土壤流失长期被视为美国农业生产力和地表水质量的严重威协,但是近年来才有资料定量评价土壤流失造成的经济损失和控制流失带来的收益。土壤流失所带来的危害,特别是在尘卷期的风蚀相当注目,以致不需试验及数学模型就可判明控制土壤流失已成为全国重点。自30年代以来,为了控制土壤流失,美国联邦政府已花费了150亿美元,同时农民也 Soil erosion has long been seen as a serious threat to US agricultural productivity and surface water quality, but in recent years there has been a quantitative assessment of the economic losses caused by soil erosion and the benefits of erosion control. The harm caused by soil erosion, especially in wind-induced wind erosion, has made it quite clear that the control of soil erosion has become a national priority without the need of tests and mathematical models. Since the 1930s, in order to control soil erosion, the U.S. federal government has spent 15 billion U.S. dollars, while peasants