Environmental sustainability has become a policy priority in China. In agriculture, China has had major success in rehabilitating desertified lands through programs to convert steeply-sloped cropland to forest and lim...Environmental sustainability has become a policy priority in China. In agriculture, China has had major success in rehabilitating desertified lands through programs to convert steeply-sloped cropland to forest and limit grazing on sensitive grasslands. However, little has been done in terms of policies for agricultural nutrient management. Runoff and leaching of nutrients in chemical fertilizers and livestock manure are widely acknowledged as significant problems in China. This paper presents an evaluation of agricultural nonpoint pollution control options for China. Options analyzed include design standards（command ＆ control）, performance standards, and design and performance incentives. Evaluation criteria include economic efficiency and effectiveness, environmental impact and risk, and social criteria such as equity and food security. The evaluation indicates that the best options for China involve subsidies to farmers for changing production practices in order to reduce nonpoint emissions, combined with appropriate farmer education and technical assistance.展开更多
This study focused on the concentration change of heavy metals of sediment cores in heavily polluted north area and less polluted middle area of Fuxian Lake in Southwest China.On the basis of the analysis of Cu,Ni,Ti,...This study focused on the concentration change of heavy metals of sediment cores in heavily polluted north area and less polluted middle area of Fuxian Lake in Southwest China.On the basis of the analysis of Cu,Ni,Ti,V,Pb,Cd,and Zn concentration-depth profiles,the pollution history of heavy metals was studied using 137cesium(137Cs) dating.The sources of heavy metals were distinguished by normalization of their profiles to aluminum and analysis of heavy metal concentrations of potential source materials.Geoaccumulation index(Igeo) was used to quantify their contamination intensity.The results showed that all the heavy metals found in the Fuxian Lake sediments originated naturally before 1980s.Cu,Ni,Ti,and V were still mainly natural in the north lake after 1980s,Cu,Ni,Ti,V,and Pb were mainly natural in the middle lake at all time,but the concentrations of Pb and Zn in the north lake were influenced by industrial wastes from the phosphorus fertilizer factory and cement plants.In all the lake,the contaminations of Cd and Zn were the results of agricultural cultivation using a large amount of fertilizers and the atmospheric fallouts of dusts from cement plants.At present,the geoaccumulation indices showed that the Fuxian Lake sediments were moderately to strongly polluted by Cd in the middle lake,and unpolluted to moderately polluted by Pb and Zn and strongly polluted by Cd in the north lake.Moreover,the pollution intensities of Cd,Zn,and Pb have been increased since 1980s.展开更多
Global food production is expected to double by 2050 for feeding 9 billion people（Godfray et al.2010）,but yields had stagnated or even collapsed in 24–39%of crop-growing areas over the period 1961–2008（Ray et al....Global food production is expected to double by 2050 for feeding 9 billion people（Godfray et al.2010）,but yields had stagnated or even collapsed in 24–39%of crop-growing areas over the period 1961–2008（Ray et al.2012）,展开更多
In the coming decades,plant agriculture must produce the food needed to sustain the world＇s burgeoning population.This challenge is made more daunting in light of a changing climate,scarcity of inputs such as water a...In the coming decades,plant agriculture must produce the food needed to sustain the world＇s burgeoning population.This challenge is made more daunting in light of a changing climate,scarcity of inputs such as water and fertilizer,and the need to grow more crops on increasingly marginal land.To achieve food security,we will need to fully exploit plant genetics to develop new crop varieties that produce higher yields of healthier food.展开更多
文摘Environmental sustainability has become a policy priority in China. In agriculture, China has had major success in rehabilitating desertified lands through programs to convert steeply-sloped cropland to forest and limit grazing on sensitive grasslands. However, little has been done in terms of policies for agricultural nutrient management. Runoff and leaching of nutrients in chemical fertilizers and livestock manure are widely acknowledged as significant problems in China. This paper presents an evaluation of agricultural nonpoint pollution control options for China. Options analyzed include design standards（command ＆ control）, performance standards, and design and performance incentives. Evaluation criteria include economic efficiency and effectiveness, environmental impact and risk, and social criteria such as equity and food security. The evaluation indicates that the best options for China involve subsidies to farmers for changing production practices in order to reduce nonpoint emissions, combined with appropriate farmer education and technical assistance.
基金supported by the National Basic Research Program (973 Program) of China (Nos.2008CB418005 and 2004CB720200)the National Natural Science Foundation of China (No.40273004)
文摘This study focused on the concentration change of heavy metals of sediment cores in heavily polluted north area and less polluted middle area of Fuxian Lake in Southwest China.On the basis of the analysis of Cu,Ni,Ti,V,Pb,Cd,and Zn concentration-depth profiles,the pollution history of heavy metals was studied using 137cesium(137Cs) dating.The sources of heavy metals were distinguished by normalization of their profiles to aluminum and analysis of heavy metal concentrations of potential source materials.Geoaccumulation index(Igeo) was used to quantify their contamination intensity.The results showed that all the heavy metals found in the Fuxian Lake sediments originated naturally before 1980s.Cu,Ni,Ti,and V were still mainly natural in the north lake after 1980s,Cu,Ni,Ti,V,and Pb were mainly natural in the middle lake at all time,but the concentrations of Pb and Zn in the north lake were influenced by industrial wastes from the phosphorus fertilizer factory and cement plants.In all the lake,the contaminations of Cd and Zn were the results of agricultural cultivation using a large amount of fertilizers and the atmospheric fallouts of dusts from cement plants.At present,the geoaccumulation indices showed that the Fuxian Lake sediments were moderately to strongly polluted by Cd in the middle lake,and unpolluted to moderately polluted by Pb and Zn and strongly polluted by Cd in the north lake.Moreover,the pollution intensities of Cd,Zn,and Pb have been increased since 1980s.
文摘Global food production is expected to double by 2050 for feeding 9 billion people（Godfray et al.2010）,but yields had stagnated or even collapsed in 24–39%of crop-growing areas over the period 1961–2008（Ray et al.2012）,
基金supported in part by grants from the National Science Foundation(Nos.IOS-1444511and IOS-1339209)
文摘In the coming decades,plant agriculture must produce the food needed to sustain the world＇s burgeoning population.This challenge is made more daunting in light of a changing climate,scarcity of inputs such as water and fertilizer,and the need to grow more crops on increasingly marginal land.To achieve food security,we will need to fully exploit plant genetics to develop new crop varieties that produce higher yields of healthier food.
