Effects of Nitreogen Patterns on Nitrogen Use and Yield Benefit of Summer Maize

Field experiments were conducted with four nitrogen patterns to clarify the effects of different nitrogen patterns on the process of matter productivity,ear traits,yield,economic benefits and N efficiency.The four nitrogen patteris were I nitrogen rate of 0kg·hm-2,Pattern N0;II nitrogen rate of 180kg·hm-2(30kg·hm-2 before sowing plus 120kg·hm-2 at big trumpet stage,30kg·hm-2 at silking stage),Pattern N1;III nitrogen rate of 180kg·hm-2(60kg·hm-2 before sowing,120kg·hm-2 at big trumpet stage),Pattern N2;IV nitrogen rate of 270kg·hm-2(30kg·hm-2 before sowing,120kg·hm-2 at big trumpet stage,120kg·hm-2 at silking stage),Pattern N3.The results showed that appropriately postponing nitrogen fertilizer can significantly improve ear traits,for example,the number of grains per ear of N1 pattern increased by 34.7 and 28.5,the harvest index increased by 11.3 and 17.1%;the yield increased by 1590kg·hm-2 and 60.6kg·hm-2,compared to N0 and N2 respectively.After treated with the same amount of nitrogen input,postponing appropriately propertion of nitrogen fertilizer can increase yield but not the net-income or the input-output rate;Nitrogen input at silking stage were also found significantly increased dry matter accumulation at grain-filling stage and the drop of LAI after silking was postponing.Nitrogen fertilizer significantly improve biomass of summer maize before and after anthesis,Moreover,postponing part of nitrogen to silking stage could increase dry matter accumulation of post-anthesis.Reducing appropriate amount of nitrogen input produced 4.3kg more corn per kilogram nitrogen;undeer the same amount of nitrogen fertilizer input,postponing part of nitrogen to silking stage produced 0.56kg corn per kilogram nitrogen more.Therefore,scientific nitrogen pattern is very important not only for yield increase,but also for improving of economic benefits.