Effects Of Irrigation And Fertilization On Yield And Nitrogen Use Efficiency Of Winter Wheat

Under the field experiment,soil nitrate nitrogen content and accumulation amount,dry matter accumulation,nitrogen accumulation and distribution and yield were systematically studied with three water treatment(W0-no irrigation,W1-once only irrigation at jointing stage,and W2-twice irrigation at the jointing stage and flowering stage)and with four nitrogen levels(0,180,240 and 300 kg N/hm2)using two wheat cultivars named Yu'mai 49-198 and Kai'mai 22 as experiment material.The study provide theoretical basis for improving the coordination rate of yield and nitrogen utilization of wheat in the region.The main results are as follows:1.Effects of irrigation and nitrogen application on soil nitrate contentThe distribution of nitrate in soil decreased with the increase of soil depth,and the ratio of nitrate 0-40 cm take up51.04%-70.13%(Yumai 49-198)and 44.23%-64.52%(Kai'mai 22)of 0-100 cm.The soil nitrate content increased with the increase of nitrogen application rate,presented the trend of N3,N2>N1>N0;Irrigation increased soil nitrate content at lower(60-100cm);At anthesis,the soil nitrate nitrogen content shows W0>W1 at 0-40 cm soil layer,and W1>W0 at40-100 cm soil layer,Yumai 49-198;the soil nitrate nitrogen content shows W0>W1 at 0-60 cm soil layer,and W1>W0 at 60-100 cm soil layer Kai'mai 22)At the maturity stage,the upper soil showed W0>W1>W2,and the lower soil showed W2>W1>W0,it showed that with the increase of irrigation times of nitrate leaching may increase to the deep,residual nitrate in soil.2.Effects of irrigation and nitrogen application on dry matter accumulation and translocation of winter wheatThe dry matter accumulation of winter wheat increased with advance in growing period,and was the highest at the maturity stage.Compared with the two cultivars,the dry matter accumulation of Yumai 49-198 was higher in the early growth stage,and the dry matter accumulation was higher after anthesis than Kai'mai 22.Irrigation and nitrogen application significantly increased dry matter accumulation.Nitrogen application improved the amount of dry matter transferred to wheat before anthesis and the contribution rate to grain effectively,also the contribution rate of post anthesis assimilates to grain and the translocation amount of dry matter before anthesis,while the pre anthesis dry matter contribution rate to grain decreased with the increase of irrigation times.The amount of grain input,the contribution rate to grain and the contribution rate of assimilates to grain increased with the increase of irrigation times.3.Effects of irrigation and nitrogen application on nitrogen accumulation and translocation in winter wheatWith the advance of the growth period,the nitrogen accumulation in wheat plants showed a trend of increasing,and reached the highest at the maturity stage.Irrigation and nitrogen application significantly increased nitrogen accumulation in plants and grains.N promoted vegetative organs to grain transfer and contribution rate to grain,the specific performance: under W0 treatment,N3 treatment transfer amount and contribution to grain was highest,in W1 and W2 treatment,N2 treatment transfer amount and contribution rate to grain highest.Irrigation significantly increased the contribution rate of nitrogen to grain,and W1 was the highest,followed by W2,which was higher than W0.4.Effects of irrigation and nitrogen application on nitrogen use efficiency of winter wheatThe application of nitrogen fertilizer could increase the nitrogen partial productivity,agronomic efficiency and nitrogen uptake efficiency.Nitrogen application significantly reduced the nitrogen production efficiency,agronomic efficiency,nitrogen uptake efficiency and nitrogen use efficiency of two cultivars.Combined with the results of this experiment,it was found that under the same yield conditions,the nitrogen production efficiency of experiment field was higher than farmers,there was a lack of attention to the reasonable ratio of N,P,K in compound fertilizer at the present stage and farmers was used to adopting the habit of once for all.The fertilizer base used can't meet the demand for nutrients at later growth stage of wheat,so that the wheat yield and nitrogen use efficiency is low.5.Effects of irrigation and nitrogen application on yield and yield structure of winter wheatNitrogen application significantly increased the grain yield of wheat,and nitrogen application increased by 24%-43%(Yu'mai 49-198)and 21%-40%(Kai'mai 22).Irrigation increased the yield of wheat,and the yield of irrigation by 5%-13%(Yu'mai 49-198)and 4%-10%(Kai'mai 22).Consideration of three elements analysis of yield,nitrogen application increased the spike number per unit area of 20%-31%(Yu'mai 49-198)and 17%-40%(Kai'mai 22)than no nitrogen,grain number increased by 22%-26%(Yu'mai 49-198)and 10%-33%(Kai'mai 22).The irrigation increased the number of panicles per unit area by5%(Yu'mai 49-198)and 7%(Kai'mai 22)without irrigation.Thousand grain weight decreased with the increase of nitrogen application rate.Based on the analysis of yield and its three factors,it was found that irrigation and nitrogen application were mainly achieved by increasing the number of panicles per unit area and the number of grains per ear.In consideration of high yield and utilization rate of nitrogen fertilizer and of wheat,under the experimental conditions,the amount of nitrogen in the whole growth period of 240kg/hm2,divided to the base fertilizer and topdressing fertilizer,ratio is 5:5,irrigation two times(jointing and flowering water)is worth popularizing cultivation technology.