种棉花节省开支的一个主要方面就是合理地使用氮肥。棉花在生长季节仅需很少的氮肥,然而当开始结蕾时,对氮肥的需要量就大大增加了。如果氮肥施得太早,就会造成浪费;如果氮肥施得太多,就会引起棉株疯长。那么什么时间施氮肥最合适,每公顷应施多少氮肥?针对这个问题,美国一些科学 One of the major aspects of saving cotton is the rational use of nitrogen fertilizers. Cotton requires only a small amount of nitrogen fertilizer during the growing season, however, the need for nitrogen fertilizer is greatly increased when the bud starts to flower. If the nitrogen fertilizer is applied too early, it will cause waste; if too much nitrogen fertilizer, it will cause cotton plants soaring. So when is the most suitable nitrogen fertilizer, fertilizer application of nitrogen per hectare? In response to this problem, the United States some science