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It is an important composition of the global nitrogen (N) cycling for N cycling and environmental effects in agro-ecosystems.Understanding nitrate accumulation,leaching and controlling factors in Chinese farmland soils can provide a theoretical basis and technological approach for improving N management and reducing water pollution.This study statistically analyzed the nitrate accumulation,leaching and controlling factors in Chinese farmland soils by collecting previous publication results and establishing relevant database.The results showed that high nitrate accumulation in 0-100cm or below 100cm soil layers in Chinese farmland due to rapid increase of N fertilizer input in last two decades.The average accumulated amount in 0-100cm soil layer was 300 kg N ha-1,185 kg N ha-1,40 kg N ha-1 and 131 kg N ha-1 in cereal crop systems (mainly wheat,maize and rice) respectively on the North China Plain,the northwest,the northeast,and the south of Yangtze River,and the national average was 254 kg N ha-1.The nitrate accumulation was higher on the North China Plain,but lower on the northwest,the northeast,and the south of Yangtze River than the national average value.It is estimated that the total nitrate accumulation in Chinese cereal farmland is between 7.42 and 13.26Mt N in the soil,which is approximately amount to 33%-60% of the total N fertilizer consumption in China in 2004.The average nitrate accumulation in 0-100cm soil layer was 1267 kg N ha-1,652 kg N ha-1 and 254 kg N ha-1 respectively in vegetable,orchard and cereal crop systems,and the accumulation in vegetable and orchard systems was remarkably higher than that in cereal crop systems.The excess input of the N fertilizer is the main reason for high nitrate accumulation in the soil profile,and N-P-K balance input could reduce the accumulation.The precipitation and the nitrate accumulation have a parabola relationship,which means that the regions with a high or low precipitation have low accumulation,and the regions with 550-800mm precipitation has a high accumulation.High amount of nitrate accumulation also means a serious leaching of the nitrate from soil profile,and the leaching amount is about 10% of the nitrate accumulation.The N fertilizer rate in each crop should be controlled below the rate for the economic optimum or the maximum yield,and apply in right stage in order to avoid surplus of N in crop system,and reducing high nitrate accumulation and leaching losses.