一、小麦氮肥运筹知识库连续六年的肥料试验表明，在不同施肥及产量水平下，氮肥的产量效应有明显差异。施肥水平较低的中低产田，氮肥的产量效应与对群体促进作用的最大效应期基本同步，均出现在倒三叶出生期以前。因此，氮肥分配方式可根据产量效应直接求得。在适期播种条件 First, wheat nitrogen fertilizer operation knowledge base Fertilizer trials for six consecutive years showed that under different levels of fertilization and yield, nitrogen yield effects were significantly different. The middle and low-yielding fields with lower fertilization levels were basically synchronized with the maximum effect period of nitrogen fertilizer on the population promoting effect, both before the birth of the inverted third leaf. Therefore, the distribution of nitrogen can be directly calculated according to the yield effect. Sowing conditions at the right time