本文对陇东黄锦土区苜蓿 NP 配施做了初步研究,研究表明:苜蓿施 N 和 NP 配施无效果,则施P效果显著。其回归方程为 Y=353.42+25.89x-1.87x;最高产量施 P 量为6.9kg/亩;最佳经济产量施 P量为3.71kg/亩;最好利润为28.83/亩。研究还确定了...本文对陇东黄锦土区苜蓿 NP 配施做了初步研究,研究表明:苜蓿施 N 和 NP 配施无效果,则施P效果显著。其回归方程为 Y=353.42+25.89x-1.87x;最高产量施 P 量为6.9kg/亩;最佳经济产量施 P量为3.71kg/亩;最好利润为28.83/亩。研究还确定了最大利润率的施 P 量。阐述了施 P 肥不仅能增加苜蓿的产量、而且在促进生态系统的良性循环过程中都起到了积极的作用。展开更多
China is now the world’s largest producer and user of industrial fertilizers and manures. Consequently China plays a substantial role in global N cycle dynamics and in man’s disruption of the nitrogen cycle though t...China is now the world’s largest producer and user of industrial fertilizers and manures. Consequently China plays a substantial role in global N cycle dynamics and in man’s disruption of the nitrogen cycle though there are still significant uncertainties about the size and importance of emission and leaching rates. A major cause of China’s global role is the overuse of nitrogen fertilizers, which is most serious with intensive vegetable production where application rates can be up to 50% greater than crop needs, but is also a problem with wheat, rice and maize. China’s overuse of nitrogen fertiliser over the past 10-20 years has resulted in non-point source (NPS) pollution from crop production becoming a major cause of water pollution, and the situation is projected to get worse. In contrast, water pollution from point sources such as intensive livestock production and urban or industrial development is being brought more under control. The consequences for air pollution are equally serious. Emissions of nitrous oxide from fertilizers and manures may be so large that China could be responsible for 25-30% of global emissions of this damaging greenhouse gas and of the global warming resulting from it. The main national and local issues relate particularly to low fertilizer use efficiency and the losses of ammonia and NOx that lead to acid precipitation, and leaching and run-off losses that result in high nitrate levels in groundwater and eutrophication of rivers and lakes. The reasons why farmers overuse nitrogen fertilizer are complex and not fully understood. They involve agro-climate differences between provinces and counties, farming systems and farm income structures. Although there is a wide range of institutional and technological improvements that can greatly reduce this overuse rapid progress in reducing NPS is unlikely.展开更多
文摘本文对陇东黄锦土区苜蓿 NP 配施做了初步研究,研究表明:苜蓿施 N 和 NP 配施无效果,则施P效果显著。其回归方程为 Y=353.42+25.89x-1.87x;最高产量施 P 量为6.9kg/亩;最佳经济产量施 P量为3.71kg/亩;最好利润为28.83/亩。研究还确定了最大利润率的施 P 量。阐述了施 P 肥不仅能增加苜蓿的产量、而且在促进生态系统的良性循环过程中都起到了积极的作用。
基金Project supported by the Canadian International Development Agency, Canada and the Chinese Academy of Sciences,China (No. KZCX2-413).
文摘China is now the world’s largest producer and user of industrial fertilizers and manures. Consequently China plays a substantial role in global N cycle dynamics and in man’s disruption of the nitrogen cycle though there are still significant uncertainties about the size and importance of emission and leaching rates. A major cause of China’s global role is the overuse of nitrogen fertilizers, which is most serious with intensive vegetable production where application rates can be up to 50% greater than crop needs, but is also a problem with wheat, rice and maize. China’s overuse of nitrogen fertiliser over the past 10-20 years has resulted in non-point source (NPS) pollution from crop production becoming a major cause of water pollution, and the situation is projected to get worse. In contrast, water pollution from point sources such as intensive livestock production and urban or industrial development is being brought more under control. The consequences for air pollution are equally serious. Emissions of nitrous oxide from fertilizers and manures may be so large that China could be responsible for 25-30% of global emissions of this damaging greenhouse gas and of the global warming resulting from it. The main national and local issues relate particularly to low fertilizer use efficiency and the losses of ammonia and NOx that lead to acid precipitation, and leaching and run-off losses that result in high nitrate levels in groundwater and eutrophication of rivers and lakes. The reasons why farmers overuse nitrogen fertilizer are complex and not fully understood. They involve agro-climate differences between provinces and counties, farming systems and farm income structures. Although there is a wide range of institutional and technological improvements that can greatly reduce this overuse rapid progress in reducing NPS is unlikely.
