Effects of Nitrogen Application Time on Dry Matter Accumulation and Nitrogen Use Efficiency of Summer Maize

Aimed to reduce pollution of nitrogen fertilizer(NF) and heighten nitrogen use efficiency(NUE) in summer maize, effects of nitrogen application time on dry matter accumulation and NUE were studied. The results showed that treatments of nitrogen application increased obviously grain yield and grain per ear, the grain yield of treatment of applied nitrogen in 3-leaf stage and 12-leaf stage was tiptop, the effects of nitrogen application time on 1 000-grain weight and ears per unit was not prominent. LAI of treatment of nitrogen application time keeping more number in later stage and stopping consenescence of leaf and accelerating more dry matter accumulation. In treatments of three nitrogen application time, the NUE of treatment of applied nitrogen in 3-leaf stage and 12-leaf stage was top, and increased 21.8 percent pionts and 22.8 persent points than the others, it improved the NUE of summer maize in the stage, and reduced the farm pollution by losing of nitrogen.