从总体上看,美国农业用水资源比较丰富,因此在本世纪70年代以前,政府的政策主要倾向于对农业水资源的开发和利用;而在80年代后,由于水资源污染严重而逐渐呈现水资源短缺,因而,政府的政策倾向则明显地加快了水资源保护的力度。美国农牧业生产自身对农业水资源污染主要来自以下几个方面:一是普遍使用化学杀虫剂造成的污染。从1950年以来,美国杀虫剂和 Generally, the agricultural water resources in the United States are abundant. Therefore, by the 1970s, government policies mainly focused on the development and utilization of agricultural water resources. However, after the 1980s, due to the serious pollution of water resources, water gradually emerged The shortage of resources, therefore, the government’s policy tendency has obviously accelerated the protection of water resources. Agriculture and animal husbandry in the United States of their own pollution of agricultural water resources mainly from the following aspects: First, the widespread use of chemical pesticides caused pollution. Since 1950, the United States pesticides and