我们知道,除草剂之所以能发挥出良好的杀灭草害的效果,是因为药剂施入土壤后能在土壤表面形成一个药层,“封锁”土表.当杂草幼芽破土而出时,必然经过药层,分布在土表的药剂就会将其杀死. We know that the reason why herbicides can exert good killing effect is that they can form a layer of soil on the soil after they are put into the soil to “block” the soil surface. , Must pass through the layer of medicine, will be distributed in the soil table will kill it.