Integrated effect of chemical nitrogen fertilizer in high-yielding wheat field system

This study deals with the integrated effects of nitrogen fertilizer on nitrate nitrogen accumulation in soil profile, yield and absorbed nitrogen of winter wheat in Huantai high-yielding wheat field system,Shandong Province.The results shown that under the condition of 150kg/hm² of nitrogen fetilizer,nitrate nitrogen amount in 0～90cm soil layer after cutting wheat in June changed a little,as compared with that prior to sowing wheat.It was also shown that the nitrate nitrogen amount in 0～90cm layer with routine rate of nitrogen fertilizer 300kg/hm² increased markedly,especially that in 60～90cm soil layer was raised from 10.3kg/hm² to 50.2kg/hm²,which might result in the pollution of shallow ground water.Under the condition of field experiment,150kg/hm² was recommended to be the rational nitrogen application rate,which could integrated yield and ecological profits.