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拔节期重施氮肥，可以显著改善群体质量，增加植株基部节间的重量、充实度和次生根条数，提高植株抗倒、抗旱能力；提高分蘖成穗率，保证稳定的成穗数；明显改善中后期光合性能，减少小穗小花退化，促进物质积累和籽粒灌浆，增加穗粒数和千粒重，具有显著提高产量的作用。但在同一密度条件下，拔节期追施氮量对小麦群体性状的改善效应和增产效果不同，均呈抛物线变化。一般情况下，拔节期追氮数量宜掌握在１５０～３００ｋｇ／ｈｍ２尿素范围内。
The nitrogen application at jointing stage can significantly improve the population quality, increase the weight of basal internode, increase the degree of secondary root number, and increase the ability of plant to resist down and drought; increase the rate of tillering to spike and ensure the stable spike number; obviously Improve photosynthesis in the mid-late stage, reduce spikelets floret degradation, promote material accumulation and grain filling, increase grains per spike and 1000-grain weight, and significantly improve the yield. However, under the same density, the effect of topdressing nitrogen at jointing stage on the population traits of wheat was improved by different effects, which showed a parabolic curve. Under normal circumstances, the number of jointing nitrogen should hold in the 150 ~ 300kg / hm2 urea range.