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大白菜是一种喜温、怕热、不耐寒的作物。播种过早,遇到高温干旱,呼吸旺盛,秧苗弱,病害死苗严重,常常造成大面积减产,甚至完全失败;播种过晚,虽然减轻病害,但由于后期温度过低,受无霜天数制约,达不到生长积温要求而生长迟缓,包心不实,直接影响着大白菜的产量和商品价值。从我区几年来看,1985年播期气温较低,8月7—8日播种的大白菜,产量仍为丰收年份,而1986年和1987年,播种期正值高温干旱阶段,虽是8月13—15日播种,大面积白菜仍然病害严重,部分田块死苗毁种。1988年推迟到8月15—18日播种恰遇低温多雨天
Chinese cabbage is a kind of temperature, fear of heat, not cold-tolerant crops. Sowing too early, encountered high temperature and drought, strong respiratory, weak seedlings, disease dead seedling serious, often resulting in large-scale production, or even completely failed; sowing too late, although reducing disease, but due to the late temperature is too low, , Not up to the growth of accumulated temperature retardation, unwary, directly affects the production of cabbage and commodity value. From my area a few years, the sowing temperature in 1985 is low, August 7-8 seeding cabbage, the yield is still harvest years, and 1986 and 1987, the sowing period is the stage of high temperature and drought, although the 8 Sept. 13-15 seeding, a large area of cabbage is still a serious disease, some fields dead seedlings destroyed. Postponed until 1988 August 15-18 Sowing low temperature and rainy weather