transpiration efficiency. Agron J 87:425–431
Pereira LS, Oweis T, Zairi A (2002) Irrigation management under water scarcity. Agr Water
Manage 57:175–206
Peterson GA, Westfall DG (2004) Managing precipitation use in sustainable dryland agroecosys-
tems. Ann Appl Biol 144:127–138. doi:10.1111/j.1744-7348.2004.tb00326.x
Pettigrew WT (2008) Potassium influences on yield and quality production for maize, wheat, soy-
bean and cotton. Physiol Plant 133:670–681
Playan E, Mateos L (2006) Modernization and optimization of irrigation systems to increase water
productivity. Agr Water Manage 80:100–116. doi:10.1016/j.agwat.2005.07.007, DOI:dx.doi.org
Polley WH (2002) Implications of atmospheric and climate change for crop yield and water use
efficiency. Crop Sci 42:131–140
Power JF (1983) Soil management for efficient water use: soil fertility. In: Taylor HM (ed.)
Limitations to efficient water use in production. ASA, CSSA, and SSSA, Madison,
pp 461–470
Purcell LC, Sinclair TR, McNew RW (2003) Drought avoidance assessment for summer annual
crops using long-term weather data. Agron J 95:1566–1576
Rajabi A, Ober ES, Griffiths H (2009) Genotypic variation for water use efficiency, carbon isotope
discrimination, and potential surrogate measures in sugar beet. Field Crops Res 112:172–181.
doi:10.1016/j.fcr.2009.02.015
Rama RN (1986) Potassium nutrition of pearl millet subjected to moisture stress. J Potassium
Res 2:1–12
Rana G, Katerji N (2007) Direct and indirect methods to simulate the actual evapotranspiration
of irrigated overhead table grape vineyard under Mediterranean conditions. Hyrol Proc
22(2):181–188
208 A. Raza et al.
Rashid A, Haris D, Hollington PA, Khattak RA, Ahmad R, Malik KA (2002) On-farm seed priming,
a key technology for improving the livelihood of resource-poor farmers of saline lands.
Prospects Saline Agric. Pakintan, pp 423–431
Rasool R, Kukal SS, Hira GS (2008) Soil organic carbon and physical properties as affected by
long-term application of FYM and inorganic fertilizers in maize-wheat system. Soil Tillage
Res 101:31–36. doi:10.1016/j.still.2008.05.015, DOI:dx.doi.org
Rasse DP, Smucker AJM (1998) Root colonization of previous root channels in corn and alfalfa
rotations. Plant Soil 204:203–121
Raven JA, Handley LL, Wollenwerber B (2004) Plant nutrition and water use efficiency. In: Bacon
MA (ed.) Water use efficiency in plant biology. Blackwell, Oxford, pp 322
Ray JD, Sinclair TR (1998) The effect of pot size on growth and transpiration of maize and soybean
during water deficit stress. J Exp Bot 49:1381–1386. doi:10.1093/jxb/49.325.1381
Rebetzke GJ, Richards RA, Fettell NA, Long M, Condon AG, Forrester RI, Botwright TL (2007)
Genotypic increases in coleoptile length improves stand establishment, vigour and grain yield
of deep-sown wheat. Field Crops Res 100:10–23. doi:10.1016/j.fcr.2006.05.001
Reynolds M, Tuberosa R (2008) Translational research impacting on crop productivity in drought-
prone environments. Curr Opin Plant Biol 11:171–179
Richards RA (2004) Physiological traits used in the breeding of new cultivars for water-scarce
environments. In: New directions for a diverse planet. Proceedings 4th international crop science
congress, Brisbane, 26 Sept–1 Oct 2004 (eds.). Fischer RA, Turner N, Angus J, McIntyre L,
Robertson M, Borrell A, Lloyd D. See www.cropscience.org.au/icsc2004
Richards RA, Watt M, Rebetzke GJ (2007) Physiological traits and cereal germplasm for sus-
tainable agricultural systems. Euphytica 154:409–425. doi:10.1007/s10681-006-9286-1
Ridley AM, Christy B, Dunin FX, Haines PJ, Wilson KF, Ellington A (2001) Lucerne in crop
rotations on the Riverine Plains 1. The soil water balance. Aust J Agric Res 52:263–277
Ritchie JT (1971) Dryland evaporative flux in a subhumid climate, I. Micrometeorological
influences. Agron J 70:723–728
Ritchie JT (1983) Efficient water use in crop production: discussion on the generality of relations
between biomass production and evapotranspiration. In: Taylor HM (ed.) Limitations to
efficient water use in production. ASA, CSSA, and SSSA, Madison, pp 29–44
Ritchie JT, Basso B (2008) Water use efficiency is not constant when crop water supply is adequate
or fixed, the role of agronomic management. Eur J Agron 28(3):273–281. doi:10.1016/j.
eja.2007.08.003, DOI:dx.doi.org
Röckström J (2001) Green water security for food makers of tomorrow: windows of opportunity
in drought-prone savannahs. Water Sci Technol 43:71–78
Römheld V, Kirkby EA (2010) Research on potassium in agriculture: needs and prospects. Plant
Soil 335:155–180. doi:10.1007/s11104-010-0520-1
Sadras VO (2009) Does partial root-zone drying improve irrigation water productivity in the field?
A meta-analysis. Irrig Sci 27:183–190. doi:10.1007/s00271-008-0141-0
Sadras V, Roget D, Krause M (2003) Dynamic cropping strategies for risk management in dry-land
farming systems. Agric Syst 76:929–948. doi:10.1016/S0308-521X(02)00010-0, DOI:dx.doi.org
Sage RF, Pearcy RW (1987) The nitrogen use efficiency of C3 and C4 plants. II. Leaf nitrogen,
effects on the gas exchange characteristics of Chenopodium album (L.) and Amaranthus retro-
flexus (L.). Plant Physiol 84:959–963
Santos TPd, Lopes CM, Rodrigues ML, Souza CRd, Maroco JP, Pereira JS, Silva JR, Chaves MM
(2003) Partial rootzone drying: effects on growth and fruit quality of field-grown grapevines
(Vitis vinifera). Funct Plant Biol 30:663–671
Sarkar S, Paramanick M, Goswami SB (2007) Soil temperature, water use and yield of yellow
sarson (Brassica napus L. var. glauca) in relation to tillage intensity and mulch management
under rainfed lowland ecosystem in eastern India. Soil Tillage Res 93(1):94–101. doi:10.1016/j.
still.2006.03.015, DOI:dx.doi.org
Saxena NP (1985) The role of potassium in drought tolerance, Potash review, No. 5, International
Potash Institute, Bern. 16, pp 1–15
Improving Water Use Efficiency for Sustainable Agriculture 209
Schillinger WF, Cook RJ, Papendick RI (1999) Increased dryland cropping intensity with no-till
barley. Agron J 91:744–752
Schmidhalter U, Studer Ch (1998) Water-use efficiency as influenced by plant mineral nutrition.
First Sino-German workshop impact of plant nutrition on sustainable agricultural production,
Kiel, 22–23 Oct 1998, 9 pp
Schulze ED, Hall AE (1982) Stomatal responses, water loss and CO2 carbon dioxide assimilation
rates of plants in contrasting environments. In: Lange OL, Nobel PS, Osmond CB, Ziegler H
(eds.) Encyclopedia of plant physiology—physiological plant ecology, vol II. Springer-Verlag,
Berlin, pp 181–230
Selvaraju R, Ramaswami C (1997) Evaluation of fallow management practices in a rainfed vertisol
of peninsular India. Soil Tillage Res 43:319–333
Shangguan ZP, Shao MA, Dyckmans J (2000) Nitrogen nutrition and water stress effects on leaf
photosynthetic gas exchange and water use efficiency in winter wheat. Environ Exp Bot
44:141–149
Shiklomanov IA (2003) World water resources at the beginning of the 21st century. Cambridge
University Press, Cambridge
Shinozaki K, Yamaguchi-Shinozaki K (2000) Molecular responses to dehydration and low
temperature: differences and cross-talk between two stress signalling pathways. Curr Opin
Plant Biol 3:217–223
Siddique KHM, Tennant D, Perry MW, Belford RK (1990) Water use and water use efficiency of
old and modern wheat cultivars in a Mediterranean-type environment. Aust J Agric Res
41:431–447
Silburn DM, Glanville SF (2002) Management practices for control of runoff losses from cotton
furrows under storm rainfall. I. Runoff and sediment on a black vertisol. Aust J Soil Res
40:1–20
Simane B, Peacock JM, Struik PC (1993) Differences in developmental plasticity and growth rate
among drought-resistant and susceptible cultivars of durum wheat (Triticum turgidum L. var.
durum). Plant Soil 157:155–166. doi:10.1007/BF00011044
Simpson JR, Pinkerton A (1989) Fluctuations in soil moisture, and plant uptake of surface applied
phosphate. Fertilizer Res 20:101–108. doi:10.1007/BF01055434
ŠimĬnek J, Šejna M, Saito H, Sakai M, van Genuchten M Th (2008) The HYDRUS-1D software
package for simulating the one-dimensional movement of water, heat, and multiple solutes
in variably saturated media. Version 4.0, HYDRUS Software Series 1, Department of
Environmental Sciences, University of California Riverside, Riverside
ŠimĬnek J, Hopmans JW (2009) Modeling compensated root water and nutrient uptake. Ecol
Model 220:505–521
Singh G, Bhushan LS (1980) Water use, water use efficiency, and yield of dryland chickpea as
influenced by P fertilization, stored soil water, and crop season rainfall. Agr Water Manage
2:299–305. doi:10.1016/0378-3774(80)90030-X, DOI:dx.doi.org
Singh KB, Malhotra RS, Saxena MC, Bejiga G (1997) Superiority of winter sowing over traditional
spring sowing of chickpea in the Mediterranean region. Agron J 89:112–118
Soracco CG, Lozano LA, Sarli GO, Gelati PR, Filgueira RR (2010) Anisotropy of saturated
hydraulic conductivity in a soil under conservation and no-till treatments. Soil Tillage Res
109:18–22. doi:10.1016/j.still.2010.03.013
Souza CRd, Maroco JP, Santos TPd, Rodrigues ML, Lopes CM, Pereira JS, Chaves MM (2003)
Partial rootzone drying: regulation of stomatal aperture and carbon assimilation in field-grown
grapevines (Vitis vinifera cv. Moscatel). Funct Plant Biol 30:653–662
Steduto P, Hsiao TC, Fereres E (2007) On the conservative behavior of biomass water productivity.
Irrig Sci 25:189–207
Steiner JL (1989) Tillage and surface residue effects on evaporation from soils. Soil Sci Soc Am
J 53(3):911–916
Strudley MW, Green TR, Ascough JC II (2008) Tillage effects on soil hydraulic properties in space
and time: state of the science. Soil Till Res 99:4–48
210 A. Raza et al.
Webb AAR, Hetherington AM (1997) Convergence of the abscisic acid, CO2, and extracellular
calcium signal transduction pathways in stomatal guard cells. Plant Physiol 114:1557–1560
Wilkinson S (2004) Water use efficiency and chemical signalling. In: Bacon M (ed.) Water use
efficiency in plant biology. Blackwell, Oxford, pp 75–112
WWAP (2003) United Nations World Water Assessment Programme. The world water development
report 1: Water for people, water for life. UNESCO, Paris
WWAP (2009) World Water Assessment Programme. The United Nations world water development
report 3, Water in a changing world, Paris, UNESCO, and London, Earthscan
Xu FA, Zhao BZ (2001) Development of crop yield and water use efficiency in Fengqiu County.
China Acta Pedol Sin 38:491–497
Xue Q, Zhu Z, Musick JT, Stewart BA, Dusek DA (2006) Physiological mechanisms contributing
to the increased water-use efficiency in winter wheat under deficit irrigation. J Plant Physiol
153:154–164. doi:10.1016/j.jplph.2005.04.026, DOI:dx.doi.org
Yusuf AM, Johansen C, Krishnamurthy L, Hamid A (2005) Genotypic variation in root systems of
chickpea (Cicer arietinum L.) across environments. J. Agron. Crop Sci 191:464–472
Zentner RP, Wall DD, Nagy CN, Smith EG, Young DL, Miller PR, Campbell CA, McConkey BG,
Brandt SA, Lafond GP, Johnston AM, Derksen DA (2002) Economics of crop diversification
and soil tillage opportunities in the Canadian Prairies. Agron J 94:216–230
Zhang J (2004) Crop yield and water use efficiency: a case study in rice. In: Bacon M (ed.) Water
use efficiency in plant biology. Blackwell, Oxford, pp 198–227
Zhang H, Oweis T (1999) Water-yield relations and optimal irrigation scheduling of wheat in the
Mediterranean region. Agr Water Manage 38:195–211. doi:10.1016/S0378-3774(98)00069-9,
DOI:dx.doi.org
Zhang H, Wang X, You M, Liu C (1999) Water–yield relations and water use efficiency of winter
wheat in the north China plain. Irrig Sci 19:37–45. doi:10.1007/s002710050069
Zhang XY, Chen SY, Liu MY (2002) Evapotranspiration, yield and crop coefficient of irrigated
maize under straw mulch conditions. Progr Geogr 21:583–592
Zhang X, Chen S, Liu M, Pei D, Sun H (2005) Improved water use efficiency associated
with cultivars and agronomic management in the North China Plain. Agron J 97:783–790.
doi:10.2134/agronj2004.0194
Zhang GS, Chan KY, Oates A, Heenan DP, Huang GB (2007a) Relationship between soil structure
and runoff/soil loss after 24 years of conservation tillage. Soil Tillage Res 92:122–128
Zhang J, Sun J, Duan A, Wang J, Shen X, Liu X (2007b) Effects of different planting patterns on
water use and yield performance of winter wheat in the Huang-Huai-Hai plain of China. Agric
Water Manage 92:41–47. doi:10.1016/j.agwat.2007.04.007
Zhang S, Lövdahl L, Grip H, Jansson P, Tong Y (2007c) Modelling the effects of mulching and
fallow cropping on water balance in the Chinese Loess Plateau. Soil Tillage Res 93:283–298.
doi:10.1016/j.still.2006.05.002
Zhao JB, Mei XR, Zhong ZZ (1996) The effect of straw mulch on crop water use efficiency in
dryland. Sci Agr Sin 29:59–66
Zuazo VHD, Pleguezuelo CRR (2008) Soil-erosion and runoff prevention by plant covers. a
review. Agron Sustain Dev 28:65–86
Zwart SJ, Bastiaanssen WGM (2004) Review of measured crop water productivity values for
irrigated wheat, rice, cotton and maize. Agr Water Manage 69(2):115–133. doi:10.1016/j.
agwat.2004.04.007, DOI:dx.doi.org
Genetic Mechanisms of Drought Stress
Tolerance, Implications of Transgenic
Crops for Agriculture
Abstract This chapter review effects of drought stress on plants, and presents a
list of transgenic plants tolerating drought stress. Many abiotic and biotic stresses
are regularly affecting agricultural production. None are now under direct human
control. Abiotic stresses such as drought, extreme temperature and salinity have
clearly changed crops growth and yields in last two decades. Drought stress is the
major stress affecting crop growth, development and yields. Drought stress may
leave the lands barren for years to come if not taken care of at the right time.
Drought is a major phenomenon leading to major crop losses. We can see the degree
of drought stress severity on plants by symptoms and effects on physiological
metabolisms and yield. Many symptoms of drought stress are clear such as leaf
rolling, yellowing (chlorosis), browning and wilting. At the physiological level,
drought stress alters the complete physiology and metabolism of plants. Drought
stress modifies photosynthetic rate, relative water content, leaf water potential, and
stomata conductance. Ultimately, it destabilizes the membrane structure and per-
meability, protein s tructure and function, leading to cell death.
We reviewed the severity of drought stress and molecular mechanisms adopted
by plants. Plants can escape, avoid or tolerate drought stress using unusual mecha-
nisms. Tolerance against drought is provided either directly through metabolites like
trehalose, mannitol, glycinebetaine or indirectly through regulation of gene expres-
sion by transcription factors and kinases in signal transduction. The molecular
response of plants to drought stress has been often considered as a complex process
mainly based on the modulation of transcriptional activity of stress-related genes.
Understanding the mechanisms behind these molecules and genes is needed for their
usage in developing transgenics that would withstand drought stress and improve
the agriculture productivity.
Abbreviations
1 Introduction
As industrialization and desertification cover more and more of the terrestrial areas,
scarcity of the fresh water resources will globalize, leading to some abiotic stresses
such as salinity, drought, freezing and extreme temperature. These stresses are
becoming the limiting factors for today’s agricultural productivity (Vinocur and
Altman 2005). We here, focus on the severity arising due to drought stress. There
are different scientific definitions of drought and its subtle and complex. In general,
drought can be defined as an extended period of deficient rainfall relative to an average
Genetic Mechanisms of Drought Stress Tolerance… 215
for a region. Drought can be categorized into three types: (1); Meteorological
drought which occurs when there is a prolonged period of below average precipita-
tion, creating a natural shortage of available water, (2); Agricultural drought, that
often occurs during dry, hot periods of low or average precipitation when the soil
conditions or the agricultural technologies require extra water, and (3); Hydrological
drought is nothing but prolonged meteorological drought which can occur even
during times of average or above average precipitation in case human demands for
water are high and increased usage has lowered the water resources below average.
The ability of plants to resist drought conditions is crucial for countries worldwide
(Umezawa et al. 2006).
Crops can grow and adapt under drought stress by using different mechanisms.
Crops resistance to drought stress can be divided into three strategies, (1) drought
escape, (2) drought avoidance and (3) drought tolerance. (1) Drought escape is
defined as the ability of a plant to complete its lifecycle before serious soil and
plant water deficit develops (Mitra 2001). This involves early flowering, early
maturity and variation in duration of growth period depending on the extent of
water deficit. (2) Drought avoidance is the ability of a plant to maintain relatively
high tissue water potential despite a shortage of soil moisture (Mitra 2001). (3)
Drought tolerance is the ability to withstand water deficit with low tissue water
potential (Mitra 2001). Plants under drought survive by maintaining a balance,
using more than one mechanism at a time. This is so because the tolerance mecha-
nisms for abiotic stresses are genetically complex being multigenic in nature
(Flowers 2004; Wang et al. 2003).
Some global problems such as increasing human population and decreasing agri-
cultural productivity are raising an alarming situation across the globe. Out of the
total potentially arable land only 10% of the world’s 13 billion hectares is farmed
(Yadav 2009). These two factors lead to a technical bottleneck for the people in all
fields of science. In India, the most drought stricken areas are Rajasthan, parts of
Gujarat, Haryana and Andhra Pradesh (Mitra 2001). Drought not only individually
affects the agriculture but also leads to other abiotic stresses such as salinity, heat
stress and scarcity of fresh water etc. in a chain reaction. It single handedly has the
power to shake the economy of the world. Hence, we need to develop transgenic
crops with better performance leading to stable crop yield in drought prone environ-
ments. These have been repeatedly reported. The parameters to evaluate plant stress
resistance should generally be the deciding factors for a genetically modified crop
but have become the major limitation. This vociferously emphasizes on the urgent
need to reframe the criteria for evaluating response of a genetically modified plant
in normal and stress conditions (Herve and Serraj 2009). Human malpractices due
to insufficient or half knowledge have lead to global warming which ultimately
leads to unexpected climate changes (Kerr 2010). The need of the hour is to shed
light on new strategies being developed which include adaptive changes ranging
from traditional agronomic practices to molecular tailoring of genes (Rivero et al.
2007). For this purpose all the fields of biotechnology and molecular biology aimed
at overcoming drought need to be clubbed together and fully implemented comple-
mentarily. Several comprehensive reviews on molecular mechanisms adopted by
216 J. Bhardwaj and S.K. Yadav
the plants against drought and other abiotic stresses have been recently published
(Herve and Serraj 2009; Umezawa et al. 2006; Vinocur and Altman 2005;
Mitra 2001). Our review focuses on the severity arising due to drought affecting the
agriculture around the globe. We have also tried to understand and present the
molecular mechanisms lying beneath the various tolerance mechanisms adopted by
transgenic plants.
Fig. 1 Effect of drought stress on wheat plants. The drought stress was induced to the plants by
withholding water for 2 weeks. Picture on right hand side presents a closer view. The damage of
the drought stress is seen as retardation in growth (a). The yellowing (chlorosis), browning, wilting
and rolling of leaves were also observed (b)
Severe stress disrupts the cellular homeostasis accompanied with the generation
of reactive oxygen species (ROS). The ROS are combated by cell’s antioxidant system
including enzymatic e.g. superoxide dismutase (SOD), catalase (CAT), peroxidases
(POD), etc. and non-enzymatic e.g. glutathione (GSH) and ascorbate (Asada 1999;
Mittler 2002). Chloroplasts are particularly susceptible to ROS because of the rela-
tively high concentration of oxygen that reacts with electrons which escape from the
photosynthetic electron transfer system (Foyer et al. 1994). Scavenging of ROS is
brought about by reduction in redox state of ascorbate and glutathione as they shift
towards their oxidized forms (Hendry et al. 1992; Tommasi et al. 1999). Changes
in the ascorbate and glutathione redox states have been shown to affect gene
expression and metabolic pathways (Noctor and Foyer 1998; Catani et al. 2001).
Most climate change studies are indicating an expansion of arid zones on our planet.
This is due to the direct effect of the global warming. This situation may transform
into severe drought conditions across globe. It is therefore, indispensible to under-
stand the molecular mechanisms relating to drought stress tolerance in plants.
Drought stress affects most of the cellular processes in plants. It generates ROS
in a plant that disrupts their metabolism. The disturbance in cellular homeostasis
leads to the dehydration. Severe drought leads to irreversible destruction of functional
and structural proteins leading to various morphological changes and ultimately
cell death.
Important advances have been made in fields of molecular biology like genetic
engineering and biotechnology in last two decades (Sinclair et al. 2004). This help
us to understand the transcriptional changes induced by drought constraints and in
the identification of signaling proteins and transcription factors which regulate the
stress-induced gene expression. Golden rice, BT brinjal, flavrsavr tomato were once
a farfetched dream for science lovers, but this challenge actualized due to advances
in molecular biology. The key point for these success stories lies in the introduction
of functional genes from related or unrelated sources (plants, animals, bacteria and
fungi etc.) into various types of plants (Passioura 2006). Plants are vulnerable in
nature being affected by the slightest of change in environmental conditions like
rainfall, temperature and soil conditions like pH, moisture, humidity etc. Nature
itself is so uncertain and unpredictable yet, it has simultaneously bestowed upon
plants the ability to protect themselves against sudden calamities such as various
biotic (bacterial/fungal infections, insects) and abiotic stresses (salinity, desiccation,
cold and drought). Out of all these, drought is remained over the years and is
still a subject of serious concern becoming a threat for agriculture all over (Nelson
et al. 2007; Zhang 2007). Several studies have reported the genes involved in stress
signaling and metabolic pathways to have a positive effect in transgenic plants
for drought tolerance (Yamaguchi-Shinozaki and Shinozaki 2006). Therefore, it
is important to create more genetically modified (GM) plants with desirable traits
showing positive effect on agricultural economy (Table 1). To reach this goal, it is
Genetic Mechanisms of Drought Stress Tolerance… 219
Table 1 Transgenics developed with different genes over the time (1990–2010) against drought
stress
Transgenic Gene name Gene source References
Tobacco AlSAP A. littoralis Saad et al. (2010)
Rice SAMDC Datura Peremarti et al. (2009)
L. chinensis TaLEA Wheat Wang et al. (2009)
Maize gdhA E. coli Lightfoot et al. (2007)
Bentgrass hva1 Barley Fu et al. (2007)
Tobacco ScTPS1 Yeast Karim et al. (2007)
Tobacco LEA T. androssowii Wang et al. (2006)
Rice COX A. pascens Jin et al. (2006)
Arabidopsis AREB1/ABF2 Arabidopsis Furihata et al. 2006
Tobacco Ots A E. coli Jun et al. (2005)
Rice MnSOD P. sativum Wang et al. (2005a, b)
M. sativa WXP1 M. truncatula Zhang et al. (2005)
Rice CBF3/ABF3 Arabidopsis/Rice Oh et al. (2005)
Arabidopsis/Canola ERA1 Arabidopsis Wang et al. (2005a, b)
Arabidopsis AtMYB60 Arabidopsis Cominelli et al. (2005)
Chinese cabbage LEA Canola Park et al. (2005)
Arabidopsis GSMT and DMT A. halophytica Waditee et al. (2005)
Tomato TPS1 Yeast Cortina and
Culianez-Macia (2005)
Petunia P5CS Arabidopsis/Rice Yamada et al. 2005
Maize NPK 1 Tobacco Shou et al. (2004)
Rice Cod A A. globiformis Sawahel (2004)
Rice RWC3 Rice Lian et al. (2004)
Rice Adc Datura Capell et al. (2004)
Rice HVA1 Barley Babu et al. (2004)
Arabidopsis SHN1/WIN1 Arabidopsis Aharoni et al. (2004)
Wheat DREB1A/CBF3 Arabidopsis Pellegrineschi et al. (2004)
Tobacco DREB1A/CBF3 Arabidopsis Kasuga et al. 2004
Arabidopsis AREB1/ABF2 Arabidopsis Kim et al. (2004a, b)
Arabidopsis CAZFP1 Pepper Kim et al. (2004a, b)
Arabidopsis STZ Arabidopsis Sakamoto et al. (2004)
Arabidopsis ANAC019/055/072(NAC) Arabidopsis Tran et al. (2004)
Arabidopsis SRK2C Arabidopsis Umezawa et al. (2004)
Cotton GF14l Cotton Yan et al. (2004)
Arabidopsis DREB1C/CBF2 Arabidopsis Novillo et al. (2004)
Arabidopsis ZmDREB1A Maize Qin et al. (2004)
Arabidopsis SPDS C. ficifolia Kasukabe et al. (2004)
Tobacco ADH S. Liaotungenisis Li et al. (2003)
Arabidopsis CBL1 Arabidopsis Cheong et al. (2003)
Rice HSP101 Arabidopsis Katiyar-Agarwal
et al. (2003)
Tobacco TPS1 S. cerevisiae Lee et al. (2003)
Rice otsA/otsB E. coli Garg et al. (2002)
Tobacco Chl-NADP-ME Maize Laporte et al. (2002)
(continued)
220 J. Bhardwaj and S.K. Yadav
Table 1 (continued)
Transgenic Gene name Gene source References
E. coli CCP-1a B. sexangula Yamada et al. (2002)
Sugarbeet Sac B B. subtilis Pilon-Smits et al. (1999)
Tobacco IMT 1 M. crystallinum Sheveleva et al. (1997)
Tobacco P5CS Mothbean Kishor et al. (1995)
Tobacco Sac B B. subtilis Pilon-Smith et al. (1995)
Tobacco BetB E. coli Holmstrom et al. (1994)
Tobacco SAMDC Human Noh and Minocha (1994)
Tobacco SOD Pea Sengupta et al. (1993)
Tobacco ODC Mouse Descenzo and Minocha
(1993)
Tobacco ODC Yeast Hamill et al. (1990)
Fig. 2 Response mechanisms adopted by the genetically modified plants to fight against drought
stress. These can be achieved directly through osmolytes, proteins like heat shock proteins (HSPs),
late embryogenesis abundant (LEA) proteins and/or indirectly through transcription factors (TFs),
protein kinases involved in signal transduction (ST) pathways. All these methods ultimately lead
to drought tolerant plants which can withstand drought stress
functions and expansive growth (Mathews et al. 1984). During severe drought stress
conditions, reduction in water potential leads to different cell dehydration levels
which are held responsible for the cell death (Flower and Ludlow 1986). Osmolytes
cause osmotic adjustment leading to maintenance of turgor at water potential which
could normally eliminate turgor (Beck et al. 2007). Recently, several successful
attempts have transferred functional genes encoding enzymes associated with the
synthesis of different osmolytes (Dobra et al. 2010; Huh et al. 2010; Goel et al.
2010). Developed transgenic plants have shown drought tolerance.
Trehalose is a non reducing sugar found in the nature in diverse organisms ranging
from algae, bacteria, insects, yeast, fungi to animals and plants (Elbein 1974). It is
known to accumulate in higher amounts in resurrection plants like Selagenella
lepidophylla (Zentella et al. 1999; Bianchi et al. 1993), some drought tolerant angio-
sperms (Drennan et al. 1993) and in anhydrobiotic organisms that survive during
complete dehydration (Crowe et al. 1992). There is a unison consensus over the fact that
trehalose is synthesized in response to various stresses including drought stress and
protects against them (Mackenzie et al. 1988; De Vigilio et al. 1994; Sharma 1997).
222 J. Bhardwaj and S.K. Yadav
Their reversible water absorption capacity protects the biological molecules from
drought induced damages. They play a greater role in protecting biological
membranes, cellular metabolism than in regulating water potential (Iordachescu
and Imai 2008; Rodríguez-Salazar et al. 2009). Trehalose has been demonstrated at
very low levels in tobacco and in many higher plants (Goddijn et al. 1997; Kosmas
et al. 2006). A yeast gene ScTPS1 was introduced in tobacco (Karim et al. 2007) and
it was found that the transgenics accumulating trehalose exhibited enhanced sur-
vival on exposure to drought. It is suggested that trehalose even at low concentrations
stabilizes proteins and membrane structures under stress (Colaco et al. 1992, 1995
Iwahashi et al. 1995) because of the glass transistion temperature, greater flexibility
and chemical stability. A yeast trehalose phosphate synthase (TPS1) gene was intro-
duced into tobacco and dramatic effects were observed on the growth even with low
levels of trehalose (Lee et al. 2003). In yeast S. cerevisiae, trehalose accumulation
has been associated with improvement in response to stresses (Eleutherio et al. 1993;
Meric et al. 1995). Transgenic tomato having TPS1 gene from yeast showed increased
shoot growth and survivability under drought stress conditions created by with-
holding water for few weeks (Cortina and Culianez-Macia 2005). Transgenic
tobacco and rice were developed by introducing otsA and otsA/otsB gene from
E. coli, respectively (Jun et al. 2005; Garg et al. 2002). The otsA gene is homologous
to eukaryotic TPS1 gene encoding for trehalose-6-phosphate synthase and otsB
gene is homologous to eukaryotic TPS2 which encodes for eukaryotic trehalose-6-
phosphate phosphatase. Their introduction in respective plants showed accumulation
of trehalose at higher amounts which imparted tolerance to drought as compared
to the wild plants.
Glycinebetaine is one of the major osmoprotectants in halophilic microorganisms
(Nyyssola et al. 2000; Waditee et al. 2003). Its accumulation has been widely studied
with respect to modifications of several metabolic steps involved in stress tolerance.
A betaine aldehyde decarboxylase encoding gene from halophyte S. liaotungensis
was introduced into tobacco and it was observed that in vitro plantlets were
significantly resistant to the stress conditions (Li et al. 2003). Higher levels of
glycinebetaine were detected in transgenic Arabidopsis having GSMT and DMT
(glycine sarcosine methyltransferase and dimethyl glycine methyltransferase) genes
from A. Halophytica (Waditee et al. 2005). Betaine molecules protect the cells by
stabilization of proteins and cell structure or by scavenging free radicals as well as
by osmotic effects (Chen and Murata 2002). Finding of a novel synthetic pathway
for glycinebetaine is one of the most recent advances in this area (Waditee et al.
2003). Identifying role of such pathways would be of interest for future agricultural
crop improvement strategies. Transgenic rice was developed with COX (choline
oxidase) gene from A. pascens and CODA (choline dehydrogenase) gene from
A. globiformis (Jin et al. 2006; Sawahel 2004). These genes are involved in bio-
synthesis of glycinebetaine. The transgenic plants were significantly resistant to
stress conditions and set seeds in contrast to the wild plants.
A betB (betaine aldehyde dehydrogenase) gene from E. coli, involved in bio-
synthesis of glycinebetaine was introduced into tobacco (Holmstrom et al. 1994).
Accumulation of glycinebetaine in higher levels confers drought tolerance to
Genetic Mechanisms of Drought Stress Tolerance… 223
LEA proteins act as protective molecules against cellular damage (Wise 2003;
Oskman-caldentkey and Sacto 2005). LEA genes from some plants have been
well characterized and studied (Liang et al. 2004; Ali-Benali et al. 2005; Goyal
et al. 2005; Park et al. 2005; Gal et al. 2004; Singh et al. 2005; Porcel et al. 2005;
Babu et al. 2004). A novel LEA gene (DQ 663481) from T. androssowii was used
for developing transgenic tobacco (Wang et al. 2006). The results suggested that
mechanism of drought tolerance by LEA proteins is through cell membrane protec-
tion from damage which is in accordance with studies of Babu et al. (2004) and
Fu et al. (2007) who introduced barley HVA1 gene into rice and bentgrass, respec-
tively. This gene encodes for a group of three LEA proteins which accumulate
in vegetative organs during drought stress and provide protection against it.
Improved salt and drought tolerance was observed in transgenic chinese cabbage
constitutively expressing a LEA gene from canola (Park et al. 2005). Transgenic rice
and wheat expressing LEA gene has been shown to confer tolerance to salt and
drought stresses (Xu et al. 1996; Rohila et al. 2002; Sivamani et al. 2000; Wang
et al. 2009).
Heat shock proteins (HSPs) prevent protein denaturation during stresses by
serving as molecular chaperones that participate in ATP dependent protein assembly
and disassembly. HSPs play important role in thermotolerance (Maestri et al. 2002).
Under heat stress, organellar HSPs associate with membranes and protect photosyn-
thetic electron transport (Debel et al. 1995; Heckathorn et al. 1998). Correlations
between expression of HSPs and thermotolerance have been found in maize, tomato
and creeping bentgrass (Park et al. 1996; Ristic et al. 1998). A significant osmo
protective effect was obtained in E.coli transformed with the cytosolic chaperonin
CCP-1a from B. sexangula (Yamada et al. 2002). Increase in growth and recovery
from heat stress was observed in rice plants overexpressing HSP101 gene from
Arabidopsis (Katiyar-Agarwal et al. 2003).
Several metabolites are known to involve in the mechanism of drought stress
tolerance of plants. Among these, proline, glycinebetaine, trehalose, and mannitol are
the most common. Additionally, LEA and HSP group of proteins are also identified
for their role in drought stress tolerance of plants.
3.2 Transcription Factors
Transcription factors (TFs) are regulatory proteins that modulate gene expression
through interactions like sequence specific DNA binding or protein-protein interac-
tions. They can switch on or off the regulatory cascades activating or repressing the
transcription of the target genes (Zhang et al. 2005). Many TFs have been found to
be involved in the plant response to drought stress. Most of these fall into large TF
families such as ERF/ABF2, bZIP, NAC and Cys2His2 zinc-finger. TFs can be of two
types; viz. transcription activators and transcription repressors. Transcription acti-
vators enhance the drought tolerance by up regulating the stress responsive genes.
Genetic Mechanisms of Drought Stress Tolerance… 225
Besides the main categories mentioned above, some other types of genes have also
been found to be involved in drought stress tolerance. Glutamate dehydrogenase
(GDH) is an important enzyme of nitrogen and carbon metabolism. Both the metabolic
processes are essential for normal and healthy plant growth but are severely affected
under drought stress conditions. Upon introduction of gdhA (NADPH-dependent
glutamate dehydrogenase) gene from E. coli into maize, germination and water
deficit tolerance was found to be increased in transgenic maize (Lightfoot et al.
2007). SOD is an important enzyme of ROS scavenging system. These ROS species
are generated during stress arising due to drought. Pea Cu/ZnSOD (superoxide
dismutase) and MnSOD (manganese superoxide dismutase) genes were introduced
into tobacco and rice, respectively (Sengupta et al. 1993; Wang et al. 2005a, b).
Their results suggested improved drought tolerance in transgenic plants. Down
regulation of a or b subunit of farnesyltransferase enhances response to ABA and
drought tolerance. ERA1 (enhanced response to ABA 1, farnesyltransferase) gene
from Arabidopsis was introduced into Canola/Arabidopsis (Wang et al. 2005a, b).
Aquaporins regulate the movement of water for the benefit of the plant under drought
stress conditions. Introduction of RWC3 gene encoding for an aquaporin from rice
into rice imparted drought tolerance (Lian et al. 2004). Similarly, GF14l (14-3-3
protein) from cotton was introduced into cotton (Yan et al. 2004). This protein con-
trolled the senescence and photosynthesis system in transgenic plants under drought
stress. An Arabidopsis calcium sensor CBL1 gene (calcineurin B-like protein)
which plays role in signal transduction pathway perceiving drought stress and other
control factors, was put into Arabidopsis and increased drought tolerance was
observed (Cheong et al. 2003). A maize Chl-NADP-ME (chlorophyll-targeting
NADP-malic enzyme) gene was put into tobacco (Laporte et al. 2002). The trans-
genic plants showed enhanced plant growth, stomatal conductance and chlorophyll
content under stress conditions.
Role of several genes have been documented in drought stress tolerance through
generating transgenic plants. Overexpression of genes encoding enzymes of ROS
quenching pathway, aquaporins and CBL have been found as a potential candidate
for imparting drought stress tolerance.
4 Conclusion
Drought is one of the most serious abiotic stresses affecting the agriculture world
over. Natural shortage of water or prolonged periods of below average rainfall/
precipitation along with increased human demands for water continuously leads to
different types of drought conditions. Most of the plants are unable to responses
to drought stress. Plants can response and adapt to drought stress by using one of these
228 J. Bhardwaj and S.K. Yadav
Acknowledgements We are grateful to Dr. P. S. Ahuja, Director, IHBT, for his continuous
encouragement and guidance. JB would like to acknowledge Council of Scientific and Industrial
Research, Govt. of India for providing Diamond Jubilee Research Internship and Department of
Science and Technology, Govt. of India for providing research funds to the laboratory.
References
Aharoni A, Dixit S, Jetter R, Thoenes E, Van Arkel G, Pereira A (2004) The SHINE clade of AP2
domain transcription factors activates wax biosynthesis, alters cuticle properties, and confers
drought tolerance when overexpressed in Arabidopsis. Plant Cell 16:2463–2480
Ali-Benali MA, Alary R, Joudrier P, Gautier MF (2005) Comparative expression of five LEA genes
during wheat seed development and in response to abiotic stresses by real-time quantitative
RT-PCR. Biochem Biophys Acta 1730:56–65
Asada K (1999) The water-water cycle in chloroplasts: scavenging of active oxygens and dissipation
of excess photons. Annu Rev Plant Physiol Plant Mol Biol 50:601–639
Babu RC, Jang ZX, Blum A, Ho THD, Wu R, Nguyen HT (2004) HVA1, a LEA gene from barley
confers dehydration tolerance in transgenic rice (Oryza sativa L.) via cell membrane protection.
Plant Sci 166:855–864
Bartels D, Sunkar R (2005) Drought and salt tolerance in plants. Crit Rev Plant Sci 24:23–58
Beck EH, Fettig S, Knake C, Hartig K, Bhattarai T (2007) Specific and unspecific responses of
plants to cold and drought stress. J Biosci 32:501–510
Bianchi G, Gamba A, Limiroli R, Pozzi N, Elster R, Salamini F, Bartels D (1993) The unusual
sugar composition in leaves of the resurrection plant Myrothamnus flabellifolia. Plant Physiol
87:223–226
Boudsocq M, Lauriere C (2005) Osmotic signaling in plants: multiple pathways mediated by
emerging kinase families. Plant Physiol 138:1185–1194
Bressan R, Bohnert H, Zhu JK (2009) Abiotic stress tolerance: from gene discovery in model
organisms to crop improvement. Mol Plant 2:1–2
Genetic Mechanisms of Drought Stress Tolerance… 229
Browne J, Tunnacliffe A, Burnell A (2002) Plant dessication gene found in a nematode. Nature
416:38
Capell T, Bassie L, Christou P (2004) Modulation of the polyamine biosynthetic pathway in
transgenic rice confers tolerance to drought stress. Proc Natl Acad Sci USA 101:9909–9914
Catani MV, Rossi A, Costanzo A, Sabatini S, Levrero M, Melino G, Avigliano L (2001) Induction
of gene expression via activator protein-1 in the ascorbate protection against UV-induced damage.
Biochem J 356:77–85
Chen TH, Murata N (2002) Enhancement of tolerance of abiotic stress by metabolic engineering
of betaines and other compatible solutes. Curr Opin Plant Biol 5:250–257
Cheong YH, Kim KN, Pandey GK, Gupta R, Grant JJ, Luan S (2003) CBL1, a calcium sensor that
differentially regulates salt, drought, and cold responses in Arabidopsis. Plant Cell 15:1833–1845
Chinnusamy V, Schumaker K, Zhu JK (2004) Molecular genetic perspectives on cross-talk and
specificity in abiotic stress signaling in plants. J Exp Bot 55:225–236
Close TJ (1997) Dehydrins: a commonality in the response of plants to dehydration and low
temperature. Plant Physiol 100:291–296
Colaco C, Sen S, Thangavelu M, Pinder S, Roser B (1992) Extraordinary stability of enzymes
dried in trehalose: simplified molecular biology. Nat Biotechnol 10:1007–1011
Colaco K, Kampinga J, Roser B (1995) Amorphous stability and trehalose. Science 268:788–789
Cominelli E, Galbiati M, Vavasseur A, Conti L, Sala T, Vuylsteke M, Leonhardt N, Dellaporta SL,
Tonelli C (2005) A guard-cell-specific MYB transcription factor regulates stomatal movements
and plant drought tolerance. Curr Biol 15:1196–1200
Cortina C, Culianez-Macia F (2005) Tomato abiotic stress enhanced tolerance by trehalose
biosynthesis. Plant Sci 169:75–82
Crowe JH, Hoekstra FA, Crowe LM (1992) Anhydrobiosys. Annu Rev Physiol 54:579–599
De Vigilio C, Hottinger T, Dominguez J, Boller T, Wiekman A (1994) The role of trehalose
synthesis for the acquisition of thermotolerance in yeast I. Genetic evidence that trehalose is a
thermoprotectant. Eur J Biochem 219:179–186
Debel K, Eberhard D, Kloppstech K (1995) Light stress: its effect on expression of small organellar
heat-shock proteins in plants. Cues to their function? In: Leigh RA, Metchteld Blake-Kalff MA
(eds) Proceedings of the second STRESSNET conference. European Commission: Directorate
General VI, pp 29–34
Descenzo RA, Minocha SC (1993) Modulation of cellular polyamines in tobacco by transfer and
expression of mouse ornithine decarboxylase cDNA. Plant Mol Biol 22:113–127
Dobra J, Motyka V, Dobrev P, Malbeck J, Prasil IT, Haisel D, Gaudinova A, Havlova M, Gubis J,
Vankova R (2010) Comparison of hormonal responses to heat, drought and combined stress in
tobacco plants with elevated proline content. J Plant Physiol 167:1360–1370
Drennan PM, Smith MT, Goldsworthy D, Van Staden J (1993) The occurence of trehalose in the
leaves of the dessication-tolerant angiosperm Myrothamnus flabellifolius Welw. J Plant Physiol
142:493–496
Elbein A (1974) The metabolism of alpha-alpha-trehalose. Adv Carbohydr Chem Biochem
30:227–256
Eleutherio ECA, Araujo PS, Panek AD (1993) Protective role of trehalose during heat stress in
Saccharomyces cerevisiae. Cryobiology 30:591–596
Escalona JM, Flexas J, Medrano H (1999) Stomatal and non-stomatal limitations of photo
synthesis under water stress in field-grown grapevines photosynthesis. Aust J Plant Physiol
26:421–433
Flower DJ, Ludlow MM (1986) Contribution of osmotic adjustment to dehydration tolerance of
water-stressed pigeon-pea (Cajanus cajan (L.) millsp.) leaves. Plant Cell Environ 9:33–40
Flowers TJ (2004) Improving crop salt tolerance. J Exp Bot 55:307–319
Fowler S, Thomashow MF (2002) Arabidopsis transcriptome profiling indicates that multiple
regulatory pathways are activated during cold acclimation in addition to the CBF cold response
pathway. Plant Cell 14:1675–1690
Foyer CH, Descourvieres P, Kunert KJ (1994) Protection against oxygen radicals: an important
defence mechanism studied in transgenic plants. Plant Cell Environ 17:507–523
230 J. Bhardwaj and S.K. Yadav
Jun SS, Yang JY, Choi HJ, Kim NR, Park MC, Hong YN (2005) Altered physiology in trehalose
producing transgenic tobacco plants: enhanced tolerance to drought and salinity stresses. J Plant
Biol 48:456–466
Karakas B, Ozias-Akins P, Stushnoff C, Suefferheld M, Rieger M (1997) Salinity and drought
tolerance of mannitol-accumulating transgenic tobacco. Plant Cell Environ 20:609–616
Karim S, Aronsson H, Ericson H, Pirhonen M, Leyman B, Welin B, Mantyla E, Palva ET,
Dijck PV, Holmstrom KO (2007) Improved drought tolerance without undesired side effects in
transgenic plants producing trehalose. Plant Mol Biol 64:371–386
Kasuga M, Miura S, Shinozaki K, Yamaguchi-Shinozaki K (2004) A combination of the
Arabidopsis DREB1A gene and stress-inducible rd29A promoter improved drought- and
low-temperature stress tolerance in tobacco by gene transfer. Plant Cell Physiol 45:346–350
Kasukabe Y, He L, Nada K, Misawa S, Ihara I, Tachibana S (2004) Overexpression of spermidine
synthase enhances tolerance to multiple environmental stresses and upregulates the expression
of various stress-regulated genes in transgenic Arabidopsis thaliana. Plant Cell Physiol
45:712–722
Katiyar-Agarwal S, Agarwal M, Grover A (2003) Heat-tolerant basmati rice engineered by
over-expression of hsp101. Plant Mol Biol 51:677–686
Kerr RA (2010) Climate change. El Niño lends more confidence to strong global warming. Science
330:1465
Kim SH, Hong JK, Lee SC, Sohn KH, Jung HW, Hwang BK (2004a) CAZFP1, cys2/His2- type
zinc-finger transcription factor gene functions as a pathogen-induced early-defense gene in
Capsicum annuum. Plant Mol Biol 55:883–904
Kim S, Kang JY, Cho DI, Park JH, Kim SY (2004b) ABF2, an ABRE-binding bZIP factor, is an
essential component of glucose signaling and its overexpression affects multiple stress tol-
erance. Plant J 40:75–87
Kishor PBK, Hong Z, Miao GH, Hu CAA, Verma DPS (1995) Overexpression of [Delta]-Pyrroline-
5-carboxylate synthetase increases proline production and confers osmotolerance in transgenic
plants. Plant Physiol 108:1387–1394
Kosmas SA, Argyrokastritis A, Loukas MG, Eliopoulos E, Tsakas S, Kaltsikes PJ (2006) Isolation
and characterization of drought-related trehalose 6-phosphate-synthase gene from cultivated
cotton (Gossypium hirsutum L.). Planta 223:329–339
Kovtun Y, Chiu WL, Tena G, Sheen J (2000) Functional analysis of oxidative stress-activated
mitogen-activated protein kinase cascade in plants. Proc Natl Acad Sci USA 97:2940–2945
Laporte MM, Shen B, Tarczynski MC (2002) Engineering for drought avoidance: expression
of maize NADP-malic enzyme in tobacco results in altered stomatal function. J Exp Bot
53:699–705
Lee SB, Kwon HB, Kwon SJ, Park SC, Jeong MJ, Han SE, Byun MO, Daniell H (2003)
Accumulation of trehalose within transgenic chloroplasts confers drought tolerance. Mol
Breed 11:1–13
Li QL, Gao XR, Yu XH, Wang XZ, An LJ (2003) Molecular cloning and characterization of
betaine aldehyde dehydrogenase gene from Suaeda liaotungensis and its use in improved
tolerance to salinity in transgenic tobacco. Biotechnol Lett 25:1431–1436
Lian HL, Yu X, Ye Q, Ding XS, Kitagawa Y, Kwak SS, Su W-A, Tang ZC (2004) The role of
aquaporin RWC3 in drought avoidance in rice. Plant Cell Physiol 45:481–489
Liang CY, Xi Y, Shu J, Li J, Yang JL, Che KP, Jin DM, Liu XL, Weng ML, He YK, Wang B (2004)
Construction of a BAC library of Physcomitrella patens and isolation of a LEA gene. Plant Sci
167:491–498
Lightfoot DA, Mungur R, Amaziane R, Nolte S, Long L, Bernhard K, Colter A, Jones K, Iqbal MJ,
Varsa E, Young B (2007) Improved drought tolerance of transgenic Zea mays plants that
express the glutamate dehydrogenase gene (gdhA) of E. coli. Euphytica 156:103–116
Mackenzie KF, Singh KK, Brown AD (1988) Water stress plating hypersensivity of yeasts: protective
role of trehalose in Saccharomyces cerevisiae. J Gen Microbiol 134:1661–1666
Maestri E, Klueva N, Perrotta C, Gulli M, Nguyen HT, Marmiroli N (2002) Molecular genetics of
heat tolerance and heat shock proteins in cereals. Plant Mol Biol 48:667–681
232 J. Bhardwaj and S.K. Yadav
Sivamani E, Bahieldin A, Wraith JM, Al-Niemi T, Dyer WE, Ho THD, Qu R (2000) Improved
biomass productivity and water use efficiency under water-deficit conditions in transgenic
wheat constitutively expressing the barley HVA1 gene. Plant Sci 155:1–9
Soulages JL, Kim K, Arrese EL, Walters C, Cushman JC (2003) Conformation of a group 2 late
embryogenesis abundant protein from soybean. Evidence of poly-(L-proline)-type II structure.
Plant Physiol 131:963–975
Taiz L, Zeiger E (1998) Stress physiology. In: Plant physiology, 2nd edn. Sinauer Associates Inc,
Sunderland, pp 725–757
Tommasi F, Paciolla C, Arrigoni O (1999) The ascorbate system in recalcitrant and orthodox
seeds. Plant Physiol 105:193–198
Tran LS, Nakashima K, Sakuma Y, Simpson SD, Fujita Y, Maruyama K, Fujita M, Seki M,
Shinozaki K, Yamaguchi-Shinozaki K (2004) Isolation and functional analysis of Arabidopsis
stress-inducible NAC transcription factors that bind to a drought-responsive cis-element in the
early responsive to dehydration stress 1 promoter. Plant Cell 16:2481–2498
Umezawa T, Yoshida R, Maruyama K, Yamaguchi-Shinozaki K, Shinozaki K (2004) SRK2C, a
SNF1-related protein kinase2, improves drought tolerance by controlling stress responsive
gene expression in Arabidopsis thaliana. Proc Natl Acad Sci USA 101:17306–17311
Umezawa T, Fujita M, Fujita Y, Yamaguchi-Shinozaki K, Shinozaki K (2006) Engineering drought
tolerance in plants: discovering and tailoring genes to unlock the future. Curr Opin Biotechnol
17:113–122
Vinocur B, Altman A (2005) Recent advances in engineering plant tolerance to abiotic stress:
achievements and limitations. Curr Opin Biotechnol 16:123–132
Waditee R, Tanaka Y, Aoki K, Hibino T, Jikuya H, Takano J, Takabe T (2003) Isolation and
functional characterization of N-methyltransferases that catalyze betaine synthesis from
glycine in a halotolerant photosynthetic organism Aphanothece halophytica. J Biol Chem
278:4932–4942
Waditee R, Bhuiyan MN, Rai V, Aoki K, Tanaka Y, Hibino T, Suzuki S, Takano J, Jagendrof AT,
Takabe T (2005) Genes for direct methylation of glycine provide high levels of glycinebetaine
and abiotic-stress tolerance in Synechococcus and Arabidopsis. Proc Natl Acad Sci USA
102:1318–1323
Wang W, Vinocur B, Altman A (2003) Plant responses to drought, salinity and extreme
temperatures: towards genetic engineering for stress tolerance. Planta 218:1–14
Wang FZ, Wang QB, Kwon SY, Kwak SS, Su WA (2005a) Enhanced drought tolerance of trans-
genic rice plants expressing a pea maganese superoxide dismutase. J Plant Physiol
162:465–472
Wang Y, Ying J, Kuzma M, Chalifoux M, Sample A, McArthur C, Uchacz T, Sarvas C, Wan J,
Dennis DT (2005b) Molecular tailoring of farnesylation for plant drought tolerance and yield
protection. Plant J 43:413–424
Wang Y, Jiang J, Zhao X, Liu G, Yang C, Zhan L (2006) A novel LEA gene from Tamarix
androssowii confers drought tolerance in transgenic tobacco. Plant Sci 171:655–662
Wang L, Li X, Chen S, Liu G (2009) Enhanced drought tolerance in transgenic Leymus chinensis
plants with constitutively expressed wheat TaLEA3. Biotechnol Lett 31:313–319
Wise MJ (2003) LEAping to conclusions: a computational reanalysis of late embryogenesis
abundant proteins and their possible roles. BMC Bioinform 4:52
Xu D, Duan X, Wang B, Hong B, Ho THD, Wu R (1996) Expression of a late embryogenesis
abundant protein gene, HVA1, from barley confers tolerance to water deficit and salt-stress in
transgenic rice. Plant Physiol 110:249–257
Yadav SK (2009) Cold stress tolerance mechanisms in plants. A review. Agron Sustain Dev
30:515–527
Yamada A, Sekiguchi M, Mimura T, Ozeki Y (2002) The role of plant CCTa in salt- and
osmotic-stress tolerance. Plant Cell Physiol 43:1043–1048
Yamada M, Morishita H, Urano K, Shiozaki N, Yamaguchi-Shinozaki K, Shinozaki K, Yoshiba Y
(2005) Effects of free proline accumulation in petunias under drought stress. J Exp Bot
56:1975–1981
Genetic Mechanisms of Drought Stress Tolerance… 235
Keywords Nematodes • Pome fruit • Stone fruit • Nuts • Bacteria • Fungi • Virus
1 Introduction
Pome, stone and nut fruits are considered a major commercial venture throughout the
temperate regions of the world, because of higher remuneration per unit area and the
realization that consumption of fruits is essential for human health and nutrition.
Among the major fruit growing countries of the world, China ranks first in the produc-
tion of apple, pear and plum, USA of almond and walnut, Italy of peaches and Turkey
of apricot and hazelnuts (Awasthi 2006). Apple, pear and plum together account for
15% of the world fruit production (Griesbach 2007). As far as overall global produc-
tion is concerned apple is followed by pear, peach, plum, cherry and almonds. The
average productivity of temperate fruits in the world is 7.4 ton/ha (Awasthi 2006).
Plant parasitic nematodes continue to threaten fruit crop production throughout
the world. They cause serious damage to many fruit and horticultural trees (Askary
et al. 2000; Askary and Haider 2010). They are microscopic, unsegmented, triplo-
blastic, bilaterally symmetrical, pseudocoelomate vermiform animal that feed on
roots, buds, stems, crowns, leaves and developing seeds (Parvatha Reddy 2008).
The extent of damage caused to plants by these tiny organisms vary with the genera
and species. Estimated overall average annual yield loss of the world’s major hor-
ticultural crops due to damage caused by plant parasitic nematodes is 13.54%
(Parvatha Reddy 2011).
The study on biodiversity of plant parasitic nematodes on fruit crops dates back
to 1889 when Neal reported root-knot nematode infestations in peach and oranges
from Florida. The discovery of citrus nematode Tylenchulus semipenetrans in 1912
(Thomas 1913; Cobb 1913) was another breakthrough in nematological research on
fruit crops. However, in the middle of the century, the discovery of certain chemicals
and other soil fumigant nematicides amply demonstrated the destructive role of
plant parasitic nematodes (Sharma 2000). Since then a lot of research work has been
done on this aspect in different parts of the world. Plant parasitic nematodes are
considered major pathogens in their own right as they cause stunted plant growth,
varying degree of chlorosis and wilting of foliage. The deleterious effect on plant
growth result in reduced yields and poor quality of crops. The roots damaged by
nematodes are not efficient to utilize available moisture and nutrients in soil that
Plant Parasitic Nematode Diversity in Pome, Stone and Nut Fruits 239
Apple is considered as one of the most important deciduous tree fruit in the world
which are propagated by budding or grafting the desired scion onto the seedling root-
stock in the nursery. A large number of plant parasitic nematodes belonging to different
genera have been reported to attack apple trees (Table 1). Among them Pratylenchus,
Meloidogyne, Paratylenchus, Xiphinema and Longidorus are of major economic
importance as they cause pronounced deleterious effects on plant growth and produc-
tivity (McElory 1972). Plant parasitic nematodes present in the soil parasitize the
roots of apple plant and thus the disease acquired in the nursery later on introduce into
the orchard. Besides, some nematode groups belonging to Xiphinema and Longidorus
have also been reported to act as vectors for transmission of virus in apple trees.
Several species of lesion nematodes are known to attack apple, the most important
of which is Pratylenchus penetrans. This nematode is the cause of ‘soil sickness’ of
apple nurseries and orchards. In the United States, the nematode causes decline
in apple and other tree fruit orchards (Arneson and Mai 1976; Mai et al. 1970).
Pratylenchus sp., 25–150/100 cm3 are considered damaging but the number can
240 T.H. Askary et al.
vary depending on soil texture, climate and additional pathogens (Nyczepir and
Halbrendt 1993). In Netherlands, 65% of the apple orchards were found infested
with Pratylenchus sp. (Bridge and Starr 2007). Crossa Raynand and Audergon
(1987) reported that an initial population of 15 P. penetrans/100 g soil can cause
growth reduction in apple trees.
Plant Parasitic Nematode Diversity in Pome, Stone and Nut Fruits 241
Symptoms
Life Cycle
The juveniles of Pratylenchus sp. enter the roots wherever the tissue is immature so
that the penetration may become easy. They move inter and intracellulary, feed on
root cortex and multiply (Walia and Bajaj 2003). Migration through host tissues and
feeding activities result in destruction of host cells which leads to the formation of
necrotic lesions. Sexual reproduction is common in P. penetrans. Eggs are laid singly
inside the roots or in the soil (Parvatha Reddy 2008). Four moulting takes place.
The first moult takes place within the egg and three moults occur outside. All the
life stages except the J1 are parasitic. Entire life cycle completes in 30–45 days.
Since Pratylenchus sp. is an endoparasite, therefore its population densities are
typically much greater in plant roots than in the surrounding soil.
Disease Complex
Utkhede et al. (1992) studied the interaction of P. penetrans with soil fungi
Phytophthora cactorum, P. cinnamomi and P. parasitica. The results indicated that
addition of P. cactorum to apple replant disease soil containing the nematode signifi-
cantly reduced plant growth compared with the corresponding individual treatments.
P. parasitica did not by itself reduce plant height but in the presence of nematode it
reduced plant height to a greater extent than did the nematode alone.
Management
(a) Use of certified planting material: Nematode free planting material should be
made available to the apple growers.
(b) Green manuring: Kauri Paasuke (1973) reported that the soil sickness in apple
nurseries caused by P. penetrans can be controlled by green manuring or adding
milled peat to the soil.
242 T.H. Askary et al.
(c) Chemicals: Khan et al. (1996) tested carbofuran and polychlorinated petroleum
hydrocarbons against P. neglectus and found that both the chemicals
significantly reduced the nematode population densities. Maqbool et al. (1988)
reported that use of carbofuran (20 g active ingredient/tree) in apple orchard
reduced the population of Pratylenchus sp. by 80–90%. In an experiment
in Poland it was observed that soil application of aldicarb significantly
reduced the number of nematodes belonging to genus Pratylenchus (Pacholak
et al. 2006).
(d) Host resistance: Resistance to P. penetrans in apple have not been reported so
far. However, research workers have got little success where apple rootstocks
favour very low population of nematodes. Mazzola et al. (2009) in an experiment
found that apple rootstocks from the Geneva series supported lower population
of P. penetrans.
They are smallest among the plant parasitic nematodes and are common in the
rhizosphere of plants. Paratylenchus sp. are ectoparasitic nematode which feed on
growing points of roots and thus provide hindrance for them to function in a normal
manner. Males and fourth stage pre-adults of Paratylenchus do not feed (Walia and
Bajaj 2003). However, feeding by adults is limited to epidermal cells and base of
root hairs.
Symptoms
Paratylenchus sp. pierce root cells from the soil outside of the plant and remain
motile throughout their lives. At times they imbed their anterior portion in the roots
and establish longer time feeding sites there (Jenkins and Taylor 1967; Evans et al.
1993). The feeding results in general decline, poor root system and brown necrotic
areas on roots. Braun et al. (1966) reported that the cause of dwarfism in apple nursery
seedlings is due to heavy infestation of Paratylenchus sp. These nematodes are
suspected as the basic cause of pre-mature leaf fall in apple tree (Khan et al. 1988;
Khan and Sharma 1991).
Life Cycle
Management
(a) Use of certified planting material: Certified planting material should be made
available to apple growers.
(b) Hot water treatment: The roots of the plant should be dipped in water at tempera-
ture above 40°C (Sharma 2000).
(c) Oil cakes: Application of oil seed cakes like neem and mustard in tree basins have
been found effective in reducing the nematode population (Sharma 2000).
(d) Chemicals: Carbofuran and polychlorinated petroleum hydrocarbons have been
found effective in reducing the population of Paratylenchus projectus to a signifi-
cant level (Khan et al. 1996).
Xiphinema sp. are commonly considered as dagger nematode due to their long dagger
shaped spear. They are migratory ectoparasites and feed on newly emerging rootlets.
These nematodes are of major economic importance in apple growing regions
throughout the world (Abawi and Mai 1990). Thorne (1961) reported that Xiphinema
sp. were extensively prevalent in declining apple orchards in USA. The damage
threshold limit of Xiphinema sp. is 1/g of soil (Bonsi et al. 1984). Nyczepir and
Halbrendt (1993) observed a significant reduction in fresh and dry weight of apple
seedlings when 100 X. americanum was present in 1 cc soil.
Symptoms
Nematodes feed behind the root-tip which results in the formation of cork due to
impregnation of cell walls with suberin and phelloderm (Cohn and Orion 1970;
Walia and Bajaj 2003). During feeding nematode thrusts its stylet which causes
rupture and killing of epidermal and cortical cells and as a result cells undergo
necrosis. Plant growth is retarded (Swarup et al. 1989) but at the later stage, the root
system is completely destroyed, with roots near the tip become curled and swollen
and proximal parts of the root shrivel up showing signs of severe necrosis. The galls
produced by X. diversicaudatum contain necrotic cells and occur on the distal
portion of root.
Life Cycle
Reproduction occurs at a very low and slow rate and entire life cycle is completed
in the soil. Reproduction is either by cross fertilization or parthenogenesis (Swarup
et al. 1989) when males are rare or absent. Adult females deposit eggs singly in the
soil adjacent to their feeding sites (Brown and Coire 1983). Four moulting takes
244 T.H. Askary et al.
place and all the four juvenile stages occur outside the egg. Juvenile stages differ
from the adults in having two stylets i.e. functional and replacement. The replace-
ment stylet is called odontostyle which lies within the walls of anterior part of
oesophagus (Walia and Bajaj 2003). Duration of individual stage and total life cycle
of Xiphinema varies with species and the environmental conditions.
Disease Complex
Forer et al. (1984) reported the transmission of tomato mosaic ring spot virus in
apple by X. rivesi and also correlated the prevalence and severity of the disease
in several apple orchards in USA with the incidence and population densities of X.
americanum and X. rivesi. Cherry rasp leaf virus transmitted by Xiphinema sp. is
reported to cause flat apple disease in the cultivars, Red and Yellow delicious
(Nyczepir and Halbrendt 1993).
Management
These nematodes can survive without host for several years. They have wide
host range and are also reported to parasitize perennial crops, therefore crop
rotation and fallowing are not very much successful in their management. However,
common methods of nematode management such as application of oil seed cakes
like castor, neem or mustard in the soil are advised to use for minimizing their
population.
(a) Chemical: Khan et al. (1996) tested carbofuran and polychlorinated petroleum
hydrocarbons against X. rivesi and found the population reduction of nematodes
to a significant level.
(b) Host resistance: Nyczepir and Halbrendt (1993) reported some apple rootstocks
resistant to tomato mosaic ring spot virus are M4, M7, Ottawa3 and Novole
whereas apple cultivars resistant to tomato mosaic ring spot virus are Quinte,
Red Delicious, Jonathan, Tydeman’s Red and Jerseymac.
They are large in size, possessing a long needle like spear in their mouth and are
ectoparasitic on roots. They feed deeply within root tips. The feeding apparatus
i.e. spear of Longidorus sp. has two parts. Anterior portion is referred to as the
odontostyle, and is used to penetrate root cells. The posterior portion is referred to
as the odontophore which contains nerve process adjacent to the food canal and is
supposed to enable the nematode to discriminate between sites deep within plant
roots (Robertson and Taylor 1975). During the feeding process viruses are acquired.
These viruses are later on transmitted by the nematodes.
Plant Parasitic Nematode Diversity in Pome, Stone and Nut Fruits 245
Symptoms
Stunting of plants, branching, swelling and curling of root tips and necrosis are
some of the common symptoms produced by L. elongatus on apple plants (Szczygiel
1976). Longidorus sp. invariably feeds at root tips that transform into terminal galls
(Cohn 1975; Sijmons et al. 1994).
Life Cycle
They are ectoparasitic nematode and complete their life cycle in the soil. Reproduction
takes place either by cross-fertilization or parthenogenesis when males are rare or
absent (Walia and Bajaj 2003). Adult female lay eggs in the soil. After hatching first
stage juveniles come out. The juvenile undergoes four successive moultings to reach
the adulthood.
Management
Application of oilseed cakes like castor, neem or mustard in the soil is generally
advised to reduce the nematode population in soil.
Pear is the second most important deciduous tree fruit, grown commercially in almost
every temperate country and are propagated by budding the desired scion onto a
rootstock in the nursery. Several nematode species are reported to be associated with
pear (Table 2) but only few of them have evidence of parasitism. Needle nematode,
Longidorus elongatus and lesion nematode, Pratylenchus penetrans are considered
of major economic importance in Europe whereas in Japan, root-knot nematodes,
M. hapla and M. incognita are parasitic on pears (Wehunt and Golden 1982). Siddiqui
et al. (1973) has reported attack of pear roots by P. vulnus in western United States.
Nyczepir and Halbrendt (1993) reported that Pratylenchus sp. is the only nematode
important for pear production in North America. In the United States and Canada
P. penetrans is a part of pear replant (Wehunt and Golden 1982). An initial population
of 30 P. penetrans/100 g soil is responsible for causing a growth reduction in pear
replant problems in USA and Canada (Nyczepir and Halbrendt 1993).
Stone fruit mainly comprises of peach, plum, cherry, almond and apricot which
are commonly grown in temperate regions of the world. These crops are attacked
by several plant parasitic nematodes belonging to different genera and species.
A brief description of key nematode pests associated with different stone fruits have
been discussed below.
Symptoms
Invasion of roots by second stage juveniles which is the only infective stage, results
in gall formation on the roots of plant (Bird 1972). The root tip is devitalized and
elongation of root ceases. Oftenly on infected roots, branches from near the region
of invasion, result in dense hairy type of root system. The above ground symptoms
are yellowing of leaves, stunted growth, premature leaf abscission, wilting and early
senescence of plant which ultimately leads to reduced fruit production and yield
loss (Jonathan 2010).
Life Cycle
Four moulting takes place, once inside the egg and three times after hatching (Fig. 1).
Second stage juvenile is the only infective stage which enters the root near the root
tip and after finding a suitable tissue settles there (Jonathan 2010). The juvenile
begins to swell. Feeding is accomplished by inserting the stylet into the cell. The cell
contents are liquefied and semi-digested extra-corporeally with the help of hydrolytic
enzymes secreted by oesophageal gland. The nematode enzymes induce excessive
conversion of tryptophan into indole acetic acid (Dasgupta and Gaur 1986).
This results into enlargement and coalescing of the pericycle cells into a group of
multinucleate giant cells around the nematode’s head (Bird 1962; Haung 1985;
Pasha et al. 1987). Giant cells serve as a food source for the nematode. The cortical
parenchymatus cells around the giant cell undergo excessive multiplication giving rise
to tiny swellings on the roots or primary galls (Loewenberg et al. 1960). The primary
galls may coalesce to form multiple galls. Sex differentiation takes place after the
third moult. After final moult eel shaped males emerge out of roots and become free
living in the soil. Adult females are pear-shaped, shiny white and immobile (Fig. 2).
The mature female deposits several hundred eggs in gelatinous matrix (Jonathan
2010) which protect the eggs from external shock and resist drying. At favourable
moisture and temperature, eggs hatch and second stage juveniles come out and move
in the soil in search of new host.
Management
(a) Use of certified planting material: The menace of root-knot nematode can be
eliminated by selection of nematode free planting material.
(b) Hot water treatment: Temperature above 40°C are generally lethal for plant
parasitic nematodes but when embedded deep into plant tissues, higher tempe
rature are required for killing them. However, a very high temperature is also
deleterious for plant tissue. Therefore, time-temperature combinations should
be carefully worked out for different planting material (Sharma 2000). Parvatha
Reddy (2008) reported that hot water treatment of peach seedling roots at
50–52°C for 5–10 min eliminates the root-knot nematode infection.
Plant Parasitic Nematode Diversity in Pome, Stone and Nut Fruits 249
They are ectoparasitic nematode bearing long stylet which they utilize to reach
cortical cells below the root epidermis. They are widely distributed in peach growing
areas. Chitwood (1949) reported a large number of ring nematodes from peach
Plant Parasitic Nematode Diversity in Pome, Stone and Nut Fruits 251
orchards in North Carolina and Maryland. These nematodes are considered as one
of the factors in bacterial canker and peach tree short life syndrome disease. Wehunt
et al. (1980) reported a loss of 30–70% after 5 years in peach orchards suffering
from peach tree short life syndrome in Georgia. The nematode shortens the tree life
and its incidence are mostly found on replanted trees.
Symptoms
The infected plant roots are darkened and often contain longitudinal cracks. The most
serious infection appears in the form of the death of finer roots due to direct feeding
by nematodes. Due to excessive killing of feeder roots, plants are stunted, showing
mineral deficiency syndrome, and more susceptible to water stress. Hung and
Jenkins (1969) reported that Criconemoides curvatum causes pits and lesions on
peach roots under sterile conditions. Lownsbery et al. (1973) found that C. xenoplax
cause chlorosis and leaf drop under green house conditions and soil in pots infested
with this nematode tended to be waterlogged. In an experiment it has been found
that C. rustica is the source of withering and injury of trunks of young peach trees
(Kamio and Taguchi 2009).
Life Cycle
Eggs are deposited singly in the soil. An adult female can lay 8–15 eggs per day
(Seshadri 1964). Four moulting take place, first inside the egg and the rest three
outside. Second stage juveniles hacth out of the eggs and feed ectoparasitcally on
roots of the plant. After fourth moult adults are produced. Entire life cycle from egg
to egg is completed in 25–34 days (Seshadri 1964).
Disease Complex
Okie et al. (2009) reported that C. xenoplax is implicated in peach tree short life,
a disease syndrome which leads to collapse and death of trees above the soil line
in late winter and spring following freeze injury and/or bacterial canker caused
by Pseudomonas syringae. Bacterial canker damaged or freeze injured bark is
invariably invaded and colonised by cytospora canker fungi, Leucostoma persooni
(Ritchie and Clayton 1981). In fact the injury caused by C. xenoplax on roots pro-
vide entry site for bacterial canker (Lownsbery 1959; Lownsbery et al. 1968, 1973).
Nyczepir (1990) also reported that peach tree in south eastern USA infested with C.
xenoplax were predisposed to cold injury and/or bacterial canker (Pseudomonas
syringae pv. syringae). Simultaneous occurrence of root-knot nematodes and crown
gall bacteria in peach has also been reported (Esser et al. 1968). Nigh (1966) found
that Meloidogyne javanica increased the incidence of crown gall of peach roots
caused by A. tumefaciens.
252 T.H. Askary et al.
Kaul et al. (1993) investigated the infestation of peach rootstocks by the root-knot
nematode, M. javanica under field conditions. Most of the galls investigated on the
peach and hybrid rootstocks contained either developing or degenerating female
nematodes and the population of juveniles in the soil was also low. Histological
changes in the infested roots were investigated. Transverse sections of the gall
indicated the coalesced condition of the multinucleated giant cells or a degenerating
syncytium. Bacterial cells identified as A. tumefaciens were observed inside cortical
cells of galls, highest incidence was found in cells near the root-knot nematode,
Meloidogyne sp. and lesion nematode, Pratylenchus sp. Presence of A. tumefaciens
in galls has also been confirmed by other researchers (Pinochet et al. 2002).
Infection on peach roots by virus takes place with the aid of nematode and
once established within the root, the virus multiplies usually become systemic
throughout the plant. Klos (1976) reported the role of nematode in transmission
of peach rosette mosaic virus causing a disease on peach trees in USA. The leaves of
the affected peach tree showed distortion and chlorotic mottling, internodes were
shortened producing a rosette appearance and delayed defoliation. In Canada,
Longidorus didecturus was reported as the vector of peach rosette mosaic virus in
peach orchard. However, the other nematode, Xiphinema americanum sensu stricto
was also present and transmitting peach rosette mosaic virus at the site (Eveleigh
and Allen 1982).
Management
(a) Cultural: Soil manipulation and application of hydrated lime is reported to alter
soil moisture, temperature and pH and can bring down the population of C.
xenoplax (Wehunt et al. 1980; Wehunt and Weaver 1982).
(b) Chemical: Nyczepir and Rodriguez-Kabana (2007) conducted a study on a site
infested with C. xenoplax and having a previous history of peach tree short life.
The experiment was conducted from 1998 to 2003 wherein sorghum was used
as a preplant green manure biofumigant management system of C. xenoplax.
The results indicated that sorghum as a green manure with and without tarp was
comparable with methyl bromide fumigation in suppressing the population of
C. xenoplax in the early stages of the experiment. Nematode population densities
were suppressed 11 months longer in sorghum with tarp and urea plots than in
sorghum without tarp and urea plots. However, nematode population densities
in sorghum with tarp and urea plots were not suppressed as long as in fumigant
methyl bromide plots.
(c) Host Resistance: Okie et al. (2009) in a an experiment in the southern United
States found that peach rootstock ‘BY520-9’ survive better on sites previously
planted with peaches which often suffer from peach tree short life syndrome.
Mantianhong, a new peach cultivar used as an ornamental and food has a high
resistance to root-knot nematode, M. incognita (GengRui et al. 2008). Some
peach cultivars/rootstocks resistant to different plant parasitic nematodes have
been enlisted (Table 4).
Plant Parasitic Nematode Diversity in Pome, Stone and Nut Fruits 253
Plum trees are subjected to severe nematode attack. However, among several nema-
tode species, root lesion nematode, Pratylenchus sp., pin nematode, Paratylenchus
sp., dagger nematode, Xiphinema sp. and ring nematode, Criconema xenoplax are
reported to be dominant in plum growing areas throughout the world (Table 5). Braun
and Lownsbery (1975) reported that infestation of Paratylenchus neoamblycephalus
on plum results in dark as well as small roots having only few feeder roots.
The damage threshold limit of Pratylenchus penetrans on plum is 320/100 g soil
(Nyczepir and Halbrendt 1993; Bridge and Starr 2007).
3.2.1 Disease Complex
Some nematode species are also reported to cause complex diseases in plum.
Interaction of root-knot nematode Meloidogyne sp. with the bacterium Agrobacterium
tumefaciens, the causal agent of crown gall has been reported in peach by Rubio
Cabetas et al. (2001). Majtahedi et al. (1975) reported that causal agent of bacterial
canker, Pseudomonas syringae in plum trees was most extensive whose roots were
infested with C. xenoplax. Auger (1989) reported ring spot nepovirus associated
with brownline disease of plum trees in Chile and the nematode acting as a vector
in transmission of the virus was X. americanum.
254 T.H. Askary et al.
3.2.2 Management
(a) Chemical: Halbrendt and Shaffer (1989) evaluated the effect of methyl bromide
and fenamiphos for the control of dagger nematode, Xiphinema sp. in a plum
orchard in USA. It was observed that methyl bromide caused a significant
reduction in the population of nematodes whereas fenamiphos showed moder-
ate reduction as compared with control. However, application of both the nem-
aticides simultaneously gave greater reduction in nematode populations.
(b) Host resistance: Some cultivars/rootstocks of plum resistant to different plant
parasitic nematode species have been enlisted (Table 6).
3.3.1 Disease Complex
The dagger nematode, Xiphinema sp. and needle nematode, Longidorus sp. are
reported to be associated with the transmission of cherry leaf roll virus (Harrison
1964; McElory 1972). Halbrendt (1993) reported that X. americanum acts as a
vector in transmission of a virus, the causal agent of cherry rasp leaf disease.
The leaves of the diseased cherry trees have enations on their underside, appearing
as leafy outgrowths. The disease symptoms first appear on the lower leaves from
where the disease slowly spreads causing death of the affected spurs. The branches
of the affected trees produce an open, bare appearance. Brown et al. (1994) described
cherry rosette virus affecting cherry trees in the Arth region of Switzerland and
the nematode acting as a vector in the transmission of disease was L. arthensis.
Plant Parasitic Nematode Diversity in Pome, Stone and Nut Fruits 255
The diseased plant show steady decline in vigour with accompanying leaf symptoms
such as distortion, enations, rosetting and oil-flecking in which the leaves appear to
have been contaminated with drops of oil. Such affected plants die eventually
(Brown et al. 2004). Kunz and Bertschinger (1998) analysed two cherry orchards in
central Switzerland for the progression of cherry rosette disease. They also observed
that L. arthensis acts as a vector in transmission of cherry rosette nepovirus, the
causal agent of the disease. Transmission of cherry rosette virus by nematode has
also been reported from East Switzerland (Kunz 2003).
3.3.2 Management
(a) Hot water treatment: Parvatha Reddy (2008) reported that hot water treatment
of cherry seedlings at 50–52°C for 5–10 min eliminates the root-knot nematode
infection.
(b) Chemical: Cherry seedlings when dipped in Diazinon (10%) for 30 min reduced
the infestation of P. penetrans (Sher 1960). Walker and Wachtel (1988) evaluated
three nematicides viz., aldicarb, fenamiphos and carbofuran at three different
doses i.e., 16.3, 24.4 and 15.0 g/tree for control of nematodes on sweet cherry
(Prunus mahaleb) in Australia. The results indicated that carbofuran significantly
reduced the number of Paratrichodorus lobatus but none of the nemati-
cides used in the experiment produced significant reduction in population of
Criconemoides or Helicotylenchus sp.
256 T.H. Askary et al.
(c) Host resistance: Direct control of the virus or nematode is difficult but the use
of resistant graft, viz., cob and colt showed potential in this regard (Kunz
1998). Cherry rootstock cob and colt is also reported to be resistant to
pfeffinger disease caused by raspberry ringspot nepovirus transmitted by the
nematode, L. macrosoma (Buser 1999). Cherry rootstocks viz., Mazzard,
Stockton Morello, English Morello and Montmorency have been found
completely resistant to root-knot nematodes whereas cherry replants on
Mahaleb rootstock were resistant to lesion nematode, P. vulnus and P. penetrans
(Parvatha Reddy 2008).
3.4.1 Disease Complex
3.4.2 Management
(a) Host resistance: Marull and Pinochet (1991) identified almond rootstocks viz.,
D-3-5, GxN No. 9 and Cachirulo as resistant to M. javanica. D-3-5 has also
been found resistant to P. vulnus (Pinochet et al. 1996).
(b) Chemical: Abbad et al. (1993) conducted a field experiment to manage root-knot
nematode, Meloidogyne sp. on almond plants in nurseries. The results indicated
that Metam-sodium at 600 and 1,000 g active ingredient/ha allowed an improve-
ment of growth and vigour to treated rootstocks. Treatment with Metam-sodium
gave good protection of roots against infesting second stage juveniles during
spring. Management of P. vulnus in almond nurseries by soil treatment with
chemicals such as methyl bromide, 1, 3-D and fenamiphos has also been reported
(Lamberti et al. 2001).
3.5.1 Management
(i) Cultural: Sharma and Kashyap (2009) reported that intercropping of apricot
trees with marigold and oat are safe and effective method in the management of
plant parasitic nematodes.
(ii) Chemical: Soil application of Phorate @ 0.03 g active ingredient/m2 has
been found effective in reducing the population of Criconemella xenoplax,
Tylenchorhynchus sp., Pratylenchus sp. and Meloidogyne sp. (Sharma and
Kashyap 2009).
258 T.H. Askary et al.
4 Nematodes of Nuts
Not much research work has been done on nematode association with pecan.
Few nematodes are reported on pecans of which root-knot nematode, Meloidogyne,
are widely distributed and most likely to be pathogenic (Table 10). Johnson et al.
(1975) observed in pecan trees distorted, yellow colour foliage with zinc deficiency
symptoms accompanied with root-knot infection.
4.1.1 Disease Complex
Nyczepir and Wood (2008) studied the effect of interaction between Meloidogyne
partityla and Mesocriconema xenoplax on nematode reproduction and vegetative
growth of pecan in field microplots. The results indicated that the presence of the
two nematode species together caused a greater reduction in root growth than
M. xenoplax alone, but not when compared to M. partityla alone. Mouse-ear symp-
tom severity in the pecan leaves was increased in the presence of M. partityla as
compared to M. xenoplax and uninoculated control. Infection with M. partityla
increased severity of mouse-ear symptoms expressed by foliage. It was concluded
that M. partityla is more detrimental pathogen to pecan than M. xenoplax. Hsu and
Hendrix (1973) reported that Criconemella rusium cause necrosis on pecan roots in
the presence of Pythium irregularae and Fusarium solani. The nematode alone did
not affect root weight, whereas both the fungi reduced root weight. The effect was
synergistic when nematode was combined with either and both of the fungi.
Among several plant parasitic nematodes associated with walnut (Table 11),
Mesocriconema xenoplax, Pratylenchus vulnus and Cacopaurus pestis are the key
nematode pests that are highly pathogenic, widely distributed and considered a
threat to walnut industry. Infestation of M. xenoplax on walnut causes pruning and
necrosis of fine feeder roots, especially on young plants and also feeds older parts
of roots (Lownsbery et al. 1977). Lownsbery et al. (1974a) in an experiment in
California observed that Juglans hindsii, J. major, J. nigra, J. regia and J. microcarpa
were susceptible to P. vulnus. In California, roots of walnut have been reported to be
parasitized by C. pestis, a sedentary ectoparasitic nematode feeding on epidermal
cells (Thorne 1943). The body of the female stayed on the outside of the root and
eggs were deposited in a gelatinous matrix exuded from the posterior end of the
female. Lownsbery et al., (1978) reported damage threshold limit of M. xenoplax on
walnut to be >4,200/100 g soil.
4.2.1 Management
Little research has been done on the nematodes of hazelnut and therefore not much
information is available on this aspect. However, like other nuts, association of many
plant parasitic nematodes viz., Coslenchus sp., Ditylenchus sp., Filenchus afghanicus,
Filenchus sp., Helicotylenchus sp., Hemicycliophora punensis, Hemicycliophora sp.
and Merlinius sp. have been reported on this crop (Kepeneckci 2002). In Spain,
Pratylenchus vulnus is reported to cause infestation on hazelnut (Pinochet et al. 1992).
260 T.H. Askary et al.
5 Conclusion
In the foregone review, the various diseases of pome, stone and nut fruits caused by
different plant parasitic nematodes singly and in association with certain microor-
ganisms have been discussed. It is evident from the literature that the nematodes
have diversified nature of attack and therefore, the above ground and underground
symptoms on the affected plant also varies. Also damage threshold limit varies
for different nematode species. Hence, to bring an improvement in management
strategies to meet the challenges requires both broader and deeper knowledge of
crop diseases caused by nematodes. Work on disease complexes where nematodes
and soil microorganisms are involved needs to be intensified with adequate collabo-
ration between nematologists and plant pathologists. A prior knowledge of host
parasite relationship of major nematode pests and techniques for precise determination
of damage threshold limit of nematode populations is a must for a successful nematode
management programme. Also while adopting a management strategy economy and
ecology must be taken into consideration. The different management methods described
in the chapter is need based and each has its own importance. Therefore, integrated
nematode management strategies should be adopted by bringing all the methods
together such as deep summer ploughing, minimal use of nematicides like nursery bed
treatment and bare root dip treatment, hot water treatment of planting material, applica-
tion of potential biocontrol agents and use of nematode resistant cultivars/rootstocks.
Chemical methods of nematode control is no doubt effective and are widely
used, however, the hazardous nature of chemical require a continuous research to
find ways to reduce its application and rates wherever possible (Rich et al. 2004).
Hot water treatment of planting material has long been used to kill plant parasitic
nematodes (Jenkins 1960; Towson and Lear 1982) but the temperature required to
kill nematodes in plant tissues are more or less similar to the temperature required
to kill plant tissues (Bridge 1996). Therefore, temperature range for each plant
species need to be worked out based on water volume, number and size of plants to be
treated, time of treatment and other factors (Halbrendt and LaMonida 2004). A safe
method of nematode management is application of biocontrol agents but its survival
and potentiality is still a debatable issue before the research workers. Therefore,
attempts should be directed for exploration of potential biocontrol agents and its
sustainability under field conditions needs to be assured for a successful nematode
management programme. Evaluation of germplasm and subsequent breeding
programme to develop cultivars/rootstocks resistant or tolerant to plant parasitic
nematodes is an important and cost effective method of nematode management.
In the recent years some cultivars/rootstocks resistant to plant parasitic nematodes
have been developed. However, for an encouraging result more emphasis is required
in this field by identifying new sources of plant resistance and its incorporation into
crops by traditional breeding or genetic engineering biotechnology.
Acknowledgements The authors would like to thank all those who have contributed to the prepa-
ration of this chapter but are particularly indebted to all the nematologists who have generated the
information present in this chapter.
Plant Parasitic Nematode Diversity in Pome, Stone and Nut Fruits 261
References
Abawi GS, Mai WF (1990) Dagger nematodes. In: Jones AL, Aldwinckle HS (eds.) Compendium
of apple and pear diseases. American Phytopathological Society Press, St. Paul, pp 73–74
Abbad FA, Bajja M, Rami A (1993) Use of metam-sodium for the control of gall nematodes
(Meloidogyne spp.) associated with almonds. Al-Awamica 80:111–122
Alcaniz E, Pinochet J, Fernandez C, Esmenjaud D, Felipe A (1996) Evaluation of prunus root
stocks for root-lesion nematode resistance. HortScience 31:1013–1016
Arneson PA, Mai WF (1976) Root diseases of fruit trees in New York state, VII. Costs and returns
of pre plant soil fumigation in a replanted apple orchard. Plant Dis Rep 60:1054–1057
Arroyo C, Mora J, Salazar L, Quesada M (2004) Population dynamics of nematodes in four peach
palm varieties (Bactris gasipaes Kunth). Agronomia Mesoamericana 15:53–59
Askary TH, Ali MS, Haider MG (2000) Occurrence of plant parasitic nematodes on forest planta-
tions in North Bihar. J Res (BAU) 12:263–264
Askary TH, Haider MG (2010) Plant parasitic nematodes associated with forest nurseries. Indian
J Nematol 40:239–240
Auger J (1989) Tomato ringspot virus (TomRsv) associated with brownline disease on prune trees
in Chile. Acta Hortic 235:197–204
Awasthi RP (2006) Strategies for improving temperate fruit crops in India. In: Kishore DK, Sharma
SK, Pramanick KK (eds.) Temperate horticulture: current scenario. New India publishing
agency, India, pp 193–200
Bajaj HK, Bhatti DS (1984) New and known species of Pratylenchus Filipjev, 1936 (Nematoda:
Pratylenchidae) from Haryana, India with remakrs on intraspecific variations. J Nematol
16:360–367
Barker KR, Olthof THA (1976) Relationship between nematode population densities and crop
responses. Annu Rev Phytopathol 14:327–353
Bird AF (1962) The inducement of giant cells of Meloidogyne javanica. Nematologica 8:1–10
Bird AF (1972) Quantitative studies on the growth of syncytia induced in plants by root knot
nematodes. Int J Parasitol 2:157–170
Bonsi C, Stonffer R, Shaffer R (1984) Effect of different initial population densities of Xiphinema
americanum and Xiphinema rivesi on growth of apple and peach seedlings. Phytopathology
74:626
Braun AL, Lownsbery BF (1975) The pin nematodes Paratylenchus neoamblycephalus in
myrobalan plum and other hosts. J Nematol 7:336–343
Braun AJ, Palmiter DJ, Keplonger JA (1966) Nematodes found in apple orchards in the Hudson
Valley, 1956–65. Plant Dis Rep 42:76–83
Braun AL, Mojtahedi H, Lownsbery BF (1975) Separate and combined effects of Paratylenchus
neoamblycephalus and Criconemoides xenoplax on “Myrobalan” plum. Phytopathology
65:328–330
Bridge J (1996) Nematode management in sustainable and subsistence agriculture. Annu Rev
Phytopathol 34:201–225
Bridge J, Starr JL (2007) Plant parasitic nematode of agricultural importance: a color hand book.
Academic Press/Elsevier, New York, pp 152
Brinkman H (1977) Nematological observations in 1975 and 1976. Gewasbischeraning
8:131–136
Brown DJF, Coire MI (1983) The total reproductive capacity and longevity of individual female,
Xiphinema diversicaudatum (Nematoda: Dorylaimida). Nematologia Mediterranea 11:87
Brown DJF, Grunder J, Hooper DJ, Klingler J, Kunz P (1994) Longidorus arthensis sp. n.
(Nematoda: Longidoridae) a vector of cherry rosette disease caused by a new nepovirus in
cherry trees in Switzerland. Nematologica 40:133–149
Brown DJF, Zheng J, Zhou X (2004) Virus vectors. In: Chen ZX, Chen SY, Dickson DW (eds.)
Nematology-advances and perspectives, vol. 2: nematode management and utilization. CAB
International/Tsinghua University Press, Beijing, pp 717–770
262 T.H. Askary et al.
Buser A (1999) Pfeffinger disease of cherry trees and its vector nematode Longidorus macrosoma.
Obst-und-Weinbau 135:42–45
Buzo T, McKenry M, Hasey J (2006) Interaction of Juglans species with Pratylenchus vulnus and
Meloidogyne incognita. Acta Hortic 705:417–423
Chitwood BG (1949) Ring nematodes (Criconematidinae) a possible factor in decline and replanting
problems of peach orchards. Proc Helminthol Soc Wash 16:6–7
Ciancio A, Grasso G (1998) Endomigratory feeding behaviour of Mesocriconema xenoplax
parasitizing walnut (Juglans regia L.). Fundam App Nematol 21:63–68
Cobb NA (1913) Notes on Mononchus and Tylenchulus. J Wash Acad Sci 3:288–289
Cohn E (1975) Relations between Xipinema and Longidorus and their host plants. In: Lamberti F,
Taylor CE, Seinhorst JW (eds.) Nematode vectors of plant viruses. Plenum press, London,
pp 365–386
Cohn E, Orion D (1970) The pathological effect of representative Xiphinema and Longidorus
species on selected host plants. Nematologica 16:423
Coiro MI, Sasanelli N (1995) Life cycle studies of individual Longidorus athesinus (Nematoda) on
S. Lucie Cherry. Nematologia Mediterranea 23:329–333
Crossa Raynand P, Audergon JM (1987) Apricot rootstocks. In: Rom RC, Carlson RF (eds.)
Rootstocks of fruit crops. Wiley, New York, pp 295–320
Crow WT, Levin R, Halsey LA, Rich JR (2005) First report of Meloidogyne partityla on pecan in
Florida. Plant Dis 89:1128
Dasgupta DR, Gaur HS (1986) The root-knot nematodes Meloidogyne spp. in India. In: Swarup G,
Dasgupta DR (eds.) Plant parasitic nematodes of India-Problems and progress. IARI, New
Delhi, pp 139–171
Eisenback JD, Reaver D, Ashley JE Jr (2007) First report of the nematode Tylenchulus palustris,
parasitizing peach in Virginia. Plant Dis 91:1683
Esmenjaud D, Minot JC, Voisin R, Pinochet J, Salesses G (1994) Inter and intraspecific resistance
variability in myrobalan plum, peach and peach-almond rootstocks using 22 root-knot nematode
populations. J Am Soc Hortic Sci 119:94–100
Esmenjaud D, Minot JC, Voisin R, Bonnet A, Salesses G (1996) Inheritance of resistance to
the root-knot nematode Meloidogyne arenaria in Myrobalan plum. Theor Appl Genet
92:873–879
Esser RP, Martine AP, Longdon KR (1968) Simultaneous occurrence of root-knot nematode and
crown gall bacteria. Plant Dis Rep 52:550–553
Evans K, Trudgill DL, Webster JM (1993) Extraction, identification and control of plant parasitic
nematodes. In: Nematodes in temperate agriculture. CAB International, Wallingford, p 648
Eveleigh ES, Allen WR (1982) Description of Longidorus diadecturus n. sp. (Nematoda:
Longidoridae), a vector of the peach rosette mosaic virus in peach orchard in south western
Ontario, Canada. Can J Zool 6:112–115
Fachinello JC, Silva CAP, Sperandio C, Rodrigues AC, Strelow EZ (2000) Resistance of rootstock
for peach tree and plum to root-knot nematodes (Meloidogyne spp.). Ciencia-Rural 30:69–72
Fliegel P (1969) Population dynamics and pathogenicity of three species of Pratylenchus on peach.
Phytopathology 59:120–124
Forer LB, Powell CA, Stouffer RE (1984) Transmission of tomato ring spot virus to apple rootstock
cuttings and to cherry and peach seedlings by Xiphinema rivesi. Plant Dis 61:1052–1053
Fotedar DN, Handoo ZA (1974) Two new species of Helicotylenchus Steiner, 1945 (Hoplolaimidae:
Nematoda) from Kashmir, India. J Sci, University of Kashmir 2:57–62
GengRui Z, Wang L, Fang W (2008) Selection and cultivation of a new peach variety Mantianhong
both for ornamental and food. J Fruit Sci 25:440–441
Gomes CB, Campos AD, Almeida MRA (2000) Occurrence of Mesocriconema xenoplax and
Meloidogyne javanica associated with peach tree short life on plum and reduction of phenol
oxidizing enzyme activity. Nematologia Brasileira 24:249–252
Griesbach J (2007) Growing temperate fruits in Kenya. World Agroforestry Centre, ICRAF,
Nairobi, p 128
Plant Parasitic Nematode Diversity in Pome, Stone and Nut Fruits 263
Gupta NK, Uma (1981) Description of two new species of genus Tylenchorhynchus Cobb, 1913- family
Tylenchorhynchidae (Eliava, 1964), Golden, 1971- from India. Helminthologia 18:53–59
Halbrendt JM (1993) Virus-vector Longidoridae and their associated viruses in the Americas. Russ
J Nematol 1:65–68
Halbrendt JM, LaMonida JA (2004) Crop rotation and other cultural practices. In: Chen ZX, Chen
SY, Dickson DW (eds.) Nematology: advances and perspectives vol. 2, nematode management
and utilization. CAB International/Tsinghua University Press, Beijing, pp 909–930
Halbrendt JM, Shaffer RL (1989) Effect of Brom-O-Gas and Nemacur 3 on dagger nematodes and
plum replants, 1985–88. Fungic Nematic Tests 44:143
Hang Y, Guojie L, Lixin Z, Wenjun W, KeGong J (2006) ‘Zhubo 4’ and ‘Zhubo 5’, 2 new peach
rootstocks. China Fruits 6:63
Harrison BD (1964) Specific nematode vectors for serologically distinctive forms of raspberry ring
spot and tomato black ring virus. Virology 22:544–550
Haung GS (1985) Formation, anatomy and physiology of giant cells induced by root-knot
nematodes. In: Sasser JN, Carter CC (eds.) An advanced treatise of Meloidogyne, vol.1, biol-
ogy and control. North Carolina State University Graphics, Raleigh, pp 154–165
Hoestra H, Oostenbrink M (1962) Nematodes in relation to plant growth. IV. Pratylenchus
penetrans (Cobb) on orchard trees. Neth J Agric Sci 10:286–296
Hsu D, Hendrix FF (1973) Influence of criconemoides quadricornis on pecan feeder root necrosis
caused by Pythium irregulare and Fusarium solani at different temperatures. Can J Bot
51:1421–1424
Hung Cia-Ling P, Jenkins WR (1969) Criconemoides curvatum and the peach tree decline problem.
J Nematol 1:12
Islam S, Khan A, Bilqees FM (1996) Survey of stylet-bearing nematodes associated with apple
(Malus pumila mill.) in swat district. Proc Parasitol 21:1–9
Islam S, Hamid F, Khan A, Poswal MA (2006) Plant parasitic nematodes associated with different
crops of Swat and Malakand Agency, under MRDP area (NWFP), Pakistan. Proc Parasitol
41:77–83
James H, LaRue R, Johnson S (1989) Peaches, plums and nectarines: growing and handling for
fresh market. Cooperative extension, University of California, Division of Agriculture and
Natural Resources, Oakland, p 144
Jenkins WR (1960) Control of nematodes by physical methods. In: Sasser JN, Jenkins WR (eds.)
Nematology-Fundamentals and recent advances with emphasis on plant parasitic and soil
forms. North Carolina State University Graphics, Chapel Hill, pp 443–446
Jenkins WR, Taylor DP (1967) Pin nematodes: Paratylenchus and sessile nematodes: Cacopaurus.
In: Plant nematology. Reinhold Publishing Corporation, New York, p 149
Johnson JD, Smith HP, Thames WH Jr, Smith LR, Brown MH, Henderson WC (1975) Nematodes,
Meloidogyne incognita, can be a problem in pecans. Pecan Q 9:6
Jonathan EI (2010) Nematology: fundamentals and applications. New India Publishing Agency,
Pitam Pura, p 280
Kamio S, Taguchi Y (2009) Relationship between withering and injury of trunks in peach trees and
plant parasitic nematode density in rhizosphere soil. Hortic Res Jpn 8:137–142
Karanastasi E, Neilson R, Decraemer W (2006) First record of two trichodorid nematode species
Paratrichodorus minor and Trichodorus sparsus (Nematoda: Trichodoridae) Thorne, 1935
from Greece. Ann Benaki Phytopathological Inst 20:129–133
Kaul VK, Chhabra HK, Singh A, Grewal SS, Singh A (1993) Response of peach rootstocks to
root-knot nematode and bacterial complex. Plant Dis Res 8:102–109
Kauri Paasuke M (1973) Biological control of replant diseases in nurseries. Lantbrukshogskolans
Meddelanden Serie A 189:17
Kepeneckci I (2002) A survey of Tylenchida (Nematoda) found in hazelnut (Corylus sp.) orchards
in the West Black Sea region of Turkey. Nematropica 32:83–85
Khan A, Bilqees FM (1993) Nematodes associated with walnut in Bajore Agency, Pakistan. Proc
Pak Congr Zool 13:67–70
264 T.H. Askary et al.
Khan ML, Khan SH (1985) Three new species of Hoplolaiminae (Hoplolaimidae: Nematoda) with
new report of Scutellonema unum Sher, 1963 from Tunisia. Indian J Nematol 14:115–120
Khan ML, Sharma NK (1991) Paratylenchus manaliensis n. sp. associated with apple plant in
India. Nematologia Mediterranea 19:271–275
Khan ML, Sharma GC (1992) Seasonal fluctuations in plant parasitic nematodes in almond,
Prunus amygdalus rhizosphere. Indian J Hill farm 5:10–13
Khan E, Siddiqi MR (1963) Criconema serratum n. sp. (Nematoda: Criconematidae)-a parasite of
peach trees in Almora, North India. Curr Sci 32:414–415
Khan E, Siddiqi MR (1964) Criconema laterale n. sp. (Nematoda: Criconematidae) from Srinagar,
Kashmir. Nematologica 9:584–586
Khan E, Chawla ML, Prasad SK (1969) Tylenchus (Aglenchus) indicus n. sp. and Ditylenchus
emus n. sp. (Nematoda: Tylenchidae) from India. Labdev J Sci Technol 7:311–314
Khan ML, Sharma GC, Sharma NK (1988) New record of Pratylenchus curvitatus and Gracilacus
peperpotti (Nematoda: Paratylenchidae). Nematologia Mediterrranea 17:11–12
Khan ML, Sharma GC, Sharma NK (1989) New record of Paratylenchus curvitatus and Gracilacus
peperpotti on apple and plum in Himachal Pradesh. Nematologia Mediterranea 17:275–276
Khan A, Islam S, Shaukat SS, Bilqees FM (1996) Efficacy of carbofuran and Tenekil against
nematodes associated with apple in swat valley, Pakistan. Afro-Asian J Nematol 6:59–62
Klos EJ (1976) Rosette mosaic: virus diseases and non-infectious disorders of stone fruits in North
America, Washington, D.C., USA. In: USDA agricultural handbook 437. US Department of
Agriculture–Agricultural Research Service, Washington, D.C., pp 135–138
Kunz P (1998) The cherry rosette disease and its vector nematode Longidorus arthensis.
Obst-und-Wenbau 134:248–250
Kunz P (2003) Transfer of cherry rosette virus also by nematodes from East Switzerland.
Obst-und-Weinbau 139:4–5
Kunz P, Bertschinger L (1998) Tracing cherry rosette disease using aerial pictures and soil analysis.
Obst-und-Weinbau 134:588–591
Lamberti F, Addabbo T, Sasanelli N, Carella A (2001) Control of Pratylenchus vulnus in stone
fruit nurseries. Proceedings of the 53rd international symposium on crop protection, Gent,
Belgium, 8 May 2001. Part II, Mededelingen, 66:629–632
Layne REC (1974) Breeding peach rootstocks for Canada and the northern United states.
HortScience 9:364–366
Lirong Z, Hui X, Mutao W, Guoqiang Z, Zhixin F (2005) Description of Trichodoridae nematodes
from rhizosphere of pear trees in Kunming region. J S China Agric Univ 26:59–61
Liskova M (2007) Morphometrics of females, juveniles and a hermaphrodite of Longidorus
distinctus Lamberti et al., 1983 (Nematoda: Longidoridae) from Slovakia. Helminthologia
44:210–213
Liskova M, Sabova M, Valocka B, Lamberti F (1993) Occurrence of Xiphinema diversicaudatum
(Nematoda) in the Slovak Republic. Nematologia Mediterranea 21:107–109
Loewenberg JR, Sullivam T, Schuster ML (1960) Gall induction by Meloidogyne incognita
by surface feeding and factors affecting the behavior patterns of the second stage larva.
Phytopathology 50:322–323
Lorrain R (2000) Nematodes in walnut tree nurseries. Realistic preventive measures are absolutely
essential. Phytoma La Defense des Vegetaux 524:38–39
Lownsbery BF (1956) Pratylenchus vulnus, primary cause of the root lesion disease of walnut.
Phytopathology 46:376–379
Lownsbery BD (1959) Studies of the nematode Criconemoides xenoplax on peach. Plant DisRep
43:913–917
Lownsbery BF, Mitchell JR, Hart WH, Charles FM, Gertz MH, Greathead AH (1968) Responses
of postplanting and preplanting soil fumigation in California peach, walnut and prune orchards.
Plant Dis Rep 52:890–894
Lownsbery BF, English H, Moody EH, Schick FJ (1973) Criconemoides xenoplax experimentally
associated with a disease of peach trees. Phytopathology 63:994–997
Plant Parasitic Nematode Diversity in Pome, Stone and Nut Fruits 265
Lownsbery BF, Martin BC, Forde HI, Moody EH (1974a) Comparative tolerant of walnut species,
walnut hybrids and wingnut to the root-lesion nematode, Pratylenchus vulnus. Plant Dis Rep
58:630–633
Lownsbery BF, Moody EH, Braun AJ (1974b) Plant parasitic nematodes of California prune
orchards. Plant Dis Rep 58:633–636
Lownsbery BF, English H, Noel GR, Schick FJ (1977) Influence of nemaguard and lovell
rootstocks and Macroposthonia xenoplax on bacterial canker of peach. J Nematol
9:221–224
Lownsbery BF, Moody EH, Moretto A, Noel GR, Bulando TM (1978) Pathogenicity of
Macroposthonia xenoplax to walnut. J Nematol 10:232–236
Mai WF, Parker KG, Hickey KD (1970) Root diseases of fruit trees in New York State II.
Populations of Pratylenchus penetrans and growth of apple in response to soil treatment with
nematicides. Plant Dis Rep 54:792–795
Majtahedi H, Lownsberg BF, Moody EH (1975) Ring nematodes increase development of
bacterial canker in plums. Phytopathology 65:556–559
Maqbool MA, Qasim M, Maqbool MA, Golden AM, Ghaffar A, Krusberg LR (1988) Control of
plant parasitic nematodes associated with apple and pistachio trees in Baluchistan. Advances in
plant nematology, proceedings of the US-Pakistan international workshop on plant nematology,
Karachi, Pakistan, pp 271–274
Marull J, Pinochet J (1991) Host suitability of Prunus to four Meloidogyne spp. and Pratylenchus
vulnus in Spain. Nematropica 21:185–195
Marull J, Pinochet J, Verdejo S (1990) Response of five almond cultivars to four root-lesion
nematodes in Spain. Nematropica 20:143–151
Marull J, Pinochet J, Verdejo S, Soler A (1991) Reaction of Prunus rootstocks to Meloidogyne
incognita and M. arenaria in Spain. J Nematol 23:564–569
Mazzola M, Brown J, Zhao XW, Izzo AD, Fazio G (2009) Interaction of brassicaceous seed meal
and apple rootstock on recovery of Pythium spp. and Pratylenchus penetrans from roots grown
in replant soils. Plant Dis 93:51–57
McElory FD (1972) Nematodes of tree fruits and small fruits. In: Webster JM (ed.) Economic
nematology. Academic, New York, pp 335–373
Melakeberhan H, Bird GW, Perry R (1994) Plant parasitic nematodes associated with cherry
rootstocks in Michigan. J Nematol 26:767–772
Meyer AJ, Hugo HJ (1994) Xiphinema americanum damaging peach trees in South Africa.
J Nematol 26:111
Neal DC (1889) The root-knot disease of peach, orange and other plants in Florida due to the work
of Anguillula. USDA Division of Entomology, Bulletin No. 2D
Nesmith WC, Zehr EI, Dowler WM (1981) Association of Macroposthonia xenoplax and
Scutellonema brachyurum with the peach tree short life syndrome. J Nematol 13:220–225
Nigh EL Jr (1966) Incidence of crown gall infection in peach as affected by the javanese root-knot
nematode. Phytopathology 56:150
Nyczepir AP (1990) Influence of Criconemella xenoplax and pruning time on short life of peach
trees. J Nematol 22:97–100
Nyczepir AP (1991) Nematode management strategies in stone fruits in the United States. J Nematol
23:334–341
Nyczepir AP, Halbrendt JM (1993) Nematode pests of deciduous fruit and nut trees. In: Evans K,
Trudgill DL, Webster JM (eds.) Plant parasitic nematodes in temperate agriculture. CAB
International, Wallingford, pp 381–425
Nyczepir AP, Rodriguez-Kabana R (2007) Preplant biofumigation with sorghum or methyl
bromide compared for managing Criconemoides xenoplax in a young peach orchard. Plant Dis
91:1607–1611
Nyczepir AP, Wood BW (2008) Interaction of concurrent populations of Meloidogyne partityla
and Mesocriconema xenoplax on pecan. J Nematol 40:221–225
Nyczepir AP, Reilly CC, Wood BW, Thomas SH (2002) First record of Meloidogyne partityla on
pecan in Georgia. Plant Dis 86:441
266 T.H. Askary et al.
Okie WR, Reighard GL, Nyczepir AP (2009) Importance of scion cultivar in peach tree short life.
J Am Pomology Soc 63:58–63
Pacholak E, Rutkowski K, Zydlik Z, Zachwieja M (2006) Effect of soil fatigue prevention method
on the microbiological soil status in replanted apple tree orchard. Part 1. Number of nematodes.
Electron J Pol Agric Univ 9:54
Parvatha Reddy P (2008) Diseases of horticultural crops: nematode problems and their management.
Scientific Publishers, Jodhpur, p 379
Parvatha Reddy P (2011) Biomanagement for sustainable horticulture principle and practices, vol
3: biomanagement of nematode pests. Studium Press India Private Limited, New Delhi, p 284
Pasha MJ, Siddiqui ZA, Khan MW, Qureshi SI (1987) Histopathology of egg plant roots infected
with root-knot nematode, Meloidogyne incognita. Pak J Nematol 5:27–34
Phukan PN, Sanwal KC (1980) Two new species of Aglenchus and record of Cephalenchus leptus
(Nematoda: Tylenchidae) from Assam. Indian J Nematol 10:28–34
Phukan PN, Sanwal KC (1982) Two new species of Hemicriconemoides Chitwood and Birchfield,
1957 (Nematoda: Criconematidae) from Assam, India. Indian j Nematol 12:215–220
Pinochet J (2009) A ‘Greenpac’, a new peach hybrid rootstock adapted to Mediterranean
conditions. HortScience 44:1456–1457
Pinochet J, Marull J, Verdejo S, Soler A, Felipe A (1990) Evaluation of rootstocks of plum,
damson, pear and quince on the gall nematode Meloidogyne incognita (Kofoid and White)
Chitwood. Boletin-de-Sanidad Vegetal-Phlagas 16:717–722
Pinochet J, Verdejo S, Soler A, Canals J (1992) Host range of a population of Pratylenchus vulnus
in commercial fruit, nut, citrus and grape stocks in Spain. J Nematol 24:693–698
Pinochet J, Rodriguez- Kabana R, Marull J, McGawley EF (1993) Meloidogyne javanica and
Pratylenchus vulnus on pecan (Carya illinoensis). Fundam Appl Nematol 16:73–77
Pinochet J, Fernandez C, Alcaniz E, Felipe A (1996) Damage by a lesion nematode, Pratylenchus
vulnus to Prunus rootstocks. Plant Dis 80:754–757
Pinochet J, Fernandez C, Cunill M, Torrents J, Felipe A, Lopez MM, Lastra B, Penyalver R, Scott
JR, Chrisosto CH (2002) Response of new interspecific hybrids for peach to root-knot and
lesion nematodes, and crown gall. Proceedings of the 5th international peach symposium, 8–11
July 2001, Davis, California, 592:707–716
Raski DJ (1986) Plant parasitic nematodes of banana, citrus, coffee, grapes and tobacco. Union
Carbide Agricultural Products Company Incorporation Publication, North Carolina, pp 43–57
Reed HE (1963) Chemical dips for eradication of root-knot nematodes for plant root. Phytopathology
53:625
Rich JR, Dunn RA, Noling JW (2004) Nematicides past and present uses. In: Chen ZX, Chen SY,
Dickson DW (eds.) Nematology: advances and perspectives vol. 2, nematode management and
utilization. CAB International/Tsinghua University Press, Beijing, pp 1179–1200
Ritchie DF, Clayton CN (1981) Peach tree short life: a complex of interacting factors. Plant Dis
65:462–469
Robertson WM, Taylor CE (1975) The structure and musculature of the feeding apparatus in
Longidorus and Xiphinema. In: Lamberti F, Taylor CE, Seinhorst JW (eds.) Nematode vector
of plant viruses. Plenum press, London, pp 179–184
Rom RC, Dozier WA, Knowels JW, Carlton CC, Arrington EI, Wehunt EJ, Yadava UL, Dond SL,
Ritichie DF, Clayton CN, Zehr EI, Gambrell CE, Brittain IA, Lockwood DW (1985) Rootstock
effect on peach tree survival, growth and yield. Regional research project report. Compact Fruit
Tree 18:85–91
Rossi CE, Ferraz LCCB (2005) Plant parasitic nematodes of the superfamily Tylenchus associated
with subtropical and temperate fruits in the states of Sao Paulo and Minas Gerais, Brazil.
Nematologia Brasileira 29:171–182
Rubio-Cabetas MJ, Minot JC, Voisin R, Esmenjaud D (2001) Interaction of root-knot nematodes
(RKN) and the bacterium Agrobacterium tumefaciens in roots of Prunus cerasifera: evidence
of the protective effect of the Ma RKN resistance genes against expression of crown gall
symptoms. Eur J Plant Pathol 107:433–441
Sasser JN (1980) Root-knot nematodes: a global menace to crop production. Plant Dis 64:36–41
Plant Parasitic Nematode Diversity in Pome, Stone and Nut Fruits 267
Seshadri AR (1964) Investigations on the biology and life cycle of Criconemoides xenoplax Raski,
1952 (Nematoda: Criconematidae). Nematologica 10:540–562
Sharma NK (2000) Nematode diseases of temperate fruits. In: Gupta VK, Sharma SK (eds.)
Diseases of fruit crops. Kalyani Publishers, New Delhi, pp 237–250
Sharma GC, Kashyap AS (2009) Effect of different intercrops on the nematode populations and
yield of apricot var. New Castle. Indian J Horticulture 66:420–421
Sharma NK, Kaur DJ (1985) Nematodes associated with temperate crops in Himachal Pradesh.
In: Chadha TR, Bhutani VP, Kaul JL (eds.) Advances in research on temperate fruits. UHF-
Solan (India) Publication, Solan, pp 358–362
Sharma GC, Sharma NK (1988a) Effect of environmental temperature on the population build up
of Pratylenchus prunii in the peach rhizosphere. Indian Phytopathol 41:469–470
Sharma NK, Sharma GC (1988b) Nematode pests of temperate and sub-tropical fruits and their
management. In: Gupta VK, Sharma NK (eds.) Tree protection. ISTS, Publication/UHF-Solan
(India) Publication, Solan, pp 192–210
Sharma GC, Sharma NK (1990) Distribution of three important nematode species in rhizosphere
of plum trees. Indian J Horticulture 47:207–209
Sharma GC, Sharma NK, Khan ML (1988) Plant parasitic nematodes of plum (Prunus domestica)
in Himachal Pradesh. Indian J Horticulture 45:355–358
Sharma GC, Sharma NK, Khan ML (1991) Parasite nematodes associated with apricot, Prunus
armeniaca in Himachal Pradesh. Himachal Pradesh J Agric Res 17:112–114
Sher SA (1960) Chemical control of pant parasitic nematodes in plant roots. Phytopathology
50:654
Siddiqui IA, Sher SA, French AM (1973) Distribution of plant parasitic nematodes in California.
State of California Department of Food Agriculture, Division of Plant Industry, Sacramento,
p 324
Sijmons PC, Atkinson HJ, Wyss U (1994) Parasitic strategies of root nematodes and associated
host cell responses. Annu Rev Phytopathol 32:235–259
Singh M, Khan E (1998) Taxonomic studies on Criconematoidea (Nematoda: Tylenchida)
associated with fruit crops from north and north-eastern regions of India-I. Description of
seven new species. Indian J Nematol 28:174–191
Singh M, Khan E (1999) Taxonomic studies on criconematoidea (Nematoda: Tylenchida) associated
with fruit crops from north and north-eastern regions of India-II. Description of five new
species. Indian J Nematol 29:48–55
Siniscalco A, Lamberti F, Inserra R (1976) Reaction of peach root stocks to Italian populations of
root-knot nematodes, Meloidogyne spp. Nematologia Mediterranea 4:79–84
Stokes DE (1966) Parasitism by Pratylenchus brachyurus on three peach rootstocks. Nematologica
13:153
Sultan MS (1980) Two new species of genus Orientylus Jairajpuri and Siddiqi, 1977 (Tylenchida:
Rotylenchoidinae). Revue de Nematologie 3:227–231
Swarup G, Dasgupta DR, Koshy PK (1989) Plant diseases. Anmol Publications, New Delhi,
pp 245–363
Szczygiel GC (1976) Plant parasitic nematodes associated with fruit trees in Kumaon. Indian
J Agric Res 10:69–72
Szczygiel A, Rebandel Z (1990) Effect of root lesion nematode (Pratylenchus penetrans) on
growth and yield of sour cherry trees. Prace-Z-Zakresu-Nauk-Rolniczych 65:199–209
Thomas EE (1913) A preliminary report of a nematode observed on citrus roots and its possible
relation with the mottled appearance of citrus trees. Circ Calif Agric Exp Stn 85:14
Thorne G. (1943). Cacopaurus pestis, nov. gen., nov. spec. (Nematoda: Criconematinae) a
destructive parasite of the walnut, Juglans regia Linn. Proc Helminthol Soc, Washington,
10:78–83
Thorne G (1961) Principles of nematology. McGraw Hill, New York, p 553
Towson AJ, Lear B (1982) Control of nematodes in rose plants of hot water treatment
preceeded by heat hardening Meloidogyne hapla and Pratylenchus vulnus. Nematologica
28:339–353
268 T.H. Askary et al.
Utkhede RS, Smith EM, Palmer R (1992) Effect of root-rot fungi and root-lesion nematodes on
the growth of young apple trees grown in apple replant disease soil. Zeitschrift fur pflanzenk-
rankheiten und pflanzenschutz 99:414–419
Verma RR (1987) Reaction of some peach cultivars to Meloidogyne incognita. Indian J Nematol
17:123–124
Vlachopoulos EG (1991) Nematode species in nurseries of Greece. Annales de-Institut Phyto
pathologique Benaki 16:115–122
Walia RK, Bajaj HK (2003) Text book on introductory nematology. Directorate of Information and
Publications of Agriculture. Indian Council of Agricultural Research, Pusa, p 227
Waliullah MIS, Kaul V (1997) Nematodes associated with cherry plants in Kashmir valley. Indian
J Nematol 27:237
Walker GE, Wachtel MF (1988) Evaluation of nematicides for nematode control in cherries,
1986–87. Fungic Nematic Tests 43:165
Walters SA, Bond JP, Russell JB, Taylor BH, Handoo ZA (2008) Incidence and influence of plant
parasitic nematodes in Southern Illinois peach orchards. Nematropica 38:63–74
Wang LY, Zhu LX, Jia KG (2008) Resistance of several Prunus plants to root-knot nematode
Meloidogyne arenaria. J China Agric Univ 13:24–28
Wehunt EJ, Golden AM (1982) Nematodes of pears. In: Childers NF (ed.) The pear. Communications
Department, Cook College, Rutgers University, New Jersey, pp 377–387
Wehunt EJ, Good JM (1975) Nematodes on peaches. In: Childers NF (ed.) The peach: varieties,
culture, marketing and pest control, 3rd edn. Communications Department, Cook College,
Rutgers University, New Jersey, pp 377–387
Wehunt EJ, Weaver DJ (1982) Effect of planting site preparation, hydrate lime and DBCP
(1,2-dibromo-3-chloropropane) on population of Macroposthonia xenoplax and peach tree
short life in Georgia. J Nematol 14:567–571
Wehunt EJ, Weaver DJ, Doud SL (1976) Effect of peach rootstock and lime on criconemoides
xenoplax. J Nematol 8:304
Wehunt EJ, Horton BD, Prince VE (1980) Effects of nematicides, lime and herbicide on a peach
tree short life site in Georgia. J Nematol 12:183–189
Willers P, Daneel M (1993) Pecan root nematode, a banned pest. Inlightings bulletin Instituut-vir-
Tropiense-en-Subtropiese-Gewasse 245:10
Yadav BS, Varma MK (1967) New host plants of Xiphinema basiri and X. indicum. Nematologica
13:469
Yujkin H, Heng Z, ShouHua W, Hao YJ, Zhai H, Wang SH (1998) Study on the pathogenesis of
Trichodorus nanjigensis to Malus buccata. J Fruit Sci 15:26–29
Zaki FA, Mantoo MA (2003) Plant parasitic nematodes associated with temperate fruits in Kashmir
valley, India. Pest Manage Econ Zool 11:97–101
Fly Ash for Agriculture: Implications
for Soil Properties, Nutrients, Heavy Metals,
Plant Growth and Pest Control
Abstract Annual fly ash production ranges from 2 MT in the Netherlands to 112
MT in India, whereas fly ash utilisation ranges from 100% in the Netherlands to
38% in India. Over the past few decades there has been interest in developing strate-
gies to use fly ash in agriculture. It is indeed economical to use fly ash as a soil
amendment. Reviews on fly ash in agriculture are scarce. The potential of fly ash as
a resource material is due to its specific physical properties such as texture, water
holding capacity, bulk density, and pH. Moreover fly ash contains almost all essen-
tial plant nutrients. Fly ash can be used as an amendment in soil. Fly ash can improve
soils physical and chemical properties, reduce pest dammade on crops and increase
crop yields. The amount and method of fly ash application to soil depend on the type
of soil, the crop grown and fly ash characteristics. Besides positive effects fly ash
may contain also toxic metals and radionuclides. Therefore use of fly ash should be
done with care, notably by taking into account the uptake of metals by plants. This
chapter describes the properties of fly ash, and the effect of fly ash on soil properties,
nutrients, heavy metals uptake by plants, yields and pest control.
Keywords Agricultural application • Soil quality • Fly ash • Plant growth • Nutrients
• Heavy metal • Radionuclide
1 Introduction
Table 1 Generation and utilization of fly ash in different countries (Source: Dhadse et al. 2008)
Annual fly ash
S. No. Country production (MT) (%) Utilization
1 India 112 38
2 China 100 45
3 USA 75 65
4 Germany 40 85
5 United Kingdom (UK) 15 50
6 Australia 10 85
7 Canada 6 75
8 France 3 85
9 Denmark 2 100
10 Italy 2 100
11 Netherlands 2 100
Fly Ash for Agriculture: Implications for Soil Properties… 271
ash (about 35–45%), hence the generation of huge quantities of fly ash in India.
In Indian, the fly ash utilization was 3% of 40 MT production in 1994, has increased
and reached about 38% (42 MT) of total production i.e., 112 MT during 2004–2005
which is far below the global utilization rate (Dhadse et al. 2008) (Table 1). The causal
of low fly-ash utilization in India is the unavailability of appropriate cost-effective
technologies as well awareness among peoples. In India, the majority of fly ash
produced is disposed off in ash ponds and landfills and rest of fly ash (<15%) is
being used for preparing bricks, ceramics and cements (Pandey et al. 2009).
Earlier by-products of coal combustion were largely treated as waste materials.
However, in the recent past years many applications have been recognized due to
the presence of essential mineral elements resembling earth’s crust, which makes
them excellent substitution for natural materials. They can be used as a substitute
for Portland cement in manufacturing roofing tiles and as structural fills, sheetrock,
agricultural fertilizer and soil amendments. In 2004–2005, total utilization of fly ash
was about 42 Million tonnes per year. The highest utilization was in cement industry
(»49%), whereas agricultural sector contributed very less (»1%). The common
practice to dispose huge quantity of fly ash is disposal at the dumping site, which
requires huge quantities of land and causes deterioration of air, soil and water qual-
ity. According to World Bank, India will require 1,000 km2 of land for the coal ash
disposal till 2015 (Parisara 2007). Earlier fly ash was seen as a waste but now time
has changed and it is now considered as a valuable resource. Fly ash can be utilized
as a soil amendment in agriculture, improving soil texture (Chang et al. 1977; Phung
et al. 1978; Garg et al. 2003), improving nutrient status of the soil (Rautaray et al.
2003), wasteland reclamation (American Coal Ash Association 1998; Jala and
Goyal 2006) etc. But most of the fly ash still remains in the ash pond, causing many
deleterious effects on the environment, resulting in the degradation of land due to
accelerated erosion rates and ground water pollution problem.
The present review governs the positive and negative aspect of agricultural utili-
zation of fly ash. Positive aspects namely: Improvement of the nutrient levels,
increasing the water holding capacity, texture, reducing the acidity of the soil, use
as an insecticide to effectively control various pests infesting several vegetables etc.
However, negative aspects namely; toxic heavy metals and radioactive content in fly
ash. Negative aspect can be nullified and be helpful in tackling the waste manage-
ment problem of fly ash.
The physicochemical properties of fly ash depends primarily on the parent coal
composition of which it is produced and secondly on its combustion condition.
Due to varying nature of coal the fly ash characteristics are also changing. The coal
is a complex polymeric solid having no repeating monomeric units. The chemical
characteristics of coal are described by the parameters such as molecular weight,
carbon aromaticity, normal aromatic and aliphatic structure and functional groups.
272 A.K. Gupta et al.
The rank of coal is described by criteria like its anthroxylon content, oxygen con-
tent, calorific value, ultimate analysis, fixed carbon etc. (Hodgson et al. 1982).
Generally Indian coals have a high mineral matter percentage, low sulphur content,
high moisture, high ash content and low calorific value of 3,500–4,000 kcal kg−1. Ash
content of Indian coals varies between 15% and 30% and the S content is generally
less than 1% (Srivastava 2003; Bhatt 2006). It is very hard to generalize the composi-
tion of ashes. Physically fly ash is very fine glass like particles with an average diam-
eter of less than 10 mm, having low to medium bulk density, large surface area and
very light texture whereas its chemical composition depends on the parent coal qual-
ity and its operating conditions. Fly ash consists of approximately 95–99% oxides of
Si, Al, Fe and Ca and about 0.5–3.5% of Na, P, K and S and the remaining ash is trace
elements. Typical coal fly ash constituents are SiO2 (49–67%), Al2O3 (16–29%),
Fe2O3 (4–10%), CaO (1–4%), MgO (0.2–2%), SO3 (0.1–2%). Certain characteristics
of fly ashes are fairly uniform. Fly ashes consists of many minute glass like particles
of 0.01–100 mm size (Davison et al. 1974) having specific gravities 2.1–2.6 g m−3
(Bern 1976). Some spheres of FA are hollow (cenospheres), while others (plero-
spheres) are filled with small amorphous particles (Hodgson and Holliday 1966).
Bulk density of fly ash ranges from 1 to 1.8 g cm,3 whereas pH varies from 4.5 to 12.0
depending on parent coal S content (Plank and Martens 1974). The alkaline pH of fly
ash may be due to the presence of Ca, Na, Mg and OH along with other trace metals.
CaO, a major constituent of the fly ash, forms Ca (OH)2 with water and, thus, attri-
butes towards alkalinity (Hodgson et al. 1982). The particle size of fly ash greatly
influences its composition; however, it also affects the soil physical properties. All
the metals present in soil are found in the fly ash. Comparative study of physico-
chemical characteristics of fly ash and soil is given in Table 2. The concentration of
Fly Ash for Agriculture: Implications for Soil Properties… 273
various elements found in fly ash varies according to the particle size (Davison et al.
1974; Khan and Khan 1996). Some of the important elements constituting fly ash are
Si, Ca, Mg, Na, K, Cd, Pb, Cu, Co, Fe, Mn, Mo, Ni, Zn, B, F and Al. So fly ash con-
tains all the important metals needed for plant growth and its metabolism except
organic carbon and nitrogen. Fly ash contains very less or no nitrogen as the N pres-
ent in the coal is volatilized during its combustion (Bradshaw and Chadwick 1980;
Singh and Yunus 2000), however it has high concentration of phosphorous (P) (400–
8,000 mg P kg−1), but the form of P is not readily available to plants, probably due to
interactions with Al, Fe and Ca present in alkaline fly ash.
The radionuclides which contribute most to the environmental radiation are the
member of the natural radioactive series and 4°K. Coal contains trace quantities of
the naturally occurring radionuclides arising from Uranium and Thorium series and
4°K. The concentration of theses lives radionuclides are usually low in the coal,
when it is burnt in power plant, the fly ash that is emitted through the stack gets
enriched in some of the radionuclides (Yeledhalli et al. 2008).
Presence of radionuclides in fly ash has been reported by several workers but the
literature on their impact has been few (Coles et al. 1978; Gowiak and Pacynas
1980; Mittra et al. 2003; Yeledhalli et al. 2008). Mittra et al. (2005) in a study ana-
lyzed the radioactivity (Bq kg−1) of fly ash and reported higher radioactivity of 226Ra,
228
Ac and 4°K was recorded in soil treated with fly ash at 40 t ha−1. The radioactivity
due to addition of fly ash was subjected to dilution effect in soil. However, these
marginal variations remained within the safe limit (Mittra et al. 2005).
The effect of fly ash amendment on soil has been extensively investigated by many
workers (Plank and Martens 1974; Adriano et al. 1980; Elseewi and Page 1984).
Fly ash amendment in soil affects all its physical characteristics such as bulk den-
sity, pH, water holding capacity, electrical conductivity etc. (Table 3). The fly ash
addition alters soil physical properties such as its texture, bulk density, water hold-
ing capacity (Chang et al. 1977) and particle size distribution (Sharma 1989)
(Table 3). Campbell et al. (1983) found that fly ash addition at the rate of 10%
increased the water holding capacity 7.2 and 413.2 times for fine and coarse sands
respectively. The fly ash amendment also stabilizes soil aggregates as it works as
soil binders or stabilizers of self cementing material which result in reduced leachable
contaminants in the fly ash. The impact of fly ash amendment depends largely on
the properties of parent coal and the soil. The electrical conductivity of the soil was
increased as a result of fly ash amendment as the levels of soluble major and minor
inorganic constituents’ increases in soil (Adriano et al. 1980; Eary et al. 1990;
Adriano and Weber 2001) (Table 3). The Indian fly ashes are mostly alkaline in
nature, hence their application increases the soil pH (Gupta and Sinha 2006, 2009;
Pandey et al. 2009). The pH of soil increases as a result of fly ash amendment with
its alkaline nature due to rapid release of Ca, Na Al and OH− from the fly ash
274 A.K. Gupta et al.
(Wong and Wong 1986) (Table 3). As fly ash contains hydroxide and carbonate
salts it has an ability to neutralize acidity in soils (Pathan et al. 2003). This property
of fly ash can be used in neutralizing the acidic soil, but using excessive quantities of
fly ash for altering soil pH can cause increase in soil alkalinity especially with
unweathered fly ash (Sharma et al. 1989). Some fly ashes are acidic in nature which
can be used in reclaiming alkaline soils (Table 3). Soil texture of sandy and clayey
soil was altered to loamy soil as a result of fly ash addition at the rate of 70 t/ha
(Fail and Wochok 1977).
A gradual increase in fly-ash amendment in the normal field soil (0%, 10%, 25%,
up to 100% v/v) was reported to increase the water holding capacity, electrical con-
ductivity, EC, and pH and (Sinha and Gupta 2005; Gupta and Sinha 2006, 2009).
This improvement in water holding capacity is beneficial for the growth of plants
especially under rainfed agriculture. Amendment with fly ash up to 40% also
increased soil porosity from 43% to 53% and water holding capacity from 39% to
55% (Singh and Siddiqui 2003).
Recently, Pandey et al. (2009) carried out a study at Balarampur, Uttar Pradesh,
India to examine the influence of fly ash amendment into garden soil for Cajanus
cajan L. cultivation and on accumulation and translocation of hazardous metals to
edible part. C. cajan L. were grown in varying concentrations of fly ash (0%, 25%,
50% and 100% w/w). Fly ash amendment from 25% to 100% in garden soil
increases the levels of pH, particle density, porosity and water holding capacity
Fly Ash for Agriculture: Implications for Soil Properties… 275
In most instances, fly ash is added to soils primarily to affect chemical properties
such as pH and fertility, and loading rates are limited by chemical effects in the
treated soils. Plant growth on fly ash-amended soils is most often limited by nutrient
deficiencies, excess soluble salts and phytotoxic B levels (Page et al. 1979; Adriano
et al. 1980). Fly ash usually contains virtually no N and has little plant-available P
(Bradshaw and Chadwick 1980; Singh and Yunus 2000; Jala and Goyal 2006; Basu
et al. 2009). Application of fly ash to soil may cause P deficiency, even when the
ash contains adequate amounts of P, because soil P forms insoluble complexes with
the Fe and Al in more acidic ashes (Adriano et al. 1980) and similarly insoluble
Ca-P complexes with Class C ashes. Amendment of K-deficient soil with fly ash
increases plant K uptake, but the K in fly ash is apparently not as available as fertil-
izer K, possibly because the Ca and Mg in the fly ash inhibit K absorption by plants
(Martens et al. 1970).
Factors against fly ash disposal in agricultural soils are especially the content of
potentially toxic elements (Ni, Pb, Cd, B, Se, Al, etc.), high salinity and reduced
solubility of some nutrients due to high pH (<7.5) of fly ash (Carlson and Adriano
1993; Gupta and Sinha 2006). As already noted the pH of fly ash can vary from 4.5
to 12 depending mainly on the S content of the parent coal (Plank and Martens
1974; Page et al. 1979). The pH of some alkaline ashes can exceed 12 and this may
be a factor limiting plant growth, particularly on unweathered deposits (Carlson and
Adriano 1993). A high pH can induce deficiencies of essential nutrients such as
276 A.K. Gupta et al.
P and essential trace elements such as Fe, Mn, Zn and Cu in plants grown in ash
deposits and soils amended with substantial amounts of ash (Cary et al. 1983;
Carlson and Adriano 1993; Adriano et al. 2002).
Application of fly ash to agricultural soil generally results in increased soil con-
centrations of extractable Ca, Ba, Mo, Se, S, B, Pb, and Cd other elements may also
be enriched depending on the rate of its application, type and composition of the soil
and properties of the fly ash (Page et al. 1979; Adriano et al. 1980; Carlson and
Adriano 1993; Bilski et al. 1995; Jala and Goyal 2006; Basu et al. 2009). Fly ash
also has been shown to supply essential nutrients to crops on nutrient-deficient soils
and has been reported to correct deficiencies of B, Mg, Mo, S and Zn (Carlson and
Adriano 1993; Singh and Yunus 2000; Jala and Goyal 2006). The availability of
Mg, Mo, S and Zn in some ashes is comparable to the availability of these nutrients
in commonly used fertilizers (El-Mogazi et al. 1988). Elevated concentrations of B,
Se, As, Mo, Sr and S are commonly reported for plants growing in fly ash or fly
ash-amended soil (Adriano et al. 1980, 2002; Carlson and Adriano 1993).
By contrast, fly ash application may tend to decrease the uptake of some ele-
ments. Concentrations of metals such as Fe, Mn, Zn, Ca, Cr, Cd as well as P in plant
tissues have after been found to decrease when fly ash is added to the soil (Adriano
et al. 1980, 2002; Wong et al. 1996; Gorman et al. 2000; Ciccu et al. 2003; Sinha
and Gupta 2005; Gupta and Sinha 2006, 2009; Gupta et al. 2007). Although, an
exact mechanism of element retention by fly ash is unclear, the main reasons are
believed to be (I) an increase in pH causing the precipitation of insoluble phases and
(II) an increase in a specific surface area, promoting metal sorption via surface com-
plexation, cation exchange reactions or both.
A pots study aimed to effect of fly ash on growth and metal accumulation in
tomato plant was conducted by Khan and Khan (1996). They found that the gradual
increase in fly-ash concentration in the normal field soil from 0%, 10%, 20% up to
100% v/v increased the pH, thereby improving the availability of sulfate, carbonate,
bicarbonate, chloride, P, K, Ca, Mg, Mn, Cu, Zn and B. They also found that addi-
tion of fly ash to acidic and alkaline soil decreased the amounts of Fe, Mn, Ni, Co
and Pb released from acid soil. However, the release of these metals from alkaline
soil remained unchanged.
Sinha and Gupta (2005) studied on the plants of Sesbania cannabina Ritz grown
on different amendments of fly ash with garden soil. They reported that the applica-
tion of fly ash reduced the levels of tested metals extracted by the diethyelen triamine
penta acetic acid (DTPA) and subsequently its accumulation in S cannabina, from
10% to 50% of the fly ash amendment. Another pots experiment was conducted
by Gupta and Sinha (2006) to study the potential of Brassica juncea for the
phytoextraction of metal from fly ash amended soil and to study correlation between
different pool of metals (total, DTPA, CaCl2 and NH4NO3) and metal accumulated
in the plant in order to assess better extractant for plant available metals. They found
that the levels of all the tested metals were decrease with an increase in fly ash
amendments ratio from 10% to 75% fly ash. Correlation coefficient between metal
accumulation by the plant tissues and different pool of metals showed better corre-
lation with DTPA in case of Fe, Zn and Ni, whereas, Cu was significantly correlated
Fly Ash for Agriculture: Implications for Soil Properties… 277
with ammonium nitrate (NH4NO3) and other metals (Pb, Mn) with CaCl2. Alkaline
ash can also cause increased accumulation of some non-essential trace elements in
plants such as As, Se and V whose solubility increase with increasing pH (Page
et al. 1979; Adriano et al. 1980).
The effect of fly ash addition on the uptake or enrichment of various nutrients and
heavy trace elements in soil as well as various crops have been investigated with
safe use of crop produced for human consumption (Page et al. 1979; Doran and
Martens 1972). Brake et al. (2004) reported variation in uptake of different metals
studied in young, middle age and mature basil (Genovese), tomato, zucchini and
sunflower plants grown in soil amended with 5%, 10% and 20% fly ash (w/w).
Uptake of As and Ti was increased by increasing FLY ASH amendment rates, As
exceeded the toxic level in basil and zucchini (7 ppm).
Mishra et al. (2007) reported that the fly ash application did not change the Na
content of rice-roots, but the contents of K, P, Mn, Ni, Co, Pb, Zn, Cu, Cr, and Cd
showed a progressive increase. Seeds of plants grown in fly ash amended soils
accumulated Cu, Pb, Cr and Cd in amounts below allowable limits. Accumulation
of Fe was maximum in all the parts of plant followed by Si and both metals
showed more translocation to leaves while Mn, Zn, Cu, Ni and Cd showed lower
accumulation and most of the metal was confined to roots in all the three culti-
vars. As was accumulated only in leaves and was not found to be in detectable
levels in roots and seeds (Dwivedi et al. 2007). In all the three cultivars of rice
heavy metal accumulation was Fe > Si > Mn > Zn > Ni > Cu > Cd > As in all the
plant parts.
Pandey et al. (2009) in a pot experiment, found that accumulation and translo-
cation of heavy metals in Cajanus cajan L depends on fly ash amendment ratios.
Addition of fly ash at lower ratios (25%) shows positive results in most of the
studied growth and yield parameters than the respective control. Means concen-
tration of Zn, Cu, Cr and Cd in edible parts (seeds) were found below the respec-
tive critical value of 100–900, 20–100, 2–30 and 0.7–200 mg g−1dw (Marchner,
1995). However, Pandey et al. (2009) reported that lower concentration of fly ash
(25%) is safe for C. cajan cultivation as it not only enhanced the yield of C. cajan
L. significantly but also ensured the translocation of heavy metals to edible parts
within the critical limits. Recently, Gupta and Sinha (2009) have reported that
the accumulation of metals in the plant of Vigna radiata increased with increasing
fly ash amendment and was greater in shoots than in roots (except for Mn and Cu)
and seeds (except Mn).
In contrast fly ash application might also decrease the uptake of heavy metals
including Cd, Cu, Cr, Fe, Mn and Zn in plant tissues (Petruzzelli et al. 1986), which
could be probably due to the increased pH of fly ash amended soil. According to
El-Mogazi et al. (1988), the supply of As from fly-ash to plants might be short-term.
278 A.K. Gupta et al.
Integrated nutrient treatments involving fly ash at 10 t ha−1, organic wastes and
chemical fertilizers resulted in higher uptake of N, P, K, Ca, Mg, Fe, Mn, Zn and Cu
in rice grain than application of only chemical fertilizers, which in turn was respon-
sible for higher rice yield (Sajwan et al. 1995; Sarangi et al. 1997; Rautaray et al.
2003). They also observed lower concentration of Cd and Ni in both grain and straw
of rice and the reason might be the increase in soil pH due to the application of fly
ash to the rice crop which precipitated the native Cd and Ni.
As fly ash contains almost all the essential plant nutrients needed for their growth
and metabolism it can be a good source of soil amendment. The use of fly ash
amendment in agriculture has been stimulated since it assists in tackling the fly ash
disposal problem and saves the large amount of land required for land filling.
Generally fly ash amendment in soil increases plant growth and nutrient uptake
(Aitken et al. 1984; Furr et al. 1977). Experiment was carried out by Singh et al.
(1997) to study the impact of fly ash amendment on seed germination, seedling
growth and metal composition of Vicia Faba L. fly ash of Talkatora thermal power
plant was amended in soil at different ratios 5%, 10%, 20% and 30%. The experi-
ment was carried out in an earthen pot. It was found that lower fly ash amendment
enhances the seed germination significantly by 68%, whereas at 30% fly ash appli-
cation rate, seed germination was inhibited. The 20% fly ash amendment delayed
the seed germination by 4 days. It might be due to higher concentration of trace ele-
ments such as Cu, Co, Ni, Se, Al, and Cr etc. at higher application rates which
delayed or inhibited the process (Vollmer et al. 1982). Lower application rate also
enhanced the plant growth, leaf area and plant height whereas higher dose (30%)
retarded the plant growth and dry matter production was reduced by 27%. The con-
centrations of all the metals were higher in roots than that in tops. It has been
reported that fly ash amendment at maximum rate of 10% in agricultural soil is
beneficial for plant growth (Singh et al. 1997).
Khan and Khan (1996) conducted a study to find out the most suitable level of fly
ash dose for addition in the soil to improve its fertility leading to higher productivity
of tomato crop, Lycopersicum esculentum. Pot experiment was carried out using
following doses 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100%
of fly ash amendment. Tomato plants responded positively to fly ash amendment
showing luxuriant growth. Shoot length enhanced in 40–90% fly ash whereas root
length increased in 20–80% fly ash amendment in comparison to unamended soil
(Khan and Khan 1996). However, shoots and roots were 9% and 5% longer in 100%
fly ash than the control, whereas, 50% and 60% fly ash amendment had greatest
enhancement (34.7% and 54.9%, respectively) (Table 4).
Ajaz and Tiyagi (2003) conducted a field experiment to study the effect of differ-
ent concentrations of fly ash (0%, 10%, 25%, 50%, 75%, 90% and 100%) on growth
of cucumber plant i.e., Cucumis Sativus. Normal soil without fly ash amendment
was treated as control. Fly ash amendment in to the soil also improves the plant
Table 4 Effect of fly ash amendment on growth, yield and heavy metal accumulation in plants
Effects on heavy metal
Plants @ Fly ash in to soil Effects on growth and yield accumulation in plants Reference
Turf grass @ 0, 280, 560 and Plants height and root depth were not – Adriano and Weber
1,120 Mg ha−1 adversely affected, however, dry (2001)
matter yields throughout the study
period affected
Cucumis Sativus @ 0%, 10%, 25%, 50%, FA amendment in the soil improves the – Ajaz and Tiyagi
75%, 90%, 100% plant growth characters such as length, (2003)
(w/w) fresh as well as dry weights, net
primary productivity and leaf area.
Plant fresh weight was found to be
decreased at higher FA amendment
rates
Vicia faba L @ 0, 10, 25, 50 and 100 Growth and biomass of the plant increased – Rai et al. (2003)
(<25%) followed by decreased with
application of FA as compared to GS
Fly Ash for Agriculture: Implications for Soil Properties…
Rice plant (Oryza sativa) @ 0%, 20%, 40%, 60%, Application of 20% and 40% FA with soil – Singh and Siddiqui
Pant-4, Pant-10 and 80% and 100% caused a significant increase in plant (2003)
Pusa Basmati growth and yield of all the three
cultivars followed by decreased at
higher percentage (60%, 80% and
100%)
Sesbania cannabina L. @ 0%, 10%,25%,50%, Growth and biomass of the plant increased Metal accumulation was found to Sinha and Gupta
75% and 100% (w/w) (<25%) followed by decreased with be in the order Fe > Mn > Zn > (2005)
application of fly ash as compared to Cu > Pb > Ni after 90 d of
garden soil exposure
(continued)
279
280
Table 4 (continued)
Effects on heavy metal
Plants @ Fly ash in to soil Effects on growth and yield accumulation in plants Reference
Brassica juncea L. var. @ 0%,10%,25%,50% and 25% fly ash amendment shown significant The metal accumulation in total Gupta and Sinha
vaibhaw 100% (w/w) increase in plant biomass, shoot and plant tissues was found in the (2006)
plant height, whereas, no significant order of Fe > Ni > Zn > Mn >
effect was observed in root length Cu > Pb and its translocation
was found more in upper part
Rice plant (Oryza sativa) @ 0, 40, 80, and The highest rice yields were achieved The application of fly ash Lee et al. (2006)
120 Mg ha−1 following the addition of »80 Mg ha−1 increased Si, P and K uptake
fly ash by the rice plants
Brassica napus (canola) @ 0%, 5%, 10%, 20%, Increases early growth vigour and seed – Yunusa et al. (2006)
50% and 100% yield by 20%
Cicer arietinum L. Various combinations of Fly ash amended with GS or PM led to a Amendment of FA with either GS Gupta et al. (2007)
varieties (var. fly ash amended with 5–10 times increase in biomass or PM only moderately
CSG-8962 and var. garden soil (GS), press compared to FA control and was most increased the contents of some
C-235) mud (PM) or saw dust pronounced in the less metal tolerant essential metals whereas the
(SD) variety CSG-8962 non-essential Cd and Cr
remained similar or decreased
slightly compared to FA control
Three rice cultivars viz., @ 10%, 25%, 50%, 75% Higher application (>50%) of FA caused The metal accumulation order in Dwivedi et al.
Saryu-52, Sabha- and 100% (w/w) reduction in growth parameters viz., three rice cultivars was Fe > Si (2007)
5204, and Pant-4 plant height, root biomass, number of > Mn > Zn > Ni > Cu > Cd > As
tillers, grain and straw weight in all the plant parts
Rice plant (Oryza sativa) @ 0, 1, 2.5, 5, 10 and 15 t Growth (shoot length, leaf area and Contents of Mn, Ni, Co, Pb, Zn, Mishra et al. (2007)
ha−1 pigment composition) and yield Cu, Cr, and Cd progressively
(panicle length, seeds per panicle, seed increased with FA application
weight and yield per plant) of rice
increased with an increase in FA
A.K. Gupta et al.
amendments
Effects on heavy metal
Plants @ Fly ash in to soil Effects on growth and yield accumulation in plants Reference
Phaseolus vulgaris @ 0%, 10% and 25%% Results indicated that lower amendment Translocation of metals was more Gupta et al. (2007)
(w/w) favored the growth of the plant from roots to shoots in the
plants grown on FA amended
soil
Beta vulgaris L. var All @ 0%, 5%, 10%, 15% and FA caused significant reductions in Concentrations of all the tested Singh et al. (1997)
Green H1 20% (w/w) growth, biomass and yield heavy metals increased
significantly with increasing
concentrations of FA
Brassica napus (canola) @ 0, 5, 25, 125, and FA at low to moderate rates of up to FA application did not influence Yunusa et al. (2006)
625 Mg/ha 25 Mg/ha enhanced growth and yield accumulation of B, Cu, Mo, or
of canola Zn in the stems at any stage of
plant growth or in the seed at
harvest
Cajanus cajan L. @ 0%, 25%, 50% and Lower concentration (25% FA) applica- – Pandey et al. (2009)
100% (w/w) tion had shown positive results in most
of the studied parameters of growth
and yield
Vigna radaiata L var @ 0%, 10% and 25% Growth parameters increased with Accumulation of metals by the Gupta and Sinha
PDM 54 (mung bean) (w/w) increasing FA amendment compared plants increased with (2009)
with GS. An increase in dry biomass increasing FA amendment and
Fly Ash for Agriculture: Implications for Soil Properties…
growth characters such as length, fresh as well as dry weights, net primary productivity
and leaf area, which increases gradually up to 50% fly ash amendment. The fresh
weight of cucumber increased maximally by 114.91% at 25% fly ash amendment
followed by 10% and 50% fly ash amendments. Plant fresh weight was found to
decrease at higher fly ash amendment rates (Ajaz and Tiyagi 2003) (Table 4).
Sinha and Gupta (2005) reported, increase in root as well as shoot length of
Sesbania cannabina grown at lower fly ash amendment rates (10% and 25% fly
ash). Growth and development of the plants occur as a result of an overall balance
between synthesis and proteolysis of proteins (Sinha and Gupta 2005) (Table 4).
A study conducted by Mishra et al. (2007) reported that the application of fly ash
caused significant improvement in soil quality and germination percentage of rice
seeds. They found that shoot length, leaf area and pigment composition, and panicle
length, seeds per panicle, seed weight and yield per plant of rice increased with an
increase in fly ash amendments. Pandey et al. (2009) reported that growth variables
such as root and shoot length, plant height, total leaf area, number of nodules per
plant and biomass increased with a decreasing ratio of fly ash incorporation. Even
fly ash addition in to the soils also affected its chemical composition due to increased
concentration of various elements, which is beneficial for plant growth when applied
at low concentrations but becomes toxic at higher doses (Gupta et al. 2004; Sinha
and Gupta 2005). Pandey et al. (1994) reported, increase in plant growth, number of
leaves, leaf area and biomass of Helianthus annuus L. grown at 0.5, 1 and 1.5 kg m−2
fly ash amended soil as compared to respective unamended control (Table 4).
Recently, Gupta and Sinha (2009) have reported that the plant height, root and shoot
lengths and dry biomass of the Vigna radiata increased with increasing fly ash
amendment compared with garden soil (Table 4).
Several reports have revealed that fly ash can be used as insecticide in agricultural
areas (Table 3). Narayanasamy and Gnanakumar Daniel (1989) have reported the
insecticidal property of lignite fly ash as an insecticide against a range of lepi-
dopterous and coleopterous pests infesting rice, vegetables, greens and certain
other field crops. Sankari and Narayanasamy (2007) worked on Bio-efficacy of fly
ash based herbal pesticides against pests infesting rice and vegetables. Amongst
all the treatments, fly ash with 10% turmeric dust and fly ash with 10% neem
seed kernel dust were found to be the most effective against all the test insects,
including Epilachna on brinjal and Spodoptera on okra, followed by fly ash with
10% vitex dust and fly ash with 10% eucalyptus dust and fly ash with 10%
ocimum dust. The whole study showed that fly ash could be a potential insecticide
and an active carrier in certain insecticide formulations like dust, wettable powder
and granules. It is concluded by successive studies that fly ash could effectively
control various pests infesting several vegetables both under laboratory and field
conditions.
Fly Ash for Agriculture: Implications for Soil Properties… 283
8 Conclusion
In view of the above discussions, the striking points from this chapter could be
summarized as follows: (A) Benefit of fly ash use in agriculture: (i) fly ash having
almost all the essential plant nutrients i.e., macronutrients including P, K, Ca, Mg
and S and micronutrients like Fe, Mn, Zn, Cu, Co, B and Mo, except organic carbon
and nitrogen. (ii) Its application also increases the soil pH, water holding capacity etc.
It will certainly reduce the availability of heavy metal in the soil subsequently its
uptake in to the plant. (iii) Fly ash is also useful for stabilizing erosion-prone soils. (iv)
fly ash is also useful to effectively control various pests infesting several vegetables.
(B) Fly ash utilization in agricultural sector also has some disadvantages espe-
cially with natural radionuclide and toxic heavy metal content.
However, care must be taken while using fly ash in agriculture. Attention should
also be given on some important areas related to its utilization, such as long term
studies of impact of fly ash on soil health, crop quality, and continuous monitoring
on the characteristics of soil as well as fly ash. There is also need of study on pres-
ence of radionuclides in fly ash as there are very few reports on this.
Acknowledgement Amit K. Gupta and Rajeev P Singh are thankful to UOU and USM respectively
for Postdoctoral fellowship and necessary help.
References
Adriano DC, Weber JT (2001) Influence of fly ash on soil physical properties and turf grass estab-
lishment. J Environ Qual 30:596–602
Adriano DC, Woodford TA, Ciravolo TG (1978) Growth and elemental composition of corn and
bean seedlings as influenced by soil application of coal ash. J Environ Qual 7:416–421
Adriano DC, Page AL, Elseewi AA, Chang AC, Straughan I (1980) Utilization and disposal of fly
ash and other coal residues in terrestrial ecosystems: a review. J Environ Qual 9:333–344
Adriano DC, Weber J, Bolan NS, Paramasivam S, Koo BJ, Sajwan KS (2002) Effects of high rates
of coal fl y ash on soil, turfgrass, and groundwater quality. Water Air Soil Pollut 139:365–385
Aitken RL, Bell LC (1985) Plant uptake and phytotoxicity of boron in Australian fly ashes. Plant
Soil 84:245–257
Aitken RL, Campbell DJ, Bell LC (1984) Properties of Australian fly ash relevant to their agro-
nomic utilization. Aust J Soil Res 22:443–453
Ajaz S, Tiyagi S (2003) Effect of different concentrations of fly-ash on the growth of cucumber
plant, Cucumis sativus. Arch Agron Soil Sci 49:457–461
American Coal Ash Association (1998) Coal combustion product (CCP) production and use.
ACAA, Alexandria. Available from: http://www.acaa-usa.org.
Basu M, Pande M, Bhadoria PBS, Mahapatra SC (2009) Potential fly-ash utilization in agriculture:
a global review. Prog Nat Sci 19:1173–1186
Bern J (1976) Residues from power generation: processing, recycling and disposal, land applica-
tion of waste materials, Soil Cons Soc Amer, Ankeny, Iowa, pp 226–248
Bhatt MS (2006) Effect of ash in coal on the performance of coal fired thermal power plants. Part
I: primary energy effects. Energ Source Part A 28:25–41
Bilski JJ, Alva AK, Sajwan KS (1995) Fly ash. In: Rechcigl JE (ed) Soil amendments and environ-
mental quality. CRC Press, Boca Raton, pp 237–363
284 A.K. Gupta et al.
Gupta DK, Rai UN, Sinha S, Tripathi RD, Nautiyal BD, Rai P, Inouhe M (2004) Role of Rhizobium
(CA-1) inoculation in increasing growth and metal accumulation in Cicer arietinum L. growing
under fly-ash stress condition. Bulletin Environ Contam Toxicol 73:424–431
Gupta AK, Dwivedi S, Sinha S, Tripathi RD, Rai UN, Singh SN (2007) Metal accumulation and
growth performance of Phaseolus vulgaris grown in fly-ash amended soil. Bioresour Technol
98:3404–3407
Hodgson DR, Holliday R (1966) The agronomic properties of pulverized fuel ash. Chem Ind
20:785–790
Hodgson DR, Dyer D, Brown DA (1982) Neutralization and dissolution of high-calcium fly-ash.
J Environ Qual 11:93–98
Jala S, Goyal D (2006) Flyash as a soil ameliorant for improving crop production – a review.
Bioresour Technol 97:1136–47
Khan MR, Khan MW (1996) The effect of fly-ash on plant growth and yield of tomato. Environ
Pollut 92:105–111
Kumar V, Mathur M, Sinha SS (2005) A case study: manifold increase in fly ash utilization in
India. Fly Ash Utilization Programme (FAUP), TIFAC, DST, New Delhi – 110016
Marchner H (1995) Mineral nutrition of higher plants. Academic, New York, pp 1–260
Lee H, Ha HS, Lee CS, Lee YB, Kim PJ (2006) Fly ash effect on improving soil properties and rice
productivity in Korean paddy soil. Bioresource Technol 97:1490–1497
Martens DC, Schnappinger MG, Zelazny LW Jr (1970) The plant availability of potassium in fly
ash. Soil Sci Soc Am Pro 34:453–456
Mishra M, Sahu RK, Padhy RN (2007) Growth, yield and elemental status of rice (Oryza sativa)
grown in fly ash amended soils. Ecotoxicology 16:271–278
Mittra BN, Karmakar S, Swain DK, Ghosh BC (2003) Fly ash—a potential source of soil amend-
ment and a component of integrated plant nutrient supply system. Available from: <http://
www.flyash.info/2003/28mit.pdf>
Mittra BN, Karmakar S, Swain DK, Ghosh BC (2005) Fly-ash a potential source of soil amend-
ment and a component of integrated plant nutrient supply system. Fuel 84:1447–1451
Narayanasamy P, A Gnanakumar D (1989) Lignite fly-ash: a nonpolluting substance for tackling
pest problems. In: Devaraj KV (ed) Progress in pollution research. University of Agricultural
Sciences, Bangalore, pp 201–206
Natusch DFS, Wallace JR (1974) Urban aerosol toxicity: the influence of particle size. Science
186:695–699
Page AL, Elseewi AA, Straughan IR (1979) Physical and chemical properties of fly ash from coal-
fired power plants with special reference to environmental impacts. Residue Rev 71:83–120
Pandey V, Mishra J, Singh SN, Singh N, Yunus M, Ahmad KJ (1994) Growth response of
Helianthus annuus L. grown on fly-ash amended soil. J Environ Biol 15:117–125
Pandey VC, Abhilash PC, Upadhyay RN, Tewari DD (2009) Application of fly ash on the growth
performance and translocation of toxic heavy metals within Cajanus cajan L.: implication for
safe utilization of fly ash for agricultural production. J Hazard Mater 166:255–259
Parisara (2007) Utility bonanza from dust, ENVIS newsletter, Department of forests, ecology and
environment, Government of Karnataka, vol. 2 No. 6, January
Pathan SM, Aylmore LAG, Colmer TD (2003) Soil properties and turf growth on a sandy soil
amended with fly ash. Plant Soil 256:103–114
Petruzzelli G, Lubrano L, Cervelli S (1986) Heavy metal uptake by wheat seedlings grown on fly
ash amended soils. Water Air Soil Pollut 32:389–395
Phung HT, Lund LJ, Page AL (1978) Potential use of fly ash as a liming material. In: Adriano DC,
Brisbin IL (eds) Environmental chemistry and cycling processes, CONF-760429. US
Department of Commerce, Springfield, pp 504–515
Plank CO, Martens DC (1974) Boron availability as influenced by application of fly ash to soil.
Soil Sci Soc Am Proc 38:974–977
Rai UN, Gupta DK, Akhtar M, Pal A (2003) Performance of seed germination and growth of Vicia
faba L. in fly-ash amended soil. J Environ Biol 24:9–15
286 A.K. Gupta et al.
Rautaray SK, Ghosh BC, Mittra BN (2003) Effect of fly ash, organic wastes and chemical fertil-
izers on yield, nutrient uptake, heavy metal content and residual fertility in a rice-mustard
cropping sequence under acid lateritic soils. Bioresour Technol 90:275–283
Sajwan KS, Ornes WH, Youngblood T (1995) The effect of fly ash/sewage sludge mixtures and
application rates on biomass production. J Environ Sci Heal 30:1327–1337
Sankari SA, Narayanasamy P (2007) Bio-efficacy of fly-ash based herbal pesticides against pests
of rice and vegetables. Curr Sci 92:811–816
Sarangi PK, Mishra TK, Mishra PC (1997) Soil metabolism, growth and yield of Oryza sativa L.
in fly ash amended soil. Indian J Environ Sci 1:17–24
Sharma S (1989) Fly ash dynamics in soil water systems. Crit Rev Env Contr 19:251–275
Sharma S, Fulekar MH, Jayalakshmi CP, Straub CP (1989) Fly ash dynamics in soil-water systems.
Crit Rev Env Contr 19:251–275
Singh LP, Siddiqui ZA (2003) Effects of fly ash and Helminthosporium oryzae on growth and yield
of three cultiver of rice. Bioresour Technol 86:73–78
Singh N, Yunus M (2000) Environmental impacts of fly-ash. In: Iqbal M, Srivastava PS, Siddiqui
TO (eds) Environmental hazards: plant and people. CBS, New Delhi, pp 60–79
Singh SN, Kulshreshtha K, Ahmad KJ (1997) Impact of fly ash soil amendment on seed germina-
tion, seedling growth and metal composition of Vicia faba L. Ecol Eng 9:203–208
Sinha S, Gupta AK (2005) Translocation of metals from fly ash amended soil in the plant of
Sesbania cannabina L. Ritz: effect on antioxidants. Chemosphere 61:1204–1214
Srivastava SK (2003) Recovery of sulphur from very high ash fuel and fine distributed pyritic
sulphur containing coal using ferric sulphate. Fuel Process Technol 84:37–46
Townsend WN, Gillham EWF (1975) Pulverized fuel ash as a medium for plant growth. In:
Chadwick MJ, Goodman GT (eds) The ecology of resource degradation and renewal. Blackwell,
Oxford, pp 287–304
Tripathi RD, Dwivedi S, Shukla MK, Mishra S, Srivastava S, Singh R, Rai UN, Gupta DK (2008)
Role of blue green algae biofertilizer in ameliorating the nitrogen demand and fly-ash stress to
the growth and yield of rice (Oryza sativa L.) plants. Chemosphere 70:1919–1929
Vollmer AT, Turner FB, Straughan IR, Lyons CL (1982) Effects of coal precipitator ash on germi-
nation and early growth of desert annuals. Environ Exp Bot 22:409–413
Wong MH, Wong JWC (1986) Effects of fly ash on soil microbial activity. Environ Pollut Ser A
40:127–144
Wong JWC, Jiang RF, Su DC (1996) Boron availability in ash sludge mixture and its uptake by
corn seedlings (Zea mays L.). Soil Sci 161:182–187
Yeledhalli NA, Prakash SS, Ravi MV (2008) Concentration of heavy elements and radionuclides
in crops grown on Coal ash amended Red and Black soil. Karnataka J Agric Sci
21(1):125–127
Yunusa IAM, Eamus D, DeSilva DL, Murray BR, Burchett MD, Skilbeck GC, Heidrich C (2006)
Fly-ash: an exploitable resource for management of Australian agricultural soils. Fuel
85:2337–2344
Organic Farming History and Techniques
Abstract Organic farming involves holistic production systems that avoids the use
of synthetic fertilizers, pesticides and genetically modified organisms, thereby mini-
mizing their deleterious effect on environment. Agriculture area under organic
farming ranges from 0.03% in India to 11.3% in Austria. Organic farming is benefi-
cial for natural resources and the environment. Organic farming is a system that
favors maximum use of organic materials and microbial fertilizers to improve soil
health and to increase yield. Organic farming has a long history but show a recent
and rapid rise. This article explains the development stages, techniques and status of
organic farming worldwide. The sections are: the development and essential charac-
teristics of organic farming; the basic concepts behind organic farming; historical
background; developmental era of organic farming; methods of organic farming;
relevance of organic farming in the Indian context; comparative account between
organic farming and conventional farming; importance of organic farming in envi-
ronmentally friendly approaches; working with natural cycles; relevance of organic
crop production in food security; yield potential and trends of organic farming; rural
economic linkage its scope and limitations; and legislation procedures adopted by
various countries. Organisations and financial aspects of organic farming are briefly
discussed.
1 Introduction
Organic agriculture is one among the broad spectrum of production methods that
are supportive of the environment. Agriculture remains the key sector for the economic
development for most developing countries. It is critically important for ensuring
food security, alleviating poverty and conserving the vital natural resources that the
world’s present and future generations will be entirely dependent upon for their
survival and well-being. The world populations will inevitably double by the middle
of the twenty-first century, that we are soon to enter, that is in the space of just two
generations. Over 90% of the developing nations, especially in Asia and to an ever
greater extent will be in the urban areas which follow up the green revolution strategy
(Rothschild 1998).
Green revolution technologies such as greater use of synthetic agro chemicals
like fertilizers and pesticides, adoption of nutrient responsive, high-yielding varieties
of crops, greater exploitation of irrigation potentials etc. has boosted the production
output in most of cases. Without proper choice and continues use of these high
energy inputs is leading to decline in production and productivity of various crops
as well as deterioration of soil health and environments. The most unfortunate
impact on Green Revaluation Technology (GRT) not only on Indian Agriculture but
also the whole world is as follows:
1 . Change in soil reaction
2. Development of nutrient imbalance/deficiencies
3. Damage the soil flora and fauna
4. Reduce the earth worm activity
5. Reduction in soil humus/organic matter
6. Change in atmospheric composition
7. Reduction in productivity
8. Reduction in quality of the produce
9. Destruction of soil structure, aeration and water holding capacity
All these problems of GRT lead to not only reduction in productivity but also
deterioration of soil health as well as natural eco-system. Moreover, today the
rural economy is now facing a challenge of over dependence on synthetic inputs
and day by day it change in price of these inputs. Further, world Agriculture will
face the market competition due to globalization of trade as per World Trade
Organization (WTO). Thus apart from quantity, quality will be the important
factor. Such as Agriculture gave birth to various new concepts of farming such as
organic farming, natural farming, bio-dynamic Agriculture, do-nothing agriculture,
eco-farming etc.
The essential concept of the practices is “Give back to nature”, where the philoso-
phy is to feed the soil rather them the crop to maintain the soil health. Therefore, for
sustaining healthy ecosystem, there is need for adoption of an alternatives farming
system like organic farming.
Organic Farming History and Techniques 289
Table 1 Area under organic farming in % of total agricultural area in important countries
(Bhattacharya and Gehlot 2003)
Country % of cultivated area Country % of cultivated area
Austria 11.30 Australia 2.31
Switzerland 9.70 France 1.40
Italy 7.94 USA 0.23
Denmark 6.51 Japan 0.10
Sweden 6.30 China 0.06
United Kingdom 3.96 India 0.03
Germany 3.70
290 K.K. Behera et al.
The concept of organic farming was started 1,000 years back when ancient farmers
started cultivation near the river belt depending on natural resources only. There is
brief mention of several organic inputs in Indian ancient literature like Rig-Veda,
Ramayana, Mahabharata and Kautilya Arthasashthra etc. In fact, organic agriculture
has its roots in traditional farming practices that evolved in countless villages and
farming communities over the millennium.
Organic Farming History and Techniques 291
the study of Henning et al. (1991) indicate that profitability is the most important
factor in their decision to go for organic farming, while 56% of producers surveyed
by Hall and Mogyorody (2001) cite profitability as a very important factor for
organic agriculture and stated that a shift has occurred in the ideological orientation
of organic farming. Similar conclusions have been drawn in the European and US
in this context (Padel 2001a, b; Rundlof and Smith 2006).
Organic farming practice is known since ages. The ancient Indian manuscripts
also describe the importance of dead and decaying matter in nourishment of life and
soil fertility, respectively. Importance of organic manure and recycling post-harvest
residues has also been dealt in various sections of these literatures. Organic farming
has been recognized worldwide for personal health, safe environment, food security
and fight against global warming. Ideological, philosophical and religious beliefs
have also triggered the use organic farming with a commercial outlook taking care
of environment and quality product.
The development of the organic farming era worldwide had gone through mainly
three stages, Emergence, Development, and Growth in chronological sequence.
The beginning of organic farming could trace back to 1924 in Germany with Rudolf
Steiner’s course on Social Scientific Basis of Agricultural Development, in which
his theory considered the human being as part and parcel of a cosmic equilibrium
that he/she must understand in order to live in harmony with the environment.
Therefore, a balance must be struck between the spiritual and material side of life
(Herrmann and Plakolm 1991). Pfeiffer has applied these theories to agriculture and
gave birth to biodynamic agriculture (Kahnt 1986). It was developed at the end of
the 1920s in Germany, Switzerland, England, Denmark and the Netherlands
(Herrmann and Plakolm 1991; Kahnt 1986; Diercks 1986). In Switzerland in 1930,
politician Hans Mueler gave impetus to organic-biological agriculture. His goals
were at once economic, social and political as they envisioned autarchy of the farmer
and a much more direct and less cluttered connection between the production and
consumption stages (Herrmann and Plakolm 1991; Niggli and Lockeretz 1996).
Maria Mueler applied these theories to orchard production (Niggli and Lockeretz
1996). Austrian doctor, Hans Peter Rush adapted these ideas and incorporated them
in a method founded on maximum utilization of renewable resources (Gliessman
1990). Hans Mueler and Hans Peter Rush laid the theoretical foundation for the
organic-biological agriculture and its development in the Germanic speaking coun-
tries and regions (Niggli and Lockeretz 1996; Rigby et al. 2001). Sir Albert Howard
Organic Farming History and Techniques 293
was the founder of the organic farming movement. His book An Agricultural
Testament summarized his research works of 25 years at Indore in India, where he
developed the famed Indore Composting Process, which put the ancient art of com-
posting on a firm scientific basis and explained the relationship between the health
of the soil, the health of plants and the health of animals (Du and Wang 2001).
Rodale. J. I. began his research and practice on organic farming in the United States
of America. His primary goal was to develop and demonstrate practical methods of
rebuilding natural soil fertility. By 1942, he published the magazine Organic
Gardening (Coleman (1989)). Lady Eve Balfour started the Haughley Experiment
the first study comparing conventional and natural farming methods. Her ideas
inspired the formation of the Soil Association that was founded in 1946 in England.
The Soil Association attempted to return humus and soil fertility to their basic
place in the biological balance. It was founded on the theories propagated by Sir
Albert Howard in his agricultural testament of 1940 (Soil Association 2001).
During 1950–1960s thanks to doctors and consumers whose awareness constantly
grew with regard to food and its effect on health, organic fanning (lemaire-boucher)
began to take hold in France (SOEL 2002). Nature and Progress Association was
founded. Mokichi Okada started natural agriculture in1935 in Japan. His main
thoughts were to respect and emphasize the function of nature and soil in the agri-
cultural production and to coordinate the relationship between human being and
nature through increasing soil humus to get the yields without fertilizer and agri-
cultural chemicals. The environmental and health issues exacerbated in the
1950s–1960s of the last centuries in Japan facilitated the development of natural
agriculture. The essentials of natural agriculture became the important contents of
Japanese agricultural, standard of organic agricultural products (Sheng et al.1995;
Yu and Dai 1995).
The research and practice of organic agriculture expanded worldwide after the
1960s. In particular, the expansion and dual polarity of organic agriculture started
with the oil crisis of 1973 and the growing sensitivity to agro-ecological issues. This
was a time of new ideas, significant sociological transformations, protest move-
ments and the proliferation of alternative life styles. The new thoughts in terms of
using natural resources rationally, protecting the environment, realizing low input
and high efficiency, ensuring food security, returning to the earth and maintaining a
sustainable development of agriculture, such as organic, organic-biological, bio-
dynamic, ecological, and natural agriculture were remarkably developed in their
concepts, research and practical activities (Herrmann and Plakolm 1991; Rigby
et al. 2001; Du and Wang 2001; May 2001; Pacini et al. 2002 ; Conacher and
Conacher 1998).William Albrecht gave a definition of ecological agriculture in
1970, in which the ecological principle was introduced to the production system of
organic agriculture (Coleman 1989). In England the Soil Association created a logo
294 K.K. Behera et al.
and in parallel introduced the notion of legally formulated specifications and quality
controls that gave a legally binding guarantee for the consumers (Yussefi and Willer
2003; Soil Association 2001). The largest non-governmental organization of organic
agriculture in the world-IFOAM (International Federation of Organic Agriculture
Movements) was founded in 1972 (Niggli and Lockeretz 1996). The major organic
agriculture associations and research institutions in the world, such as FNAB
(Federation Nationaled’ Agriculteurs Biologiques), FIBL (For Schungs Institute
Fuer Biologischen Landbau), now the largest organic research institute worldwide,
were founded during 1970s–1980s (FAO 2007; Greene 2001). These organizations
played an important role in standardizing the production and market of organic
products and promoting research and consumer’s awareness. The legislative action
on organic farming started gradually in the different countries and regions as the
guidelines for organic farming. In the United States the regulation on organic farm-
ing was implemented in the state of Oregon in 1974 and in the state of California
in1979, respectively (Greene 2001). The United States Department of Agriculture
(USDA) made an investigation on a large scale on organic farming in the 69 organic
farms of 23 states and published the Report and Recommendations on Organic
Farming, in which the development status and potential remained as issues and the
research directions were analyzed. In this report the definition and guideline for the
organic farming were given, and an action plan for the development of organic
farming was called for. The publication of this report was a milestone in legislation
and development of organic farming in the United States (USDA 1980). In France,
the organic farming regulation was implemented in 1985 (Graf and Willer 2001;
Dai 1999).
The development of organic agriculture initiated the use of natural resources to
protect the environment and to ensure food security with sustainable development
of agriculture. Subsequently many organizations and Associations were created
with legally formulated specifications and quality controls. All these organizations
played a pivotal role and made valiant efforts to investigate large scale organic farming
with precise scientific validation.
The organic farming worldwide entered a new stage of growth in the 1990s. The
trade organizations for organic products were founded, organic farming regulations
were implemented and organic farming movement was promoted by both govern-
mental and nongovernmental organizations. In 1990, the first BioFach Fair – now
the biggest fair for organic products worldwide, emerged in Germany (ITC 1999).
The federal government of the United States published the regulation for organic
food products in 1990 (Greene (2001)). The European Commission adopted EU
regulation 209191 on organic agriculture in 1991. This regulation became a law
in 1993 and was granted in almost all European Union countries since 1994
Organic Farming History and Techniques 295
(IFOAM and FAO 2002). In the North America, Australia and Japan, the major
markets for organic products, published and implemented organic regulations in
succession (Yussefi and Willer 2003; Niggli and Lockeretz 1996). The International
Federation of Organic Agriculture Movements (IFOAM) and the Food and
Agriculture Organization of the United Nations (FAO) set out Guidelines for the
Production, Processing, Labeling and Marketing of Organically Produced Foods in
1999. This guide line is of importance to international harmonization of the organic
farming standards (FAO and WHO 2001). Organic farming had rapidly developed
worldwide during this stage. The main drivers of steady market and production
growth were the commitment of many retail chains as well as favorable policy con-
ditions. Together these had created conditions favoring a harmonious increase in
supply and demand. The state support for organic farming research and legal frame
work was increasingly gaining importance since the end of the 1990s. Organic agri-
culture is holistic production management systems which promotes and enhances
agro-ecosystem health, including biodiversity, biological cycles, and soil biological
activity. It emphasizes the use of management practices in preference to the use of
farm inputs, taking into account that regional conditions require locally adapted
systems. This is accomplished by using, where possible, cultural, biological and
mechanical methods, as opposed to using synthetic materials, to fulfils any specific
function within the system terms, such as Organic, Biological, Biodynamic, and
Ecological are recognized as organic farming in the EU regulations (Yussefi and
Willer 2003; FAO 2002; FAO and WHO 2001). Although organic agriculture is one
among the broad spectrum of methodologies which are based on the specific and
precise standards with different names such as organic, biological, organic-biological,
bio-dynamic, natural and ecological agriculture, there are some common followed
principles in the organic agriculture (Henmann et al. 1991; Kahnt 1986; Niggli and
Lockeretz 1996; IFOAM and FAO 2002; FAO and WHO 2001). These principles
are summarized as follows:
1 . Maintain long-term soil fertility though biological mechanism.
2. Recycle wastes of plant and animal origin in order to return nutrients to the land,
thus minimizing the use of external inputs outside systems, and keep the nutrients
cycle within the system.
3. Prohibit the use of synthetic materials, such as pesticides, mineral fertilizers,
chemical ingredients and additives.
4. Using natural mechanism and rely on renewable resources to protect the natural
resources.
5. Raise animals in restricted areas and guarantee the welfare of the animals.
6. Adapt local environment and diversified organization.
The rapid growth of organic farming at global scale started during the end part of
twentieth century, several trade organizations were founded, regulations were imple-
mented and movements were promoted by both governmental and nongovernmental
organizations. This led to rapid development of organic farming with co-ordinate
and rational approach.
296 K.K. Behera et al.
The farming practice which involves the use of eco-friendly methods to grow crops
and the exclusion of synthetic products, such as chemical fertilizers, insecticides
and pesticides are described as organic farming. It is practiced on 32.2 million
hectares of land over the world (Bhattacharya and Gehlot 2003). The International
Federation of Organic Agriculture Movements (IFOAM) carries out the tasks related
to setting standards and regulation of organic farming activities worldwide. A holistic
approach towards growing crops, organic farming methods helps apply simple and
eco-friendly techniques in farming. Use of compost fertilizers, crop rotation and
biological pest control, are some of the features of organic farming methods. The
farming methods that make use of the various traditional agricultural practices like
minimum tillage, composting, crop rotation, biological pest control, etc., and
exclude the application of synthetic fertilizers, insecticides, growth regulators
and genetic modification of crop species, are included in organic farming methods.
The use of modern technology in combination with organic farming practices helps
in creating a balanced and sustainable environment for crop growth (Anonymous
2000). Organic farming methods take a integrated approach in growing crops rather
than exploiting the available natural resources The use of organic farming methods is
aimed at enhancing the productivity of crops without the use of any kind of synthetic
materials and adopting a sustainable approach towards farming (Luttikholt 2007).
Organic agriculture systems are based on four strongly interrelated principles
under autonomous ecosystems management: mixed farming, crop rotation and
organic cycle optimization. The common understanding of agricultural production
in all types of organic agriculture is managing the production capacity of an
agro-ecosystem. The process of extreme specialization propagated by the green
revolution led to the destruction of mixed and diversified farming and ecological
buffer systems. The function of this autonomous ecosystem management is to
meet the need for food and fibres on the local ecological carrying capacity
(Smukler et al. 2010).
5.1 Cultivation
a variety of crops are cultivated on a single piece of land. It helps attract different
soil microbes. Some crops act as repellents to pest and these results in pest control,
in an organic manner (Walker 1992; Gitay et al. 1996).
In organic agriculture systems, one strives for appropriate diversification, which
ideally means mixed farming, or the integration of crop and livestock production on
the farm. In this way, cyclic processes and interactions in the agro-ecosystem can be
optimized, like using crop residues in animal husbandry and manure for crop pro-
duction. Diversification of species biotypes and land use as a means to optimize the
stability of the agro-ecosystem is another way to indicate the mixed farming
concept. The synergistic concept among plants, animals, soil and bio-sphere support
this idea (James 1998; Albrecht and Mattheis 1998).
5.2 Fertility
Organic farming has expanded rapidly in recent years and is seen as a sustainable
alternative to intensive agricultural systems, developed over the last 50 years
(Stockdale et al. 2001). Nutrient management in organic systems is based on fertility
building leys to fix atmospheric nitrogen (N), combined with recycling of nutrients
via bulky organic materials, such as farmyard manure (FYM) and crop residues, with
only limited inputs of permitted fertilizers (Torstensson 1998; Faerge and Magid
2003). Composts are used to enhance soil fertility in organic farming methods. Green
manuring too, is a nice way to add nutrients to the soil. It is the practice of growing
plants with prolific leaf growth like alfalfa and burying them in the soil before the
cultivation of the main crop. The green manuring crops add organic matter to the soil
that is necessary for plant growth (Berry et al. 2002; Pulleman et al. 2003).
5.3 Crop Rotation
Within the mixed farm setting, crop rotation takes place as the second principle of
organic agriculture. Besides the classical rotation involving one crop per field per
season, inter cropping, mixed cropping and relay cropping are other options to opti-
mize interactions. In addition to plant functions, other important advantages such as
weed suppression, reduction in soil-borne insects and diseases, complimentary
nutrient supply, nutrient catching and soil covering can be mentioned (Wibberley
1996; Berzsenyi et al. 2000).
Atmospheric N 2 Fixation
NUTRIENT SUPPLY
SOILS CROPS
CROP RESIDUES
FOOD
SEWAGE,SLUDGE,
COMPOST etc.
FEED STRAW
MANURES PEOPLE
LIVESTOCK
5.5 Pest Control
• In India, only 30% of total cultivable area is covered with fertilizer, where irriga-
tion facilities are available and in the remaining 70% of arable land, which is
mainly rainfed, negligible amount of fertilizers is being used. Farmers in these
areas often use organic manure as sources of nutrients are readily available either
in their own farm or in their locality.
• The North Eastern Hills of India provides considerable opportunity (18 million
hectare) for organic farming due to least utilization of chemical inputs, which
can be exploited for organic production.
• India is an exporting country and does not import any organic products. The
main market for exported products is the European Union. Recently India has
applied to be included on the “EU-Third-Country-List”, another growing market
is USA.
• There has been plenty of policy emphasis on organic farming and trade in the
recent years in India.
• There are many states and private agencies involved in promotion of organic
farming in India. These include-various ministries and department of the govern-
ment at the central and state levels such as;
• Universities and Research centres
• Non Govt. organizations (NGO)
• Eco farms
• Certification bodies like INDOCERT, ECOCERT, SKAL and APOF etc.
The central and state governments have also identified Agri-Export Zone for
agricultural exports in general and organic products in some states:
• In Uttar Pradesh and Uttaranchal the Diversified Agriculture Support Project
(DASP) is promoted for organic farming.
• In Bangalore (Karnataka) and Nilgiris (Tamil Nadu); with 50 outlets in south
India helps for supply the organic products from small growers.
300 K.K. Behera et al.
Since one of the key aspects of organic farming is to forsake the use of synthetic
chemical fertilizers, pesticides, and feed additives, in contrast to other agricultural
production approaches, organic farming is conducive to protection of surface and
underground water from these pollutants. Organic farming benefits the environment
through protection of wildlife habitats, conservation of landscapes, and reduction of
environmental pollution. It is well documented that organic agriculture contributes
to long-term conservation of soil, water, air and protection of wild life, their habi-
tats, and their genetic diversity (Redman 1992; Van Mansvelt and Mulder 1993;
Lampkin 1997). Reganold et al. (2001) assessed the environmental impact of organic
and conventional apple production systems by using a rating index employed by
scientists and growers to determine the potential adverse impact of pesticides and
fruit thinners (Reed 1995). The results show that the total environmental impact
rating of the conventional system was 6.2 times that of the organic system. Organic
farming also aims to maintain and improve soil fertility over the long run. It may be
expected to produce a satisfactory and high quality crop with minimal use of
resources. An organic farming system requires the use of catch crops, the recycling
of crop residues, and the use of animal manure and the use of organic rather than
artificial fertilizer. All these measures are assumed to promote accumulation of
organic matter in the soil (Hansen et al. 2001). Organic farming prohibits the use of
pesticides and artificial fertilizers and encourages sympathetic habitat management,
such as nitrogen-building leys to increase soil fertility (Lampkin 1990). Organic
matter has profound impacts on soil quality, such as enhancing soil structure and
fertility and increasing water infiltration and storage. If the soil organic matter con-
tent drops below3.5%, the soil suffers an increased risk of erosion (Brady and Weil
1999; Redman 1992). Stolze et al. (2000) concluded that organic farming performs
better than conventional farming with regard to soil organic matter. A major objec-
tive of organic farming is to encourage a higher level of biological activity in the
soil, in order to sustain its quality and thereby promote metabolic interactions
between the soil and plants. Axelsen and Elmholt (1998) estimated that a transition
to 100% organic farming in Denmark would increase microbial biomass by 77%,
the population of springtails by 37%, and the density of earthworms by 154% as a
nationwide average. Conversion to organic farming provides opportunities to sig-
nificantly increase biological activity of the soil. Microbial biomass in soil was
higher in organic farming systems receiving higher amounts of organic inputs
(Gunapala and Scow 1998; Bossio and Scow 1998; Lundquist et al. 1999). In a
long-term field trial in northwestern Switzerland, the effects of organic and conven-
tional land use managements on earthworm populations and on soil erodibility were
investigated. The study result shows that earthworm biomass and density, as well as
the population diversity were significantly greater in the organic plots than in the
conventional plots. Likewise, the aggregate stability of the organic plots, when
determined by means of percolation, was significantly better. Therefore, erosion
susceptibility is greater on plots farmed conventionally (Siegrist et al. 1998).
302 K.K. Behera et al.
Organic farming is a concept for following the rule of nature. It is also operates
on the natural principles of sustainability. Soil is one of the most important natural
resources, which needs proper management for organic production requirement.
For doing so, one should rely on organic techniques like crop rotation, using natural
manures and green manures, no addition of synthetic substances, proper manage-
ment of air and water, providing drainage, following integrated pest control, using
biological methods of disease and pest control. Using traps, use of predators,
increasing the population of beneficial plants and animals, addition of organic mate-
rial in the soil, using legume, use of bio fertilizers, modifying cropping systems, use
of cover crops, catch crops and establish proper soil-crop-animal-human being system.
Such a system should follow an integrated system approach so as to make the entire
production system biologically active, ecologically sound and economically viable.
In short locally available natural material should be used to increase soil productivity
by improving soil environment.
Organic farming is considered a promising solution for reducing environmental
burdens related to intensive agricultural management practices. Organic agriculture
combines tradition, innovation and science to benefit the shared environment and
promote fair relationships and a good quality of life for all involved. The main
strengths lie in better resource conservation, since the farm relies mainly on internal
resources and limits the input of external auxiliary materials. This results in less
fossil and mineral resources being consumed. A further important effect is the very
restrictive use of pesticides, leading to markedly lower eco-toxicity potentials on the
one hand and higher biodiversity potentials on the other.
7.1 Quality Product
In the consumer’s mind, organic produce must be better and healthier than that pro-
duced under conventional farming system. This image is also the main motive for
consumers who are willing to pay premium prices for purchasing organic food.
Organic agriculture can be viewed as an attempt to overcome at the individual, as
much as the collective, level the “risky freedoms,” such as contamination of food
supplies with pesticides, pollution, and radioactive fallout etc., associated with pro-
cessed food and a chemically based agriculture (Lockie et al. 2000). From a scien-
tific point of view, however, it is difficult to provide or substantiate the supposed
health benefits, since food quality is composed of various partial aspects and with-
out uniform evaluation standards. Crop quality is put forward as an important argu-
ment for organic farming (Adam 2001; Koepf et al. 1976). Several investigations
have clearly shown that the type of fertilizations, contrary to the principle of organic
farming, does not affect plant quality (Hansen 1981; Evers 1989a, b, c). Crop quality
is not dependent on the principle difference between inorganic fertilization and
organic manuring. Side-effects caused by synthetic pesticides and drug feeding are
not found in organic farming, which is a positive result. The use of herbicides has
Organic Farming History and Techniques 303
7.2 Appearance
Normally, product appearance refers to size, shape, color, and taste, etc. Organically
produced food sometimes fails to match the perfection achieved through conven-
tional farming, especially for fruit and vegetables. It is widely believed that
organically produced food tastes better than conventional, but conclusive scien-
tific evidence to prove that this is the case is hard to come by. Lindner (1985)
using a panel of 30–50 consumers who were deliberately not informed about the
basis of the comparison, found that vegetables produced organically under care-
fully controlled experimental conditions did taste better. However, in the same
study, a panel of trained tasters found no significant differences (Lindner 1985).
Duden (1987) has also found taste differences in favor of organically produced
tomatoes and potatoes respectively. It is also demonstrated that in all aspects of
fruit quality, the organic fruit was at least equal to fruit produced in the conven-
tional farming system, and was higher in some important variables (taste, firm-
ness, dietary fiber, phenolic compounds, vitality index) (Weibel et al. 1998;
Reganold et al. 2001).
304 K.K. Behera et al.
7.3 Nutritional Value
Zwankhuizen et al. 1998; Eltun 1996). All the above quality characteristics can be
measured quantitatively thus providing a basis for comparison. But subjective values
will also play a major role in the consumer’s perception of quality. The main reason
of consumer’s increasing recognition of and interests in organic food is due to con-
sumer’s identification that comparing with conventional farming approaches, organic
plays a significant role in environmental protection and farming sustainability.
8.1 Soil Fertility
Organic farming also aims to maintain and improve soil fertility over the long run.
It may be expected to produce a satisfactory and high quality crop with minimal use
of resources. An organic farming system requires the use of catch crops, the recy-
cling of crop residues, the use of animal manure, and the use of organic rather than
artificial fertilizer. All these measures are assumed to promote accumulation of
306 K.K. Behera et al.
organic matter in the soil (Hansen et al. 2001). Organic farming prohibits the use of
pesticides and artificial fertilizers and encourages sympathetic habitat management,
such as nitrogen building leys to increase soil fertility (Lampkin 1990). Organic
matter has profound impacts on soil quality, such as enhancing soil structure and
fertility and increasing water infiltration and storage. If the soil organic matter con-
tent drops below 3.5%, the soil suffers an increased risk of erosion (Brady and Weil
1999; Redman 1992). Stolze et al. (2000) concluded that organic farming performs
better than conventional farming with regard to soil organic matter. A major objec-
tive of organic farming is to encourage a higher level of biological activity in the
soil, in order to sustain its quality and thereby promote metabolic interactions
between the soil and plants. Axelsen and Elmholt (1998) estimated that a transition
to 100% organic farming in Denmark would increase microbial biomass by 77%,
the population of springtails by 37%, and the density of earthworms by 154% as a
nation wide average. Conversion to organic farming provides opportunities to sig-
nificantly increase biological activity of the soil. Microbial biomass in soil was
higher in organic farming systems receiving higher amounts of organic inputs
(Gunapala and Scow 1998; Bossio and Scow 1998; Lundquist et al. 1999).
In a long-term field trial in northwestern Switzerland, the effects of organic and
conventional land use managements on earthworm populations and on soil erodibil-
ity were investigated. The study result shows that earthworm biomass and density, as
well as the population diversity, were significantly greater in the organic plots than in
the conventional plots. Likewise, the aggregate stability of the organic plots, when
determined by means of percolation, was significantly better. Therefore, erosion sus-
ceptibility is greater on plots farmed conventionally (Siegrist et al. 1998).
8.2 Nutrient Management
Nutrient elements, essential to crop growing, include N, P, K, Ca, Mg, and some
trace elements. Among them, nitrogen is of great importance in organic plant grow-
ing because of its influence on plant yields. The N-cycling of an organic farm should
be based mainly on a site-specific and market-oriented crop rotation including green
manure planting and on an optimized manure handling and application system.
Nutrient cycling is relatively efficient in organic farming system (Cobb et al. 1999).
Long term rotation trials on sandy loam confirm the outstanding importance of legu-
minous fodder crops in terms of humus accumulation (26 t/ha after five courses of
a 5-year crop rotation) and continuous yield security of succeeding crops. A biennial
alfalfa crop could accumulate 1,000 kg N per ha, of which 600 kg was used as animal
fodder, 320 kg bound in the roots, and 80 kg calculated as loss due to volatilization
and de-nitrification. A substantial amount of the residual N could be determined as
additional N2 sources for the succeeding crops (Rauhe et al. 1987). Hodtke et al.
(1998) reported that if maize was inter cropped with either cowpea or jack bean in
an organic farming system, N-content in the leaves of the maize was significantly
increased and grain yield of the maize was markedly improved too.
Organic Farming History and Techniques 307
Organic farming has developed from a wide number of disparate movements across
the world into a more uniform group of farming systems, which operate broadly
within the principals of the International Federation of Organic Agriculture
Movements (Stockdale et al. 2001). Though the exact production methods vary con-
siderably, general principals include the exclusion of most synthetic biocides and
fertilizers, the management of soils through addition of organic materials and use of
crop rotation (IFOAM 1998). The exclusion of soluble mineral fertilizers and the
very limited use of biocides in organic agriculture mean that it is reliant largely on
biological processes for supply of nutrients, including the reliance on N2 fixation as
the main source of N2 to crops, and for protection of crops from pests and disease.
Indeed, it is one of the central paradigms of organic agriculture that an active soil
microbial community is vital for functioning of the agro ecosystem (Lampkin 1990).
Within this paradigm, AMF (Arbuscualr Mycorrhizal Fungi) are usually considered
to play an important role and it is assumed that they can compensate for the reduced
use of P fertilizers (Galvez et al. 2001).
Many authors report higher levels of AMF colonization, higher propagules num-
bers or higher diversity in organic farming. However, the actual importance of AMF
to the functioning of organic agro ecosystems and in particular to crop performance
remains to be determined. Some evidence indicates that AMF are indeed capable of
compensating for lower inputs of P fertilizer in organic systems. Kahiluoto and
Vestberg (1998) found that AMF in an organically managed soil were as effective at
increasing crop available P as super phosphate was on a conventional soil. However,
this does not always translate into higher yields even when phosphorus use effi-
ciency is higher (Ryan et al. 1994; Galvez et al. 2001). Prolific AMF colonization in
organic systems may even be associated with reduced yield in some cases because
of the carbon drain by the AMF (Dann et al. 1996). Other authors have found AMF
to be no more effective, and in some cases less effective than rock phosphate at
increasing crop growth on organically managed soils (Scullion et al. 1998). Dann
et al. (1996) showed that even where there was good, AMF colonization on an
organically managed soil, crops responded positively to super phosphate fertilizer
in a similar way to crops on conventional soil, suggesting that AMF do not provide
a unique method of accessing Phosphorous to the host plant, a conclusion also
reached by Ryan and Ash (1999).
Determining the reason for the apparently poor performance of AMF in some
organic systems is difficult because organic systems vary considerably in the detail
of their management practices and the practices used prior to conversion. As a
result, there are likely to be different reasons for poor performance of AMF in
different systems. Long-term conventional, high input management reduces AMF
diversity and may favour inefficient AMF (Helgason et al. 1998; Daniell et al. 2001;
Johnson et al. 1992; Johnson 1993).
Thus, at conversion the AMF population may be reduced to a small number of
species tolerant of intensive farming practices. Building up species diversity will be
important to ensuring the development of an effective AMF community. However,
308 K.K. Behera et al.
there are no available data to indicate the mechanisms involved in the re-colonization
of agricultural land, the time required, or the most effective management options to
accelerate the process. Some data have indicated that organic systems may fail to
develop an effective AMF community even after several years (Scullion et al. 1998).
This may be the result of management practices unfavorable to AMF. For instance,
soil P concentrations may remain too high if the P fertilizers permitted in organic
production are used frequently (Dekkers and Vander Werff 2001; Scullion et al.
1998). Excessive tillage to control weeds and frequent cultivation of non-mycorrhizal
crops could also hamper development of a diverse AM community. Unfavorable
soil moisture and temperature, and plant disease, can also suppress the AM associa-
tion and consequently community development. Another reason for the failure of
some organic systems to develop an effective AMF community may be the limited
availability of AMF propagules of new species. Re colonization is likely to occur
from adjacent natural and semi-natural habitats such as hedges, woodland and
unmanaged grassland. The vectors of propagules may include animals, growing
roots, agricultural machinery and soil eroded by wind and water (Ryan and Graham
2002; Warner et al. 1987). While root growth and movement by animals is likely to
be slow and involve small numbers of propagules, tillage operations can move soil
and propagules more than a meter in a single operation, depending on the machin-
ery in question and the slope (Rew et al. 1996; Tsara et al. 2001; van Muysen and
Govers 2002; Quine et al. 2003). Single water erosion events can move soil several
hundred meters while wind can disperse spores very large distances as can farm
machinery. Evidence from re-colonization of abandoned agricultural land suggests
large numbers of AMF species can establish after only 2 years (Warner et al. 1987;
Morschel et al. 2004; Hedlund 2002; Hedlund and Gormsen 2002).
However, the early stages of re-colonization of soils are characterized by signifi-
cant heterogeneity including areas with potentially very low infectivity. This is likely
to be especially true of large fields where distance from the source of propagules may
be large, or in intensively managed landscapes, where semi-natural habitats may be
few in number. Another factor that may help explain the poor performance of AMF
in some organic systems is the suggestion that modern crop cultivars are not respon-
sive to AMF and therefore receive little benefit from the AM association, even though
colonization with effective AMF may be high (Boerner et al. 1996; Manske 1990;
Hetrick et al. 1996; Aguilera-Gomez et al. 1998). However, a wide degree of varia-
tion in AMF dependency in both modern and old cultivars has been demonstrated.
Stoppler et al. (1990), Hetrick et al. (1993, 1996) suggesting that this is not the only
factor. The apparent lack of benefit for the host crop may even be simply a result of
the host crop receiving benefits other than those being measured.
Global food production increased by 70% from 1970 to 1995, largely due to the
application of modern technologies in developing countries, where food production
increased by 90%. However, global food production must grow to the same extent
Organic Farming History and Techniques 309
in the coming three decades, as pointed out above, to meet human demand (Bruinsma
2003; Cassman et al. 2003; Eickhout et al. 2006). Two principal possibilities for
achieving this increase have been identified: intensifying agricultural production on
existing cropland or ploughing up natural land into cropland, i.e. clearing pastures
and rangelands, cutting forests and woodland areas, etc. Some experts have a posi-
tive view that food production can be greatly increased if high-yielding production
is widely applied and the expansion of arable land in the world is expected to only
slightly increase from 1,400 Mha in 2006 to 1,600 Mha in 2030 (Bruinsma 2003;
FAO 2007; Bouwman et al. 2005). In 2025, the world’s farmers will be expected to
produce an average world cereal yield of about 4 metric tons per hectare if condi-
tions are optimized. There are recent claims that sufficient food can be produced by
organic agriculture, expressed in terms such as ‘organic agriculture can feed the
world (Dyson 1999; Woodward 1995; Vasilikiotis 2000; Leu 2004; Tudge 2005;
Badgley and Perfecto 2007). The following three arguments have been put forward:
(i) Lower production of most crops can be compensated for by increased production
of legumes, in particular of grain legumes, while a change to a diet based mainly
on vegetables and legumes will provide enough food for all (Woodward 1995).
(ii) Realities in developing countries must be taken into account: Increased food
supply does not automatically mean increased food security for all. Poor and
hungry people need low-cost and readily available technologies and practices to
increase food production (Pretty et al. 2003). (iii) Organic agriculture can get the
food to the people who need it and is therefore the quickest, most efficient, most
cost-effective and fairest way to feed the world (Leu 2004). These arguments
confuse the original scientific question with other realities interacting with food
sufficiency, such as change in dietary composition, poverty, finance, markets, dis-
tribution system, etc. However, the basic scientific question remains and requires a
stringent review and evaluation of the production potential of organic and conven-
tional systems. A fundamental question is whether organic yields can be increased
radically or whether more natural ecosystems have to be converted into cropland.
The following four observations indicate that intensification rather than area expan-
sion is necessary:
(1) Agricultural land is steadily decreasing as it is being taken over for urban or
industrial use (Blum et al. 2004), (2) global warming may reduce the potential for
higher yields in large parts of the world (Parry et al. 2005), (3) significant areas of
farmland may be used for fuel production, competing with food production
(Nonhebel 2005) and (4) cropland simply cannot be expanded, due to shortage of
suitable land. On the other hand, current yield increases appear to be falling below
the projected rate of increase in demand for cereals challenging scientists to do their
best to increase crop productivity per unit area (Cassman et al. 2002; Evans 1998).
Food production is coupled to a moral imperative, as sufficient food supply is a
cornerstone of human welfare. Development of agricultural practices ensuring food
sufficiency is a basic human requirement, a prerequisite for satisfactory social
conditions and a necessity for civilizations to flourish. Lack of food, on the other
hand, is a tragedy leading not only to suffering and loss of life but also to inhuman
behavior, political instability and war (Borlaug 1970). In fact, eradication of
famine and malnutrition has been identified as the most important task on Earth
310 K.K. Behera et al.
(UN Millennium Project 2005). Thus, when discussing different forms of crop
production, it is of the utmost importance to examine without prejudice the forms of
agriculture that can contribute to food sufficiency and security, at present and in the
future. Separation of facts and wishful thinking is absolutely necessary and only an
unbiased review of the scientific literature can provide objective answers to the
questions put forward below. A strong belief and enthusiasm for certain solutions
cannot be allowed to hamper the search for objectivity. The overall aim of this chapter
was to examine a morally important aspect of organic agriculture. This was achieved
by examining the following questions:
1. Can sufficient crop production be obtained through conversion to and/or intro-
duction of organic production?
2. Can future food demand be covered by organic agriculture?
3. Is it possible to significantly increase organic yields in the future
A review by Badgley et al. (2007) points out that organic agriculture is misjudged
concerning crop production and its potential to supply sufficient food. According
to their review, only small yield reductions occur through organic agriculture in
developed countries, but organic yields are higher than conventional yields in
developing countries. This conclusion is supported by a large number of other
papers, which may be taken as evidence of its scientific reliability. We re-examined
the papers cited by Badgley et al. (2007) to determine whether their conclusions
are based on valid assessments. However, due to their limited accessibility and
often lower scientific credibility, non-peer-reviewed conference papers, institu-
tion reports and magazine articles were not considered. The reexamination of
papers reporting high organic yields showed that the data were used in a biased
way, rendering the conclusions flawed. Firstly, none of the organic studies cited
reported higher crop output from organic production than from conventional over
a whole rotation, but only for single years. Secondly, when yields were higher
during a single year in organic production, this was coupled to one or both of the
following conditions: (1) The amount of nutrients applied to the organic system
through manure and compost was equal to or even higher than that applied to the
conventional system through inorganic fertilizers, (2) non-food crops (legumes)
were grown and incorporated in the preceding year to provide the soil with N.
Thirdly, on-farm data were compared with mean yield data within a region. Such
comparisons have no validity, since the possible factors behind the differences
are not given.
In summary, the yield data reported were misinterpreted and any calculations
based on these data are likely to be erroneous. The paper by Badgley et al. (2007)
also presents comprehensive yield figures from developing countries. However, of
the 137 yield figures reported, 69 originate from the same paper (Pretty and Hine
Organic Farming History and Techniques 311
2001). A closer inspection revealed that crop yields were based on surveys and
there was no possibility to check crop performance variables and the science behind
the data. In fact, only six papers for developing countries cited by Badgley et al.
(2007) were derived from peer-reviewed journals. In four papers, rice yields in con-
ventional systems were compared with so-called intensified rice production.
However, intensified rice production uses mineral fertilizers, although at lower
rates, and is not an organic form of agriculture by European standards (Sheehy et al.
2004; Latif et al. 2005).
Our conclusion is therefore that the argument that organic agriculture can
produce similar or even higher yields than conventional does not hold given the
boundary conditions outlined above.
Yield trends over time were analyzed in four Swedish comparative studies to deter-
mine the potential to increase production through organic and conventional man-
agement. The underlying question is whether yields are following the same trends
in organic agriculture as in conventional. In the study by Kirchmann et al. (2007),
the initial 10-year period was characterized by a relatively constant yield differ-
ence between the organic and conventional system. Thereafter, yields increased in
both systems but the increase was larger in the conventional system than in the
organic, despite higher additions of animal manure to the organic system. In two
other studies without animal manure which used green manure for organic produc-
tion and fertilizer for conventional, the relative yield differences between systems
were much larger (Torstensson et al. 2006; Aronsson et al. 2007). Furthermore, no
yield increase was observed in the organic system over the 5–6-year experimental
period, where as conventional yields increased in one experiment and remained
constant in the other. In studies without animal manure, there is good reason to
assume that organic yields barely increase over the longer term, as residual soil
nutrients are depleted at faster rates than in studies with manure application. For
instance, in relatively fertile soils, a decade or more may be needed before residual
soil nutrients are sufficiently exhausted for a yield reduction to become apparent
(Denison et al. 2004). In another experiment run for 12 years at a fertile site, each
crop in the rotation was grown every year and animal manure was applied in rela-
tion to the level of nutrient removal by harvested crops (Ivarson and Gunnarsson
2001). Differences between organic and conventional yields were smaller at this
site, in particular for forage crops. However, there were no indications that organic
yields would increase more or decrease less over time than conventional yields.
Based on the four experiments presented above, we conclude that there is no
evidence that yields increase more in organic agriculture than in conventional.
However, there is evidence that conventional agriculture has a greater capacity for
increased yields than organic agriculture.
312 K.K. Behera et al.
In summary, this review shows that the reduction in crop yields through large-scale
conversion to organic agriculture would, on average, amount to 40%, with a range
of variation of 25–50%. A 40% reduction in yield on a global scale is equivalent to
the amount of crops required by 2.5 billion people. This estimate is in fact identical
to that calculated by Smil (2001), who assessed the role of industrial nitrogen
fixation for global food supply. Smil (2001, 2002) concluded that the Haber-Bosch
process for industrial fixation of atmospheric nitrogen provides the very means of
survival for 40% of humanity and that only half of the current world population
could be supported by pre-fertilizer farming, even with a mainly vegetarian diet.
The similarity of these estimates confirms the strategic role of fertilizers as a
keystone for the well-being and development of mankind. It is obvious that world-
wide adoption of organic agriculture would lead to massive famine and human
death. This is something that advocates of organic agriculture are silent about,
perhaps because of the severe moral dilemma it poses.
13 Restoration of Biodiversity
Compared to conventional farms, 2–3 times more individual birds; greater numbers
of earthworms and biomass; more individuals species of spiders; more non-pest
species of butterflies were found on organic farms (Braae et al. 1988; Whalen et al.
1998; Feber et al. 1997, 1998; Krebs et al. 1999; Chamberlain et al. 1999). Mander
et al. (1999) showed that organic agriculture had a large positive impact on biological
and landscape diversity. The diversity (population or species or individuals) of
vascular plants, different invertebrate groups and birds was 0.5–20 times higher on
organic than on conventional farms. Cobb et al. (1999) captured significantly more
butterflies and spiders, in terms of both individuals and species, from the organic
than the conventional fields. It was also found that in contrast to the conventional
management system, the populations of endangered species in organic fields were
considerably higher (Albrecht and Mattheis 1998). Through crop rotations in
organic farming encourages diversity at the landscape scale. Such retention of a
diversity of habitats renders obvious benefits on local wildlife populations (Edwards
and Howells 2001). On the other hand, sometimes conversion shows only small
benefits to species diversity because of a long history of mechanical weeding and
the use of herbicides before conversion (Albrecht and Mattheis 1998). Kleijn et al.
(2001) found no positive effects on plant and bird species diversity infields where
farmers were paid to delay mowing or grazing, and to reduce the amount of fertil-
izer they used. The four most common wader species were observed even less fre-
quently on those fields. By contrast, hoverflies and bees showed modest increases in
species richness. Birds actually seemed to prefer intensively farmed fields possibly
because reduction in fertilizer use led to smaller invertebrate populations and so less
food for birds. Further more, it is also often over looked that some conventional
mixed farming can maintain species diversity. For example, conventional mixed
farming in smaller plots (providing more field margins) or farming based on the
traditionally system (for example under sowing wheat with legumes) maintains con-
ventional yields and low costs. The benefits for wildlife equal those provided by
organic farming but at a far lower cost to the consumer (HLSCEC (1999)). However,
it can be argued that agriculture has, to a certain extent, responsibility for all species
and communities which co-evolved with farming over 10,000 years irrespective
their utility (Wood and Lenné 1999).
More recently, researchers have focused their attention to evaluate the efficacy of
organic farming in the rural economy and specifically, the potential for organic
farming to contribute to rural development (Darnhofer 2005; Marsden et al. 2002;
Pugliese 2001). In this context it is frequently argued that organic farming can
promote much employment in rural areas and thus contribute to rural development
by reducing the wide gap between rich and poor (Morison et al. 2005; Smith and
Marsden 2004; Midmore and Dirks 2003; Hird 1997). Despite these claims, it has
been also argued that research on the wider “social impacts of organic farming is
314 K.K. Behera et al.
very limited” (Morris et al. 2001). Significantly, Smith and Marsden (2004) have
argued that considering organic farming as a panacea for the problems of “rural
economic development has to be seriously qualified by examining particular types
of overall supply chain dynamics which are operating in particular types of organic
sectors indifferent local, regional and national settings”. In parallel with the growth
of, and interest in, the organic sector, ‘local food’ has also taken on increased eco-
nomic, environmental and symbolic importance. Much of this is concerned with
reducing environmental costs, particularly food miles, but also a desire to increase
local economic multipliers and contribute to the reconnection linkage of farmers
and consumers (Cranbrook 2006; Ilbery and Maye 2005; Pretty et al. 2005). It has
also been suggested that patterns of increased local food purchases, rather than
revealing a strong turn to quality and locally produced organic food, actually points
to a politics of “defensive localism” (Winter 2003). Although organic produce is not
necessarily ‘local’ (even locally supplied organic boxes may not contain exclusively
locally produced food), and local produce does not equate with organic, there is
never the less a perceived close alliance between local food and organic food move-
ments. For instance, although the majority of organic sales via supermarkets, sales
through direct routes, such as local box schemes, rose by 53% between 2005 and
2006 (Soil Association 2007). Combining a greater degree of localness in food
sourcing with increased organic production would lead to considerable savings
associated with the reduction of environmental externalities (Pretty et al. 2005).
Where as the economic and social benefits of reducing negative externalities and
increasing positive externalities have long been recognized, the renewed research
focus on the ‘local economy’ and interactions, clusters and networks within it may
point to a role for organic farming and local food in developing and sustaining local
economies(Winter and Rushbrook 2003). Certainly writers such as Van der Ploeg
and Renting (2000) have suggested that the operators of farm businesses have par-
ticular advantages to bring to the process of rural development, while Renting et al.
(2003a; b) have demonstrated aggregate benefits in terms of additional net value
added stemming from a number of “short food supply chains” (including organics
and direct sales) and Smithers et al. (2008) pointed to the benefits of retaining a
greater proportion of farming and food expenditure within the local economy.
Similarly, in discussing the multiple rationales associated with the promotion of
locally sourced organically produced food. Seyfang (2006) argues that such food
supply chains can, amongst other things, favour new socially embedded economies
of place and make a significant contribution to rural development by giving farmers
greater control of their market and retaining a greater proportion of food spend in
the local economy. The assumed localized nature of organic food and associated
social and economic benefits are not uncontested. For instance, Clarke et al. (2008)
have recently commented on the “supposedly localized nature of organic food” and
called for more critical and reflexive accounts of what it is organic food networks
can do for us. Against the background of claims concerning the rural development
potential of farmers generally and organic farming in particular, Building on a meth-
odology developed by Harrison (1993) and modified by Errington and Courtney
(2000) emphasized the socio-economic linkages associated with different types of
farming and also evidence of social embedded ness of the principal farmer.
Organic Farming History and Techniques 315
For most purposes the term ‘rural economy’ is a shorthand way of considering a
range of ‘economies’ rather than discussing a discrete, unified and homogenous
economy (Winter and Rushbrook 2003). These various economies may share similar
characteristics but may also be quite different in terms of economic linkages with
the wider economy and reliance on different sectors, for instance. The shift in rural
policy towards more of a territorial focus and the growing policy emphasis on
regional and local sustainable economic development is associated with the devel-
opment of research addressing interactions within ‘local’ economies. For example,
writers such as Courtney et al. (2007), Courtney and Errington (2000) have consid-
ered economic linkages between businesses and localities. Analysis of purchase and
sales links provides a method of exploring the extent to which farms (or indeed, any
business) of different types are connected to local economies. There are a number
of ways of approaching the concept of economic connectivity. Earlier studies of
economic linkages (focused on the proportions of sales and purchases by businesses
within certain localities (Curran and Blackburn 1994) whereas Harrison (1993)
extended the approach to include the monetary values of sales and purchases.
Clearly, the local economic impact of a farm, whether it is organic or not goes
beyond the employment issues (Bateman et al. 1993).
There are several challenges that must be overcome to achieve sustainable agricul-
ture in Asia. First, Asian countries must impose restrictions on environmentally
damaging activities, review the ways they go about development, and create ways to
support the development and deployment of eco-friendly technologies. For exam-
ple, pesticide damage must be addressed by quickly teaching farmers how to prop-
erly use the chemicals, by carrying out comprehensive registration and management,
and by banning or regulating hazardous pesticides. To address the problem of
unsuitable irrigation schemes, it is imperative that small-scale environmentally
compatible projects be implemented in place of standardized large-scale projects
that ignore local environmental conditions. Promoting the development of IPM and
other agro ecological technologies is also essential (Marsden et al. 2000; Potter and
Burney 2002). Prerequisites for these initiatives are support for the transition to eco-
friendly farming, and the reevaluation of public research agencies, which should
take the lead in developing basic technologies because these are not considered
important in commercial development by businesses (UNDP 2003; Holzschuh et al.
2007). Second is enhanced monitoring of agribusiness, which is the primary entity
behind the internationalization of agro-food issues, and international growth man-
agement for agriculture- and food-related trade and investment of export-oriented
agriculture, and the internationalization of trade and investment have expanded rap-
idly, but the flip side is trans border environmental damage. As in the conventions
316 K.K. Behera et al.
on prior informed consent and persistent organic pollutants and the resource
management project for shrimp farming (Wood et al. 2006; Hole et al. 2005). There
is a growing necessity to create an Asian system—with the same level of regulatory
measures as those in other parts of the world, that can formulate business codes of
conduct and environmental conventions in order to internationally control the cha-
otic development of agribusiness, and that can use capital investment returns to
benefit local environmental conservation. An international framework like this and
action based on it would make it possible to steer the growth of trade and investment
in a sustainable direction. Asian governments must also reevaluate their agricultural
policy in connection with food imports. Some countries have become dependent on
imports for basic foods because of their policy emphasis on industrialization or
production for export, but since the Asian economic crisis some Southeast Asian
countries have a renewed awareness about the importance of food security. Under
the WTO system, domestic policies cannot be adequately implemented due to limi-
tations imposed from above on protecting domestic agriculture, but the sustainable
development of agriculture and food production is indispensable to attain food
sovereignty (Pretty et al. 2005; Pugliese 2001). Third is bringing together the actors
who will achieve sustainable agriculture and food production. Fixing the current
agro-food system, which is the cause of environmental damage and food uncer-
tainty, requires that governments switch to eco-friendly policies that protect agricul-
ture, receive the support of international agencies, and regulate and monitor
agribusiness. But such policies will become reality only through collaboration
among NGOs, farmers’ organizations, labor unions, cooperatives, and other entities
as they raise questions and exercise their influence toward creating that policy.
Consumers have to rethink their lifestyles and how excessive food consumption and
imports affect the environment. Producers must take advantage of both modern
environmental science and traditional local knowledge while working toward eco-
friendly farming and local resource management. It would be the first step toward
achieving the development of sustainable agriculture in which both farmers and
consumers take the initiative in cooperating globally and locally (Allan and Kovach
2000; Courtney et al. 2006; Lamine and Bellon 2009).
4. Farming the organic way enables farmers to get rid of irksome weeds without the
use of any mechanical and chemical applications. Practices such as hand-weeding
and soil enhancement with mulch, corn gluten meal, garlic and clove oil, table
salt and borax not only get rid of weeds and insects, but also guarantee crop
quality.
5. The use of green pesticides such as neem, compost tea and spinosad is environ-
mentally friendly and non-toxic. These pesticides help in identifying and
removing diseased and dying plants in time and subsequently, increasing crop
defense systems.
16 Conclusion
This chapter has focused on agricultural sustainability, and its relationship to vari-
ous alternative agricultural approaches. It has, quite deliberately, not offered any
new definitions of sustainability or sustainable agriculture. Sustainable practices
will vary both temporally and spatially and can only truly be identified in retrospect.
It is not simply a question of tools and inputs, but the context in which they are used.
Farming meant many different things to many different people: “its lack of specific
definition allowed many of us to associate it with certain important characteristics of
scale, locality, control, knowledge, nutrition, social justice, participation, grower/eater
318 K.K. Behera et al.
relationships and the connections with schools and communities”. Duesing goes on
to contrast this with the current situation. He argues that these desirable food system
characteristics seem threatened as the definition of organic farming and food is nar-
rowed to a set of standards which deal with growing and processing methods. The
exclusively organic standards become established in an increasing number of coun-
tries, and these standards become more co-ordinate and integrated, the degree to
which the organic producer and organic consumer may be geographically separated
grows. Furthermore, the trade in organic farm inputs may also grow, with organic
producers having the option of buying in mulch or organic fertilizers from distant
sources. There may be doubts regarding the sustainability of the systems which
have generated these purchased inputs. In addition, organic producers may be skep-
tical of such developments because they farm in this way to escape from many
aspects of the global trade in food stuffs, and aim to produce for local markets
because of concern regarding the energy deficiency implications of such a trade in
organic products. Producers, traders, and consumers of organic food regularly use
the concept of the natural naturalness to characterize organic agriculture and or
organic food, in contrast to the unnaturalness of conventional agriculture. Critics
sometimes argue that such use lacks any rational of scientific basis and only refers
to sentiment. The organic agriculture movement had its roots in a philosophy of life
and not in the agricultural science (Kirchmann, 1994). A common belief within the
organic movement is that natural products are good, whereas man-made chemicals
are bad or at least not as good as natural ones. This idea may also be used to explain
why organic farming avoids the use of synthetic fertilizers and pesticides etc. In any
case, one fundamental reason for increasing interests in organic agriculture is due to
the requirements and attention of health, environmental protection, and food safety.
This paper shows that organic agriculture has obvious environmental benefits. The
basic standards of organic farming provide suitable tools to minimize environmen-
tal pollution and nutrient losses on the farm level However, there is a high variability
within organic farms in relation to their efforts and their nutrient efficiency.
Concerning soil fertility and nutrient management, comparative studies show that
organic farming is suited to improve soil fertility and nutrient management mark-
edly on the farm level. With reference to biodiversity, organic agriculture is commit-
ted to conservation of biodiversity within agricultural systems. Research projects
have accumulated evidence that organic systems are beneficial to biodiversity. In
relation to product quality, there is no sufficient evidence for a system-related effect
on product quality due to the production method. Product quality is primarily a
function of farm management, showing a high variability in both organic and con-
ventional production. Organic farming emphasizes integrated strategies, rather than
individual control methods, both in crop protection and animal husbandry. Biological
control methods may be components of such strategies. Conservation biological
control and the use of predators and parasites are favoured methods. However, on-
native predators and parasites should only be used if this causes no threat to the
native fauna. The use of microbial control agents is also possible, but is not favoured
by the major regulations and standards. In the authors’ personal view, the use of
microbial control agents can be preferable to the use of plant or mineral derived
Organic Farming History and Techniques 319
References
Adam D (2001) Nutritionists question study of organic food, Nature 412, 666. In: 12th interna-
tional IFOAM scientific conference, Mar del Plata, Argentinean, 1998, pp 147–153
Aguilera-Gomez LI, Ramirez-Moreles P, Frias-Hernandez JT, Chapa- Elizondo A, Olalde-Portugal
V (1998) Influence of Glomus fasciculatum on physiology and growth of three kinds of maize.
Phyton-Int J Exp Bot 62:101–107
Albrecht H, Mattheis A (1998) The effect of organic and integrated farming on rare arable weeds
on the Forschungsverbund Agrarokosysteme Munchen (FAM) Research Station in Southern
Bavaria. Biol Conserv 86:347–356
Allan P, Kovach M (2000) The capitalist composition of organic: the potential of markets in fulfilling
the promise of organic agriculture. Agric Hum Values 17:221–232
Anonymous (2000) Principles of organic farming. Danish Research Centre for Organic Farming
(DARCOF), Foulum, 36 pp
Aronsson H, Torstensson G, Bergstr¨om L (2007) Leaching and crop uptake of N, P and K from
organic and conventional cropping systems on a clay soil. Soil Use Manag 23:71–81
Axelsen JAA, Elmholt S (1998) Scenarium om 100% økologisk jordbrug i Danmark, A3.4,
Jordbundens biologi, Rapport for Bichel-Udvalget
Badgley C, Perfecto I (2007) Can organic agriculture feed the world? Renew Agric Food Syst
22:80–82
Badgley C, Moghtader J, Quintero E, Zakern E, Chappell J, Avil´es-V´azquez K, Samulon A, Perfecto
I (2007) Organic agriculture and the global food supply. Renew Agric Food Syst 22:86–108
Bateman DI, Hughes GO, Lampkin NH, Midmore P, Ray C (1993) Pluriactivity and the rural
economy in less favoured areas of wales. Report for the ESRC, Department of Economics and
Agricultural Economics, University of Wales, Aberystwyth
Bengtsson J, Ahnström J, Weibull AC (2005) The effects of organic agriculture on biodiversity and
abundance: a meta-analysis. J Appl Ecol 42:261–269
Berry PM, Sylvester-Bradley R, Philipps L, Hatch DJ, Cuttle SP, Rayns FW, Gosling P (2002) Is
the productivity of organic farms restricted by the supply of available nitrogen? Soil Use Manag
18:248–255
Berzsenyi Z, Gyorffy B, Lap D (2000) Effect of crop rotation and fertilization on maize and wheat
yields and yield stability in a long-term experiment. Eur J Agr 13(2–3):225–244
Bhattacharya P, Gehlot D (2003) Current status of regulatory mechanism in organic farming.
Fertilizer News 49(11):33–38
Blum WEH, Buesing J, Montanella L (2004) Research needs in support of the European thematic
strategy for soil protection. Trends Anal Chem 23:680–685
320 K.K. Behera et al.
Boerner REJ, DeMars BG, Leicht PN (1996) Spatial patterns of mycorrhizal infectiveness of soils
long a successional chronosequence. Mycorrhiza 6:79–90
Borlaug NE (1970) The green revolution, peace and humanity-nobel Lecture, December,11,970,
Agbioworld, Tuskegee Institute, AL 36087–0085, USA. www.agbioworld.org/biotech-info/
topics/borlaug/nobelspeech. html. Accessed 24 Nov 2007
Bossio DA, Scow KM (1998) Impact of carbon and flooding on PLFA profiles and substrate utili-
zation patterns of soil microbial communities. Microb Ecol 35:265–278
Bouwman AF, van der Hoek KW, Eickhout B, Soenario I (2005) Exploring changes in world
ruminant production systems. Agric Syst 84:121–153
Braae L, Nøhr H, Petersen BS (1988) Fuglefaunaen påkonventionelle of økologiske landbrug,
Miljøprojekt 102, Danish Environmental Projection Agency, Copnehagen
Brady NC, Weil RR (1999) The nature and properties of soils, 12th edn. Prentice Hall, Upper
Saddle River, pp 468–469
Bruinsma J (2003) World agriculture towards 2015/2030–An FAO perspective. Earthscan, London,
432p
Cacek T, Langner L (1986) The economic implications of organic farming. Am J Altern Agric
1(1):25–29
Cassman KG, Dobermann AD, Walters DT (2002) Agroecosystems, N-use efficiency and N
management. Ambio 31:132–140
Cassman KG, D¨obermann AD, Walters DT, Yang H (2003) Meeting cereal demand while protecting
natural resources and improving environmental quality. Ann Rev Environ Resour
28:10.1–10.44
Chamberlain DE, Wilson JD, Fuller RJ (1999) A comparison of bird populations on organic and
conventional farm systems in southern Britain. Biol Conserv 88:307–320
Clarke N, Cloke P, Barnett C, Malpass A (2008) The spaces and ethics of organic food. J Rural
Stud 24(3):219–230
Cobb DR, Feber A, Hopkins L, Stockdale T, O’Riordan B, Clements L, Firbank K, Goulding SJ,
Macdonald D (1999) Integrating the environmental and economic consequences of converting
to organic agriculture: evidence from a case study. Land Use Policy 16:207–221
Coleman DC (1989) Agro-ecosystems and sustainable agriculture. Ecology 70:15–90
Conacher J, Conacher A (1998) Organic farming and environment, with particular reference to
Australia: a review. Biol Agric Hortic 6:45–171
Courtney P, Errington A (2000) The role of small towns in the local economy and some implica-
tions for development policy. Local Econ 15(4):280–301
Courtney P, Hill G, Roberts D (2006) The role of natural heritage in rural development: an analysis
of economic linkages in Scotland. J Rural Stud 22(4):469–484
Courtney P, Mayfield L, Tranter R, Jones P, Errington A (2007) Small towns as ‘sub-poles’ in
English rural development: Investigating rural–urban linkages using sub-regional social
accounting matrices. Geoforum 38(6):1219–1232
Cranbrook C (2006) The real choice: how local foods can survive the supermarket onslaught.
CPRE, London, 24 pp
Curran J, Blackburn R (1994) Small Firms and Local Economic Networks. Chapman, London,
224 pp
Dai J (1999) Quality identification and logo systems for agricultural products in France. World
Agric 243:11–12 (in Chinese)
Daniell TJ, Husband R, Fitter AH, Young JPW (2001) Molecular diversity of arbuscular mycor-
rhizal fungi colonising arable crops. FEMS Microbiol Ecol 36:203–209
Dann PR, Derrick JW, Dumaresq DC, Ryan MH (1996) The response of organic and convention-
ally grown wheat to superphosphate and reactive phosphate rock. Aust J Exp Agric 36:71–78
Darnhofer I (2005) Organic farming and rural development: some evidence from Austria. Sociol
Rural 45(4):308–323
Dekkers TBM, Vander Werff PA (2001) Mutualistic functioning of indigenous arbuscular mycor-
rhizae in spring barley and winter wheat after cessation of long-term phosphate fertilization.
Mycorrhiza 10:195–201
Organic Farming History and Techniques 321
Denison RF, Bryant DC, Kearney TE (2004) Crop yields over the first nine years of LTRAS, a
long-term comparison of field crop systems in a Mediterranean climate. Field Crops Res
86:267–277
Diercks R (1986) Alternativen im Landbau: Eine kritische Gesamtbilanz. Ulmer, Stuttgart,
pp 280–291
Du XG, Wang HM (2001) An introduction to organic farming. China Agricultural University
Press, Beijing, in Chinese
Duden R (1987) Image ans Qualitat von Tomaten. Gordian 6:118–119
Dyson T (1999) World food trends and prospects to 2025. Proc Natl Acad Sci USA 96:5929–5936
Edwards JG, Howells O (2001) The origin and hazard of inputs to crop protection in organic
farming systems: are they sustainable? Agric Syst 67:31–47
Eickhout B, Bouwman AF, Van Zeijts H (2006) The role of nitrogen in world food production and
environmental sustainability. Agric Ecosyst Environ 116:4–14
Eltun R (1996) The Apelsvoll cropping system experiment, III. Yield and grain quality of cereals.
Nor J Agric Sci 10:7–21
Errington A, Courtney P (2000) Tracing the “Economic Footprint” of market towns: a method-
ological contribution to rural policy analysis. In: Agricultural Economics Society Annual
Conference, Manchester
Evans LT (1998) Feeding the ten billions – plants and population growth. Cambridge University
Press, Cambridge, 247p
Evers AM (1989a) Effects of different fertilization practices on the carotene content of carrot.
J Agric Sci Finland 61:7–14
Evers AM (1989b) Effects of different fertilization practices on the glucose, fructose, sucrose, taste
and texture of carrot. J Agric Sci Finland 61:113–122
Evers AM (1989c) Effects of different fertilization practices on growth, yield and drymatter
content of carrot. J Agric Sci Finland 60:135–152
Faerge J, Magid J (2003) Assessment on organic farming benchmark trials in Denmark. Acta Agric
Scand Sec B Soil Plant Sci 53:64–68
FAO (2002) Organic agriculture, environment and food security. Environment and Natural
Resources Service Sustainable Development Department. Retrieved July 20 2007 from http://
www.fao.org/DOCREP/005/Y4137E/y4137e00.htm#TopOfPage
FAO (2007) Food and Agriculture Organization of the United Nations, Statistical Yearbook, 2005/06,
Rome. www.fao.org/statistics/yearbook/vol.11/siteen.asp?page= resources. Accessed 28 Ap 2007
Food and Agriculture Organisation of the United Nations (FAO)/World Health Organisation
(WHO) (2001) Guidelines for the production, processing, labeling and marketing of organi-
cally produced foods (GL 32–1 999/2001). Codex Alimentarius, pp 5–11
Feber RE, Firbank LG, Johnson PJ, Macdonald DW (1997) The effects of organic farming on pest
and non-pest butterfly abundance. Agric Ecosyst Environ 64:133–139
Feber RE, Bell J, Johnson PJ, Firbank LG, Macdonald DW (1998) The effects of organic farming
on surface-active spider (Araneae) assemblages in wheat in southern England, UK. J Arachnol
26:190–202
Freese L, Friedrich R, Kendall D, Tanner S (2000) Variability of deoxynivalenol measurements in
barley. J AOAC Int 83:1259–1263
Gabriel D, Roschewitz I, Tscharntke T, Thies C (2006) Beta diversity at different spatial scales:
plant communities in organic and conventional agriculture. Ecol Appl 16:2011–2021
Galvez L, Douds DD Jr, Drinkwater LE, Wagoner P (2001) Effect of tillage and farming
system upon VAM fungus populations and mycorrhizas and nutrient uptake of maize. Plant
Soil 118:299–308
Gitay H, Wilson JB, Lee WG (1996) Species redundancy: a redundant concept? J Ecol
84:121–124
Gliessman SR (1990) Agro-ecology: researching the ecological basis for sustainable agriculture.
Springer, New York, pp 3–10
Graf S, Willer H (2001) Organic agriculture in Europe-current status and future prospects of organic
farming in twentyfive European countries. Stiftung Okologie and Landbau (SOEL), pp 8–21
322 K.K. Behera et al.
Greene CR (2001) U.S. Organic farming emerges in the 90s:Adoption of certified systems.
Agriculture Information Bulletin, pp 770
Gunapala N, Scow KM (1998) Dynamics of soil microbial biomass and activity in conventional
and organic farming systems. Soil Biol Biochem 30:805–816
Haas G, Wetterich F, Köpke U (2001) Comparing intensive, extensified and organic grassland farm-
ing in southern Germany by process Life Cycle Assessment. Agric Ecosyst Envion 83:43–53
Hald AB (1999) Weed vegetation (wild flora) of long established organic versus conventional
cereal fields in Denmark. Ann Appl Biol 134:307–314
Hald AB, Reddersen J (1990) Fugleføde i kornmarker- insekter og vilde planter, Miljøprojekt 125,
Miljøstyrelsen, Kbh
Hall A, Mogyorody V (2001) Organic farmers in Ontario: an examination of the conventionaliza-
tion argument. Sociol Rural 41(4):399–422
Hansen H (1981) Comparison of chemical composition and taste of biodynamically and conven-
tionally grown vegetables, Qualitas plantarium. Plant Foods Hum Nutri 30:203–211
Hansen JW, Jones JW (1996) A systems framework for characterizing farm sustainability. Agric
Syst 51:185–201
Hansen B, Alrqe HF, Kristensen ES (2001) Approaches to assess the environmental impact of
organic farming with particular regard to Denmark. Agric Ecosyst Envion 83:11–26
Harrison L (1993) The impact of the agricultural industry on the rural economy— tracking the
spatial distribution of farm inputs and outputs. J Rural Stud 9:81–88
Haslberger A (2001) GMO contamination of seeds. Nat Biotechnol 19(7):613
Haslberger A (2010) Genetically modified and organic crops in developing countries: a review of
options for food security. Biotechnol Adv 28:160–168
Hedlund K (2002) Soil microbial community structure in relation to vegetation management on
former agricultural land. Soil Biol Biochem 34:1299–1307
Hedlund K, Gormsen D (2002) Mycorrhizal colonization of plants in setaside agricultural land.
Appl Soil Ecol 19:71–78
Helgason T, Daniell TJ, Husband R, Fitter AH, Young JPW (1998) Ploughing up the wood-wide
web? Nature 394:431
Henning J (1994) The economics of organic farming in Canada. In: Lampking N, Padel S (eds.)
The economics of organic farming: An international perspective. CAB International,
Wallingford, pp 143–160
Henning J, Baker L, Thomassin P (1991) Economic issues in organic agriculture. Can J Agric
Econ 39(4):877–886
Herrmann G, Plakolm G (1991) Oekologischer landbau, grundwissenfuer die praxis. Wien,
Verlagsunion Agrar, pp 27–32
Hetrick BAD, Wilson GWT, Cox TS (1993) Mycorrhizal dependence of modern wheat cultivars
and ancestors a synthesis. Can J Bot 71:512–518
Hetrick BAD, Wilson GWT, Todd TC (1996) Mycorrhizal response in wheat cultivars, relationship
to phosphorus. Can J Bot 74:19–25
Hird V (1997) Double yield. SAFE Alliance, London
Hodtke M, Araujo PA, Kopke U, Almeida DL (1998) Nutritional status, grain yield and N-balance
of organically grown maize intercropped with green manure. In: Foguelman D, Lockeretz W
(eds.) Organic Agriculture-the Credible Solution for the XXIst Century: Proceedings of the
12th international IFOAM scientific conference, Mar del Plata, Argentinien (1998), pp
135–141
Hole DG, Perkins AJ, Wilson JD, Alexander IH, Grice PV, Evans AD (2005) Does organic farming
benefit biodiversity? Biol Conserv 122:113–130
Holzschuh A, Steffan-Dewenter I, Kleijn D, Tscharntke T (2007) Diversity of flower-visiting bees
in cereal fields: effects of farming system,landscape composition and regional context. J Appl
Ecol 44:41–49
Hong CW (1994) Organic farming and the sustainability of agriculture in Korea. Suweon, Korea:
Agricultural Science Institute, Rural Development Association.
Organic Farming History and Techniques 323
House of Lords Select Committee on European Communities (HLSCEC) (1999) 16th report:
organic farming and european union (HMSO, London)
Howlett B, Connolly L, Cowan C, Meehan H, Neilsen R (2002) Conversion to organic farming:
Case study report. Working Paper DL 3.1. The National Food Centre, Dublin, Ireland
IFOAM (1998) Basic standards for organic production and processing. IFOAM General Assembly,
Argentinia, Nov 1998
IFOAM (2000) Comments on the USDA proposed rule: Submitted by International Federation of
Organic Agriculture Movements. www.ifoam.org/final_comment_06-08.html. Accessed 7
June 2000
IFOAM (2010) International Federation of Organic Agriculture Movements-The principles organic
agriculture. http://www.ifoam.org/about_ifoam/principles/index. html
IFOAM (International Federation of Organic Agriculture Movements), Food and Agriculture
Organisation of the United Nations (FAO) (2002) Conference conclusions, IFOAM conference
on organic guarantee systems- international harmonization and equivalence on organic agricul-
ture, Nuremberg, Germany, 17–19 Feb 2002, pp 11–18
Iglesias J, Castillejo J, Castro R (2003) The effects of repeated applications of the molluscicide
metaldehyde and the biocontrol nematode Phasmarhabditis hermaphrodita on molluscs, earth-
worms, nematodes, acarids and collembolans: a two-year study in north-west Spain. Pest
Manag Sci 59:1217–1224
Ilbery B, Maye D (2005) Food supply chains and sustainability: evidence from specialist food
producers in the Scottish/English borders. Land Use Policy 22:331–344
International Federation of Organic Agriculture Movements (IFOAM) (2000) Basic standards for
organic production and processing, Fa. Werbedruck, Germany
International Trade Centre (ITC) (1999) Organic food and beverages: world supply and major European
markets. International Federation of Organic Agriculture Movements (IFOAM), pp 46–71
Isart J, Llerena JJ (eds.) (1996) Biodiversity and land use: the role of organic farming. Proceedings
of the first ENOF workshop, Barcelona, 1996
Ivarson J, Gunnarsson A (2001) Forsok med konventionella och ekologiska odlingsformer
1987–1998, Meddelande fran Sodra Jordbruksfors¨oksdistriktet Nr 53, Swedish University of
Agricultural Sciences, Uppsala, Sweden, 165 pp (In Swedish)
Jackson MC (1997) Pluralism in systems thinking and practice. In: Mingers J, Gill A (eds.) Multi
methodology: the theory and practice of combining management science methodologies.
Wiley, New York, pp 347–378
James S (1998) Mixed farming in Africa: the search for order, the search for sustainability. Land
Use Policy 5(4):293–317
Johnson NC (1993) Can fertilisation of soil select less mutualistic mycorrhizae? Ecol Appl
3:749–757
Johnson NC, Copeland PJ, Crookston RK, Pfleger FL (1992) Mycorrhizae possible explanation for
yield decline with continuous corn and soybean. Agron J 84:387–390
Kahiluoto H, Vestberg M (1998) The effect of arbuscular mycorrhiza on biomass production and
phosphorus uptake from sparingly soluble sources by leek (Allium porrum L.) in Finnish field
soils. Biol Agric Hortic 6:65–85
Kahnt G (1986) Biologischer Pflanzenbau: Moeglichkeiten und Grenzen Biologischer
Anbausysteme. Ulmer, Stuttgart, pp 19–36
Kaltoft P (1999) Values about nature in organic farming practice and knowledge. Sociol Rural
39(1):40–53
Kirchmann H, Thorvaldsson G (2000) Challenging targets for future agriculture. Eur J Agron
12:145–161
Kirchmann H (1994) Biological dynamic farming an occult form of alternative agriculture.
J Agric Environ Ethics 7:173–187
Kirchmann H, Bergstr¨om L, K¨atterer T, Mattsson L, Gesslein S (2007) Comparison of long-term
organic and conventional crop-livestock systems in a previously nutrient- depleted soil in
Sweden. Agron J 99:960–972
324 K.K. Behera et al.
Niemeyer K, Lombard J (2003) Identifying problems and potential of the conversion to organic
farming in South Africa. Paper presented at the 41st annual conference of the Agricultural
Economic Association of South Africa (AEASA), Pretoria, South Africa, 2–3 Oct 2003
Niggli U, Lockeretz W (1996) Development of research in organic agriculture. In: Stergaard T (ed)
Proceedings of the 11th IFOAM international Scientijk conference on fundamentals of organic
agriculture, vol 1, pp 11–15, Copenhagen
Nonhebel S (2005) Renewable energy and food supply: will there be enough land? Renew Sustain
Energy Rev 9:191–201
Oehl F, Sieverding E, Mader P, Dubois D, Ineichen K, Boller T, Wiemken A (2004) Impact of
long-term conventional and organic farming on the diversity of arbuscular mycorrhizal fungi.
Oecologia 138:574–583
Oram JO (2003) Regaining the land, Lessons from farmers’ experience with sustainable agriculture
in the Philippines. CIIR
Pacini C, Wossink A, Giesen G, Vzazana C, Huirne R (2002) Evaluation of sustainability of
organic, integrated and conventional farming systems: a farm and field-scale analysis. In:
Agriculture, Ecosy and Envi, pp 1–16
Padel S (2001a) Conversion to organic farming: a typical example of the diffusion of an innova-
tion? Sociol Rural 41(1):40–61
Padel S (2001b) Information and advisory services for organic farming in Europe. In: Abstract for
15th ESEE workshop. Wageningen, Aug 2001
Parry M, Rosenzweig C, Livermore M (2005) Climate change, global food supply and risk of
hunger. Phil Trans R Soc B Biol Sci 360:2125–2138
Ploeger AM, Vogtmann H (1996) Product and environment: quality and public health. In:
Ostergaard TV (ed.) Fundamentals of organic agriculture. Proceedings of the 11th international
IFOAM scientific conference, vol 1, Copenhagen, pp 176–189
Potter C, Burney J (2002) Agricultural multifunctionality in the WTO – legitimate non-trade
concern or disguised protectionism? J Rural Stud 18:35–47
Pretty JN, Hine RE (2001) Reducing food poverty with sustainable agriculture: a summary of new
evidence, Centre for Environment and Society, Essex University,UK. www.essex.ac.uk/ces/
esu/occasionalpapers/SAFE%20FINAL% 20-%20Pages1-22.pdf. Accessed 29 Dec 2007
Pretty JN, Morison JLL, Hine RE (2003) Reducing food poverty by increasing agricultural sustain-
ability in developing countries. Agric Ecosyst Environ 95:217–234
Pretty J, Ball A, Lang T, Morison J (2005) Farm costs and food miles: an assessment of the full
cost of the UK weekly food basket. Food Policy 30:1–19
Pugliese P (2001) Organic farming and sustainable rural development. A multifaceted and promising
convergence. Sociol Rural 41(1):112–131
Pulleman M, Jongmans A, Marinissen J, Bouma J (2003) Effects of organic versus conventional
arable farming on soil structure and organic matter dynamics in a marine loam in the
Netherlands. Soil Use Manag 19:157–165
Quine TA, Basher LR, Nicholas AP (2003) Tillage erosion intensity in the South Canterbury
Dowlands, New Zealnd. Aust J Soil Res 41:789–807
Rai M (2006) Organic farming: potentials and strategies; Available on: http://www.icar. org.in/
dgspmr/03062005.htm. Retrieved 10 Aug 2009
Ram RA, Pathak RK (2008) Integration of organic farming practices for sustainable production of
Guava: a case study. Accessed 24 Mar 2008
Rauhe K, Leithold G, Michel D (1987) Untersuchungen zur Ertrags- und Humusreproduktion
sleistung der Luzerne auf sandigem Lehmboden in Trockenlagen. Arch. Acker- Pflanzenbau
Bodenkd 31:695–702
Reddersen J (1999) Naturindhold i økologisk jordbrug. Natur, miljø og ressourcer i økologisk
jordbrug. FQJO Rapport 3, Forskningscenter for Qkologisk Jordbrug, pp 69–84
Redman M (ed.) (1992) Organic farming and the countryside: a special report from British organic
farmers in conjunction with the soil association. Organic Food and Farm Centre, Bristol
Reed N (1995) In: Hull JJ (ed.) 125th Annual Report of the Secretary of the State Horticultural
Society of Michigan, Mich. State Hort. Co., East Lansing, pp 68–78
326 K.K. Behera et al.
Reganold JP, Glover JD, Andrews PK, Hinman HR (2001) Sustainability of three apple production
systems. Nature 410:926–929
Renting H, Marsden T, Banks J (2003a) Understanding alternative food networks: exploring the
role of short food supply chains in rural development. Environ Plann A 35:393–411
Renting H, Marsden TK, Banks J (2003b) Understanding alternative food networks: exploring the
role of short food supply chains in rural development. Environ Plann A 35:393–411
Rew LJ, Froud-Williams RJ, Boatman ND (1996) Dispersal of Bromus sterilis and Anthriscus
sylvestris seed within arable field margins. Agric Ecosyst Environ 59:107–114
Rigby D, Young T, Burton M (2001) The development of and prospects for organic farming in the
UK. Food Policy 26(6):599–613
Roger FH (1987) Importance of bio-fertilizers in intensive cropping. Haryana Farming, Hisar
Rothschild M (1998) The butterfly gardeners by Miriam Rothschild and elive farell, Great Britain,
pp128–130
Rundlöf M, Smith HG (2006) The effect of organic farming on butterfly diversity depends on
landscape context. J Appl Ecol 43:1121–1127
Ryan MH, Ash J (1999) Effects of phosphorus and nitrogen on growth of pasture plants and VAM
fungi in SE Australian soils with contrasting fertiliser histories (conventional and biodynamic).
Agric Ecosyst Environ 73:51–62
Ryan MH, Graham JH (2002) Is there a role for arbuscular mycorrhizal fungi in production agri-
culture? Plant Soil 244:263–271
Ryan MH, Chilvers GA, Dumaresq DC (1994) Colonisation of wheat by VA mycorrhizal fungi
was found to be higher on a farm managed in an organic manner than on a conventional neigh-
bour. Plant Soil 160:33–40
Schupbach M (1986) Spritzmittelruckstande in Obst und Gemuse. Deutsche Lebensmittel
Rundschau 82(3):76–80
Schuphan W (1975) Yield maximization versus biological value. Qual Plant 24:281–310
Scullion J, Eason WR, Scott EP (1998) The effectivity of arbuscular mycorrhizal fungi from
high input conventional and organic grassland and grass–arable rotations. Plant Soil
204:243–254
Seyfang G (2006) Ecological citizenship and sustainable consumption: examining local organic
food networks. J Rural Stud 22(4):383–395
Sheehy JE, Peng S, Dobermann A, Mitchell PL, Ferrer A, Yang J, Zou Y, Zhong X, Huang J (2004)
Fantastic yields in the system of rice intensification: fact or fallacy? Field Crops Res 88:1–8
Sheng DZ, Xie JR, Zhang QW (1995) Natural agriculture in Japan. World Agric 195:9–11 (in
Chinese)
Siegrist S, Staub D, Pfiffner L, Mäder P (1998) Does organic agriculture reduce soil erodibility?
The results of a long-term field study on loess in Switzerland. Agric Ecosyst Environ
69:253–264
Smil V (2001) Enriching the earth: Fritz Haber, Carl Bosch, and the transformation of world food
production. MIT Press, Cambridge, 338p
Smil V (2002) Nitrogen and food production: proteins for human diets. Ambio 31:126–131
Smith E, Marsden T (2004) Exploring the ‘limits to growth’ in UK organics: beyond the statistical
image. J Rural Stud 20(3):345–357
Smithers J, Larmarche J, Joseph A (2008) Unpacking the terms of engagement with local food at
the farmers’ market: insights from Ontario. J Rural Stud 24(3):337–350
Smukler SM, Sánchez-Moreno S, Fonted SJ, Ferris H, Klonsky K, O’Green AT, Scowb KM,
Steenwerthg KL, Jackson LE (2010) Biodiversity and multiple ecosystem functions in an
organic farmscape agriculture. Ecosyst Environ 139:80–97
Soil Association (2001) The organic food and farming Report 2000. Soil Association
Publications
Soil Association (2007) Organics market report 2007. Soil Association, Bristol
Stiftung Oekologie and Landbau (SOEL) (2003) Organic Agriculture Worldwide 2000–2002/
Statistics and Future Prospects. SOEL, Feb 2003. www.ifoam.org
Organic Farming History and Techniques 327
Stockdale EA, Lampkin NH, Hovi M, Keatinge R, Lennartsson EKM, Macdonald DW, Padel S,
Tattersall FH, Wolfe MS, Watson CA (2001) Agronomic and environmental implications of
organic farming systems. Adv Agron 70:261–325
Stolton S, Geier B, Jeffrey A (2000) Biodiversity and organic agriculture. Ecology and farming,
No. 23, January–April, IFOAM. 22–25
Stolze M, Piorr A, Häring A, Dabbert S (2000) The environmental impact of organic farming in
Europe. In: Organic farming in Europe: economics and policy, vol 6. University of Hohenheim,
Stuttgart, pp 1437–6512
Stoppler H, Kolsch E, Vogtmann H (1990) Vesicular-arbuscular mycorrhiza in varieties of winter-
wheat in a low external input system. Biol Agric Hortic 7:191–199
Sullivan S, McCann E, Young R, Erickson D (1996) Farmers’ attitudes about farming and the
environment: a survey of conventional and organic farmers. J Agric Envion Ethics
9(2):123–143
Svensson I (1991) Governmental subsidy to organic farming 1989: “A mail inquiry”. Altern Odl
7:88–92
Temperli AT, Künsch U, Schärer H (1982) Einfluss zweier Anbauweisen auf den Nitratgehalt von
Kopfsalat, Schweizerische landwirtschaftliche. Forschung 21:167–196
Thorup-Kristensen K, Magid J, Jensen LS (2003) Catch crops and green manures as biological
tools in nitrogen management in temperate zones. Adv Agron 79:227–302
Torstensson G (1998) Nitrogen delivery and utilization by subsequent crops after incorporation of
leys with different plant composition. Biol Agric Hortic 16:129–143
Torstensson G, Aronsson H, Bergstrom L (2006) Nutrient use efficiency and leaching of N, P and
K of organic and conventional cropping systems in Sweden. Agron J 98:603–615
Trewavas A (2001) Urban myths of organic farming. Nature 410:409–410
Tsara M, Gerontidis S, Marathianou M, Kosmas C (2001) The longterm effect of tillage on soil
displacement of hilly areas used for growing wheat in Greece. Soil Use Manag 17:113–120
Tudge C (2005) Can organic farming feed the world?, Oxford, England. http://www.colintudge.
com. Accessed 29 Dec 2007
UN Millennium Project (2005) Task force on hunger. In: Sanchez P et al. (ed.) Halving hunger:
it can be done. Earthscan, London, 272 p www.unmillenniumproject.org/documents/Hunger-
lowres-complete.pdf
UNDP (2003) Human development report 2003 – millennium development goals: a compact
among nations to end human poverty. UNDP, New York
United States Department of Agriculture (USDA) (1980) Report and recommendations on organic
farming. U.S. Department of Agriculture, US Government Priting Office, Washington DC, p 94
Uzogara SG (2000) The impact of genetic modification of human foods in the 21st Century: a
review. Biotechnol Adv 18:179–206
Van der Ploeg JD, Renting H (2000) Impact and potential: a comparative review of European rural
development practises. Sociol Rural 40(4):529–543
Van Elsen T (2000) Species diversity as a task for organic agriculture in Europe. Agric Ecosyst
Environ 77:101–109
Van Mansvelt JD, Mulder J (1993) European features for sustainable development: a contribution
to the dialogue. Landsc Urban Plann 27:67–90
Van Muysen W, Govers G (2002) Soil displacement and tillage erosion during secondary tillage
operations, the case of rotary harrow and seeding equipment. Soil Tillage Res 65:185–191
Vasilikiotis C (2000) Can organic farming Feed the World?, University of California Berkeley, CA.
http://nature.berkeley.edu/christos/espm118/articles/organic feed world.pdf. Accessed 29 Dec
2007
Vogtmann H, Temperli AT, Kunsch U, Eichenberger M, Ott P (1984) Accumulation of nitrates in
leafy vegetables grown under contrasting agricultural systems. Biol Agric Hortic 2:51–68
Walker BH (1992) Biodiversity and ecological redundancy. Conserv Biol 6:18–23
Warner NJ, Allen MF, Macmahon JA (1987) Dispersal agents of vesiculararbuscular mycorrhizal
fungi in a disturbed arid ecosystem. Mycologia 79:721–730
328 K.K. Behera et al.
Weibel FP, Bickel R, Leuthold S, Alfoldi T, Niggli U (1998) Are Organically Grown Apples
Tastier and Healthier? A comparative field study using conventional and alternative methods to
measure fruit quality. In: Foguelman D, Lockeretz W (eds.) Organic agriculture — the credible
solution for the XXIst century: Proceedings of the12th international IFOAM scientific confer-
ence, Mar del Plata, Argentinean, pp 147–153
Whalen JK, Parmelee RW, Edwards CA (1998) Population Dynamics of Earthworm Communities
in Corn Agroecosystems Receiving Organic or Inorganic Fertilizer Amendments. Biol Fertil
Soils 27:400–407
Wibberley J (1996) A brief history of rotations, economic considerations and future directions.
Asp Appl Biol 47:1–10
Willer H, Gillmor D (1992) Organic agriculture in the Republic of Ireland. Irish Geogr
25(2):149–159
Winter M (2003) Embeddedness, the new food economy and defensive localism. J Rural Stud
19:23–32
Winter M, Rushbrook L (2003) Literature review of the English rural economy. Research Report
Prepared for Defra, Centre for Rural Research, University of Exeter, Exeter
Woese K, Lange D, Boess C, Bögl KW (1997) A comparison of organically and conventionally
grown foods-results of a review of the relevant literature. J Sci Food Agric 74:281–293
Wood ward L (1995) Can organic farming feed the world?, Elm Research Centre, England. www.
population growth migration. nfo/essays/wood wardorganic.html. Accessed 29 Dec 2007
Wood D Lenne JM (1999) Agrobiodiversity and natural biodiversity: some parallels. In: Wood D,
Lenne J (eds.) Agrobiodiversity: characterization, utilization and management. CABI
Publishing, UK, pp 425– 445
Wood R, Lenzen M, Dey C, Lundie S (2006) A comparative study of some environmental impacts
of conventional and organic farming in Australia. Agric Syst 89(2–3):324–348
Youngberg EG, Parr JG, Papendick RL (1984) Potential benefits of organic farming practices for
wildlife and natural resources. Trans N Am Wildlife Nat Resour Conf 49:141–153
Yu HF, Dai JY (1995) The trend of thoughts in modem agriculture. World Agric 200:9–11 (in
Chinese)
Yussefi M, Willer H (2003) The world of organic agriculture-statistics and future prospects.
International Federation of Organic Agriculture Movements (IFOAM). www.soel.de/inhalte/
publikation/s/s-74. pdf
Zehnder G, Gurr GM, Kühne S, Wade MR, Wratten SD, Wyss E (2007) Arthropod pest manage-
ment in organic crops. Annu Rev Entomol 52:57–80
Zhu Y, Chen H, Fan J, Wang Y, Li J, Chen J, Fan S, Yang L, Hu H, Leung TW, Mew PS, Teng ZW,
Mundt CC (2000) Genetic diversity and disease control in rice. Nature 406:718–722
Zwankhuizen MJ, Govers F, Zadoks JC (1998) Development of potato late blight epidemics: dis-
ease foci, disease gradients, and infection sources. Phytopathology 88:754–763
Index
H
Habitat management, 301, 306 K
Haigis, J., 28 Kahiluoto, H., 307
Halbrendt, J.M., 243, 244, 246, 250, Karam, N.S., 182, 195
254, 255 Karanastasi, E., 240
Hall, A., 292 Karim, S., 219
Hamill, J.D., 219 Karlsson, S., 76, 89
Handoo, Z.A., 240, 247 Karrou, M., 179
Hang, Y., 250 Kashyap, A.S., 257
Hansen, M.N., 86, 87, 89, 95 Kasuga, M., 219
332 Index
Nutrients, 5–8, 11, 19, 21, 30, 42, 47, 49–53, Pleguezuelo, C.R.R., 190, 191
69, 110–115, 117, 122, 123, 125, 126, Polley, W.H., 171
136, 150, 152–156, 158, 159, 161, 162, Pome fruit, 237–260
176, 179–181, 183, 184, 186, 187, 193, Pond, 6, 271
238, 269–283, 288, 290, 295–300, 303, Poth, M., 86, 87
304, 306, 307, 310, 311, 316, 318 Pozo, M.J., 109
Nutrition, 11, 24, 40, 42–46, 49, 55, 122, 187, Pretty, J., 7, 28
197, 238, 317 Productivity, 2, 5–7, 25, 28, 49, 53, 118,
Nuts, 237–260 137–139, 142, 144, 152–157, 162, 170,
Nyczepir, A.P., 244, 246, 250, 251, 258 179, 180, 182, 184, 214, 215, 228, 238,
239, 278, 282, 288, 290, 296, 302, 309,
312
O Purvis, G., 35, 41
Oenema, O., 69
Oestenbrink, M., 255
Ogola, J.B.O., 185 Q
Oh, S.J., 219 Qin, F., 219
Okie, W.R., 251 Quick, J.S., 187
Olesen, J.E., 81
Organic agriculture, 24, 25, 136, 143,
149–162, 268, 290–297, 301, 302, 304, R
307, 309–313, 317, 318 Radionuclide, 273, 283
Organic farming, 25, 141–144, 153, 287–319 Rai, U.N., 279
Osada, T., 84 Ramaswami, C., 191
Osmolytes, 220, 221, 226, 228 Rana, G., 182
Oweis, T., 182, 194 Raski, D.J., 247
Raven, J.A., 183
Raza, A., 167
P Rebandel, Z., 255
Pacholak, E., 240 Reed, H.E., 250
Page, A.L., 274 Rees, M., 50
Pain, B.F., 92 Reganold, J.P., 301
Pala, M., 179, 181, 182 Reijnders, L., 136, 140
Panda, R.K., 195 Renting, H., 314
Pandey, V.C., 274, 277, 281, 282 Research policy, 54–57
Park, B.J., 219 Rhizosphere, 109–129, 173,
Parvatha Reddy, P., 255 189, 242
Passioura, J., 171, 179 Rickerl, D., 19, 29
Pasture management, 42, 49, 52, 53 Ritchie, J.T., 179
Paul, N.D., 181 Robertson, G.P., 19, 29
Payne, W.A., 186 Rochette, P., 89, 93
Pellegrineschi, A., 219 Rodhe, L., 67, 89, 93
Pereira, L.S., 171 Rodriguez-Kabana, R., 251
Peremarti, A., 219 Rom, R.C., 250
Petersen, S.O., 80, 87 Roose, E., 188
Peterson, G.A., 191 Root parasitic plants, 114, 118,
Phukan, P.N., 247 123–129
Pikul, J.L. Jr., 190 Root water uptake, 180, 185,
Pilon-Smits, E.A.H., 219 192, 196
Pinochet, J., 250, 254, 257, 258 Rossi, C.E., 247
Plant growth, 47, 110, 111, 115, 118, 122, Rubio-Cabetas, M.J., 253
125, 126, 156, 172, 175, 180, 184, 188, Ruminant production systems,
227, 228, 238, 239, 241, 243, 246, 45–54
269–283, 297 Ryan, M.H., 307
334 Index