Reducing agricultural carbon emissions is important to enable carbon emission peaking by 2030 in China.However,China's transformation towards large-scale farming brings uncertainties to carbon emission reduction.T...Reducing agricultural carbon emissions is important to enable carbon emission peaking by 2030 in China.However,China's transformation towards large-scale farming brings uncertainties to carbon emission reduction.This study quantifies the carbon emissions from cropping based on life cycle assessment and estimates the effects of farm size on carbon emissions using a fixed effects model.Furthermore,the variations of the carbon emissions from cropping driven by the changes in farm size in future years are projected through scenario analysis.Results demonstrate an inverted U-shaped change in total carbon emission from cropping as farm size increases,which is dominated by the changes in the carbon emission from fertilizer.Projections illustrate that large-scale farming transformation will postpone the peak year of total carbon emission from cropping until 2048 if the change in farm size follows a historical trend,although it is conducive to reducing total carbon emission in the long run.The findings indicate that environmental regulations to reduce fertilizer usages should be strengthened for carbon emission abatement in the early stage of large-scale farming transformation,which are also informative to other developing countries with small farm size.展开更多
China's crop structure has undergone significant changes in the last two decades since 2000,with an increase in the share of cereals,vegetables,and fruit,squeezing out other crops.As a result,land productivity,nut...China's crop structure has undergone significant changes in the last two decades since 2000,with an increase in the share of cereals,vegetables,and fruit,squeezing out other crops.As a result,land productivity,nutrient supply,and carbon emissions have changed.How to reallocate limited farmland among crops to achieve the multiple goals of agrifood systems becomes an important issue.This study explores the sources of land productivity and nutrition supply growth and carbon emissions reduction,and identifies the multiple roles of crop structural change from 2003 to 2020 based on a decomposition analysis.The results reveal that the growth within crops is still the primary driver in land productivity and nutrition supply and the reduction in carbon emissions.However,structural change also plays various roles at different periods.From 2003 to 2010,crop structural change increased the total calorie supply but lowered land productivity and contributed at least 70%of the total growth of carbon emissions.The crop structure was relatively stable,and their effects were modest from 2010 to 2015.From 2015 to 2020,the crop structural change began to play a greater role and generate synergistic effects in improving land productivity,micronutrient supply,and reducing carbon emissions,contributing to approximately a quarter of the growth of land productivity and 30%of total carbon emissions reduction.These results suggest that strategies for crop structural change should comprehensively consider its multiple impacts,aiming to achieve co-benefits while minimizing trade-offs.展开更多
A modified CQESTR model, a simple yet useful model frequently used for estimating carbon sequestration in agricultural soils, was developed and applied to evaluate the effects of intensive cropping on soil organic mat...A modified CQESTR model, a simple yet useful model frequently used for estimating carbon sequestration in agricultural soils, was developed and applied to evaluate the effects of intensive cropping on soil organic matter （SOM） dynamics and mineralization as well as to estimate carbon dioxide emission from agricultural soils at seven sites on the Huang-Huai-Hai Plain of China. The model was modified using site-specific parameters from short- and mid-term buried organic material experiments at four stages of biomass decomposition. The predicted SOM results were validated using independent data from seven long-term （10- to 20-year） soil fertility experiments in this region. Regression analysis on 1 151 pairs of predicted and measured SOM data had an r2 of 0.91 （P≤0.01）. Therefore, the modified model was able to predict the mineralization of crop residues, organic amendments, and native SOM. Linear regression also showed that SOM mineralization rate （MR） in the plow layer increased by 0.22% when annual crop yield increased by 1 t ha^-1 （P ≤ 0.01）, suggesting an improvement in SOM quality. Apparently, not only did the annual soil respiration efftux merely reflect the intensity of soil organism and plant metabolism, but also the SOM MR in the plow layer. These results suggested that the modified model was simple yet valuable in predicting SOM trends at a single agricultural field and could be a powerful tool for estimating C-storage potential and reconstructing C storage on the Huang-Huai-Hai Plain of China.展开更多
Livestock cultivation is a significant source of greenhouse gas(GHG) emissions, accounting for 14.5% of the total anthropogenic emissions. China is responsible for a considerable share of the global livestock emission...Livestock cultivation is a significant source of greenhouse gas(GHG) emissions, accounting for 14.5% of the total anthropogenic emissions. China is responsible for a considerable share of the global livestock emissions, particularly caused by pork production. We used the Kaya identity and the logarithmic mean Divisia index(LMDI) to decompose the national annual GHG emissions from enteric fermentation and manure management in pig farming in China from 1976 to 2016. We decomposed the sources of the emissions into five driving factors:(1) technological progress(e.g., feed improvement);(2) structural adjustment in the livestock sector;(3) structural adjustment in agriculture;(4) affluence;and(5) population growth. The results showed that the net GHG emissions from the pig sector in China increased 16 million tons(Mt) of carbon dioxide equivalents(CO2 eq) during the study period. The decomposition analysis revealed that structural adjustment in agriculture, growing affluence, and population growth contributed to an increase of the GHG emissions of pork production by 23, 41, and 13 Mt CO2 eq, respectively. The technological progress and structural changes in animal husbandry mitigated emissions by –51 and –11 Mt CO2 eq, respectively. Further technological progress in pig production and optimizing the economic structures are critical for further reducing GHG emissions in China's pig industry. Our results highlight the dominant role of technological changes for emission reductions in the pig farming.展开更多
Genetically Modified Crops (GMCs) and Climate Change (CC) are the two most contentious ecological issues the world faces today. Application of transgenics in agriculture is most debated because of its direct and indir...Genetically Modified Crops (GMCs) and Climate Change (CC) are the two most contentious ecological issues the world faces today. Application of transgenics in agriculture is most debated because of its direct and indirect implications. The advertized benefits in the backdrop of the potentially harmful effects on health and environment make this an issue of greater concern. On the other hand, Climate Change is a problem of enormous scale and its after-effects even more grave. The impact of climate change on agriculture, though well researched, is still very uncertain. Further, the introduction and global embrace of a technology with unverified credentials may prove to be an ill-conceived and ill-timed act. The future of GMC technology in India will be both challenging as well as exciting. Therefore any decision on this front should be taken with scientific rigor and logic. Our aim is to explore this complex inter-relationship and provide impetus for further research.展开更多
In the context of global warming,agriculture,as the second-largest source of greenhouse gas emissions after industry,had attracted widespread attention from all walks of life to reduce agricultural emissions.The carbo...In the context of global warming,agriculture,as the second-largest source of greenhouse gas emissions after industry,had attracted widespread attention from all walks of life to reduce agricultural emissions.The carbon footprint of the planting production system of the Heilongjiang Land Reclamation Area(HLRA),an important commodity grain base in China,was evaluated and analyzed in this paper.On this basis,this paper sought feasible strategies to reduce carbon emissions from two aspects:agronomic practices and cropping structure adjustment,which were particularly crucial to promote the low-carbon and sustainable development of agriculture in HLRA.Therefore,using the accounting methods in IPCC and Low Carbon Development and Guidelines for the Preparation of Provincial Greenhouse Gas Inventories compiled by the Chinese government,relevant data were collected from 2000 to 2017 in HLRA and accounted for the carbon emissions of the planting production system in four aspects:carbon emissions from agricultural inputs,N_(2)O emissions from managed soils,CH_(4) emissions from rice cultivation and straw burning emissions.Then carbon uptake consisted of seeds and straws.Finally,with farmers'incomes were set as the objective function and carbon emissions per unit of gross production value was set as the constraint,this paper simulated and optimized the cropping structure in HLRA.The results showed that there was a“stable-growing-declining”trend in the total carbon emissions and carbon uptake of the planting production system in HLRA,with total carbon emissions of 2.84×10^(10) kg and total carbon uptake of 7.49×10^(10) kg in 2017.In the past 18 years,carbon emissions per unit area and carbon emissions per unit of gross production had both shown a decreasing trend.To achieve further efficiency gains and emission reductions in the planting production system,it was recommended that the local governments strengthen the comprehensive use of straw resources,optimize irrigation and fertilization techniques,and adjust the cropping structure,i.e.,increase the planting area of maize and soybeans and reduce the planting area of rice,and increase subsidies to protect the economic returns of planters.展开更多
农业温室综合能源系统(agricultural greenhouse integrated energy system,AGIES)需深入考虑作物安全生长环境条件,优化调控多源设备功率,实现系统经济、低碳运行。提出了一种基于作物安全性的AGIES低碳控制方法,构建含电、气、热AGIE...农业温室综合能源系统(agricultural greenhouse integrated energy system,AGIES)需深入考虑作物安全生长环境条件,优化调控多源设备功率,实现系统经济、低碳运行。提出了一种基于作物安全性的AGIES低碳控制方法,构建含电、气、热AGIES供能架构,建立各农业设备功率模型,阐明能量流和功率耦合设备的能量转换机制。研究农作物生长的光照、温度、供水安全边界条件,提出作物的日光照量与小时光照量合理范围、室内恒温供热功率范围、科学供水用电功率范围与用电时间范围,并采用数学模型详细描述。提出了电、气、热碳排放核算指标,建立综合运行成本和碳排放成本最低的功率优化控制模型,采用粒子群算法求解,得到优化用能方案。通过算例仿真验证了所提方法的可行性和有效性。展开更多
基金the Natural Science Foundation of China–Bill&Melinda Gates Foundation Joint Agricultural Research Project(NSFC–BMGF72261147758)+2 种基金the National Social Science Foundation of Chinathe China Resource,Environmental and Development Research Institute,Nanjing Agricultural University,Chinathe Research Funding Project of Anhui Agricultural University,China(rc402108)。
文摘Reducing agricultural carbon emissions is important to enable carbon emission peaking by 2030 in China.However,China's transformation towards large-scale farming brings uncertainties to carbon emission reduction.This study quantifies the carbon emissions from cropping based on life cycle assessment and estimates the effects of farm size on carbon emissions using a fixed effects model.Furthermore,the variations of the carbon emissions from cropping driven by the changes in farm size in future years are projected through scenario analysis.Results demonstrate an inverted U-shaped change in total carbon emission from cropping as farm size increases,which is dominated by the changes in the carbon emission from fertilizer.Projections illustrate that large-scale farming transformation will postpone the peak year of total carbon emission from cropping until 2048 if the change in farm size follows a historical trend,although it is conducive to reducing total carbon emission in the long run.The findings indicate that environmental regulations to reduce fertilizer usages should be strengthened for carbon emission abatement in the early stage of large-scale farming transformation,which are also informative to other developing countries with small farm size.
基金This work was supported by the National Natural Science Foundation of China(72061147002 and 72373143)the National Social Science Fund of China(22&ZD085).
文摘China's crop structure has undergone significant changes in the last two decades since 2000,with an increase in the share of cereals,vegetables,and fruit,squeezing out other crops.As a result,land productivity,nutrient supply,and carbon emissions have changed.How to reallocate limited farmland among crops to achieve the multiple goals of agrifood systems becomes an important issue.This study explores the sources of land productivity and nutrition supply growth and carbon emissions reduction,and identifies the multiple roles of crop structural change from 2003 to 2020 based on a decomposition analysis.The results reveal that the growth within crops is still the primary driver in land productivity and nutrition supply and the reduction in carbon emissions.However,structural change also plays various roles at different periods.From 2003 to 2010,crop structural change increased the total calorie supply but lowered land productivity and contributed at least 70%of the total growth of carbon emissions.The crop structure was relatively stable,and their effects were modest from 2010 to 2015.From 2015 to 2020,the crop structural change began to play a greater role and generate synergistic effects in improving land productivity,micronutrient supply,and reducing carbon emissions,contributing to approximately a quarter of the growth of land productivity and 30%of total carbon emissions reduction.These results suggest that strategies for crop structural change should comprehensively consider its multiple impacts,aiming to achieve co-benefits while minimizing trade-offs.
基金Project supported by the National Key Technologies Research and Development Program of China during the 10th Five-Year Plan Period (No. 2004BA520A14C02) and the Program for Changjiang Scholars and Innovative Research Team in University of China (No. IRT0412).
文摘A modified CQESTR model, a simple yet useful model frequently used for estimating carbon sequestration in agricultural soils, was developed and applied to evaluate the effects of intensive cropping on soil organic matter （SOM） dynamics and mineralization as well as to estimate carbon dioxide emission from agricultural soils at seven sites on the Huang-Huai-Hai Plain of China. The model was modified using site-specific parameters from short- and mid-term buried organic material experiments at four stages of biomass decomposition. The predicted SOM results were validated using independent data from seven long-term （10- to 20-year） soil fertility experiments in this region. Regression analysis on 1 151 pairs of predicted and measured SOM data had an r2 of 0.91 （P≤0.01）. Therefore, the modified model was able to predict the mineralization of crop residues, organic amendments, and native SOM. Linear regression also showed that SOM mineralization rate （MR） in the plow layer increased by 0.22% when annual crop yield increased by 1 t ha^-1 （P ≤ 0.01）, suggesting an improvement in SOM quality. Apparently, not only did the annual soil respiration efftux merely reflect the intensity of soil organism and plant metabolism, but also the SOM MR in the plow layer. These results suggested that the modified model was simple yet valuable in predicting SOM trends at a single agricultural field and could be a powerful tool for estimating C-storage potential and reconstructing C storage on the Huang-Huai-Hai Plain of China.
基金financially supported by the National Social Science Fund of China (16CJL035)the China Scholarship Council Program for Visiting Scholars。
文摘Livestock cultivation is a significant source of greenhouse gas(GHG) emissions, accounting for 14.5% of the total anthropogenic emissions. China is responsible for a considerable share of the global livestock emissions, particularly caused by pork production. We used the Kaya identity and the logarithmic mean Divisia index(LMDI) to decompose the national annual GHG emissions from enteric fermentation and manure management in pig farming in China from 1976 to 2016. We decomposed the sources of the emissions into five driving factors:(1) technological progress(e.g., feed improvement);(2) structural adjustment in the livestock sector;(3) structural adjustment in agriculture;(4) affluence;and(5) population growth. The results showed that the net GHG emissions from the pig sector in China increased 16 million tons(Mt) of carbon dioxide equivalents(CO2 eq) during the study period. The decomposition analysis revealed that structural adjustment in agriculture, growing affluence, and population growth contributed to an increase of the GHG emissions of pork production by 23, 41, and 13 Mt CO2 eq, respectively. The technological progress and structural changes in animal husbandry mitigated emissions by –51 and –11 Mt CO2 eq, respectively. Further technological progress in pig production and optimizing the economic structures are critical for further reducing GHG emissions in China's pig industry. Our results highlight the dominant role of technological changes for emission reductions in the pig farming.
文摘Genetically Modified Crops (GMCs) and Climate Change (CC) are the two most contentious ecological issues the world faces today. Application of transgenics in agriculture is most debated because of its direct and indirect implications. The advertized benefits in the backdrop of the potentially harmful effects on health and environment make this an issue of greater concern. On the other hand, Climate Change is a problem of enormous scale and its after-effects even more grave. The impact of climate change on agriculture, though well researched, is still very uncertain. Further, the introduction and global embrace of a technology with unverified credentials may prove to be an ill-conceived and ill-timed act. The future of GMC technology in India will be both challenging as well as exciting. Therefore any decision on this front should be taken with scientific rigor and logic. Our aim is to explore this complex inter-relationship and provide impetus for further research.
基金the National Key Research and Development Project,Ministry of Science and Technology(Grant No.2016YFE0204600)the Innovation Team Project of the Ministry of Education(Grant No.IRT_17R105).
文摘In the context of global warming,agriculture,as the second-largest source of greenhouse gas emissions after industry,had attracted widespread attention from all walks of life to reduce agricultural emissions.The carbon footprint of the planting production system of the Heilongjiang Land Reclamation Area(HLRA),an important commodity grain base in China,was evaluated and analyzed in this paper.On this basis,this paper sought feasible strategies to reduce carbon emissions from two aspects:agronomic practices and cropping structure adjustment,which were particularly crucial to promote the low-carbon and sustainable development of agriculture in HLRA.Therefore,using the accounting methods in IPCC and Low Carbon Development and Guidelines for the Preparation of Provincial Greenhouse Gas Inventories compiled by the Chinese government,relevant data were collected from 2000 to 2017 in HLRA and accounted for the carbon emissions of the planting production system in four aspects:carbon emissions from agricultural inputs,N_(2)O emissions from managed soils,CH_(4) emissions from rice cultivation and straw burning emissions.Then carbon uptake consisted of seeds and straws.Finally,with farmers'incomes were set as the objective function and carbon emissions per unit of gross production value was set as the constraint,this paper simulated and optimized the cropping structure in HLRA.The results showed that there was a“stable-growing-declining”trend in the total carbon emissions and carbon uptake of the planting production system in HLRA,with total carbon emissions of 2.84×10^(10) kg and total carbon uptake of 7.49×10^(10) kg in 2017.In the past 18 years,carbon emissions per unit area and carbon emissions per unit of gross production had both shown a decreasing trend.To achieve further efficiency gains and emission reductions in the planting production system,it was recommended that the local governments strengthen the comprehensive use of straw resources,optimize irrigation and fertilization techniques,and adjust the cropping structure,i.e.,increase the planting area of maize and soybeans and reduce the planting area of rice,and increase subsidies to protect the economic returns of planters.
文摘农业温室综合能源系统(agricultural greenhouse integrated energy system,AGIES)需深入考虑作物安全生长环境条件,优化调控多源设备功率,实现系统经济、低碳运行。提出了一种基于作物安全性的AGIES低碳控制方法,构建含电、气、热AGIES供能架构,建立各农业设备功率模型,阐明能量流和功率耦合设备的能量转换机制。研究农作物生长的光照、温度、供水安全边界条件,提出作物的日光照量与小时光照量合理范围、室内恒温供热功率范围、科学供水用电功率范围与用电时间范围,并采用数学模型详细描述。提出了电、气、热碳排放核算指标,建立综合运行成本和碳排放成本最低的功率优化控制模型,采用粒子群算法求解,得到优化用能方案。通过算例仿真验证了所提方法的可行性和有效性。
