Effects Of Slow And Controlled Release Nitrogen Fertilizer On Nitrogen Utilization And Yield Of Summer Maize

The experiment was conducted in Xinji experimental station of Hebei Agricultural University from June to October,2019.Two maize varieties Xianyu 688 and Jifeng 2 were selected to study the effects of different slow and controlled-release nitrogen fertilizer treatments on nitrogen utilization and yield of summer maize,including no nitrogen application(NO),conventional nitrogen application(CK),conventional nitrogen application(CN),polyaspartic acid chelating nitrogen(PN)and slow-release nitrogen(HN)The main results are as follows1.Polyaspartic acid chelating nitrogen fertilizer(PN)treatment improved the light energy use efficiency of maize.Compared with CN and HN,PN treatment significantly increased leaf net photosynthetic rate and leaf photosynthetic nitrogen use efficiency.Under PN treatment,the net photosynthetic rate of the two maize varieties increased by 12.9%～26.3%and 1.1%～20.8%at milk stage,and 8.7%～9.7%and 0.3%～12%at full ripening stage,respectively.The leaf photosynthetic nitrogen use efficiency of the two maize varieties increased by 5.1%～29.2%and 7.4%～18.7%,respectively.2.Polyaspartic acid chelating nitrogen(PN)treatment increased nitrogen use efficiency.Compared with CN and HN treatments,PN treatment increased nitrogen uptake efficiency by 6.3%～6.9%and 3.3%～17.2%respectively.Nitrogen partial productivity and nitrogen harvest index of PN treatment were significantly higher than those of CN and HN treatment.3.Polyaspartic acid chelating nitrogen(PN)treatment increased the dry matter accumulation of corn after anthesis.Compared with CN and HN,the dry matter accumulation after anthesis increased by 3.8%～10.6%and 2.5%～4.2%respectively under PN treatment.4.Polyaspartic acid chelating nitrogen(PN)treatment increased maize yield.Compared with CN and HN,the yield of two maize varieties increased by 6.3%～11%and 5.6%～6%respectively under PN treatment.Compared with CN and HN,there was no significant difference in 100 grain weight and ear number per mu,but the number of grains per spike in PN treatment was significantly higher than that in CN and HN treatments.From the above results and analysis,the following conclusions are drawn1.Compared with conventional urea and slow-release fertilizer urea,polyaspartic acid chelating nitrogen fertilizer treatment increased plant nitrogen absorption by 15.6%～50.4%after anthesis,and maintained high photosynthetic rate and photosynthetic nitrogen use efficiency throughout the whole stage after anthesis,which was conducive to the accumulation of more dry matter,which was conducive to the improvement of Maize yield.2.The grain yield and nitrogen use efficiency of Xianyu 688 were significantly higher than those of Jifeng 2.The results showed that Xianyu 688 had high nitrogen uptake after anthesis and nitrogen transport in vegetative organs before anthesis,high photosynthetic rate and photosynthetic nitrogen use efficiency of leaves,which was conducive to the accumulation of more dry matter after anthesis,which was conducive to the increase of maize yield.Therefore,nitrogen efficient varieties and polyaspartic acid can be selected to promote in Hebei plain to stabilize yield and increase.