Effects of Different Nitrogen Regulation on Nitrogen Fertilizer Use of Winter Wheat and Content of Soil Nitrate-N

In order to increase the crop production and reduce the environment pollution by N fertilizer,a field experiment was conducted to study the effects of different nitrogen regulation on grain yield,nitrogen utilization,accumulation of NO-3-N in soil and economic benefit.The result showed that optimized fertilization(OPT) and controlled-released fertilizer(CRF+OF and CRF) could increase grain yield and yield components,compared with farmer practice(FP).Part chemical fertilizer substituted by organic fertilizer(OPT+OF) could increase the harvest index and thousand-grain weight,but the yield was lower relatively.Much attention should be paid for the reasonable ratio of organic and inorganic fertilizers.Furthermore,the application of four measures could enhance the utilization efficiency and agronomic efficiency of nitrogen fertilizer,significantly reduce the remains of NO-3-N in 0-120 cm soil layer,and thus reduce to the nitrate pollution for ground water.The economic efficiency analysis indicated that the two measures of OPT and CRF could increase income by 744.68,883.02 Yuan/hm2 respectively,compared with FP.Took economic benefit and ecological benefit into account,the optimized fertilization reduced by 30% amount of nitrogen fertilizer and controlled-released fertilizer reduced by 53% amount of nitrogen fertilizer could be more reasonable than farmer practice,and worth to be recommended.