几年来河北叶城县棉花打顶尖的时间不一致,早者在白露节,(8月初)晚者在二伏末和三伏初。为了正确的找出棉花不同时间的打顶尖增产关键时期,1958年于城关公社北马大队,选择了一块地势平坦,土壤肥沃,常年植棉的壤土地,同河北农科所、县农业部、北马生产队技术员,共同作了一块棉花不同时间打顶尖试验。试验的项 Over the past few years, Yecheng County, Hebei Province, cotton top time inconsistent, early in the white dew, (early August) late at the end of the two-volts and three volts early. In order to correctly identify the key period of top-cutting cotton production at different times, in 1958, at the Chengmai Commune, the BeiMa Brigade chose a loamy land with flat and fertile soil and cotton planting all the year round, North horse production team technicians, worked together to fight a piece of cotton top time test. Test items