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一般来说,旱土对氮的利用率不高,主要原因是旱土易造成氨的挥发、硝酸盐的淋失以及反硝化脱氮。要想提高旱土施氮的肥效,减少氮肥在旱土中的损失,在施用氮肥时应特别注意以下几点:抓住关键时期施氮。作物各个生育期施氮肥的效果是不同的。一般来说,农作物苗期需氮量不多,而在抽穗结实期需氮较多。如玉米在抽穗开花前后,追施氮肥能显著增产。
In general, the utilization rate of nitrogen in dry land is not high, mainly because the dry land can easily cause ammonia volatilization, nitrate leaching and denitrification and denitrification. In order to improve the efficiency of nitrogen fertilizer in dry land and reduce the loss of nitrogen fertilizer in dry land, we should pay special attention to the following points when applying nitrogen fertilizer: Grasp the nitrogen application in the key period. The effect of nitrogen fertilizer on crops during different growth stages is different. In general, crop nitrogen demand is low at seedling stage, but more nitrogen is required at heading and heading stage. Such as corn before and after heading, topdressing nitrogen can significantly increase production.