化学除草是现代农业科学技术的新成就,特别是把化学除草纳入耕作制度之后,就能够有效地提高产量和劳动生产率。因此,这一科学的发展很受各国的重视。美国自一九四四年开始应用“2,4-滴”防除杂草以来,到一九六一午,全国化学除草面积已达五亿余亩;同年日本使用化学除草的面积达二千五百万亩,苏联一九六○年为三千万 Chemical weeding is a new achievement of modern agricultural science and technology, especially after chemical weeding is integrated into farming systems, which can effectively increase output and labor productivity. Therefore, the development of this science is very much valued by all countries. Since 1944, the United States started to apply “2,4-D” control of weeds. By 1961, the chemical weed-free area in the country has reached over 500 million mu. In the same year, the area of ​​chemical weed control in Japan reached 2,500 Million mu, the Soviet Union in 1960 to 30 million