氮肥运筹对玉米氮素动态变化和氮肥利用的影响

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。

Effects of Nitrogen Application on Nitrogen Dynamic Changes and Nitrogen Use Efficiency in Maize

Nitrogen accumulation reached the peak around 45 days after silking stage and high population was helpful to nitrogen accumulation. Total N content of the plant was positively correlated with yield and it got closer in higher density. Grain nitrogen content and nitrogen harvest index were significantly positively correlated with yield in higher density. Nitrogen application high ratio in silking stage was beneficial to N accumulation in leaf and ear, as well nitrogen translocation in stem and sheath, nitrogen application high ratio in earlier stage delayed nitrogen metabolism. Nitrogen uptake peak was from silking stage to 15 days after silking stage, nitrogen uptake rate increased in later growth stages under nitrogen application high ratio in silking stage and moved forward in higher population. It was advantaged for nitrogen fertilizer efficiency on condition that nitrogen application was moved backward. Accumulating too much nitrogen in earlier stages had inhibition on nitrogen uptake in later periods.