氮肥运筹对大豆氮素利用特性的影响

在平衡施肥的基础上，设置三种氮肥运筹模式：N1: 1次性基施；N2: 1/2 N基施+1/2 N中耕培土结合追肥(开花初期）；N3: 1/2 N基施+1/4 N中耕培土结合追肥(开花初期)+ 1/4 N根外追施尿素(结荚鼓粒期)。探讨氮肥运筹对大豆生育期内干物质积累、产量和氮肥效益的影响。研究表明，从始花期至鼓粒期干物质积累速率最快，占总量的40%以上，平衡施氮量不同运筹模式上，N3的累积速率最大，其次为N1、N2处理。氮肥运筹模式显著提高大豆产量，其大小为：N3＞N2＞N1。氮肥运筹对氮肥利用率有一定影响，其中N3更有利于提高氮肥利用率；从氮肥偏生产力方面看，每千克氮肥对大豆产量贡献大小为：N3﹥N2﹥N1，进一步表明，氮肥运筹是提高大豆产量和氮肥高效利用的关键之一。

Effect of Nitrogen Management on Characteristics of Nitrogen Utilization of Soybean

Basing on optimum fertilzer level,dry matter accumulation,yield and nitrogen efficiency of soybean were studied at nitrogen management of nirogen fertilizer.There were three methods of monitrogen management in the experiment.As follow,the total basal fertilizer （N1）,half of rate as basal fertilizer combined with the half of N rate as topdressing in the florescence stage （N2）,half of rate as basal fertilizer combined with the quarter of N rate as topdressing in the florescence stage and quarter of N rate as topdressing in the seed filling stage （N3）.The results showed that the speed of dry matter accumulation of soybean was higher from florescence stage to seed filling stage.In all the period,which was accounted for over per 40.The dry matter accumulation of N3 was highest among the different applying methods.The effect of different applying methods on yield of soybean was following：N3 N2 N1.The nitrogen efficiency of N3 was highest among the different applying methods.As far as partial factor productivity（PFP） for different applying methods,N3 N2 N1.The results further indicated that applying nirogen method was one of the key factors on increase effective utilization of nitrogen fertilzer and yield.