Effect Of Nitrogen Reduction And Optimized Fertilization On Winter Wheat Yield,Water And Fertilizer Utilization In Loess Plateau

Through field experiments,the effects of five nitrogen reduction and optimized fertilization treatments on wheat yield,fertilizer utilization,nutrient uptake and transfer,and soil nutrients in dryland were studied.The fertilization treatments including farmers fertilization(FP),measured and controlled fertilization(OF),slow release urea(OFN),organic-inorganic application(OFM),inorganic fertilizer application(OFB).The results are as follows:(1)Through the measurement and control of quantitative fertilization technology,under the condition of 62.7%nitrogen reduction,the grain yield OF of winter wheat had no significant difference compared with FP,and OFM and OFB increased grain yield by 17.5%and 22.4%,respectively(P<0.05).Each of the nitrogen reduction optimized fertilization treatments mainly increases the yield by affecting the number of ears per hectare of wheat.The net income of OF,OFN,OFM and OFB treatment increased by 23.6%?125.2%compared with FP.(2)Nitrogen and phosphorus uptake in various organs of wheat at maturity are mainly distributed in the grain,and potassium is mainly distributed in the stems and leaves.Nitrogen uptake OFM and OFB increased by 15.7%and 24.2%,respectively.The uptake of OFN,OFM and OFB increased by 21.5%?44.9%(P<0.05).The uptake of potassium by OFO,OFM,OFB Compared with FP,the increase ranged from 13.7%to 18.5%(P<0.05).The potassium absorption of OFN,OFM and OFB in stems and leaves increased by 6.3%?35.8%compared with FP.It is indicated that the optimized fertilization treatment can improve the nutrient content of wheat grains,and the effect of applying organic fertilizer and biological fertilizer is better.At the same time,OFB increased the nitrogen transfer and flowering phosphorus transfer before flowering,OFM mainly increased the nitrogen absorption after flowering,and OFN contributed a lot to the phosphorus absorption after flowering.(3)The change of water storage in 0-200cm soil layer was mainly concentrated in 0-100cm soil layer,and OFM and OFB were increased by 10.1%and 9.7%,respectively(P<0.05).The water use efficiency OFM and OFB increased by 25.9%and 33.9%,respectively,compared with FP(P<0.05).During the growth period,the production efficiency of OFM and OFB was significantly higher than that of FP by 17.4%and 22.1%(P<0.05).The apparent recovery rate,partial productivity and agronmic efficiency OFB increased by 239,0%,228.0%and 239.0%(P<0.05),respectively,and OFM increased by 1 85.0%,215.0%and 185.0%(P<0.05).The partial productivity of nitrogen fertilizer OFN and OF increased by 184.0%and 182.0%compared with FP(P<0.05).(4)FP mainly increased the risk of nitrate leaching in 100?200cm soil layer.The residual nitrate content of OFN,OFM and OFB decreased by 49.4%?53.9%(P<0.05).0-200cm soil available phosphorus storage changes mainly concentrated in the 0-40cm soil layer.OFB increased the total storage of available phosphorus in the 0-200cm soil layer by 200%(P<0.05).The changes of available potassium storage in 0-200cm soils showed significant increases in OFB,OFM and OFN,FP and OF decreased,and FP decreased most.(5)The recombinant organic carbon and recombinant organic nitrogen treated by OFB increased by 23.4%and 34.2%,respectively(P<0.05).The soluble organic carbon treated by FP increased by 12.6%?14.0%(P<0.05)compared with OFN and OFB.The soluble organic nitrogen in FP treatment increased by 29.8%?61.4%(P<0.05)compared with OF,OFN,OFM and OFB.(6)Nitrogen-optimized fertilization has different degrees of soil microbial activity.Among them,OFM and OFB significantly increased the soil microbial biomass carbon,soil microbial biomass nitrogen,soil microbial biomass phosphorus activity from jointing to flowering stage;OFB significantly increased soil urease activity and catalase activity from 0-20 cm in jointing to flowering stage;OFN significantly increased the invertase activity of 0-20 cm soil from wheat to maturity.In summary,on the basis of measurement and control quantitative fertilization,combined with slow release of urea,organic fertilizer,biological fertilizer to help winter wheat yield and fertility,it is suitable for promotion in dryland wheat.