摘要
In China,the crop acreage using chemicalherbicides has now reached 53 millionhectares,over 10 times that of 1980.Theland needing herbicides increases by 2 millionhectares every year.Over 80 000 tonsof herbicide active ingredients are used inChina every year.By now,more than 100types of herbicides have been used in China.Among them,the top 20 accounted
