一、留苗密度偏大主要表现:行距窄,株距小,封行过早,田间郁闭,通风透光不良,蕾铃脱落严重,下部结铃少。产生原因:一是受棉花苗病的影响。多年连作造成棉花立枯病、炭疽病、红腐病等苗期病害加重,为防止苗病造成死苗缺苗,棉农多 First, the Liao Miao density is too large mainly performance: narrow row spacing, plant spacing is small, premature closure, field canopy, poor ventilation and light, Lei Ling off serious, the lower part of the bell less. Cause: First, affected by cotton seedling disease. For many years even caused by cotton blight, anthracnose, red rot disease and other diseases at increased severity, in order to prevent Miao Miao caused dead seedling lack of seedlings, cotton farmers and more