棉花现蕾、开花以后,营养生长和生殖生长同时进入高峰,需要更多的养分。如果这一时期棉株体内养分供应失调,就会造成大量的蕾铃脱落。适时打顶,可以调节棉株养分的运转,使原先供给主茎生长的大量养分节省下来,供给蕾铃生长。这样,可以使蕾铃脱落减少,棉桃结得多,长得大,成熟早。但是,打顶的关键在于正确决定打顶时间和打顶技术。打得过早,不仅限制了有效果枝数的增长,现蕾开花数目减少,影响棉花产量,而且往往造成赘芽增加,上部果枝延伸过长,形成“一把伞”,导致中下部郁蔽,通风透光差,增加蕾铃脱落。打得过迟,上部无效果枝数和无效花蕾数增加,白白消耗一部分养分,失去了打顶的作用,不能早熟高产。因此,打顶的适期要根据天 Cotton budding, flowering, vegetative and reproductive growth at the same time into the peak, the need for more nutrients. If this period cotton plant nutrient supply disorders, it will cause a lot of buds fall off. Timely topping, you can adjust the operation of cotton plant nutrients, so that the original supply of nutrients to save a large number of stem growth, supply of bud growth. In this way, you can reduce the loss of buds, bolls more, grows large, mature early. However, the key is to determine the right topping time and topping technology. Playing too early, not only limited the effective growth of the number of branches, reduce the number of flowering buds, affecting cotton yield, and often result in increased buds, the upper branches extended too long, forming an “umbrella” Poor ventilation, increase the loss of buds. Playing too late, the upper part of the number of invalid fruit buds and invalid increase in vain consumption of nutrients in part, lost the role of topping, can not be premature and high yield. Therefore, topping the appropriate period to be based on the day