夏季杂草的生长盛期是7、8月份,此期夏播作物正处于幼苗期,根系小,长势弱,而杂草密度大,长势旺,加之这一段时间雨量多,杂草往往会盖住作物幼苗形成草荒,严重影响作物幼苗生长,一般减产20%～30%,重者50%～60%。化学除草省工省时,快捷高效,但要取得理想防效必须注意以下问题:1.科学选用除草剂。须针对不同作物和杂草种类, Summer weeds grow in July and August, this summer sowing crops are in seedling stage, the root system is small, weak growth, and weeds density, growing vigorously, combined with rainfall over this period of time, weeds tend to cover Crop seedlings formed grassland shortage, a serious impact on crop seedling growth, the general reduction of 20% to 30%, severe cases of 50% to 60%. Chemical weeding workers save time, fast and efficient, but to achieve the desired control effect must pay attention to the following questions: 1. Science and use of herbicides. Must be for different crops and weed species,