Effects Of Slow-release Nitrogen Fertilizer And Urea Blending On Summer Maize/winter Wheat Growth And Nitrogen Utilization

Research under different nitrogen allocation amount of urea and slow-release nitrogen fertilizer mixing with urea on field summer maize and winter wheat growth,dry matter accumulation amount,yield,physiological characteristics,nitrogen absorption and the influence of soil NO3--N residue,in order to explore increase crop yield,decrease soil NO3--N leaching and improve the utilization ratio of nitrogen efficient nitrogen management mode.An experiment with a high yielding ‘Zhengdan 958’ and ‘Xiaoyan 22’ using a randomized complete block design in Guanzhong Plain.Three nitrogen fertilizer types(U: conventional urea,S: slow-release urea and SU: a mixture of slow-release and conventional urea with N ratio 7∶3).The total nitrogen application of summer maize-winter wheat rotation system was 345 kg/hm2.Among them,four levels of nitrogen were applied in the growth period of summer maize.N1(90 kg/hm2),N2(120 kg/m2),N3(180 kg/hm2)and N4(240 kg/hm2)were applied to the study.Four levels of nitrogen application in winter wheat growth period,N4(255 kg/hm2),N3(225 kg/m2),N2(165 kg/hm2)and N1(105 kg/hm2)were applied to the study.For the control(CK),we designed a plot received no nitrogen.Thus,13 treatments were established.The plant height,stem diameter,leaf area index and physiological indexes of summer maize and winter wheat were observed.The amount of dry matter accumulation,yield and yield components,nitrogen use,the content of plant nutrition and NO3--N concentrations in soil were statistically analyzed on summer maize and winter wheat were mainly grown.The test results are as follows:(1)The growth indexes and physiological indexes of summer maize and winter wheat were all presented as SU treatments>S treatments>U treatments.Summer corn and winter wheat,respectively,the best growth index and physiological index of urea mixed with slow-release nitrogenous fertilizer treatment with 120-180 kg/hm2 and 225-255 kg/hm2,respectively.(2)Dry matter accumulation are presented as SU treatments>S treatments>U treatments.The maximum dry matter accumulation of summer maize and winter wheat under the N application rate of 180 kg/hm2 and 255 kg/hm2 of urea mixed with slow-release nitrogen treatments increased by 16.0%-61.7% and 5.7%-77.6% compared with other treatments,respectively.Urea mixed slow-release nitrogen fertilizer treatment can significantly increase the amount of dry matter accumulated in the middle and late stages of crop growth and delay crop senescence.(3)Summer maize growth phase urea mixed with slow-release nitrogen under 180 kg/hm2 N application rate,the production of urea treatment 180 kg/hm2 and slow release nitrogen fertilizer 120 kg/hm2 N application rate,the yield increased by 20.7% and 19.8%,respectively.Winter wheat growth stage,mixing slow-release urea nitrogen under 255 kg/hm2 N application rate,the production of urea treatment 225 kg/hm2 and slow release nitrogen fertilizer amount of 255 kg/hm2 nitrogen production increased by 11.4% and 11.4%,respectively.Slow-release nitrogenous fertilizer and urea mixed with slow-release nitrogen fertilizer,the yield was equal or increased when the nitrogen treatment was reduced by 30%(4)The translocation of nitrogen to grain from the vegetative organs of flowering and post-harvest period of urea mixed with slow-release nitrogen treatment of summer maize and winter wheat were the highest,which were increased by 17.2%、25.9% and 9.0%、7.3%,respectively,compared with the other treatments.During the growth stage of summer maize,the maximum plant nitrogen assimilation and gain nitrogen assimilation with mixing slow-release urea nitrogen treatment 180 kg/hm2 N application rate,compared with the other treatments were increased by 8.1%-67.3% and 6.2%-54.1%,respectively,During the growth stage of winter wheat,255 kg/hm2 N application rate were increased by 8.1%—78.0% and 9.3%—97.0%,respectively.(5)During the growth stage of summer maize,under the same nitrogen application rate,the amount of nitrate accumulation in soil treated with urea blended slow-release nitrogen fertilizer was reduced by 17.0%—26.8% and 5.8%—14.0% compared with that of urea and slow-release nitrogen fertilizer,and during the growth stage of winter wheat,was reduced by 7.2%—12.0% and 3.0%—5.4%.Compared with slow-release nitrogen and urea treatments,urea mixed with slow-release nitrogen treatment nutrients are mainly distributed in 0-40 cm soil layer,is not only beneficial to the absorption of crops,reduce the leaching nitrogen to deeper soil layer,reduce the risk of deep soil environmental pollution.(6)Urea blended slow-release nitrogen fertilizers capable of promoting crop growth;physiological growth,significantly increasing crop yield,and reducing nitrate leaching in soil were selected.The nitrogen application rate of 120 kg/hm2 during the growth stage of summer maiz.The nitrogen application rate of 225 kg/hm2 during the growth stage of winter wheat.It was the summer maize-winter wheat rotation system in Guanzhong region to promote crop growth and increase yield of nitrogen fertilizer and nitrogen application rate.