Effects Of Slow-release Nitrogen And Urea Blending Ratio On Different Winter Wheat Yield And Water And Nitrogen Utilization

To explore the optimal blending ratio and high nitrogen use efficiency cultivar that is beneficial to increase the yield of winter wheat in Guanzhong Plain,Shaanxi.The field experiments were conducted to study the effects of slow-release nitrogen fertilizer and common urea blending on the growth,yield and economic benefits,nitrogen uptake and utilization,water and nitrogen use efficiency,soil nitrate nitrogen distribution and residue of three different winter wheat cultivars under different nitrogen fertilizer types and blending ratios.There were three nitrogen fertilizer types and two blending ratios?U:urea,S:slow-release nitrogen fertilizer,SU₁:a mixture of slow-release nitrogen fertilizer and urea with N ratio of 8?2 and SU₂:a mixture of slow-release nitrogen fertilizer and urea with N ratio of6?4?in this experiment,and three different winter wheat cultivars mainly planted by farmers in Guanzhong Plain?Xiaoyan 22?XY22,1990s?,Xinong 979?XN979,2000s?and Zhengmai 379?ZM379,2010s??were used as the experimental material to study the effects of slow-release nitrogen fertilizer and common urea blending on plant height,leaf area index,dry mater accumulation,yield and economic benefits,nitrogen uptake and utilization of winter wheat,soil water and soil nitrate nitrogen distribution and residue.180 kg·hm^-2nitrogen was applied in this research,and no nitrogen plot was designed as the control.The main results are as follows:?1?Compared with U and S treatment,slow-release nitrogen blending with urea applied as base fertilizer in one time could improve the plant height,leaf area index,dry matter accumulation,yield and economic benefits of winter wheat significantly,and all showed a trend of SU₂treatment>SU₁treatment>S treatment>U treatment.The maximum yield and economic benefits were 7551 kg/hm²and 14552 yuan/hm²,respectively.Therefore,blending60%slow-release nitrogen with 40%urea was the most favorable to promote the growth of winter wheat and increase the yield and economic benefits?2?Compared with U and S treatment,slow-release nitrogen blending with urea applied as base fertilizer in one time helps greatly to increase the nitrogen transport of vegetative organs,the nitrogen content in the maturity stage,the apparent recovery N use efficiency,N agronomic use efficiency,partial factor productivity from applied N and the water use efficiency of different winter wheat cultviars,and all showed a trend of SU₂treatment>SU₁treatment>S treatment>U treatment.Among them,the mixing ratio of 6:4 of slow-release nitrogen fertilizer and urea was the best.?3?Blending 60%slow-release nitrogen with 40%urea,soil nitrate nitrogen was significantly higher than that under U treatment before topdressing.At the filling stage and the maturity stage,the trend of nitrate nitrogen content in the surface soil gradually showed as SUtreatment>U treatment,which is conducive to crop absorption and utilization.The deep leakage and the nitrate nitrogen residue were significantly reduced at the same time.All showed a trend of SU₂treatment>SU₁treatment>S treatment>U treatment.This showed that the combination of slow-release nitrogen fertilizer and urea can alleviate the problem of rapid release of urea in the early stage,provide sufficient nutrients for plant growth in the late stage of crop growth,fully reduce nitrogen leaching loss,improve nitrogen utilization efficiency and reduce soil environmental pollution simultaneously.?4?Considering the yield and economic benefits,as well as the utilization efficiency of water and fertilizer,blending 60%slow-release nitrogen with 40%urea was the most suitable ration in this experiment.