除莠剂的新成员近年来,有一种化学除莠(杂草)的药剂很惹人注目,它叫做残留性除莠剂。这种除莠剂撒布在表土层中,能长期存留,保持药效,使草籽出芽一批,就“夭折”一批。杂草种子刚萌发不久,幼芽就变黄、脱绿,好像没有晒到阳光、严重缺乏营养一样,很快萎蔫,留下一段段死苗。这种新型的除莠剂是人们在研究了好几种除莠剂以后找到的。最早出现的除莠剂是一些无机盐,如硫酸铜、氯酸钾、亚砷酸钠等。它们的除草效果较差,还常引 In addition to the new members of tinctures, in recent years, there has been a remarkable chemical called weeds (weeds), which are called residual herbicides. This herbicide is scattered in the topsoil and can persist for a long time. It can maintain its efficacy and cause a batch of grass seeds to germinate. As soon as the weed seeds begin to germinate, the young shoots turn yellow and green, as if they did not reach the sun and are seriously deprived of nutrients. They quickly wilted and left a period of dead seedlings. This new type of herbicide was found after studying several herbicides. The earliest herbicides were inorganic salts such as copper sulfate, potassium chlorate, and sodium arsenite. Their weeding effect is poor and often cited