Effect Of Different Nitrogen Application Date And Ratios On Individual Production Capacity Of Summer Maize(Zea Mays L.)

This study was conducted from 2013 to 2014 in Xinji experimental station of Hebei Agricultural University in frield condition using eight treatments. Two cultivars Weike702(WK702) and Xianyu335(XY335) were used as experimental materials. The research detected the effect of the N application date and ratios on photosynthetic characteristics, dry matter accumulation and distribution, N dynamic changing, grain filling and yield. In order to improve single plant production capacity under the condition of steady current plant colony and provide theoretical references for the reasonable application of nitrogen fertilizer. Main results were as follows:The LAI, net photosynthetic rate and chlorophyll content increased and the descending of these indexes after silking stage developed slowly after postponing nitrogen fertilizer under sufficient seed fertilizer condition; the higher levels of LAI, net photosynthetic rate and chlorophyll content were playing the advantageous function on the dry matter accumulation.The summer maize`s dry matter accumulations of different treatments increased with growth stage and reached a maximum at R6 stage. The percentage of dry matter accumulation in vegetative organs decreased, while that in grain increased with growth stage. The dry matter accumulation decreased after lacking seed fertilizer, while under seed fertilizer in plentiful supply and nitrogen fertilizer appropriate backwards condition and the percentage of dry matter accumulation in the grain also increased which indicated that more dry matter was distributed into the grain.Lacking seed fertilizer, the amounts of accumulated nitrogen in plant decreased significantly, while under sufficient seed fertilizer condition and nitrogen fertilizer appropriate backwards condition the amounts of accumulated nitrogen in plant increased, improved the nitrogen tranlocation, in was conducive to the nitrogen transfer from vegetative organs to grain and improved the amounts of accumulated nitrogen in kernel.Nitrogen fertilizer influenced the grain-filling significantly. The less seed fertilizer applied would postpone the time of grain-filling peak, decrease the maximum grain-filling rate and the grain weight while the results were just contrary when more seed fertilizer applied.The filament growth rate increased after postponing nitrogen fertilizer under sufficient seed fertilizer condition and the greater amount of filament would improve the fertilization rate and decrease the abortion rate to improve the amount of normal kernel.Different nitrogen application date and raitos had significant effects on the grain yield and yield constition of summer maize, the grain yield in response to different treatments showed: N5>N6>N4>N3>N2>N7>N1>N8. Grain yield of N7 and N8 were 12.06% and 6.14% lower than N1, while that of N5 was 9.60% greater than N1. The 1000-grain weight and kernels per ear of N7 decreased by 2.89% and 4.52% compared to N1; those of N8 decreased by 1.04% and 3.96%. The 1000-grain weight and the kernels per ear of N5 increased 3.87% and 3.74%. These indicated that lack of seed fertilizer had great effect on the kernel formation of summer maize even topdressing in R1 stage, and seed fertilizer in plentiful supply and nitrogen fertilizer appropriate backwards increased the grain yield significantly.