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追肥是夏玉米增产的主要因素,近几年来各地研究甚多。追肥多以氮肥为主,其方式有前重后轻式(叶龄指数30%时追施氮肥总量的70%左右,叶龄指数60%时追施氮肥总量的30%左右);前轻后重式(叶龄指数30%左右追施氮肥总量的30%,叶龄指数60%时追施氮肥总量的70%);“一炮轰”式(叶龄指数40%左右,即播后30天左右,一次追入全部氮肥)。据调查,大部分低产地块和高而不稳的玉米田,是由于氮
Top dressing is the main factor for increasing summer maize yield, and there are many studies all over the country in recent years. Nitrogen fertilizer is mainly used in topdressing. There are pre-and post-light methods (about 70% topdressing nitrogen fertilizer at 30% leaf age index and 30% top-dressing nitrogen fertilizer at 60% leaf age index); (30% leaf top index topdressing nitrogen fertilizer 30%, 60% leaf top index topdressing 70% of the total nitrogen fertilizer); “a shelling ” type (leaf age index 40% About 30 days after sowing, chase all nitrogenous fertilizer once). According to the survey, most low yield plots and high and unstable corn fields are due to nitrogen