一、施用除草剂对杂草群落的影响我国稻田中最早使用的苯氧羧酸类(2.4—滴丁酯,2甲4氯等),使双子叶杂草下降为次要杂草,而单子叶杂草如稗草等上升为主要杂草。60年代以后广泛推广敌稗、杀草丹、丁草胺、禾大壮等杀稗剂之后稗草受到有效控制,而莎草科杂草、 First, the impact of herbicides on weed communities The earliest used phenoxycarboxylic acids (2.4-D butyl, 2, 4-chloro, etc.) in paddy fields in China reduced dicotyledonous weeds to secondary weeds, Leaf weeds such as barnyardgrass and the like rise to the main weeds. After the 1960s, barnyardgrass was effectively controlled after the promotion of propanil, fenitrothion, butachlor,