棉花开花结铃期,一般自七月上、中旬至九月上、中旬,是棉花一生中生长发育最旺盛的时期。花铃期需要大量的营养物质供蕾铃生长,是棉花一生中需肥最多的时期,吸肥量约占它一生中总吸肥量的三分之二左右。这个时期如果缺肥缺水或肥水过多,就会造成早衰或 Cotton flowering boll period, generally from July onwards, mid-September to mid-September, is the growth and development of cotton during the most vigorous period. The need for a large number of flowers and bolls of nutrients for the growth of buds is the most needed fertilizer in the life of cotton period, the amount of fat absorption accounts for about two-thirds of the total amount of fat in its life. This period if lack of water or too much fertilizer, it will cause premature aging or