It is never an easy task for China to feed 1.4 billion people with only 7%of the world's arable land.With nearly 30%of the world's nitrogen(N)fertilizer applied,China achieves high crop yields while facing N p...It is never an easy task for China to feed 1.4 billion people with only 7%of the world's arable land.With nearly 30%of the world's nitrogen(N)fertilizer applied,China achieves high crop yields while facing N pollution result-ing from excessive N input.Here,we calculate the farmland N budget on the national and regional scales.The N use efficiency(NUE)in China increased by 28.0%during 2005-2018.This improvement is due to the reduction in fertilization and the improvement of crop management.The fragmented farmland is changing to large-scale farmland with the increase in cultivated land area per rural population and the development of agricultural mech-anization.This opportunity brings more possibilities for precision farmland management,thus further improving NUE.The goal of an NUE of 0.6 may be achieved in the 2040s based on the current development trend.This striking N use shift in China has important implications for other developing countries.展开更多
【目的】海南省是我国稻菜轮作和香蕉种植面积较大的省份,农户投入的氮(N)和磷(P)肥远超过了作物的养分需求,对海南生态环境可能造成不利影响。研究海南典型作物体系氮磷输入、输出、盈余及土壤硝态氮累积,为评价其养分损失及环境影响...【目的】海南省是我国稻菜轮作和香蕉种植面积较大的省份,农户投入的氮(N)和磷(P)肥远超过了作物的养分需求,对海南生态环境可能造成不利影响。研究海南典型作物体系氮磷输入、输出、盈余及土壤硝态氮累积,为评价其养分损失及环境影响、提高养分管理水平提供科学依据。【方法】2021—2022年选取海南稻菜轮作和香蕉种植典型区域澄迈县为研究区,确定20个稻菜轮作田块和15个香蕉园。采用跟踪记录的方法获取所有地块的化肥施用量、有机肥施用量和秸秆还田方式及还田量等信息。采用跟踪采样的方法测定作物生物量及其养分含量。采用文献调研的方法获取研究区域土壤-作物体系养分沉降和生物固氮等其他来源数据。选取5个旱地香蕉园,采用土钻法采集土壤并测定0—400 cm土壤剖面硝态氮累积量。【结果】海南典型稻菜轮作区氮肥和磷肥投入量分别为1308 kg N·hm^(-2)(化肥和有机肥分别为975和333 kg N·hm^(-2))和515 kg P·hm^(-2)(化肥和有机肥分别为385和130 kg P·hm^(-2)),作物地上部吸氮量和吸磷量分别为248 kg N·hm^(-2)和48 kg P·hm^(-2),稻菜轮作区氮素和磷素盈余分别为1196 kg N·hm^(-2)和484 kg P·hm^(-2)。香蕉园氮肥和磷肥投入量分别为1340 kg N·hm^(-2)(化肥和有机肥分别为1293和47 kg N·hm^(-2))和447 kg P·hm^(-2)(化肥和有机肥分别为442和5 kg P·hm^(-2)),香蕉地上部吸氮量和吸磷量分别为242 kg N·hm^(-2)和23 kg P·hm^(-2),氮素和磷素盈余分别为1271 kg N·hm^(-2)和435 kg P·hm^(-2)。香蕉园0—400 cm土壤剖面硝态氮累积量为1131 kg N·hm^(-2)。【结论】过量施用氮肥和磷肥,导致海南典型区土壤-作物体系存在大量的养分盈余,旱地土壤也累积了大量的硝态氮。海南以较大的养分损失和环境代价生产热带高值水果和蔬菜,未来必须优化农田养分管理措施以保障其生态环境安全。展开更多
The nitrogen balance can serve as an indicator of the risk to the environment of nitrogen loss from agricultural land. To investigate the temporal and spatial changes in agricultural nitrogen application and its poten...The nitrogen balance can serve as an indicator of the risk to the environment of nitrogen loss from agricultural land. To investigate the temporal and spatial changes in agricultural nitrogen application and its potential threat to the environment of the Haihe Basin in China, we used a database of county-level agricultural statistics to calculate agricultural nitrogen input, output,surplus intensity, and use efficiency. Chemical fertilizer nitrogen input increased by 51.7% from1990 to 2000 and by 37.2% from 2000 to 2010, concomitant with increasing crop yields.Simultaneously, the nitrogen surplus intensity increased by 53.5% from 1990 to 2000 and by16.5% from 2000 to 2010, presenting a continuously increased environmental risk. Nitrogen use efficiency decreased from 0.46 in 1990 to 0.42 in 2000 and remained constant at 0.42 in 2010,partly due to fertilizer composition and type improvement. This level indicates that more than half of nitrogen inputs are lost in agroecosystems. Our results suggest that although the improvement in fertilizer composition and types has partially offset the decrease in nitrogen use efficiency, the environmental risk has still increased gradually over the past 20 years, along with the increase in crop yields and nitrogen application. It is important to achieve a better nitrogen balance through more effective management to significantly reduce the environmental risk,decrease nitrogen surplus intensity, and increase nitrogen use efficiency without sacrificing crop yields.展开更多
Many grassland-based dairy farms are intensifying production,i.e.,produce more milk per ha of land in response to the increasing demand for milk(by about 2%per year)in a globalized market.However,intensive dairy farmi...Many grassland-based dairy farms are intensifying production,i.e.,produce more milk per ha of land in response to the increasing demand for milk(by about 2%per year)in a globalized market.However,intensive dairy farming has been implicated for its resources use,ammonia and greenhouse gas emissions,and eutrophication impacts.This paper addresses the question of how the intensity of dairy production relates to N and P surpluses and use efficiencies on farms subjected to agri-environmental regulations.Detailed monitoring data were analyzed from 2858 grassland-based dairy farms in The Netherlands for the year 2015.The farms produced on average 925 Mg·yr^(-1)milk.Milk production per ha ranged from<10 to>30 Mg·ha^(-1)·yr^(-1).Purchased feed and manure export strongly increased with the level of intensification.Surpluses of N and P at farm level remained constant and ammonia emissions per kg milk decreased with the level of intensification.In conclusion,N and P surpluses did not differ much among dairy farms greatly differing in intensity due to legal N and P application limits and obligatory export of manure surpluses to other farms.Further,N and P use efficiencies also did not differ among dairy farms differing in intensity provided the externalization of feed production was accounted for.This paper provides lessons for proper monitoring and control of N and P cycling in dairy farming.展开更多
基金supported by the National Natural Science Foun-dation of China(Grants No.U21A2025 and 41907151)the National Key Research and Development Program of China(Grant No.2022YFD1700700).
文摘It is never an easy task for China to feed 1.4 billion people with only 7%of the world's arable land.With nearly 30%of the world's nitrogen(N)fertilizer applied,China achieves high crop yields while facing N pollution result-ing from excessive N input.Here,we calculate the farmland N budget on the national and regional scales.The N use efficiency(NUE)in China increased by 28.0%during 2005-2018.This improvement is due to the reduction in fertilization and the improvement of crop management.The fragmented farmland is changing to large-scale farmland with the increase in cultivated land area per rural population and the development of agricultural mech-anization.This opportunity brings more possibilities for precision farmland management,thus further improving NUE.The goal of an NUE of 0.6 may be achieved in the 2040s based on the current development trend.This striking N use shift in China has important implications for other developing countries.
文摘【目的】海南省是我国稻菜轮作和香蕉种植面积较大的省份,农户投入的氮(N)和磷(P)肥远超过了作物的养分需求,对海南生态环境可能造成不利影响。研究海南典型作物体系氮磷输入、输出、盈余及土壤硝态氮累积,为评价其养分损失及环境影响、提高养分管理水平提供科学依据。【方法】2021—2022年选取海南稻菜轮作和香蕉种植典型区域澄迈县为研究区,确定20个稻菜轮作田块和15个香蕉园。采用跟踪记录的方法获取所有地块的化肥施用量、有机肥施用量和秸秆还田方式及还田量等信息。采用跟踪采样的方法测定作物生物量及其养分含量。采用文献调研的方法获取研究区域土壤-作物体系养分沉降和生物固氮等其他来源数据。选取5个旱地香蕉园,采用土钻法采集土壤并测定0—400 cm土壤剖面硝态氮累积量。【结果】海南典型稻菜轮作区氮肥和磷肥投入量分别为1308 kg N·hm^(-2)(化肥和有机肥分别为975和333 kg N·hm^(-2))和515 kg P·hm^(-2)(化肥和有机肥分别为385和130 kg P·hm^(-2)),作物地上部吸氮量和吸磷量分别为248 kg N·hm^(-2)和48 kg P·hm^(-2),稻菜轮作区氮素和磷素盈余分别为1196 kg N·hm^(-2)和484 kg P·hm^(-2)。香蕉园氮肥和磷肥投入量分别为1340 kg N·hm^(-2)(化肥和有机肥分别为1293和47 kg N·hm^(-2))和447 kg P·hm^(-2)(化肥和有机肥分别为442和5 kg P·hm^(-2)),香蕉地上部吸氮量和吸磷量分别为242 kg N·hm^(-2)和23 kg P·hm^(-2),氮素和磷素盈余分别为1271 kg N·hm^(-2)和435 kg P·hm^(-2)。香蕉园0—400 cm土壤剖面硝态氮累积量为1131 kg N·hm^(-2)。【结论】过量施用氮肥和磷肥,导致海南典型区土壤-作物体系存在大量的养分盈余,旱地土壤也累积了大量的硝态氮。海南以较大的养分损失和环境代价生产热带高值水果和蔬菜,未来必须优化农田养分管理措施以保障其生态环境安全。
基金supported by the National Natural Science Foundation of China (No. 41371538)international cooperative project of the Chinese Academy of Sciences (No. KZCX2-YW-T13)the Innovation Project of the State Key Laboratory of Urban and Regional Ecology of China (No. SKLURE2013-1-02)
文摘The nitrogen balance can serve as an indicator of the risk to the environment of nitrogen loss from agricultural land. To investigate the temporal and spatial changes in agricultural nitrogen application and its potential threat to the environment of the Haihe Basin in China, we used a database of county-level agricultural statistics to calculate agricultural nitrogen input, output,surplus intensity, and use efficiency. Chemical fertilizer nitrogen input increased by 51.7% from1990 to 2000 and by 37.2% from 2000 to 2010, concomitant with increasing crop yields.Simultaneously, the nitrogen surplus intensity increased by 53.5% from 1990 to 2000 and by16.5% from 2000 to 2010, presenting a continuously increased environmental risk. Nitrogen use efficiency decreased from 0.46 in 1990 to 0.42 in 2000 and remained constant at 0.42 in 2010,partly due to fertilizer composition and type improvement. This level indicates that more than half of nitrogen inputs are lost in agroecosystems. Our results suggest that although the improvement in fertilizer composition and types has partially offset the decrease in nitrogen use efficiency, the environmental risk has still increased gradually over the past 20 years, along with the increase in crop yields and nitrogen application. It is important to achieve a better nitrogen balance through more effective management to significantly reduce the environmental risk,decrease nitrogen surplus intensity, and increase nitrogen use efficiency without sacrificing crop yields.
文摘Many grassland-based dairy farms are intensifying production,i.e.,produce more milk per ha of land in response to the increasing demand for milk(by about 2%per year)in a globalized market.However,intensive dairy farming has been implicated for its resources use,ammonia and greenhouse gas emissions,and eutrophication impacts.This paper addresses the question of how the intensity of dairy production relates to N and P surpluses and use efficiencies on farms subjected to agri-environmental regulations.Detailed monitoring data were analyzed from 2858 grassland-based dairy farms in The Netherlands for the year 2015.The farms produced on average 925 Mg·yr^(-1)milk.Milk production per ha ranged from<10 to>30 Mg·ha^(-1)·yr^(-1).Purchased feed and manure export strongly increased with the level of intensification.Surpluses of N and P at farm level remained constant and ammonia emissions per kg milk decreased with the level of intensification.In conclusion,N and P surpluses did not differ much among dairy farms greatly differing in intensity due to legal N and P application limits and obligatory export of manure surpluses to other farms.Further,N and P use efficiencies also did not differ among dairy farms differing in intensity provided the externalization of feed production was accounted for.This paper provides lessons for proper monitoring and control of N and P cycling in dairy farming.