Salinity: Interpretation Guide
Salinity: Interpretation Guide
Salinity: Interpretation Guide
Interpretation Guide
CONTENTS
1 1
.
A
i
m
o
f
t
h
e
i
n
t
e
r
p
r
e
t
a
ti
o
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i
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.2 3
B
a
c
k
gr
o
u
n
d
fa
ct
s
a
b
o
ut
s
al
in
it
y
3
What cau
ses salini
ty damag
e in plant
?s
How does salin
ity affect wine g
rape productio
?n
Assessment - diagnosis to deter .3
mine if a problem really is related t
o salinity 11
1
.4
Monitoring: I
s salinity get
ting better or
?worse
Th
e i 1
mp
ort
an
ce
of
mo
nit
ori
ng
Ir
ri 1
g
a
ti
o
n
b
a
s
e
d
m
o
n
it
o
ri
n
g
3
3
4
4
R 5
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e
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Aim of the interpretation guide
Aim of the int .1
erpretation guid
e
This Guide is a practical referen
ce for vineyard managers who
want to learn more
about the principles of ‘best ma
.nagement practice’ for salinity
The following questions are add
:ressed
?What is salinity •
How is a salinity problem cau •
?sed
What are the affects of salinit •
?y on wine grape production
How can salinity be identified •
? and monitored in a vineyard
How can salinity be managed •
? to minimise future impacts
If your vineyard is not showing a
ny signs of salinity, this guide wi
ll inform you how
to monitor your vineyard (vine,
soil and water) on an on-going
basis to help identify
any developing salinity problem
.
If salinity has been identified as
an issue on your property, this
guide will also help
you to understand and apply m
anagement practices that redu
ce salinity impacts
on your vineyard through a vari
ety of ‘best management practic
e’ options. Some
of these best management opti
ons are well established while o
thers are not and
are more based on emerging sc
ience in relation to the interactio
n between the
vine and saline conditions (eg i
ntra-seasonal variation in salt a
ccumulation in
vines). Hence, any change in m
anagement to combat salinity s
hould always be
accompanied with a monitoring
program to check its effectiven
.ess
The associated issue of sodicity
limitations in vineyards is also d
.iscussed
Sodicity is a soil property which
is often associated with irrigatio
n with saline or
brackish water, as a result of th
e accumulation of too much sod
ium leading to
.structural decline of the soil
It is important to note that salinit
y and/or sodicity problems in vi
neyards are not
terminal. The processes involve
d are reversible, albeit over a pe
riod of time (ie
years). Like most agronomic pr
oblems, prevention is always be
.tter than a cure
However, some problems in the
vineyard are inherent and requir
e unique solutions
.)eg shallow duplex soils(
This guide does not set out to b
e a comprehensive textbook ab
out salinity in
vineyards. However, enough inf
ormation has been provided to
allow growers to
ask good questions of their advi
sors and get high-quality vineya
rd management
guidelines for their particular cir
.cumstances
It is recognised that some of the
terms used in this guide may no
t be familiar to
some readers. A glossary is pro
vided at the back of this publica
tion that lists terms
that are used throughout the int
erpretation guide and more gen
.erally
Background facts about salinity
Background f .2
acts about salinit
y
?What is salinity
The term salinity refers to the pr
esence of soluble salts in water
.and soil systems
The presence of salinity in the pl
ant root zone can have a major i
mpact on the
performance of a crop and is arg
uably the biggest threat to irrigat
.ed agriculture
The sources of soluble salts that
can accumulate in the soil water
beneath
;grapevines include
Salt imported to a field via irrig •
,ation water
Saline ground water/water tab •
,les
Weathering of soil minerals, or •
ganic materials and the underlyi
e
ng rock in a
1:5
,vineyard
Ocean-derived salts blown inl •
and and carried to ground in rai
,n and/or dust
3 2 Soluble nutrients and ameliora •
3 nts such as fertilisers and gypsu
m that are
2 4 applied to soil, and
Cleaning agents added to drip •
3
irrigation systems (eg. the use
of sodium
hypochlorite is a source of chl
oride that adds to the salt load of
the
.)irrigation water
Salinity is commonly measured a
s the Electrical Conductivity (EC)
of a water
solution. EC is a measure of the
ability of a liquid to pass an elect
ric current; it
increases as the salinity (salt con
centration) of a liquid increases.
EC is commonly
given in units of dS/m (deci-
Siemens per metre). Salinity can
be measured directly
from a sample of irrigation water
but is measured in soil using eith
er one of two
methods: saturated paste extract
(EC ) or, the inexpensive but les
s reliable 1:5 soil
.water extract (EC )
A soil is defined as being saline
when the level of salinity of soil w
ater
adversely )concentration of ions(
affects plant growth. However, p
lants have
different susceptibilities to soil sal
inity. In Australia, soil salinity is p
redominantly
due to salts of sodium: sodium c
hloride (NaCl), sodium carbonat
e (Na CO ) and
sodium bicarbonate (NaHCO ).
Whilst all salts contribute to a sal
inity effect, some
salts have beneficial effects to cr
ops outside of salinity like fertilis
.ers and gypsum
Gypsum (calcium sulphate; CaS
O .2H O) is regarded as a desira
ble salt because
it is only sparingly soluble and co
ntains beneficial components – p
articularly
calcium and sulphur. Calcium ca
rbonate (CaCO ) is another salt t
hat can be
introduced via irrigation water. It i
s only slightly soluble in water an
d a valuable
source of calcium, but is associa
ted with alkaline conditions that
may limit nutrient
.availability to plants
Salinity derived from a rising watertable
Salt occurs naturally in the soil but salinit
y can become a major problem when the
groundwater is allowed to rise close to th
e soil surface. Shallow saline water table
s
at less than about two metres from the s
urface can cause salt to accumulate
in the root zone of crops. The drier soil s
urface condition allows capillary action DRY WEATHER
to transport saline ground water to the s
oil surface. Evaporation and plant
transpiration removes soil water leaving t
he salts behind in the upper layers of soi
l
.profile (Figure 2.1)
Capillary
rise
1.5m
b Free a
Saline Groundwater
water
in well
Figure 2.1. Processes associated with the develop
ment of salinity problems via capillary rise: (a)
Negligible salinisation of the topsoil from capillary ris
e; (b) Active capillary rise, in response to
evaporation during dry weather, from a water table
within 2 metres of the soil surface
The degree of salinisation as a result of r
ising ground water is a function of depth
and salinity of ground water, rainfall, the
hydraulic properties of soil and the
vegetation cover of the soil surface. This
form of salinity often results in land scald
and the effects are easily visible on the s
.urface
Transient salinity
Transient salinity (Figure 2.2) is an accu
mulation of salt in the root-zone that
can cause significant productivity losses.
This accumulation of salt usually
occurs without the influence of rising sali
ne groundwater. The level of salinity
under these conditions may not be as hi
gh as levels found in salinity caused
by shallow groundwater, but it can be su
fficient to cause significant crop yield
Background facts about salinity
losses, particularly in dry season
s. Transient salinity is caused by
a reduction in
the movement of water and salts
out of (below) the root-zone. Eva
potranspiration
removes water from the root zon
e and leaves behind salt at the s
ame time. It
occurs in soils where the movem
ent of water through the soil profi
le is slow and
can fluctuate according to soil de
.pth, irrigation and rainfall
Figure 2.2. Formation of transient salinity
as
the result of a sub-surface sodic layer wit
h
poor hydraulic conductivity. A sodic layer
has
an excess of sodium ions on the clay par ti
,cles
which leads to waterlogging when wet and
.excessive hardness when dry
Accumulation of salts
Perched Watertable
Sodic Layer
Little or no leaching to
remove salts from the root zone
#
The amount of salt that is import
ed via irrigation has a significant
effect on
transient salinity. The amount of
water applied and quality of the ir
rigation water
determine the amount of salt that
is applied to a vineyard (Table 2.
.1)
Table 2.1. Kilograms of salt applied per h
ectare for different salinity irrigation water
and different
irrigation rates
Water Irrigation wat
Salinit er applied (m
y *m)
dS/m
200
0.2
256
0.5
640
1
64 960 1280
0
1.5
144 1920
0
2
128 640 1281920 2560
0 0
2.5
160 1602400 3200
0 0
mm of water applied to 1 hectare is equivalent to 1 100*
ML
units conversions are found in the appendix (Table B. #
2)
What causes salinity damage in pla
?nts
There are two main causes of salinity da
.mage in plants
.1
The osmotic effect, which adversely affe
cts energy expenditure
and water uptake by plants. This creates
a condition referred to as
.2
chemical drought” – plants wilt because “
of a shortage of water, even
.though the soil remains moist
Direct toxicity of salts – particularly from
sodium (Na) and chloride (Cl)
ions though boron (B) toxicity can also b
.e an issue
Crops may be affected by either the osm
otic effect or salt toxicity or by both. At
low salt concentrations toxic ions play a
dominant role; at high salt concentration
,s
it is the osmotic effect that plays a major
.role
The osmotic effect
Figure 2.3 shows the osmotic effect in pl
ants. Water moving into roots is slowed
down as the concentration of salt in the
soil water increases. This reduces the
water available to plants for growth and
.yield
Soil moisture content can change drama
tically between rainfall events. This
variation in soil moisture directly affects t
he salt concentration of the soil water. Th
e
higher the soil moisture content (wetter th
e soil), the lower the concentration of
salts, and conversely, the lower the soil
moisture content (drier the soil) the highe
r
concentration of salts. As soils become d
rier there is less water accessible for
plants and the soil water becomes increa
singly difficult to extract (matric potential
effect). In saline soils there is the added
complexity that as salt concentration
increases as the soil dries then the plant’
s ability to ‘suck’ water from the soil is
further reduced (osmotic effect). The effe
ct of increasing salt concentration in the
soil on plant available water is shown in
.Table 2.2
Ionic toxicity
Sodium, chloride and boron are specific
components of soil and water salinity th
at
can negatively impact on vine growth. Th
:ese ions can reduce growth in two ways
Direct toxicity •
Indirect effects on nutrient uptake and •
balance
Many of the effects of sodium and chlori
de are difficult to tell apart and these two
elements are commonly found together i
.n soil and water
Sodium is not an essential element with
most plants being natrophobic (sodium
hating) and having mechanisms to exclu
de sodium from uptake by the roots. The
use of rootstocks that limit the uptake of
sodium can form an effective sodium
.management strategy
6
Background facts about salinity
However, vines that can exclude
sodium at the roots may still suff
er damage from
leaf-absorption of sodium. High l
evels of sodium in the soil can al
so interfere with
the uptake of potassium and calc
ium by the vines leading to poten
tial deficiencies
.in these essential nutrients
Chloride is an essential plant mic
ro-nutrient and is easily absorbe
d through the
roots and leaves of the vine. Ho
wever, high concentrations can l
ead to chloride
toxicity and can also reduce prod
uction through imbalances with o
.ther nutrients
Chloride can compete with nitrat
e-nitrogen and phosphates for u
ptake by plant
roots leading to deficiencies in th
ese elements at high levels of so
.il water chloride
Boron, like chloride, is a negativ
ely charged anion. While low con
centrations
of boron are essential for plant g
rowth, it becomes toxic at conce
ntrations only
slightly higher than that required
.for optimum growth
Sourec: Kelly and Rengasamy (2006)
Figure 2.3. The relative water uptake by pl
ants in saline and non-saline soils. In the s
aline soil the
osmotic pressure associated with the salt r
educes the pressure gradient between the
,soil and the root
reducing the flow of water into the root. Th
is reduces the water available to the plant
.for growth and yield
7
Table 2.2. Percentage of available soil water not tak
en up by plants in different soil types, due to osmotic
.effect of a given soil salinity
LaboratoryPercentage of available soil water not t
measured soi aken up by plants due to osmotic
pressure (>1000 kPa) o
l
salinity f soil water salinity 1:5
EC (dS/m
) Sand Sandy lo Clay lo Clay
am am
0.11
0
0.25
2 0
5
0.39
5 0
0
0.50
7 2 0
0 5
0.72
10 5 1 0
0 0 5
1.00
10 8 4 4
0 1 0
1.11
10 9 5 12
0 4 0
1.25
10 1 6 22
0 0 3
0
1.50
10 1 8 40
0 0 5
0
1.64
10 1 9 50
0 0 8
0
1.75
10 10 1 58
0 0 0
0
2.00
10 10 1 76
0 0 0
0
2.33
10 10 10 100
0 0 0
Note: Field soil moisture is on the basis of gravimetric water content.
Available soil water is calculated from the field capacity and wilting
point for each soil type. It is assumed that soil salinity is due to highly
soluble salts such as sodium chloride. These data are not valid when
.the salts present are sparingly soluble such as gypsum
How does salinity affect wine grap
?e production
Grapevines are regarded as moderately
sensitive to salinity. Salinity affects
wine grape production through both os
motic and ionic processes. The effect
of increasing salinity is first observed by
a reduction in vine growth followed by
a decline in vine yield if saline conditions
persist. The reduction in vine growth
generally occurs when the average root
zone salinity over the growing period
exceeds a designated threshold value. O
ur understanding of thresholds is not
comprehensive, so we can only suggest
indicative values and is dependent on
variety and what rootstock is used. A list
of variety and rootstock threshold values
is given in Appendix A. A generalised re
sponse of own rooted grapevine growth t
o
increasing soil water salinity is given in Fi
.gure 2.4
Background facts about salinity
Re
lati
ve
gr
ow
th
rat
)%(e
is the electrical se se
Figure 2.4. The relative response of vine growth to soil salinity (EC ) where EC
conductivity of the saturated extract (Source: Mass and Hoffman 1977)
The degree of salinity also affects the amount of ions that accumulate in
,the vine
grape and ultimately wine. Our understanding of ion accumulation dyna
mics in
grapes is not comprehensive but is dependent on variety and what roots
− tock is
used (see Appendix A). The Australian Food Standards Code (P4)
+
specifies an upper limit of 1,000 mg/L solu )www.foodstandards.gov.au(
+ ble
chlorides expressed as sodium chloride (606 mg/L of Cl ). Whilst there i
s
no standard for sodium (Na ) in Australia, there are some potential expo
rt
destinations including Canada, Switzerland and Poland that do specify
. maximums for sodium which range from 60 to 500 mg/L of Na
Saline soil conditions can also cause soil to become sodic. If sodium is
present
9
in high amounts in poor quality irrigation water, it may replace calcium at
tached
to clay particles. Soil then becomes sodic causing soil structural declin
e and is
more prone to waterlogging and setting hard when dry. Hence, there is
a close
.relationship between salinity and sodicity
The following sections detail how to asse
ss the presence of a salinity problem
such as visual signs and analytical tests
(Section 3), how to monitor changes in
vineyard salinity such as routine petiole t
ests (Section 4), and what management
practices can be used to combat the pre
sence and development of saline
and related conditions such as sodic soil
s (Section 5). The key to good salinity
management is based on the principles
of assess, manage and monitor whereby
the effectiveness of a management pract
ice is monitored and assessed and
.changes made accordingly
10 Arris Agricultural & Environmental
Assessment
.3
Assessm
ent – dia
gnosis to
determin
e if
a prob
lem reall
y is relat
ed to sali
nity
There are many r
easons why vines
might perform po
orly or decline in
.health
To determine wh
ether a salinity pr
oblem is developi
ng or developed
you can
us a number of vi
sual and analytic
al methods. It is b
est not to rely on j
ust one
observation but t
o use a number o
f different diagno
stic tools e.g. vis
ual cues and
.tissue testing
Visual signs
There are a num
ber of visual sign
s of a developing
or developed sali
.nity problem
Whilst visual sign
s of salinity can b
e dramatic they s
hould always be
accompanied
with either soil an
alytical testing or
vine tissue testin
g so that misdiag
nosis is
avoided (Figure 3
.2). Some genera
l visual signs are l
.isted below
Vine signs
Shoot growth •
declines
Leaves appear •
smaller and dark
er than normal
Marginal and ti •
p burning of leav
es, followed by y
ellowing and bro
nzing
Figure 3.1a-(
Visual sympt( .)d
oms of sodium an
d chloride toxicity
are very
)similar
Mid-row signs
Slow germinati •
on and growth of
inter-row pasture/
crop species
An increase in t •
he variability of in
ter-row pasture/c
rop health
Increasing num •
bers of salt-
tolerant weeds
Soil signs
A white crust o •
n the soil surface
(Figure 3.1e)
Unusually friabl •
e soil structure in
low-lying areas
Flocculation of •
suspended clay p
articles to give un
usually clear wat
er in
puddles and d
rains
Damp patches •
in otherwise dry s
oil
Site signs
Death of trees i •
n surrounding ar
eas where sever
e problems occur
)Figure 3.1f(
So
aurc
e:
Alf
&Ca
Environmentss
al
So So
urc urc
e: e:
Wa Wa
rre rre
n B n B
urg urg
ess ess
So So
urc urc
e: e:
CSI Mc
RO Ke
Lan nzi
d a e
nd
Wa
ter
Assessment
So So
urc urc
e: e:
Pet Ma
er r ti
Dry Lo
ng a
bot
to Figure 3.2. Examples
m
of visual symptoms th
at could be confused
with salinity symptoms
: (a) potassium
deficiency and (b) leaf
senescence from heat
.stress
Note: The osmotic effect of sa
line conditions in the soil can
cause an increase in the susc
eptibility of vine to heat stress
and the resultant
.leaf senescence
Vine analysis
Grapevines integr
ate a broad range
of topsoil and sub
soil factors includi
ng the
quality of the avail
able water in the r
oot zone. Hence,
the measurement
of salt
levels in grapevin
e tissue offers the
most direct meth
od in assessing t
he presence
of problematic sal
ine conditions. Th
is is often done th
rough the collecti
on of
petioles at floweri
ng and analysis t
hrough a recogni
sed laboratory. P
etiole analysis
values at flowerin
g of greater than
0.5% sodium and
more than 1.0-
1.5% chloride
are considered to
be toxic to vine h
ealth and are sur
e signs of a salini
ty problem
.)Robinson 1992(
Adapting informat
ion from sources
such as Robinso
,n 1992
Robinson et al. (1
997) and referenc
es therein simple
interpretation cha
rts can be
developed to ass
ess the petiole an
alysis against (Fi
gure 3.3 to Figure
.3.6)
Measurements p
erformed later in t
he season, such
as petiole analysi
s at veraison
and juice analysis
during vintage, pr
ovide little opport
unity to initiate m
anagement
strategies to redu
ce the effects of s
alinity within the s
eason and are m
ore suitable
for inter seasonal
monitoring (Secti
on 4). However, t
hese measures c
an be used to
assess the prese
nce of saline con
ditions in the vine
yard (Figure 3.5 t
o Figure 3.7)
which will be usef
ul for adjusting m
anagement practi
ces in subsequen
.t seasons
Petiole Chloride (%) (Flowering)
0.0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
Non saline De Salin
vel e
opi
ng
Figure 3.3. Interpretation of flowering petiole results
for chloride (%) on a dry weight basis
Petiole Sodium (%) (Flowering)
0.0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Petiole Chloride (%) (Veraison)
0.0
0.3 0.6 0.9 1.2 1.4 1.6 1.8 2.0 2.2 2.4
Petiole Sodium (%) (Veraison)
0.0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Free run juice Chloride (mg/l)
0.0
50 100150200250300350400450 500
Develop
ing
Non salin
e
Saline
Figure 3.7. Interpretation of free run juice chloride (
mg/l)
Assessment
Soil analysis
Soil sampling for
salinity analysis i
s often used as a
diagnostic tool to
identify the
existence of salin
e soils. However,
its use in assessi
ng the cause of vi
ne growth
decline should be
treated with care.
The problem with
using a soil analy
e
sis is that
the soil samples t
aken do not nece
ssarily represent t
he root zone in w
hich the vine
is growing. In so
me instances, es
pecially in drip irri
gated vineyards,
areas in the
soil profile can de
velop significantly
high salinity level
s but only repres
ent a small
portion of the soil
volume accessed
by the vine roots.
This is illustrated
in Figure
showing 4 zo 3.8
nes of interest wh
en assessing sali
nity, as well as as
sociated soil
properties and ro
ot growth, in an e
stablished vineya
rd. Nevertheless,
an overview
of the sensitivity o
f grapevines to av
erage soil salinity
in the root zone is
presented
in Table 3.1. Thes
e threshold value
s are often asses
sed against soil s
amples taken
along the vine ro
w which have be
en sent to a reco
gnised laboratory
where the EC
level is determine
d by saturated ext
.ract (EC )
- Vine row
between emitters
Vine row - under
an emitter
Under the wheel
tracks
Middle of the
inter-row
Figure 3.8. Soil sampli
ng positions that take i
nto account the patter
ns of variation in
soil condition induced
by a drip irrigation syst
em (Source: McKenzie
.)
Figure 3.9. Surface so
il
inspection (0-10 cm)
15
Table 3.1. Criteria for average root zone soil salinity
(EC ) and potential yield reductions for vines
e
Salinity haz
ard EC dS/ Vine yield red
Effects on grapevine e
m uction growth
)%(
Non-
saline < Negligible effect o
1 n vines
0
Slightly s
aline Own-rooted vines
2 10-
begin to be
– 25
affected
4
Own rooted vines s
Sali 25- everely
ne 50 affected but some
rootstocks
are unaffected
is 1:5 measured in the field using a 1:5 soil water suspension (EC ). Whilst EC
1:5
Very sal
ine Grapevines cannot
e
8 >
be grown
– 5
successfully
0
1
6
1:5
Highly sal
ine > 0 All grapevines
will die
1
6
)adapted from Cass et al. 1995(
Soil salinity can be tested in the field unli
ke petiole analysis. Soil salinity is usually
related to the salinity determined by satu
rated extract (EC ) the relationship is
influenced by soil type. This general relati
onship is shown in Figure 3.10 as well as
its interpretation to salinity severity of the
soil. Measuring soil salinity in the field is
shown diagrammatically (Figure 3.9) and e
.using the following steps
:To measure EC in the field
Put 50-80 ml of air dried, loose soil int .1
o an appropriate sized jar (minimum
.)capacity 500 ml
Add distilled water or clean rainwater i .2
nto the jar at 5 times the volume of the
soil sample. Example: 50 ml of soil =
250 ml water. Marking the side of the ja
r
.will aid with ratio, (see figure 3.9)
Put the lid on and shake the solution f .3
or two to five minutes then allow it to
.settle for five minutes
Dip the EC meter into the top, clear pa .4
rt of the solution and take a reading
.and note the units
Remember to wash the EC probe in r .5
.ainwater after using it
Note: EC meters can give readings in a variety of different units. This
is dependant on the brand of meter and the salinity level of the sampl
.e
It is impor tant to conver t the reading into the correct units before you
do any conversion to EC or compare your readings to any Soil
salinity threshold tables. This test is only approximate and should be f
ollowed up by laboratory analysis. However, if on-farm measurements
are done properly they can be effective in assessing and benchmarki
ng soil salinity and hence be relied upon when making management
.decisions
16
Assessment
}
Loamy sa 1.54
nd
1.82
Loam
2.22
Sandy cla
2.86
y loam
4.00
EC Light clay
1:5
Heavy cla
y
}
0
e EC
saline saline Non
Slightly Highly
saline
e 1:5
Figure 3.10. Interpreta
tion of soil EC (dS/m)
measurements determi
ned by 1:5 soil water s
Put 2 lines on uspension
or by saturated paste e
a small, clear ) EC(
9 1
0
xtract (EC ) (adapted from Ca
container 1 cm
ss e
and 6 cm from
8
7
.the bottom t al. 1995)
6 Add loose soil
5 to the bottom Fill the conta
4
.mark iner
1 3
2 up to the top
1
mark with
distilled wat
er or
clean rainwa
Put the cap on
.ter
and shake for
.minutes 10
.Leave to settle
3 Once the sa
mple
has settled a
nd a
fairly-clear s
olution
is present, di
p an
EC meter ge
ntly
into the solut
,ion
but do not di
sturb
the soil. Rea
Figure 3.9. Rapid ass
essment of salinity in t
he field using a por tab
.le EC meter
Remote sensing
The development of a salinity problem is
not usually uniform and is influenced by
underlying geology, soil profile properties,
position in the landscape and previous
land use. Variation in vine performance ac
,ross a vineyard, often related to vine size
can be assessed using remote sensing te
chnology such aerial imagery (Figure
Sampling areas or zones of differe .)3.11
nt performance, either vine or soil, can
help determine whether the variation in vin
e performance is related to salinity. An
alternative method is the use of electrom
agnetic induction (EM) devices such as
the EM38 (Figure 3.12a). EM38 surveys a
re often associated with the measurement
of salinity however the EM38 device resp
onds to a number of soil factors eg soil
moisture, clay content and salinity. If using
this device to determine salinity variation
soil sampling should always be carried ou
t at each site to calibrate the instruments
against measured soil properties. The res
ult maps of the EM38 output (Figure 3.12
b)
can then be related to the soil property do
.minating the variation in the EM38 output
Figure 3.11a. Digital aerial im
Figure 3.11b. Resultant PC
agery data is used D map from aerial
to create maps of indices of vi imagery data
ne variations eg PCD
Figure 3.12a. EM38 bein Figure 3.12b. Resultant E
g used to determine M38 map showing the
potential salinity variation variation in the vineyard
in a vineyard
18
Monitoring
Monitoring: Is salinity getting .4
?better or worse
The importance of monitoring
The previous section described options for the assessment of salinity stat
us in
vineyards via the consideration of visual cues and vine and soil measure
.ments
These observations represent a snapshot in time and are influenced by s
easonal
conditions, sampling location and inter seasonal variation. Because of the
se
potential variations it is important to establish a vineyard monitoring progr
am
to quantify the trends in vineyard salinity over time. A monitoring program
in
vineyards allows managers to assess whether management practices are
lowering, maintaining or increasing salinity risk in the vineyard. It provides
an
early warning system of salinity trends that may eventually lead to serious
salinity
problems. Anticipation of a problem allows preventative action to be take
n by
vineyard managers in a cost-effective manner. This section outlines a num
ber of
.monitoring options as well as how to interpret the data you collect
Irrigation based monitoring
Water quality (e.g. salinity level) must be measured and recorded, as poo
r quality
water can affect fruit quality and create long-term soil problems. Measure
ment
of water quality for potential problems associated with salinity and sodicit
y will
indicate if there is any deterioration of the water supply. Management cha
nges can
then be implemented if potential problems with water quality are evident s
uch as
.extra leaching events and applications of gypsum
19
Quality of the irrigation water should be assessed at least 4 times during t
he
.growing season
Salinity
The addition of salts to the soil has both a toxic and osmotic effect on vin
e growth
and health. The osmotic pressure of the irrigation water is often overlooke
d. Table
shows that considerable osmotic pressure exists for water qualities gr 4.1
eater
than 1 dS/m that are outside the readily available water range. The vine is
required
to work against osmotic potential as well as the matric potential (what is
measured
.when using a tensiometer) when this water is added to the soil
Table 4.1. Relationship between water EC (dS/m) and the osmotic water potential
Osmotic Potential (kPa)
5- 10 - 24- 36 - 48- 96- 192-
Salinity thresholds for irrigation water in v
ineyards are presented in Table 4.2. To
help you to relate to the EC values in Tab
le 4.2, the human taste threshold for
salinity is 1.8 dS/m; seawater has an EC
value of 63 dS/m. It is suggested that if
irrigation water salinity is between 1.0 –
1.8 dS/m, management options such as
planting salt tolerant rootstocks, mulchin
g, maintaining ground covers, changing
the irrigation system and increasing the l
eaching fraction should be considered
.)see section 5(
Table 4.2. Guidelines for interpreting laboratory dat
a on water suitability for grapes. ‘Severe’ in this tabl 1
e
reflects an expected 25% reduction in productivity w
Degree
Potential IrrigaUnits None of Severe 2 +
tion Restriction o
Problem n Use 2 -
Slight to Mo
derate
Osmotic effects
-3
EC
< 1.0 2.7 > )Source: Neja et al. 1978; Ayers and Westcot 1994; Nicholas 2004(
1 2.7 1
2
Toxicity effects
Sodium (Na
) mg/l or p < -
pm 460
Chloride (Cl
) mg/l or < 140 530 >
ppm 140 530
Boron (B)
mg/l or 1 3 >
ppm –
3
Nitrate-
nitrogen mg/l or p – 5 30 >
)NO N( pm 30
Assumes that rainfall and extra water applied owing to inefficiencies o
f normal irrigation will supply the crop needs plus about 15 percent
.extra for salinity control
With overhead sprinkler irrigation, sodium or chloride in excess of 3 m
e/l under extreme drying conditions may result in excessive leaf
absorption, leaf burn and crop damage. If overhead sprinklers are us
ed for cooling by frequent on-off cycling, damage may occur even at
.lower concentrations
Sodicity
Water quality should also be monitored f
or its likely impact on soil structure
through its potential impact on soil sodici
ty. The amount and type of salts present
in the irrigation water have different impa
.cts on the development of soil sodicity
A high sodium adsorption ratio (SAR) ca
n cause the development of sodic soils
but the damaging effects of sodicity (dis
persion) can be reduced by high salinity
which maintains the clay in a flocculated
.state
Criteria by which to assess irrigation wat
er as to its potential sodicity hazard are
presented in Table 4.3. The potential pro
blems associated with low EC water
can easily )either from rain or irrigation(
be rectified through the application of
gypsum or by the addition of fertiliser. Sa
lts applied in this manner will elevate
the EC of the soil solution preventing pot
ential dispersion associated with the
.development of sodicity
20
Monitoring
Table 4.3. Criteria fo
r assessing the sodic
is electrical conductivity of the irrigation water iw ity hazard, and henc
a result of irrigating with various water qualities where EC
e the likely developm
iw
ent of soil sodicity, a
iw iw s
and SAR is )dS/m(
sodium adsorption r
atio of the irrigation
.water
SAR
Soil sodic
ity hazard
0.7>
None
3 – 0
Slight to mo
0.7
0.2 derate
0.2<
Severe
1.2>
None
6 – 3
Slight to mo
1.2
0.3 derate
0.3<
Severe
1.9>
None
12 – 6
Slight to mo
1.9
0.5 derate
0.5<
Severe
2.9>
None
– 12
20 2.9
Slight to m
1.3 oderate
1.3<
Severe
)source Ayers 1977(
Vine based m
onitoring
The use of vine
based measure
ments to assess
changes in vine
yard salinity
levels are the m
ost direct metho
ds to use. Plant
based measure
ments are more
representative o
f ‘average’ condi
tions as they ca
n integrate varia
ble saline
conditions over t
ime and space.
However, vine b
ased measurem
ents should not
be used in isolat
ion particularly a
s some seasona
l conditions and
lagging vine
responses can
mask an underl
ying and develo
ping problem. O
ver time, vine
based measure
ments will reflec
t the changes in
salinity conditio
.ns
Some vine base
d measurement
s are more usef
ul than others d
epending on
what the aim of
the measureme
nt is (i.e. intra or
inter seasonal
.management)
Vine based me
asurements sho
uld be performe
d each season
within a
designated repr
esentative zone
within the viney
ard. Representa
tive zones can
be established
based on existi
ng soil maps or
yield monitoring
and aerial
imagery data.
Whilst there is n
ot an establishe
d preferred met
,hod to zoning
once a samplin
g strategy is est
ablished it is im
portant to maint
ain this strategy
in order to moni
tor robust trend
.s
Petiole testing
Monitoring petiole sodium and chloride
during the growing season can potential
ly
be used to change the potential chloride
levels in the harvested fruit and the
following season. A recent study by Goo
dwin et al (2009) showed that for own
rooted shiraz vines the relationship betw
een petiole sodium levels and juice
chloride levels depended on phonologic
.al stage and environmental conditions
Whilst sodium petiole levels at flowering
were positively correlated with juice
chloride levels the relationship varied de
pending on management practices and
climate (rain) post the flowering period (
Figure 4.1a). In contrast, the relationship
between sodium petiole levels at veraiso
n and juice chloride levels was consisten
t
.)Figure 4.1b(
Petiole testing at flowering Used as an i
ndicator of potential salinity problems th
at
might be lo Fre Fre
e r e r
oming. Changes in management practic un un
Management
es juic influence juic
can influenc e C e C
.e the accumulation of salts in the grape l ( l (
mg mg
Also an indi l) l)
.cator of effective winter leaching
Petiole testing at
Used as an indicator of accu
veraison
mulated salts in the
grape. Changes in manage
ment practices have
little effect on salt levels in t
he grape. Also used to
adjust management practice
s if trending levels
are
.problematic
200
200
100
100
0
0.0 0
0.2 0.4 0.6 0.8 0.4 0.2 0.0 1.2 1.0
0.8 0.6 1.6
Petiole N Petiole N
)%( a )%( a
Figure 4.1a. Relationship b
)%( etween Petiole Na Figure 4.1b. Relationship be
levels measured at flowering tween Petiole Na
and the resultant levels measured at varai )%(
chloride levels in the free ru son and the resultant
:n juice (Source Chloride levels in the free ru
)Goodwin et al 2009 :n juice (Source
)Goodwin et al 2009
Note: Figure 4.1 should not be used as a universal relationship. It is b
ased on data derived from own root shiraz vines. Vine chloride and
sodium uptake varies depending on rootstock and variety (Walker et
.al 2010)
Monitoring
Grape juice testi
ng
The measureme
nt of grape juice
salt levels at har
vest reflects sea
sonal salinity
fluctuations and
management. T
able 4.4 shows t
he approximate
relationship
≈ % Wine Cl
between juice c
hloride levels an
d the resultant w
ine chloride leve
ls. The Europea
n
Union and Austr
alian bilateral ag
reement on win
e quality require
s wine to contai
n
less than 394 m
g/l of sodium an
d 606 mg/l of ch
.loride
Table 4.4. Relations
hip between Juice ch
loride and the resulta
nt wine chloride level
s
White vari
etiesWine Cl %
≈ Juice Cl
%
Red vari
eties .5
( Juice
ferment )%( Cl
ed on s
)kins
)Source: Walker et al 2010(
Soil based mo
nitoring
Soil based moni
toring is commo
nly used to asse
ss changes in s
.oil salinity
However, meas
urements of soil
salinity are not n
ecessarily a goo
d indication of
the salinity expe
rienced by the vi
ne. The main re
ason for this is t
he heterogeneo
us
nature of soil sal
inity within and
around the root
zone and drip e
mitter in relation
to the soil sampl
es taken. When
monitoring soil s
alinity it is import
ant to follow
consistent proce
dures and timin
g of sampling. It
is a direct meas
ure of soil salinit
,y
or sodicity, and
will provide a ve
ry useful tool in
monitoring soil s
alinity over time
i.e. looking for ‘(
trends’ over tim
.)e
The timing and f
requency of soil
based sampling
is dependent on
the type of
monitoring used
. Irrespective of
the soil based m
onitoring used t
he sampling
locations or zon
es should reflect
the major soil ty
pe of the vineya
rd and be
representative o
f the vineyard ar
ea to be monitor
.ed
Some excellent
new options are
available to mon
itor soil salinity.
The accuracy of
any monitoring
program, howev
er, has to be bal
anced against it
s cost and likely
.benefits
Soil sampling
Soil samples ar
e often used to
monitor change
s in soil conditio
.n over time
Collection is sim
ple but it can be
time consuming
if deep subsoil s
amples are
required and vin
e material gets i
n the way. Spec
ialist soil sampli
ng equipment c
an
be used but in
most cases soil
augers are all th
at are required.
When taking soi
l
samples you ne
ed consider the
time and freque
ncy and the sa
.mpling location
Location
For most consis
tent results soil
samples should
be collected un
der the drip
emitter. This are
a, however, may
not reflect the av
erage root zone
salinity. To reflec
t
average root zone salinity soil samples s
hould be collected 15-20 cm away from
the drip emitter along the vine row. Selec
t 3-4 sites using either pegs or fixed
reference points. These areas should be
.consistent from year to year
Depths
Soil sampling depths are typically at targ
et depths of 20 cm (major root zone in
topsoil), 50 cm (mid subsoil), 80 cm (bot
tom of root zone). Sampling at these soi
l
depths will typically cover the rooting de
pth of vines growing on their own roots
.and on rootstocks
Figure 4.2. Soil sampling by auger along the vine ro
w and packaging in plastic bags to send to laborator
y
Time and frequency
Samples should be taken once yearly. S
amples should be collected in early
spring (salinity levels at their lowest) or e
arly autumn before opening rains (salinity
levels at their highest). Sampling in early
spring gives you a snapshot of the soil
condition at the start of season whereby
.action can be taken if needed
Note: Soil sampling should not occur if ei
ther nutrients or gypsum have
recently been applied to the soil. Sampli
ng at this time could lead to
elevated levels of recorded salinity. Pref
erence is to sample just prior to
.these additions
All soil samples from a particular depth s
hould be bulked together, mixed and
g sent to a recognised laboratory for 500
analysis or tested on site following good
preparation practices (see Figure 3.9). It
is not necessary to go to the expense
of measuring a saturated paste extractio
n for EC measurements. The aim of the
24
Monitoring
are sufficient so
long
1:5
sampling program is monitoring and measurements of EC
as the sampling
sites are not alt
ered (i.e. remain
within the same
.soil type)
The soil sample
s can be tested
for both salinity
and sodicity. Sal
inity can be test
ed
on each soil lay
er while sodicity
may only be test
ed on the heavie
.st clay layer
Dispersion testi
ng (Figure 4.3)
provides a simpl
e way of monito
ring soil sodicity
.over time
o
n
N
o
s
l
a
k
i
n
g
,
n
o
d
i
s
p
e
r
s
i
n
o
d
S i
l s
a p
k e
i r
n s
g i
, o
n
Sl Sl
aki ak
ng in
, m g,
od str
er on
ate g
dis di
pe sp
rsi er
on si
on
Figure 4.3. Assessm
ent of an undisturbe
d soil crumb after it h
as been placed in di
stilled water for a
period of 2 hours. Hi
gher the dispersion t
he higher the sodicit
y (Source: Cass)
™FullStop
The FullStop™
Wetting Front D
etector (FullStop
WFD) is a soil w
ater monitoring
device which is
buried in the soil
and captures w
ater as it passes
through the
soil profile (Figur
e 4.4). It is a sim
ple device that r
equires no wires
,, batteries
computers or lo
ggers. The devi
ce consists of a
collection funnel
at the base and
extension tube r
ising above the
soil surface. As
water percolate
s through the so
il
profile, water ‘co
nverges’ in the
base of the funn
el and allows a f
loat to lift the
indicator at the t
op of the extens
.ion tube
A reservoir in the
base of the funn
el collects and re
tains a 5 ml sam
ple of soil
water. The samp
le is retained unti
l it is extracted. T
his soil water sa
mple is manually
extracted using
a syringe for ana
lysis of salts and
/or nutrients in th
.e soil profile
25
Location
The preferred location to install the FullSt
op WFD is directly beneath the drip
emitter. Wherever possible, FullStop WF
D should be installed in areas that are
representative of a block or irrigation zon
e. However, they may also be used
in areas where soil type or other factors
.make irrigation scheduling difficult
Furthermore, FullStop WFD can be used
in areas with known soil salinity issues in
.order to collect soil water samples
Depths
The installation depth for FullStop WFD i
s between 15 cm to 80 cm beneath
the soil surface however, in a drip irrigat
ed vineyard situation, the suggested
installation depths are 30 cm and 50 cm
placed directly beneath the dripper
These suggested depths va .)Figure 4.4(
ry depending on dripper output, irrigation
duration and root depth. For example, sh
allower placement is suitable for lower
output drippers, shorter irrigation frequen
cy, more infrequent irrigation application
or shallow rooted vines. Conversely, dee
per placement would suit higher output
drippers, longer irrigation duration or mor
e frequent irrigation application. With
more experience, placement depths ma
y be altered to suit local conditions and
.management styles
Time and frequency
The FullStop WFD should be monitored f
requently during the irrigation season
and during th )if irrigation volumes allow(
e winter period. If the indicator is in the
up position, it means that more than 20
ml of water was collected by the FullStop
WFD. The ‘indicator’ must be reset manu
.ally before it can lift for the next irrigation
After each irrigation, captured water will
wick out of the funnel, however, a 5 ml
sample of soil water will be retained for n
utrient or salt testing. The collected
water sample is drawn from the FullStop
using a syringe via 4 mm flexible tubing
attached to the base of the funnel. The s
ample should be taken as soon as
possible after irrigation as the compositio
n of the water captured in the FullStop
.can change over time
Salt and nutrient concentrations tend to
.be quite variable over short distances
Taking 5 ml from a number of FullStops
and bulking the sample can reduce the
time and cost of solution monitoring. A s
oil water sample can be measured usin
g
a hand-held salinity meter (Figure 4.4d).
Alternatively a water sample can be sent
to a laboratory for analysis of salinity and
/or nutrient levels. Laboratories usually
.require at least a 10 ml sample
Short infrequent irrigations can cause a
build up of salt at a particular point in
the soil. This build up can potentially occ
ur above the FullStop WFD (usually
associated with a lack of extractable wat
er samples). When an irrigation or
rainfall event eventually wets the soil pas
t the FullStop WFD the salts that have
accumulated above the FullStop WFD wi
ll move downwards and form part of the
26
Monitoring
Indicator up
Drippers
20 40
50
a
c
Figure 4.4. a) The F
ullStop wetting front
detector, b) suggeste
d placement of the F
ullStop wetting front
detectors beneath dr
ippers, c) extracting t
he soil water sample
, and d) testing a soil
water sample
extracted from the F
ullStop for salts. (So
urce: CSIRO)
water sample in
the FullStop WF
D. This can lead
to very high sali
nity readings
.)Figure 4.5(
Whilst this can b
e alarming it sim
ply indicates tha
t salts were
accumulating ab
ove the collectio
n point due to s
hallow irrigation
and further
leaching by irrig
ation or rainfall
may be required
.
Since the FullSt
op WFD collects
water under nea
r or saturated w
ater conditions
its interpretation
for monitoring p
urposes is very
similar to the soi
l EC saturated
extract (ECe). T
he interpretation
guide (Figure 4.
6) relates to the
soil salinity
condition at that
point in time but
remember monit
oring is about th
e observation of
trends over time
.
27
Wetted
Zone
Salt accumulation
Accumulated salt
FullSto FullS moved downward
p top
into collection tub
e
Figure 4.5. The effect of shor t infrequent irrigation e
vents that can result in the accumulation of salt
above the FullStop WFD. Larger wetting events can
then migrate these salts into the collection tube
.resulting in very high salinity readings
0 8 10 12 14 16 18 20
salineModerately
saline
Ver
saline Slightly Non
y s
alin
e
Figure 4.6. Interpretation of EC (dS/m) measuremen
t of the sample extract from the FullStop WFD
:Advantages
A simple tool for water management a •
nd soil water sample collection
A FullStop does not require any wiring •
, batteries or loggers
Detects moderate – strong wetting fro •
nts well
Stores a 5 ml soil water sample for salt •
or nutrient analysis and monitoring
Provide information on depth of irrigat •
ion
Can help detect water logging •
:Disadvantages
Cannot detect weak wetting fronts •
Requires regular monitoring •
Float must be reset manually •
Water sample must be collected man •
ually and soon after wetting event
Reservoir must be emptied before any •
additional sample can be taken
Large soil disturbance on installation. •
It may take a full season for the site to
settle back to its original compaction l
evel and provide accurate samples
For a full description, cost and ordering o
f the FullStop WFD refer to the website
.www.fullstop.com.au
28
Monitoring
SoluSAMPLER
TM
The SoluSAMPL
ER™ is compris
ed of an inert ce
ramic cup and s
ampling tube
)Figure 4.7(
buried into the s
oil. Suction is ap
plied and water
from surroundin
g soil
enters the void
within the ceram
ic cup via the dif
ferential pressur
e gradient. Wat
er
is retained withi
n the SoluSAMP
LER™ (approxi
mately 70-75 ml
of soil water) an
d is
extracted manu
ally via the sam
pling tube using
a syringe for an
alysis of salts a
/nd
or nutrients in th
e soil profile. Th
e SoluSAMPLE
R™ provides an
inexpensive way
of extracting soil
water and monit
oring soil salinit
y throughout the
,growing season
allowing u
sers to pot
entially ad
just their ir
rigation m
anageme
nt accordi
.ngly
Figure 4.7.
SoluSAMPL
ER™ compr
ises
of an iner t
ceramic cup
and samplin
g tube
.buried into the soil
Location
The SoluSAMPL
ER™ collects so
il water for testin
g and therefore,
should be
installed in area
s of the vineyard
that are of intere
st for salt or soil
nutrients. The
ceramic cup sh
ould be located
15 cm away fro
m a dripper, dir
ectly beneath th
e
dripper line. Thi
s will ensure soil
water is sample
d around the ‘dr
ying-wetting’ zo
ne
margin. When in
stalling the Solu
SAMPLER™, p
articular note sh
ould be taken to
ensure water fal
ls directly down
ward from the dr
ipper, rather tha
n running along
the dripper tube
and falling som
e distance away
.
Depths
It is recommend
ed that three Sol
uSAMPLER™ u
nits should be in
serted in the
plant root zone
at each samplin
g site. Common
installation dept
hs are 30, 60
and 90 cm withi
n 15 cm of a dri
pper (or your tar
get soil depths).
It should also
be noted that th
e SoluSAMPLE
R™ should not
be operated bef
ore irrigation
water or rainfall
reaches the tip
of the ceramic c
up, because the
suction applied
can dissipate qu
ickly and water
samples of the
wetting front ca
n potentially be
collected rather
than post irrigati
.on conditions
Time and freque
ncy
Samples should
be taken at leas
t every fortnight
during the peak
of irrigation
and once per m
onth during othe
r times. In norm
al conditions, su
ction should be
applied to the c
eramic cup appr
oximately 1 day
after irrigation or
rainfall event
and a soil water
sample can be c
ollected in the n
ext day or two. I
f the soil is
particularly dry,
suction should b
e applied imme
diately after the
irrigation and
Salinity Management Interpretation Guide
a b
c d
e f
Figure 4.8. SoluSAMPLER™ installation and measur
ement a) augering hole to desired depth, b) inser tion
of the SoluSAMPLER™, c) placement of a bentonite
plug to prevent preferential flow, d) tagged extractor
tubes, e) application of suction to collect soil water s
ample, and f) measurement of the soil water sample
using an EC meter. (Source: SARDI)
sample taken soon after. In the case of d
ry soil, water will redistribute faster prior t
o
the sample being collected and a strong
er suction may be needed. Be aware tha
t
the collection of soil water samples at dif
ferent soil water conditions will result in
more variability in the readings observed
. The important point here is to collect th
e
sample in the same manner each time li
miting the variability in the readings whic
h
allows trends to be observed more readil
.y
As previously mentioned short infrequent
irrigations can cause a build up of salt
at a particular point in the soil (see Figur
e 4.5). This build up can potentially occu
r
above the SoluSAMPLER™ (usually acc
ompanied by a lack of extractable water
samples). This can lead to very high salin
ity readings when water eventually move
s
30 Arris Agricultural & Environmental
Monitoring
past the SoluSA
MPLER™. How
ever, unlike the
FullStop WFD w
hich collects wat
er
as the wetting fr
ont passes the
SoluSAMPLER
™ can collect so
il water after the
salt
front has moved
e past allowing us
ers to monitor th
e result of irrigat
ion as opposed
to activity during
.irrigation
salineSince the SoluS
saline
AMPLER™ coll
ects water after
a period of drain
age and vine wa
ter
extraction the c
oncentration of
salts in the soil
water solution w
ill vary dependin
g
on the length of
time after an irri
gation event. W
ater extraction b
y vine roots cau
ses
an increase in t
he concentratio
n of salts in the
soil water soluti
on. Hence, it is
important to try
and use the Sol
uSAMPLER™ a
t the same time
after each irrigat
ion
event to minimiz
e this variation.
Studies have sh
own that the Sol
™uSAMPLER
EC readings are
approximately t
wice that of the
soil EC . The int
erpretation guid
e
)Figure 4.9(
relates to the soi
l salinity conditio
n at that point in
time but remem
ber
monitoring is ab
out the observat
ion of trends ov
.er time
0 40
Non Hi
gh
ly
sa
lin
e
Figure 4.9. Interpret
ation of EC (dS/m) m
easurement of a sam
ple extract from a Sol
™uSAMPLER
Advantage
Easy to install •
and use
Minimal expe •
nse and disturb
ance to root zon
e
Delivers relati •
vely small volu
me samples (up
to 70 ml)
Can be perm •
anently installed
and sampled on
demand
Enables soil •
water to be extr
acted over a ran
ge of soil moistu
re conditions
Provides infor •
mation on the tr
ends of nutrient
(e.g. nitrogen) a
nd salt transport
through soil
profiles
Disadvantage
Requires re •
gular monitoring
and maintenanc
e
Water samp •
le must be colle
cted manually a
nd soon after w
etting event
The cerami •
c cup must be s
terilised in situ a
gainst fungi eve
ry six months if
nutrient me
asurement of th
e soil water is re
quired
Sampling at •
different soil m
oisture conditio
ns increases sal
inity monitoring
variability
Further informati
on and instructio
n manual for the
SoluSAMPLER
™ can be found
on the Sentek w
ebsite www.sent
.ek.com.au
31
Salinity Management Interpretation Guide
Interpretation of trends
Once a monitoring program is in place it
is important to understand how to
interpret the data collected. The followin
g schematic diagrams represent an arra
y
of trends that can be used to interpret sh
ort (monthly) as well as longer (yearly)
measured changes in soil profile salinity
data (Figure 4.10). It is also important th
at
the interpretation is not based on a few d
ata points but many data points. Field
measurements are often variable particul
arly those that are not taken from the
.same location (e.g. soil sampling)
Note: The depths indicated in these grap
hs are arbitrary and the time and
EC scale is relative. Trends can be obser
ved intra-seasonal if samples are
able to be collected. However, samples
collected at the end (autumn) or
the beginning of the season (spring) are
a more reliable indicator of salinity
.trends
.Increasing salinity at both soil depths
Salinity conditions deteriorating
Usually associated with increasing salinity of irrigati
on
.water and irrigation reaching deeper soil layers
Should also see rising vine chloride levels. This is no
t
a sustainable practice. Need to reduce reliance on
irrigation water or use better quality water if available
.
.Decreasing salinity at both soil depths
Salinity conditions improving
Usually associated with decreasing salinity of
irrigation water, good seasonal rainfall and better
.quality water reaching deeper soil layers
Be mindful not to over irrigate and induce
.waterlogging and nutrient leaching
.Steady salinity levels at both soil depths
Salinity conditions at equilibrium
Current management practices neither increasing nor
.decreasing salinity levels in the soil profile
Assess vine chloride levels to decide whether chang
es
.to management practices are required
32 Arris Agricultural & Environmental
Monitoring
Increasing salinity at
.60 cm depth only
Salinity conditions
moderated
Usually associated w
ith deficit irrigation pr
actices, no
leaching fraction and
irrigation volumes eq
ual to water
use and evaporation.
Also associated with
ineffective
leaching by winter rai
.nfall
Monitor vine chloride
and sodium levels to
decide
whether changes to
management practic
es are
required. Will most li
kely require leaching
at some
.point
Increasing salinity at
.30 cm depth only
Salinity conditions d
eteriorating
Usually associated w
ith deficit irrigation a
nd shor t
infrequent irrigation b
elow crop requireme
nt and/or
ineffective leaching b
.y winter rainfall
Should also see risin
g vine chloride levels
. This is
not a sustainable pra
ctice. Either increase
the volume
of water applied duri
ng the season or run
irrigation
intervals for longer to
.leach salts
Decreasing salinity a
t 30 cm and increasi
ng at 60 cm
.depth
Salinity conditions i
mproving
Usually associated w
ith deficit irrigation pr
actices, no
leaching fraction and
irrigation volumes eq
ual to water
use and evaporation.
Also associated with
rainfall
moving salts down th
.e soil profile
Will most likely requir
e leaching at some p
oint but only
if evident in vine chlo
.ride analysis
Increasing salinity at
30 cm and decreasin
g at 60 cm
.depth
Salinity conditions u
nknown
Usually associated w
ith bypass flow or po
or
placement of sensor
s. Could be the rise o
f a high
quality water table c
ausing the capillary r
ise of salts to
.the soil surface
Check installation of
monitoring equipmen
t and
.groundwater levels
33
Salinity Management Interpretation Guide
.Decreasing salinity at 60 cm depth
Salinity conditions improving
Usually associated with increased amounts of water
.applied and/or more effective winter leaching
Be mindful not to over irrigate and induce waterloggi
ng
.and nutrient leaching
.Decreasing salinity at 30 cm depth
Salinity conditions improving
Usually associated with decreasing salinity of irrigati
on
water, irrigation reaching deeper soil layers, and/or
.more effective winter leaching
Monitor vine chloride levels. If levels do not fall then
.leaching will be required past the 60 cm soil depth
Figure 4.10. Schematic illustrations of changes in re
corded EC levels with time measured at two different
.soil depths
34
Management
.5
Manage
ment Pra
ctices
Irrigation man
agement
The management
of salinity is often
considered to be a
n irrigation issue r
elated to
water quality and l
eaching requirem
ents. However, th
ere a number of ot
her factors
such as design of
the irrigation syste
m that should be c
onsidered for effe
ctive
.control of salinity
Method of irrigatio
n
Our understandin
g of different irriga
tion methods for t
he control of salini
,ty
particularly in relat
ion to buried drip, i
s not comprehensi
ve. Table 5.1 desc
ribes
salinity managem
ent issues associa
ted with a range of
pressurised irrigati
on
systems. The wett
ing patterns and r
ates of flow of irrig
ation water produc
ed by
these contrasting
systems are also
strongly influence
d by soil factors, p
articularly
structure, texture,
organic matter co
ntent and the degr
ee of water repelle
.nce
Table 5.1. Salinity man
agement issues associ
ated with contrasting irri
.gation system designs
Irrigation
method Negati
ve sali
nity fe
atures
.1
Less surf
StandardWhere wetting
ace area
above-spheres benea
wetted
ground dri th low output
than clos
emitters do not
p
ely space
with wide overlap, salts t
spaced end to concent
d
emitters u
emitters ( rate
sing low
1.0m) on the fringes
output
of the spheres.
drippers. This salt
High outp
concentration i
n zones betwe
ut
emitters c
en the emitters
an create can
create proble
continuou
ms for root gro
s wetting
wth, par ticular
patterns a ly when
nd unifor
mobilised by r
m .ainfall
wetting
Above-
drip with c
.2spaced emitter
ground losely
s
)0.5m More expensive
Where the
(
than Option 1
wetting sp
Likely to have g
heres
beneath e
reater surface e
vaporation loss
ach emitte
r es
than Option 1
overlap, a
continuou
s
wetting fro
nt is creat
ed that
allows a r
elatively u
niform
flushing of
salts from
the
root zone
Microjets .4
-A relatively
Water losses vi
or mini
uniform wet
a evaporation t
sprinklers
end to be great
ting
front is crea er
ted that allo
with spray syst
ems than with
ws
a thorough
drip systems. T
flushing of he
resultant increa
salts
from the rose in near-
ot zone
ground humidit
y can
encourage vine
growth in dry w
eather, but ther
e
may be a great
er risk of fungal
outbreaks with
sprinklers unde
r moist conditio
.ns
Leaching of salts
Leaching of salts from the root-zone remai
ns the most effective technique for salt
management. Irrigation scheduling strateg
’ies such as ‘regulated deficit irrigation
and ‘partial root-zone drying’ minimise dee
p leaching and tend to accumulate
imported salts in the root-zone. The leachi
ng fraction refers to the amount of water
that needs to be applied in excess of vine
evapotranspiration requirements to flush
out accumulated salt. The extra water appl
.ied can come from irrigation or by rainfall
Low leaching fractions, caused by little rai
nfall or low irrigation allocations, increases
the net salinity retained in the root zone le
ading to a potential requirement to use salt
.tolerant rootstocks (Appendix A)
The application of leaching irrigation eve
nts has commonly been associated
with the management of salt in the root z
one. The common suggestion was that
leaching of salts can be done either as p
art of each irrigation, or it can be achieve
d
via a single large irrigation soon after har
vest. The use of leaching events during
periods of high transpiration demand is le
ss effective and efficient as leaching
events during low transpiration demand (
Figure 5.1). Best leaching of salts from th
e
topsoil occurs when the soil profile is nea
r saturation and the water applied has littl
e
salt and water is applied slowly and evenl
.y, either by rainfall or irrigation
High Low
evapotransp evapotransp
iration iration
Dry so Wet so
il il
Wetted depth
Wetted depth
Figure 5.1. Difference in water movement through t
he soil profile for the same quantity of water applied
during summer and winter (either through irrigation
or rainfall)
Table 5.2 shows the importance of rainfal
l in the salt leaching process. As rainfall
increases (e.g. moving from the Langhor
,ne Creek region to the Adelaide Hills)
there is a decrease in the number of leac
hing irrigation events that need to be
applied to prevent salt build-up in the roo
.t zone of grapevines
36
Management
The effectiveness
of rainfall assumes
that rainfall enters
the soil rather than
runs
off, hence the term
‘effective rainfall’.
This table also ass
umes that the wat
er
entering the soil is
100% effective in l
.eaching salts
Table 5.2. Leaching req
uirements (the extra irri
gation water required in
%) to maintain average
root zone
salinity less than 2 dS/
m (grapevine tolerance)
, where the total irrigati
on for the season is 0.5
and 2
megalitres1, for a range
of effective annual rainf
all totals. (Source: Tanji
and Kielen 2002)
2.0
Effective a
nnual rain
W fall, mm
a
t
e
r
q
u
a
li
t
y
,
dS/m
600
1
3%
2
25%
3
8%
4
11%
1
assumes that the amount of irri
gation applied equates to the w
ater demand of the vineyard
Recent research h
as shown that the
leaching process i
s not always comp
letely
efficient. This is th
ought to be due to
the presence of pr
eferred pathways
of water
movement throug
h the soil, which r
esults in salt build-
up in other parts o
f the
root-zone. In some
situations where s
hrinkage cracks fo
rm in saline clay s
oil, salt
crystals form on th
e crack faces in re
sponse to evapora
tion losses. If runo
ff water
can be directed d
own these cracks
before they close
up, substantial am
ounts of
salt can be leache
d quickly and dee
.ply
Application of leac
hing fractions is on
ly effective if the w
ater table is deep
enough to
receive the extra w
ater without advers
ely affecting vine g
rowth. Hence, mon
itoring
the water table usi
ng test wells and/o
r piezometers is re
commended. Subs
oil drains
may have to be ins
talled if the water t
able is high enoug
h to adversely affe
ct vine
.performance
A common practic
e in determining t
he depth of irrigati
on for leaching pu
rposes
is through soil wat
er monitoring. Wat
er monitoring allo
ws objective meas
urement
of factors such as
depth of penetrati
on of rainwater or
flood water – a ke
y factor
when assessing th
e effectiveness of
salt leaching progr
ams in vineyards.
Salinity
is usually monitor
ed in conjunction
with soil water con
tent using devises
such as
capacitance prob
es and neutron pr
.obes
Scheduling water r
esources
When growing win
e grapes under dri
p irrigation it is nec
essary to be mindf
ul of
irrigation frequenci
es to reduce the s
alt uptake by the vi
ne. Soils should no
t be
allowed to dry out t
oo much, as the sa
lts become concen
trated in the soil so
lution
as the soil dries an
d the vine may tak
e up the salt. This
will harm the vine,
wine
grapes and finally t
he wine quality. Fr
equent irrigations i
n drip will keep the
soils
close to field capacity and move salts to t
he edge of the wetted zone away from th
e
bulk of the root system. However, with lim
ited water supply this may not be possible
.
Where a range of water supplies is availa
ble that are of variable quality (i.e. level
of salinity), it is desirable that these wate
r resources be scheduled according to
phenological stage. Whilst our understan
ding of variable water quality application
s
within a growing season is still developin
g, recent research suggests that chloride
accumulation in the grape berries is mor
e related to the environmental conditions
leading up to veraison than after veraiso
n. This suggests that it may be best to
use the better quality water (e.g. runoff w
ater stored in a dam) early in the season
to maintain a low saline soil conditions d
uring the period of rapid cell growth and
division and then apply the poorer qualit
y water (eg. from a bore or a salt-
affected
river) after veraison during fruit develop
ment and maturity. This is a topic that
.requires further research
Soil management
The use of soil management practices to
.control salinity is often not considered
However, there are a number of manage
ment practices that can be used to
mitigate and control the effects of salinity
.
Mulching soil surface
Water dripping onto bare soil is undesira
:ble for several reasons
It is prone to loss by evaporation, parti •
.cularly when the soil surface is very hot
Surface sealing may occur beneath e •
ach dripper, leading to reduced
.infiltration rates
Surface soil chemical properties tend t •
o become very heterogeneous, with
strong salt concentration gradients al
ong the vine rows (mid-way between the
drippers tends to be more saline than
.) directly under the drippers
Organic mulches/composts (e.g. Figure
:5.2) can overcome these problems
The mulch/compost can act as a wick •
, which tends to produce a more
uniform downward flow of irrigation w
.ater and dissolved salts
Burrow-forming soil fauna tend to bec •
ome active at the soil-compost
boundary; this improves soil structure
(Figure 5.3), infiltration rates and
.rootzone aeration
Rapid percolation of water into the co •
/ol subsoil beneath the protective mulch
compost reduces the risk of loss by e
vaporation and encourages the leaching
.of unwanted salts in the topsoil
When applying mulch, however, the win
e grape grower must know what they are
applying. They need to ensure that the i
mported mulch is free of contaminants
and that the nutrient content is taken into
account when planning vineyard fertiliser
.strategies
Management
Figure 5.2. Compost a)
and straw mulch b) app
lied along the vine rows
to improve the physical
fer tility
of a poorly structured to
psoil
Figure 5.3. Ver tical bio
pores created by soil fa
una
beneath straw mulch al
.ong vine rows
Sodicity managem
ent in a saline envi
ronment
Gypsum is itself a
salt, albeit only sp
aringly soluble. It
provides two distin
ct soil
structural benefits
when applied to s
:odic soils
.1
Gypsum provides
calcium cations, w
hich replace sodiu
m and
magnesium cation
s associated with t
he dispersion of n
egatively
charged clay parti
.cles
The gypsum als .2
o provides a mildl
y saline soil soluti
on that suppresse
s
dispersion. How
1:5
rainfall, flooding) flow through the soil and reduce topsoil EC
.about 0.1 dS/m
ever, this “electrol
yte effect” of disso
lved gypsum only
persists while a
supply of undissol
ved gypsum is av
.ailable in the soil
The use of coar
se-crystalline mine
d gypsum (solubilit
y approximately
dS/m) maint 0.4
ains the electrolyt
e effect for longer
than finely divided
gypsum (solubil
ity approximately
1.9 dS/m). Where
the soil already
is moderately s
aline, avoid the us
e of finely divided
gypsum that may
push up the sali
nity stress on plan
ts substantially – i
nstead, use a
coarse-grade g
ypsum if a sodic la
yer requires treat
ment under these
.circumstances
Figure 5.4 shows
the combined effe
cts of gypsum app
lication on soil sta
bility
and salinity hazar
d. A gypsum treat
ed soil without resi
dual gypsum parti
cles can
become dispersiv
e and poorly drain
ed if large amount
s of low-salinity w
.ater (ie
values to less tha
n
39
20
A
Potentially 18
Dispersive B
Soils Dispersive Soils
16 Ex
ch
14 an
C ge
abl
D 12
e S
odi
Non Dispersive Soils 10 um
Per
8 ce
nta
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 ge
6
(E
Soil Electrical Conductivity. Ec1:5 (dS/m)
SP
4 )
Figure 5.4. Prediction of the changes in dispersion
and salinity characteristics with time after the initial
application of 5 t/ha gypsum to the soil (adapted from Reng 2
asamy et al. 1984). A. Initial condition of th
e 0
soil, B. Increasing soil EC as gypsum dissolves into
the soil water solution, C. Gypsum solubility reaches
maximum and displaces the sodium ions with calciu
m ions leaving the sodium ions in solution, D. Winter
rains leach the sodium ions from the soil profile ther
.eby reducing salinity
There are three main ways of applying g
:ypsum to a vineyard soil
A spreader towed by a tractor is an eff .1
ective way of adding gypsum
to the zones requiring treatment. Mec
hanical incorporation is not
essential – the gypsum will dissolve an
d travel with the wetting front
the next time it rains and/or irrigation
.water is applied
Gypsum can be applied to a field via a .2 .3
n aircraft in situations where the
ground is too boggy for ground sprea
ders and application is required
.urgently
The gypsum can be dissolved in irrigatio
n water and then be applied
.through the irrigation system
Mid-row management
The management of water from rainfall is
critical for vineyard salinity management
plans. The more rainwater that can be ca
ptured in a vineyard, the less irrigation
40
Management
water is required.
Any reduction in ir
rigation water appl
ication will therefo
re reduce
the total amount of
salt imported via t
hat water. Rainwat
er usually has a m
uch
lower salt load tha
n irrigation water,
so as much of it a
s possible needs t
o be
captured and stor
ed within vineyard
.s
One method of inc
reasing stored rai
n water in the vine
yard is good mana
+ gement
of the inter-row soi
l. If serious compa
ction is present an
d the soil has a po
or
inherent ability to r
egenerate soil stru
cture through shri
nk-swell processe
,s
ripping will improv
e the ability of that
soil to accept and
then store rain wat
er. The
transformation of
a compacted soil i
nto friable soil can
double its water h
olding
.capacity
Once the properti
es of the inter-row
are able to accept
and store rainwate
r through
appropriate soil re
mediation, it is im
portant to ensure t
hat the vine roots
are able to
grow through the
wheel compaction
zone. This will allo
w the vine roots to
access
the stored water in
the inter-row readil
.y
Ripping
Biological looseni
ng
Where the soil ha
s an inherent abilit
y to shrink and sw
ell (cation exchan
ge capacity
greater than about
15 cmol( )/kg for t
hose familiar with
the terminology), l
oosening
of compacted laye
rs can be achieve
d through wetting
and drying cycles
in the
inter-row. The use
of inter-row specie
s such as chicory
can also provide d
eep
macropores (creat
ed by deep taproo
ts) that improve th
e ability of a soil to
transmit
water. Increasing t
he transmission of
water improves th
e effectiveness of l
eaching
during periods of
high rainfall or rain
.fall intensities
Mechanical loosen
ing
When treating soil
compaction mech
anically, ensure th
at the following iss
ues are
taken into account
:
The soil needs t •
o be at its plastic l
imit (ability to han
d roll a 3 mm dia
meter
rod before brea
king – but no smal
)ler
Select a tyne de •
sign that maximis
es subsoil disturb
ance in a cost-
effective
fashion without
lifting subsoil frag
ments to the surfa
ce (e.g. Figure 5.5
)
When ripping the i
nter-row in establi
shed vineyards, c
onsider the possib
ility of
only ripping every
second inter-row if
there is concern a
bout excessive vin
e root
pruning. If the soil
is prone to dispers
ion, the benefits fr
om ripping will soo
n be lost
unless it is treated
with gypsum or a
gypsum-lime blen
d to prevent slum
ping and
.hard setting
41
Figure 5.5. Disrupting compaction zones from viney
-ard wheel tracks to improve accessibility of the inter
.row soil by grapevine roots
Nutrition
Nutrient application to overcome salinity
problems
Although studies have shown that salinit
,y reduces nutrient uptake within plants
the addition of nutrients in excess of am
-ounts considered optimal under non
saline conditions tends not to improve yi
elds. However, where chloride toxicity is
a
problem, application of nitrate compoun
ds (e.g. calcium nitrate) can improve cro
p
performance but only in nitrogen limited
.situations
Aggravation of salinity problems
Fertilizers, manures, and soil amendmen
ts include many soluble salts in high
concentrations. If placed too close to the
growing plant, the fertilizer may cause
or aggravate a salinity or toxicity proble
m. Care, therefore, should be taken in
placement as well as timing of fertilizatio
n. The lower the salt index of the fertilizer
,
the less danger there is of salt burn and
damage to seedlings or young plants. Sa
lt
indices for various fertilizers are shown in
the appendix Table C.1. If fertiliser is to
be applied in a high saline environment,
it is best to apply a little often rather than
.apply the fertiliser in one application
Nutrient deficiencies caused by irrigation
water
Water high in calcium or magnesium car
bonates/bicarbonate salts, such as bore
water from limestone aquifers, can caus
e a lime precipitation in the soil adjacent
to drip system emitters. This can cause t
he soil to become more alkaline over
time. The associated increase in alkalinit
y may lead to a decrease in availability of
.nutrients such as zinc, iron and copper
42
Glossary
Glossa
ry
Acidic soil soil
with a pH valu
e less than 7.0
.
Aggregate a gr
oup of soil part
icles that cohe
re to each othe
r (also known
as a ped
or clod). Soil a
ggregates are
the small clum
ps soil breaks i
nto when you
;dig it
small aggregat
es (microaggr
egates) clump
together to for
m aggregates.
,The size
shape and per
centage of agg
regates are ind
icators of struc
.tural form
Alkaline soil soi
l with a pH val
ue greater tha
.n 7.0
Ameliorate to i
.mprove
Anion an ion wi
th a negative c
.harge
Aquifer a water
-bearing rock f
ormation capa
ble of yielding
useful quantiti
es of
water to bores
.or springs
Biopore a large
pore created b
y biological act
ivity in the soil,
e.g. old root ch
annels
and earthworm
.tunnels
Calcareous a s
oil containing s
ignificant amo
unts of naturall
y occurring cal
cium
carbonate (Ca
CO3 – lime), w
hich fizzes wh
en dilute acid i
.s added
Cation exchang
e capacity the t
otal amount of
exchangeable
cation, or the a
bility of
negatively-
charged clay
minerals to hol
d cations, ofte
n referred to a
s the CEC. A
guide to the nu
trient status an
d structural res
ilience of a soil
.
Capillary rise th
e rise of water
through the soi
l pore system f
rom a free wat
er
.surface
Cation an ion w
ith a positive c
.harge
Clay soil particl
es smaller tha
n 0.002 mm in
diameter. Clay
particles hold
water and
exchangeable
.cations
Compaction co
mpression of s
oil into a small
er volume so t
hat porosity is
.decreased
Crusts hard sur
face layer up t
o 1 cm thick, w
hich occur mai
nly on bare soi
l when
soil aggregate
s have dispers
.ed
Deep tillage an
y tillage deepe
r than that nee
ded to produce
loose soil for a
seedbed, or de
eper than nee
ded to kill wee
ds. Its usual p
urpose is to lo
osen a
compacted su
.bsoil
Dispersion disi
ntegration of s
oil aggregates
into single soil
particles upon
;wetting
the opposite of
.flocculation
Duplex soil a s
oil which show
s a clear or abr
upt change in
soil texture bet
ween the
topsoil and the
subsoil, e.g. a
loam topsoil o
verlying a clay
.subsoil
EC is electrical
.conductivity
S
EC the electrical conductivity of a 1:5 so
.il:water extract
EC the electrical conductivity of a saturat 1:5
ed soil paste; the preferred measure of e
electrical conductivity as it is not depend
ent on soil texture and best reflects how
.salinity will affect plant growth
Exchangeable cations the positively charg
,ed cations calcium, magnesium
.potassium, sodium and aluminium
Exchangeable sodium percentage (ESP) the
amount of sodium in a soil expressed as
a percentage of the total cation exchang
.e capacity
Fertility the capacity of a soil to support
:plant growth. It has three components
.chemical, biological and physical fertility
h
Field capacity the content of water remaini
ng in a soil after free drainage is
negligible (following rain or irrigation whe
.re the soil is saturated or full of water)
Flocculation clustering of clay particles in
to microaggregates; the opposite of
.dispersion
Gravitational Potential (ψ ) the hydraulic p
otential determined by the height of the
point relative to some reference plane. A
point higher than the reference point has
.a positive gravitational potential
Gypsum calcium sulfate, used to reduce
.swelling and dispersion in sodic soil m
Hardsetting describes soil which dries ver
,y hard so that air and water movement
root penetration and seedling establishm
.ent are adversely affected
Infiltration the movement of water into a
o
.soil
Ion atomic or molecular particle carrying
.an electrical charge
Leaching downward movement of dissolv
.ed materials
Lime calcium carbonate, used to increas
e the pH of the soil (reduce acidity) and
to
improve structural stability in soil which i
.s both acidic and dispersive
Matric Potential (� ) the hydraulic potenti
al determined by the height of the water
column of the point of interest. The matri
c potential of unsaturated soil is negative
.
Nutrients required for good plant growth,
e.g. nitrogen, phosphorus and
.potassium
Organic matter living and dead plant and
.animal material
Osmotic Potential (� ) the pressure potent
ial created by different concentrations of
solutes on opposite sides of a semi-
.permeable membrane
Percolation the movement of water throu
.gh the soil
Permanent wilting point the water content
of a soil at which plant roots cannot
extract water, and plants wilt and cannot
.recover
44
Permeability a
bility of a soil t
o transmit wat
.er and gases
pH a measure
of how acidic o
r alkaline a soil
.is
Plant available
water water hel
d between fiel
d capacity and
permanent wilt
.ing point
Plastic limit the
water content
of soil above w
hich it can be r
emoulded (is p
lastic)
and below whi
ch it cannot be
remoulded (is
brittle). Soil wit
h a water cont
ent just
below the plast
ic limit is said t
o be at the ide
al soil water co
ntent for cultiv
.ation
Pore the space
between soil p
articles and soi
.l aggregates
Porosity the de
gree to which
a soil is perme
ated with pore
.s
Readily availabl
e water water h
eld between fi
eld capacity an
d refill point, of
ten
referred to as
.RAW
Refill point the
water content
of a soil where
it becomes diffi
cult for plants t
o extract
water and mor
e water is requ
ired to maintai
.n growth rates
Remote sensing
an activity that
involves obser
ving or measur
ing characteris
tics of a
certain feature
or target from
.a distance
Root zone that
part of a soil w
here the majori
ty of live plant
roots are locat
.ed
Salinity an exc
ess of water-
soluble salts (
dominantly so
dium chloride i
n Australia)
that restricts pl
ant growth, ind
icated by elect
rical conductivi
.ty
Sand soil partic
les between 0.
02 mm and 2
mm in diamete
.r
Saturated soil s
oil which is so
wet that it cont
.ains no air
Silt soil particl
es between 0.
002 mm and 0.
02 mm in diam
eter, intermedi
ate
between clay a
.nd sand
Slaking collaps
e of aggregate
s into microag
gregates upon
.wetting
Sodicity an ex
cess of excha
ngeable sodiu
m causing dis
persion to occ
.ur
Sodic layer a la
yer in the soil p
rofile that exhi
.bits sodicity
Sodium adsorpt
ion ratio (SAR) i
s the ratio of s
odium (detrime
ntal element) t
o the
combination of
calcium and m
agnesium (be
neficial eleme
.nts)
Soil profile the
vertical sequen
ce of layers in t
he soil. The thr
ee main horizo
ns are
the A (topsoil),
B (subsoil) and
C (parent rock)
.horizons
Soil structure s
oil structure is
the arrangeme
nt of the solid
component of
soil and
the spaces in
between (pore
s). Sometimes
referred to as
.structural form
Structural form
the arrangeme
nt of the solid
component of
soil and the sp
aces in
between (pore
.s)
Structural stabil
ity a measure
of aggregate c
ollapse (slakin
g and dispersi
on) upon
wetting that ch
anges structur
.al form
Structural resilience the ability of a soil to r
egain desirable structural form after
damage (e.g. compaction caused by he
.avy machinery)
Soil texture the proportion of sand, silt an
d clay in a soil, estimated by the
behaviour of a small handful of soil when
moistened and kneaded into a ball and
pressed out between the thumb and fore
.finger
Soil water water stored in, or in transit by
.drainage through, the soil
Subsoil soil between the depths 30–120
.cm T
Subsurface soil soil between the depths o
.f 10–30 cm
Topsoil soil between the depths of 0–10
.cm
Total Potential (� ) the sum of matric, gra
.vitational and osmotic potentials
Toxicity the upper limit of an elemental c
oncentration after which plant growth
.declines
Unavailable water water stored in very sm
all pores or held tightly around soil
particles that cannot be extracted by pla
.nt roots
Waterlogging saturation of a soil with wat
er caused by the application of excessiv
e
.amounts of water and /or poor drainage
Watertable upper surface of groundwater
, below which the layers of soil, rock, san
d
.or gravel are saturated with water
Appendi
xes
A. Rootstock/v
ariety salinity
tolerances
Table A1.: A guide to
salt tolerance of a ran
ge of varieties and roo
.tstocks
Soil salin
Salt-
ity thresh
Grapevine
toleranc
old (ECe)
Variety or R
e forootstock
classific
ation
0% 25% 50%
Own Roots:
Sensit Sultana, Shir
6.7
ive dS/m ,az
Chardonnay,
Pinot Noir, R
iesling
Semillon, Me
rlot, Caberne
t Franc
Cabernet Sa
uvignon, Gre
nache
Rootstocks:
3309, 1202
C, K51-40
Moder
ately Own Roots:
sensitiv Colombard
7.4
e Rootstocks:
dS/m
Kober 5BB, 5
C Teleki
Richter 110,
Richter 99,
K51-32, SO
4
Moder
ately Rootstocks:
tolerant Rupestris St.
8.2
dS/mGeorge
Ruggeri 140,
Schwarzma
nn, 101-14
Ramsey
Toler
ant 5.6
Rootstocks:
7.9
10.5
dS/
dS/m
1103 Pauls
dS/m
m en
Source: Walker et al. 2002, Tee (
et al. 2003, Zhang
) et al. 2002 and Adams et al. 2006
Note: These values are based
on field trials over a 4-6 year
period. More recent studies s
uggest that longer term expos
ure to saline
conditions results in greater a
nd more sustained yield losse
.s at lower salinity levels
47
B. Salinity conversion ta
bles
Table B1.: Multiplier factors for differe e 1:5
nt soil textures to conver t EC to EC
San
d, lo 12.4
amy
sand
Silty loa 10.2
m
8.8
S
a 7.7
n )x 11 0.1( eEC 1- of 0.1 dS m 1:5
1 -
d 6.6
y
l
o
a
m
,
l
o
a
m
equivalent to mg L
1 -
Sandy clay lo
am, clay loam
, silt
clay loam
Sandy clay, sil
ty clay, loamy 5.7
clay
Source: Cass (
) et al. 1996 4.2
Note: If the salt in
the soil is domina
ted by gypsum th
ese
conversions are
.unreliable
Example: A loam wi
th a EC dS 1.1 =
m
Table B2.: Relationship between elec
trical conductivity units and approxima
te salt concentrations
deciSiemen
s parts p
milliequival
per metre
milliSiemeEC units er ence
microSiem
)dS/m( million
per litre
ns ens
per centim
per centim ^ (
etre etre m.equiv/L
(
(
mS/cm µS/cm
0.1
100 =
100 1
1
= =
1000 1000640 10
10
= 10000
10000 = 6400 100
^
48
C. Fertiliser ef
fects on soil sal
1 inity
2 Table C1. Relative eff
ect of fer tilizer materi
3 als on the soil solution
3 4
M
4 2 4
a
4 2 4
A
n
3 2A 2 4
m
3
A
m 2 3
A
2 4 m
4 2 4
m
o
4 2 n
i
3
u
2 4 2 m
3 d
i
h
y
d
r
4 2 o
g
3
e
4 2
n
3 2 2 p
h
4 2 4
o
4 2 4 2 s
p
2 4 2
h
a
2 2
t 1
e
The salt index is for various fer tilizer materials when applied at equal weights. Sodium nitrate, with a salt index of 100, is used as a base 2
for the index
(
N
H
H
P
2
9
D
i
a
m
m
o
n
i
u
m
h
y
d
r
o
g
e
n
p
h
o
s
p
h
a
t
e
(
(
N
H
)
H
P
O
)
P
o
P
o
S
u
U
r
References and
further readin
g
Adams T, Biswas T, and Ske
wes M (2006) Monitoring soil
salinity for irrigated
horticulture. PIRSA. Report n
o. 31/02/06
Ayers RS (1977) Quality of w
ater for irrigation. Journal of Ir
rigation and Drainage
.ASAE 103, 135-154
Ayers RS and Westcot DW (1
994) Water quality for Agricult
ure, FAO Irrigation and
Drainage Paper 29 Rev. 1, FA
O Rome
Biswas TK, Dalton M, Buss P
, and Schrale G (2007) Evalu
ation of salinity-capacity
probe and suction cup device
for real time soil salinity moni
toring in South
Australian irrigated horticultur
e. In Proc. 2nd International S
ymposium on Soil
Water Measurement, 28 Oct-
2 Nov, Beltsville, Maryland, U
.SA
Biswas T and Schrale G (200
7) Sentek soluSAMPLERTM -
A Tool for Managing
Salt & Nutrient Movement in t
he Root Zone. An Instruction
:Manual Version 2.0
CRC for Irrigation Futures
Biswas TK, Cutting M, Pitt T,
Zurcher P, Hoare T, and Schr
ale G (2008) Rootzone
salinity management of premi
um wine grapes irrigated with
.poor quality water
Irrigation Australia 2008, Mel
bourne Australia
Cass A, Walker RR and Fitzp
atrick RW (1995) Vineyard so
il degradation by salt
accumulation and the effect o
n the performance of the vine
. Proceedings of the
Ninth Australian Wine Industr
y Technical Conference, Adel
.aide pp.153-160
Goodwin I, McClymont L, La
nyon D, Zerihun A, Hornbuck
le J, Gibberd M, Mowat
D, Smith D, Barnes M, Correll
R. (2009) Managing soil wate
r to target quality
and reduce environmental im
pact, GWDC Final Report: Pr
,oject No. DPI04/04
Department of Primary Indust
ries / Grape and Wine Resear
ch and Development
Corporation, Adelaide
Kamburova K and Kirilov Pl (
2008) Calculating the salt ind
ex of PK and NPK
liquid fertilizers from potassiu
m phosphates, Journal of the
University of Chemical
Technology and Metallurgy, 4
3(2): 227-230
Kelly J and Rengasamy P (2
006) Diagnosis and manage
:ment of soil constraints
transient salinity, sodicity and
alkalinity, The University of A
delaide, South Australia
Keren R (2000) Salinity In. Su
mner ME (Ed.) Handbook of s
oil science
)CRC Press: Boca Raton(
Lanyon DM, Cass A and Han
sen D (2003) The effect of soi
l properties on vine
performance, CSIRO Technic
al Report No. 34/04, CSIRO,
Australia
Mass EV and Hoffman GJ (1
977) Crop salt tolerance - cur
.rent assessment
Journal of the Irrigation and
Drainage Division 103, 115-
.134
Mullins MG, Bou
quet A, Williams
LE (1992) Biolog
y of the grapevin
e (Cambridge
)University Press
Murphy, Lawrie
& Stanger (undat
ed) Do your soils
have any of thes
e problems? If
they have, then y
ou should test yo
ur soils to see if t
hey are sodic! (N
SW Dept. of
Land & Water Co
)nservation
Nicholas P (Ed.)
(2004) Grape pr
oduction series n
o. 2: Soil, irrigati
on and nutrition
)SARDI(
Northcote, K.H. (
1979). A Factual
Key for the Reco
gnition of Australi
an Soils. 4th
Ed.(Rellim: Adela
ide)
Prior LD, Grieve
AM and Cullis B
R (1992a) Sodiu
m chloride and s
oil texture
interactions in irri
gated field grown
sultana grapevin
es. I. Yield and fr
.uit quality
Australian Journ
al of Agricultural
Research 43, 10
.51-1066
Prior LD, Grieve
AM and Cullis B
R (1992b) Sodiu
m chloride and s
oil texture
interactions in irri
gated field grown
sultana grapevin
es. II. Plant mine
,ral content
growth and physi
ology. Australian
Journal of Agricul
tural Research 4
.3, 1067-1083
Prior LD, Grieve
AM, Slavich PG
and Cullis BR (1
992c) Sodium chl
oride and soil
texture interactio
ns in irrigated fiel
d grown sultana
grapevines. III. S
oil and root
system effects. A
ustralian Journal
of Agricultural Re
search 43, 1085-
.1100
Rader LF Jr, Whi
te LM and Whitta
ker CW (1943) T
he salt index - a
measure of the
effect of fertilizer
s on the concentr
ation of the soil s
olution. Soil Scie
–nce 55:201
.208
Reuter DJ, Robin
son JB (1997) Pl
ant analysis: an i
nterpretation ma
nual, second
edition. (CSIRO:
Collingwood)
Rengasamy P an
d Olsson KA (19
91) Sodicity and
soil structure. Au
stralian Journal
of Soil Research
29, 935-952
Rengasamy P, G
reene RSB, Ford
GW and Mehanni
AH (1984) Identifi
cation of
dispersive behav
iour and the man
agement of Red-
brown Earths. A
ustralian
Journal of Soil R
esearch 22, 413-
431
Robinson JB (19
92) Grapevine nu
trition. In: ‘Viticult
ure: Volume 2 Pr
.actices’. Eds
BG Coombe and
PR Dry (Winetitle
, Adelaide) pp. 1
.78-208
Robinson JB, Tre
eby M, and Step
henson RA (199
7) Fruits, Vines a
nd nuts, in
Plant analysis: A‘
n interpretation
manual’ 2nd Editi
on Eds Reuter D
J and Robinson
JB pp 349-382
Skewes M, Ada
ms T, and Steve
ns R (2007) Salin
ity impacts of low
Murray River
flows in the Sout
h Australian Rive
rland. PIRSA. Re
port no. 05/07
Slavich PG, Pete
rson GH (1993)
Estimating the el
ectrical conductiv
ity of saturated
paste extracts fro
m 1:5 soil-water
suspensions and
texture. Australia
n Journal of
Soil Research 31
, 73-81
Tanji KK and Kielen NC (200
2) Agricultural Drainage Wate
r Management in Arid
and Semi-Arid Areas, FAO Irr
igation and Drainage Paper 6
1, FAO Rome
Tee E, Burrows D, Boland A
M & Putland S 2003, Best Irri
gation Management
Practices for Viticulture in the
Murray Darling Basin, Cooper
ative Research Centre
.for Viticulture, Adelaide
Walker RR, Blackmore DH, C
lingeleffer PR, Correll RL (20
02) Rootstock effects on
salt tolerance of irrigated field
-grown grapevines (Vitis Vinif
.era L. cv. Sultana). 1
Yield and vigour inter-
relationships. Aust. J. Grape
.Wine Res., 8:3-14
Walker RR, Blackmore DH an
d Clingeleffer PR (2010) Impa
ct of rootstock on
yield and ion concentrations i
n petiole, juice and wine of S
hiraz and Chardonnay
in different viticultural environ
ments with different irrigation
.water salinity. Aust. J
Grape Wine Res., 16:243-
.257
White RE (2003) Soils for fine
wines (Oxford University Pres
s)
Zhang X, Walker RR, Stevens
RM & Prior LD (2002) Yield s
alinity relationships of
grapevine (Vitis vinifera L.) o
n own roots and a range of ro
otstocks, Aust. J. Grape
Wine Res., 8:150-156
Salinity
Interpretation Guide
A practical reference for vineyard managers who want to learn more
.about the principles of ‘best management practice’ for salinity
:The following questions are addressed
?What is salinity •
?How is a salinity problem caused •
?What are the affects of salinity on wine grape production •
?How can salinity be identified and monitored in a vineyard •
?How can salinity be managed to minimise future impacts •
If your vineyard is not showing any signs of salinity, this guide will
inform you how to monitor your vineyard (vine, soil and water) on an
.on-going basis to help identify any developing salinity problem