Effects of Nitrogen Application Period on Nitrogen Accumulation,Translocation and Nitrogen Use Efficiency of Summer Maize

Effects of nitrogen application period on nitrogen accumulation,translocation and nitrogen use efficiency were studied.The main results as following: compared with CK,nitrogen application increased NHI and amounts of nitrogen accumulation in plants and grain.The amounts of nitrogen accumulation in ear increased quickly after silking,nitrogen translocation of stem and sheath happened mostly in early filling stage,nitrogen translocation of leaf happened mostly in middle and later filling stage.Nitrogen application made nitrogen physiological efficiency declined 16%,nitrogen fertilizer efficiency was no obvious difference among three treatments.The 60%-70% in total nitrogen accumulation amounts of plants was accumulated from silking to maturing stage,the nitrogen accumulation amounts and nitrogen use efficiency of T4 were highest,compared with T2 and T3,the NUE of T4 heightened 21.8 and 22.8 percent points.