The increasing drought hazard is one of the increasingly severe challenges of China′s crop produc... more The increasing drought hazard is one of the increasingly severe challenges of China′s crop production under impact of climate change. Agriculture in arid and semi-arid regions has been considered very susceptible to climate change, especially to the increasing drought impacts. In this paper, data was collected of winter wheat yield both from farm survey and field experiments in a normal climate year of 2003 and a drought year of 2009, respectively. As in the studied region, drought frequency has been increased and winter wheat yield had been much impacted by spring drought during wheat active growing. Wheat yield was seen decreased by over 30% and the plot yield variability increased from 10% to 22%~42% in the drought year of 2009 compared to of 2003. Nevertheless, in unirrigated rainfed fields, yield reduction was seen at 6% under well fertilization treatments, while irrigation only and better fertilization only brought an yield increase by 48%~64% and 30%~44% respectively compared to unirrigated respectively in the drought year. However, better fertilization in irrigated fields resulted in high yield, even higher by 36%~77% than the mean yield in the normal year. In addition, field variability of wheat yields was also reduced under irrigation and better fertilization. Therefore, drought impacts had been effectively mitigated using better designed fertilization and proper irrigation performed for the production of dry land wheat. It is suggested that available nutrient amendment and irrigation will have much potential for mitigating drought impacts on rainfed agriculture.
Microbial communities of soil aggregate-size fractions were explored with molecular and networkin... more Microbial communities of soil aggregate-size fractions were explored with molecular and networking assays for topsoil samples from a clayey rice paddy under long-term fertilization treatments. The treatments included no fertilizer (NF) as control, chemical fertilizer only (CF), chemical fertilizer with swine manure (CFM), and chemical fertilizer with rice straw return (CFS). Following a wet-sieving protocol, water-stable aggregates were separated into size fractions of large macroaggregates (L-MacA, >2,000 μm), macroaggregates (MacA, 2,000–250 μm), microaggregates (MicA, 250–53 μm), fine microaggregates (F-MicA, 53–2 μm), and fine clay (F-Clay, <2 μm). Mass proportion was 32.3–38.2% for F-MicA, 23.0–31.5% for MacA, 19.0–23.1% for MicA, 9.1–12.0% for L-MacA, and 4.9–7.5% for F-Clay, respectively. The proportion of MacA was increased, but F-Clay was reduced by fertilization, whereas the mean weight diameter was increased by 8.0–16.2% from 534.8 μm under NF to 621.5 μm under CFM....
Biochar-based compound fertilisers (BCF) are gaining increasing attention as they are cost-effect... more Biochar-based compound fertilisers (BCF) are gaining increasing attention as they are cost-effectiveness and improve soil fertility and crop yield. However, little is known about the mechanisms by which micron-size BCF particles enhance crop growth. In the present study, Wuyunjing7 rice seedlings were exposed to micron-size particles of wheat straw-based BCF (mBCF) diffused through a 25-μm nylon mesh. The control was fertilised with urea, diammonium phosphate, and potassium chloride to ensure that both treatments received comparables level of N, P, and K. The effects of mBCF on rice seedling growth were evaluated by determining the changes in nitrogen uptake and utilisation via nitrogen content measurements, short-term 15N-NH4+ influx assays, and analyses of transcript-level nutrient transporter gene expression. The shoot biomass of rice seedling treated with mBCF at the rate of 5 mg/ g soil was 33% greater than that for the control. Root and shoot 15N accumulation rates were 44% and 14% higher, respectively, in the mBCF-treated than the control. The mBCF-treated rice seedlings had higher phosphorus, potassium, and iron content than the control. Moreover, the treatments significantly differed in terms of their nutrient transporter gene expression levels. Spectroscopy and microscopy were used to visualise nutrient distributions across transverse root sections. There were relatively higher iron oxide nanoparticle and silicon-based compound concentrations in the roots of the mBCF-treated rice seedlings than in those of the control. The foregoing difference might account for the fact that the growth of the mBCF-treated rice was superior to that of the control. We demonstrated that the mBCF treatment created a more negative electrical potential at the root epidermal cell layer (~ - 160 mV) than the root surface. This potential difference may have been the driving force for mineral nutrient absorption.
An inventory of topsoil organic carbon content in household farms was performed in a village from... more An inventory of topsoil organic carbon content in household farms was performed in a village from a typical rural area with poor soil fertility in a red earth region in Jiangxi Province, South China in 2003. A statistical analysis of SOC variation with land use and household management types, and with crop management practices was conducted. The size of plots surveyed ranged from 0.03 ha to 0.63 ha, with a mean of 0.1 ha, showing consider cropland fragmentation. Topsoil SOC content ranged from 1.72 g/kg to 25.2g/kg, with a mean of 12.7g/kg, varying widely with a variety of household land management and agricultural practices arising from individual household behaviours. Land fragmentation played a minor role in SOC variation with the mean SOC content in plot size <0.1 ha being 20% lower than plot size ≥0.1ha. Nevertheless, the land use (rice fields or dry croplands) and the land contractual system (direct contract or subcontracted land) had greater impacts; SOC content in the plo...
Journal of Biology, Agriculture and Healthcare, 2014
An experiment was conducted to determine the nutrient contents and manurial value of biocompost,... more An experiment was conducted to determine the nutrient contents and manurial value of biocompost, collected from Matiari Sugar Mill, Matiari and analyzed for macro nutrients N, P and K. The biocompost was evaluated in a pot experiment on maize crop with eight treatments in factorial combinations of two rates of biocompost (0 and 10 tons ha -1 ) and four fertilizer treatments (0-0-0, 150-0-0, 150-75-0 and 150-75-60 kg ha -1 N, P and K) . The treatments were replicated three times in a randomized complete block design and maize was grown for 7 weeks. The soil was a clay loam (31% clay) with EC 0.35 dSm -1 , pH 7.87, low in organic matter (0.80%) and Olsen P (7.0 mg kg -1 ) and high in NH 4 OA C -K (320 mg kg -1 ). The nutrient contents of biocompost were 1.8% N, 1.83% P and 0.9% K. Results revealed that there were pronounced positive effects of addition of biocompost, as well as N on plant height and dry weights of maize. Plant analysis data showed that the effect biocompost and mine...
While high soil carbon stability had been well known for biochar‐amended soils, how conversion of... more While high soil carbon stability had been well known for biochar‐amended soils, how conversion of crop residues into biochar and subsequent biochar amendment (BA) would favor microbial carbon use and carbon sequestration had not been clearly understood. In this study, topsoil samples were collected from an upland soil and a paddy soil, both previously amended with straw and straw‐derived biochar. These samples were incubated with 13C‐labeled maize residue (LMR) for 140 days to compare carbon mineralization, metabolic quotient (qCO2), and microbial carbon use efficiency (CUE) under laboratory incubation. 13C‐phospholipid fatty acid (13C‐PLFA) was used to trace the use of substrate carbon by soil microorganisms. Comparing to straw amendment (SA), BA significantly decreased the native soil organic carbon (SOC) mineralization rates by 19.7%–20.1% and 9.2%–12.0% in the upland and paddy soils, respectively. Meanwhile, total carbon mineralization from the newly added LMR was significantly ...
Environmental Science and Pollution Research, 2021
As one of the most important nutrients for plant growth, phosphorus was often poorly available in... more As one of the most important nutrients for plant growth, phosphorus was often poorly available in soil. While biochar addition induced improvement of soil structure, nutrient and water retention as well as microbial activity had been well known, and the effect of biochar soil amendment (BSA) on soil phosphorus availability and plant P uptake had been not yet quantitatively assessed. In a review study, data were retrieved from 354 peer-reviewed research articles on soil available P content and P uptake under BSA published by February 2019. Then a database was established of 516 data pairs from 86 studies with and without BSA in agricultural soils. Subsequently, the effect size of biochar application was quantified relative to no application and assessed in terms of biochar conditions, soil conditions, as well as experiment conditions. In grand mean, there was a significant and great effect of BSA on soil available P and plant P uptake by 65% and 55%, respectively. The effects were ge...
Application of iron (Fe)- and silica (Si)-enhanced biochar compound fertilisers (BCF) stimulates ... more Application of iron (Fe)- and silica (Si)-enhanced biochar compound fertilisers (BCF) stimulates rice yield by increasing plant uptake of mineral nutrients. With alterations of the nutrient status in roots, element homeostasis (e.g., Fe) in the biochar-treated rice root was related to the formation of biominerals on the plaque layer and in the cortex of roots. However, the in situ characteristics of formed biominerals at the micron and sub-micron scale remain unknown. In this study, rice seedlings (Oryza sativa L.) were grown in paddy soil treated with BCF and conventional fertilizer, respectively, for 30 days. The biochar-induced changes in nutrient accumulation in roots, and the elemental composition, distribution and speciation of the biomineral composites formed in the biochar-treated roots at the micron and sub-micron scale, were investigated by a range of techniques. Results of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) showed that biochar treatmen...
Summary Projected global climate change is a potential threat for food security. Both rising atmo... more Summary Projected global climate change is a potential threat for food security. Both rising atmospheric CO2 concentrations ([CO2]) and temperatures have significant impacts on crop productivity, but the combined effects on grain quality are not well understood. We conducted an open‐air field experiment to determine the impacts of elevated [CO2] (E‐[CO2], up to 500 μmol mol−1) and warming (+2°C) on grain yield, protein and amino acid (AAs, acid digests) in a rice–winter wheat rotation system for 2 yr. E‐[CO2] increased grain yield by 11.3% for wheat and 5.9% for rice, but decreased grain protein concentration by 14.9% for wheat and by 7.0% for rice, although E‐[CO2] slightly increased the ratio of essential to nonessential AAs. With a consistent decline in grain yield, warming decreased protein yield, notably in wheat, despite a smaller increase in protein concentration. These results indicate that warming could partially negate the negative impact by E‐[CO2] on grain protein concen...
The increasing drought hazard is one of the increasingly severe challenges of China′s crop produc... more The increasing drought hazard is one of the increasingly severe challenges of China′s crop production under impact of climate change. Agriculture in arid and semi-arid regions has been considered very susceptible to climate change, especially to the increasing drought impacts. In this paper, data was collected of winter wheat yield both from farm survey and field experiments in a normal climate year of 2003 and a drought year of 2009, respectively. As in the studied region, drought frequency has been increased and winter wheat yield had been much impacted by spring drought during wheat active growing. Wheat yield was seen decreased by over 30% and the plot yield variability increased from 10% to 22%~42% in the drought year of 2009 compared to of 2003. Nevertheless, in unirrigated rainfed fields, yield reduction was seen at 6% under well fertilization treatments, while irrigation only and better fertilization only brought an yield increase by 48%~64% and 30%~44% respectively compared to unirrigated respectively in the drought year. However, better fertilization in irrigated fields resulted in high yield, even higher by 36%~77% than the mean yield in the normal year. In addition, field variability of wheat yields was also reduced under irrigation and better fertilization. Therefore, drought impacts had been effectively mitigated using better designed fertilization and proper irrigation performed for the production of dry land wheat. It is suggested that available nutrient amendment and irrigation will have much potential for mitigating drought impacts on rainfed agriculture.
Microbial communities of soil aggregate-size fractions were explored with molecular and networkin... more Microbial communities of soil aggregate-size fractions were explored with molecular and networking assays for topsoil samples from a clayey rice paddy under long-term fertilization treatments. The treatments included no fertilizer (NF) as control, chemical fertilizer only (CF), chemical fertilizer with swine manure (CFM), and chemical fertilizer with rice straw return (CFS). Following a wet-sieving protocol, water-stable aggregates were separated into size fractions of large macroaggregates (L-MacA, >2,000 μm), macroaggregates (MacA, 2,000–250 μm), microaggregates (MicA, 250–53 μm), fine microaggregates (F-MicA, 53–2 μm), and fine clay (F-Clay, <2 μm). Mass proportion was 32.3–38.2% for F-MicA, 23.0–31.5% for MacA, 19.0–23.1% for MicA, 9.1–12.0% for L-MacA, and 4.9–7.5% for F-Clay, respectively. The proportion of MacA was increased, but F-Clay was reduced by fertilization, whereas the mean weight diameter was increased by 8.0–16.2% from 534.8 μm under NF to 621.5 μm under CFM....
Biochar-based compound fertilisers (BCF) are gaining increasing attention as they are cost-effect... more Biochar-based compound fertilisers (BCF) are gaining increasing attention as they are cost-effectiveness and improve soil fertility and crop yield. However, little is known about the mechanisms by which micron-size BCF particles enhance crop growth. In the present study, Wuyunjing7 rice seedlings were exposed to micron-size particles of wheat straw-based BCF (mBCF) diffused through a 25-μm nylon mesh. The control was fertilised with urea, diammonium phosphate, and potassium chloride to ensure that both treatments received comparables level of N, P, and K. The effects of mBCF on rice seedling growth were evaluated by determining the changes in nitrogen uptake and utilisation via nitrogen content measurements, short-term 15N-NH4+ influx assays, and analyses of transcript-level nutrient transporter gene expression. The shoot biomass of rice seedling treated with mBCF at the rate of 5 mg/ g soil was 33% greater than that for the control. Root and shoot 15N accumulation rates were 44% and 14% higher, respectively, in the mBCF-treated than the control. The mBCF-treated rice seedlings had higher phosphorus, potassium, and iron content than the control. Moreover, the treatments significantly differed in terms of their nutrient transporter gene expression levels. Spectroscopy and microscopy were used to visualise nutrient distributions across transverse root sections. There were relatively higher iron oxide nanoparticle and silicon-based compound concentrations in the roots of the mBCF-treated rice seedlings than in those of the control. The foregoing difference might account for the fact that the growth of the mBCF-treated rice was superior to that of the control. We demonstrated that the mBCF treatment created a more negative electrical potential at the root epidermal cell layer (~ - 160 mV) than the root surface. This potential difference may have been the driving force for mineral nutrient absorption.
An inventory of topsoil organic carbon content in household farms was performed in a village from... more An inventory of topsoil organic carbon content in household farms was performed in a village from a typical rural area with poor soil fertility in a red earth region in Jiangxi Province, South China in 2003. A statistical analysis of SOC variation with land use and household management types, and with crop management practices was conducted. The size of plots surveyed ranged from 0.03 ha to 0.63 ha, with a mean of 0.1 ha, showing consider cropland fragmentation. Topsoil SOC content ranged from 1.72 g/kg to 25.2g/kg, with a mean of 12.7g/kg, varying widely with a variety of household land management and agricultural practices arising from individual household behaviours. Land fragmentation played a minor role in SOC variation with the mean SOC content in plot size <0.1 ha being 20% lower than plot size ≥0.1ha. Nevertheless, the land use (rice fields or dry croplands) and the land contractual system (direct contract or subcontracted land) had greater impacts; SOC content in the plo...
Journal of Biology, Agriculture and Healthcare, 2014
An experiment was conducted to determine the nutrient contents and manurial value of biocompost,... more An experiment was conducted to determine the nutrient contents and manurial value of biocompost, collected from Matiari Sugar Mill, Matiari and analyzed for macro nutrients N, P and K. The biocompost was evaluated in a pot experiment on maize crop with eight treatments in factorial combinations of two rates of biocompost (0 and 10 tons ha -1 ) and four fertilizer treatments (0-0-0, 150-0-0, 150-75-0 and 150-75-60 kg ha -1 N, P and K) . The treatments were replicated three times in a randomized complete block design and maize was grown for 7 weeks. The soil was a clay loam (31% clay) with EC 0.35 dSm -1 , pH 7.87, low in organic matter (0.80%) and Olsen P (7.0 mg kg -1 ) and high in NH 4 OA C -K (320 mg kg -1 ). The nutrient contents of biocompost were 1.8% N, 1.83% P and 0.9% K. Results revealed that there were pronounced positive effects of addition of biocompost, as well as N on plant height and dry weights of maize. Plant analysis data showed that the effect biocompost and mine...
While high soil carbon stability had been well known for biochar‐amended soils, how conversion of... more While high soil carbon stability had been well known for biochar‐amended soils, how conversion of crop residues into biochar and subsequent biochar amendment (BA) would favor microbial carbon use and carbon sequestration had not been clearly understood. In this study, topsoil samples were collected from an upland soil and a paddy soil, both previously amended with straw and straw‐derived biochar. These samples were incubated with 13C‐labeled maize residue (LMR) for 140 days to compare carbon mineralization, metabolic quotient (qCO2), and microbial carbon use efficiency (CUE) under laboratory incubation. 13C‐phospholipid fatty acid (13C‐PLFA) was used to trace the use of substrate carbon by soil microorganisms. Comparing to straw amendment (SA), BA significantly decreased the native soil organic carbon (SOC) mineralization rates by 19.7%–20.1% and 9.2%–12.0% in the upland and paddy soils, respectively. Meanwhile, total carbon mineralization from the newly added LMR was significantly ...
Environmental Science and Pollution Research, 2021
As one of the most important nutrients for plant growth, phosphorus was often poorly available in... more As one of the most important nutrients for plant growth, phosphorus was often poorly available in soil. While biochar addition induced improvement of soil structure, nutrient and water retention as well as microbial activity had been well known, and the effect of biochar soil amendment (BSA) on soil phosphorus availability and plant P uptake had been not yet quantitatively assessed. In a review study, data were retrieved from 354 peer-reviewed research articles on soil available P content and P uptake under BSA published by February 2019. Then a database was established of 516 data pairs from 86 studies with and without BSA in agricultural soils. Subsequently, the effect size of biochar application was quantified relative to no application and assessed in terms of biochar conditions, soil conditions, as well as experiment conditions. In grand mean, there was a significant and great effect of BSA on soil available P and plant P uptake by 65% and 55%, respectively. The effects were ge...
Application of iron (Fe)- and silica (Si)-enhanced biochar compound fertilisers (BCF) stimulates ... more Application of iron (Fe)- and silica (Si)-enhanced biochar compound fertilisers (BCF) stimulates rice yield by increasing plant uptake of mineral nutrients. With alterations of the nutrient status in roots, element homeostasis (e.g., Fe) in the biochar-treated rice root was related to the formation of biominerals on the plaque layer and in the cortex of roots. However, the in situ characteristics of formed biominerals at the micron and sub-micron scale remain unknown. In this study, rice seedlings (Oryza sativa L.) were grown in paddy soil treated with BCF and conventional fertilizer, respectively, for 30 days. The biochar-induced changes in nutrient accumulation in roots, and the elemental composition, distribution and speciation of the biomineral composites formed in the biochar-treated roots at the micron and sub-micron scale, were investigated by a range of techniques. Results of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) showed that biochar treatmen...
Summary Projected global climate change is a potential threat for food security. Both rising atmo... more Summary Projected global climate change is a potential threat for food security. Both rising atmospheric CO2 concentrations ([CO2]) and temperatures have significant impacts on crop productivity, but the combined effects on grain quality are not well understood. We conducted an open‐air field experiment to determine the impacts of elevated [CO2] (E‐[CO2], up to 500 μmol mol−1) and warming (+2°C) on grain yield, protein and amino acid (AAs, acid digests) in a rice–winter wheat rotation system for 2 yr. E‐[CO2] increased grain yield by 11.3% for wheat and 5.9% for rice, but decreased grain protein concentration by 14.9% for wheat and by 7.0% for rice, although E‐[CO2] slightly increased the ratio of essential to nonessential AAs. With a consistent decline in grain yield, warming decreased protein yield, notably in wheat, despite a smaller increase in protein concentration. These results indicate that warming could partially negate the negative impact by E‐[CO2] on grain protein concen...
Uploads
Papers by Genxing Pan