Effects of Nitrogen Fertilizer Rate and Combined Application of Organic Manure and Chemical Fertilizer on the Yield of Winter-wheat and Accumulation of NO_3-N in Soil

The influence of combined application of organic and chemical fertilizer at different nitrogen levels on the yield of winter-wheat and the accumulation of NO3-N in soil were studied in this paper.The yield of winter-wheat increased with the increasing of nitrogen levels.At the same nitrogen level,the yield under the combined application condition of organic and chemical fertilizer were higher than that under single application conditon.The content of soil NO3-N increased with increas ing of nitrogen application rate in different stages of winter wheat.Compared with the single application of chemical fertilizer, application of organic fertilizer and combined application of organic manure and chemical fertilizer could effectively decrease the content of soil NO3-N.Taking a comprehensive consideration on the yield of winter wheat and the accumulation of NO3-N in soil,the best nitrogen level was 200 kg/hm2 provided by organic fertilizer and chemical fertilizer with the proportion of 75%and 25%respectively.