化学除草剂属接触内吸性药剂,药液喷施以后,深入表土下层,触及杂草根系,达到除草助苗的作用。具有效率较高、用工较省的优点。为了促进麦苗的早发冬壮,各地社队在普遍使用。据我县东湖原种场等单位的试验,在同一种类的除草剂(25%绿麦隆粉剂)和亩用剂量(5两/亩)相同的情况下,不同时期的麦苗,使用除草剂,除草和增产效果显殊不同。大麦“早熟三号”播后芽前除麦田主要杂草凡缕草和看麦娘86.5%,增产10.3%,一叶一心期除草95.4%,增产11.7%,二叶一心期除草97.3%,增产 Chemical herbicide is the contact with the internal absorption of drugs, chemical spray after deep into the surface soil, touch weeds roots to achieve the role of weeding aids. Has the advantage of higher efficiency, more labor-saving. In order to promote the earliest winter wheat strong, around the community in widespread use. According to the experiment conducted by our county Donghu original seedling field and other units, in the same type of herbicide (25% chlorothalonil powder) and the mu dose (5l / mu), the wheat seedlings in different periods were treated with herbicides, Weeding and yield significantly different results. Barley “precocious three ” sowing before bud after addition of wheat weeds in the main weeds Verbena 86.5% and see Maitis, an increase of 10.3%, 95.4% leaf weaning period, an increase of 11.7%, two leaf weaning 97.3% , Increase production