Effects of Nitrogen Fertilizer Rate and Ratio of Base and Topdressing on Winter Wheat Yield and Fate of Fertilizer Nitrogen

【Objective】This research was conducted to determine the effects of nitrogen fertilizer rate and ratio of base and topdressing fertilizer on wheat(Triticum aestivum L.) grain yield,fertilizer-N use efficiency,fertilizer N loss and residual N in 0～200cm layers soil under high-yield condition.Researchers had to choose the appropriate nitrogen rate and ratio of base and topdressing for obtaining profitable yield,high fertilizer N use efficiency,and reduction of possible environmental pollution.【Method】Seven treatments were included in the experiment:no N fertilizer(N0);N application rate of 168 kg and 240 kg N per ha,1:1(N1 and N4),1:2(N2 andN5) and 0:1(N3 and N6) ratios of base to topdressing N.【Result】The results showed that under a high-yield condition with this study,applying N fertilizer significantly increased grain yield and protein content,and treatment N2 and treatment N5,N6 gained higher grain yield and grain protein content;treatment N2 enhanced FNUE significantly and decreased fertilizer-N loss rate.Results also showed that the increase of either basal or topdressing r-N rate increased fertilizer N residual amount in the 0-200cm layers.It made fertilizer N move to a deeper layer.At maturity,basal fertilizer N residues proportion in 0-40,40-100,and 100-200cm to total basal residues were 38.3%-48.7%、39.7%-51.3%.0%-22%;topdressing fertilizer N of treatment N4,N5 was moved to 140-160cm,while treatment N3,N6 moved to 160-180cm and 180-200cm respectively.Basal and topdressing nitrogen residues of treatment N2 was not found in 100-200cm layers in whole growth stage.【Conclusion】As far as grain yield,FNUE,fertilizer N residue in 0-200cm layers,and fertilizer N loss are concerned,the most appropriate nitrogen fertilizetion for recommendation is treatment N2 with nitrogen rate of 168 kg·ha-1 and base to topdressing N ratio of 1:2.