杂草是棉花夺取高产的重要障碍,尤其是早期草害,影响棉苗生长、发育,损失最大。1980～1983年我们开展了棉田草害调查,调查结果,上海郊县棉田杂草有138种,其中主要有马唐(Digitaria Sanguinalis L.)、千金子(Leptochloa chinesis L.)、稗草(Echi-nochloa crusgallis Beauv)、鲤肠(Ecliptaprostrata)、牛劲草(Eleusine indica)等10多种,危害面积约达36.4、58.8、14.4、5.5、2.4％。马唐、千金子的出现频率达94％和99.6％,危害最严重。为了配合草害调查,我们选择了马唐、千金子这两种杂草进行其 Weeds are an important obstacle to the high yield of cotton, especially the early weeds, affecting the growth, development and loss of cotton seedlings. From 1980 to 1983, we conducted a survey on grassland weeds in cotton fields. The survey results showed that there were 138 weeds in cotton fields in the suburbs of Shanghai, including Digitaria Sanguinalis L., Leptochloa chinesis L., Echi -nochloa crusgallis Beauv, Ecliptaprostrata, Eleusine indica and so on. The damage area is about 36.4, 58.8, 14.4, 5.5 and 2.4%. Crabgrass, thousands of gold appear frequency of 94% and 99.6%, the most serious harm. In line with the grass-roots survey, we chose the crabgrass, Qianjin two weeds carried out