Nitrogen fertilizer use in China – Contributions to food production, impacts on the environment and best management strategies

China is a big country with a huge population and limited farmland area per capita. To produce enough food for feeding the population is of vital importance for the county. A huge achievement in food production since 1949 has been made. The regression analysis in each period of 10 years shows that there is a significant positive linear correlation between the annual food production and annual chemical fertilizer N (CF-N) consumption throughout 1949–1998. However, the regression coefficient, b, in each period of 10 years since 1949 has been declining rapidly. Meanwhile, environmental pollution is becoming a serious issue. In last 20 years, N concentratjons in surface and ground water have been increasing, `Alga blooms' in lakes and `red tides' in estuaries occur frequently, and the emissions of N2O and NH3 from farmlands rise. This paper reviews the causes for the declining N efficiency and rising environmental impacts, and the strategies for better fertilizer management.

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