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通过氮肥运筹对雨养条件下玉米氮素动态变化和氮肥利用的影响研究表明,氮素积累量在吐丝后45d前后达到最大;高密度有利于氮量积累;植株总氮量与产量呈正相关,高密度下相关系数大;高密度下子粒氮含量和氮收获指数均与产量呈显著正相关;吐丝期氮肥比例相对高有利于叶片和穗部(子粒+苞叶+穗轴)氮素在生育后期的积累及茎鞘氮素的转运,前期氮肥比例大易造成穗部氮代谢延后。氮素吸收高峰在吐丝到吐丝后15 d;吐丝期氮肥比例高的施肥方式提高了生育后期的氮素吸收速率,在较高密度下吸收速率前移。氮肥施用比例适当后移有利于氮肥利用;前期氮素累积太多对后期氮素吸收利用有抑制作用。
The results showed that the nitrogen accumulation reached the maximum 45 days after silking, and the high density was conducive to the accumulation of nitrogen. The total nitrogen of the plant was positively correlated with the yield of nitrogen , And the correlation coefficient was high under high density. Under high density, the nitrogen content and nitrogen harvest index of grain were significantly and positively correlated with grain yield. The relatively high proportion of nitrogen fertilizer during silking stage was beneficial to the nitrogen content of leaves and panicles (grains + husk + cob) Accumulation in the later stages of growth and stem-sheath nitrogen transport, a large proportion of early nitrogen fertilizer cause panicle nitrogen metabolism delayed. The peak of N uptake was 15 days after silking. The high N application rate at silking stage increased the N uptake rate at late growth stage and the absorption rate at higher density. Appropriate proportion of nitrogen fertilizer back shift is conducive to the use of nitrogen; too much nitrogen accumulation in the early stage of nitrogen absorption and utilization inhibited.