Effects of Nitrogen Application Levels on Nitrogen Absorption and Utilization of Spring Maize under the High Yield Cultivation

Using Jinshan27 as experimental materials,effects of levels of nitrogen application on nitrogen absorption and utilization of spring maize were studied under high yield cultivation by the methods of field experiment.The results showed that with the improvement of levels on nitrogen application,content of nitrogen in maize plant generally increased while nitrogen accumulation increased first and then decreased.Biomass,grain yield and nitrogen distribution ratio in grain were all the largest under the 300 kg/ha nitrogen application.Nitrogen physiologi-cal efficiency was the lowest under the 390 kg/ha nitrogen application,nitrogen utilization efficiency was the highest under the 210 kg/ha nitrogen application and nitrogen harvest index was the largest under the 300 kg/ha nitrogen application.Compared with 210 kg/ha,rate of nitrogen fertilizer physiological utilization,nitrogen fertilizer efficiency and nitrogen fertilizer absorbing efficiency was reduced under high level of application,but which was contrary under low level of application 210 kg/ha.Rate of nitrogen fertilizer utilization was the highest under the 300 kg/ha nitrogen application,while treatments of 390 kg/ha nitrogen application and one-time topdressing of nitrogen of farmer were both relatively lower.In the researching region,the suitable applying amount of nitrogen fertilizer was 300 kg/ha whose ratio of seed manure,jointing fertilizer and large mouth fertilizer was 1∶3∶6.