Science. 1977 Aug 12;197(4304):625-30. doi: 10.1126/science.197.4304.625.
A recent survey of five watersheds in south-central Wisconsin, where corn is now the dominant annual crop, illustrates the soil erosion damage that is occurring on sloping land under modern agricultural technology and prevailing market forces. In 70 percent of the 93 quarter-sections sampled, estimated soil losses, on the average, were more than twice the amounts considered compatible with permanent agriculture. Scattered studies by others indicate that the findings are meaningful for a large area in the United States when row cropping is prevalent on sloping soils. Pressures on cultivated land, in general, are mounting rapidly because of the rising demand for meat in industrialized nations and the soaring numbers of marginally fed people in Third World countries. The world population-food problem makes increasing stress on U.S. soils inevitable in the foreseeable future. Adequate protection against excessive loss of productive topsoil requires that the level of publicly supported soil conservation activities be promptly adjusted to this circumstance.
最近对威斯康星州中南部五个流域的调查表明，在现代农业技术和市场力量的作用下，玉米已成为主要的一年生作物，这导致了坡地土壤侵蚀的破坏。在所调查的 93 个四分之一地段中，有 70%的地段的土壤流失估计数平均是与永久性农业相容数量的两倍以上。其他人的分散研究表明，当在坡地上普遍实行条播耕作时，这些发现对美国的一个大地区是有意义的。由于工业化国家对肉类的需求不断增加，以及第三世界国家边缘地区人口的迅速增加，对耕地的压力普遍迅速增加。在可预见的未来，世界人口与粮食问题使得美国土壤承受的压力不可避免地增加。要防止生产性表土的过度流失，就必须迅速调整公共支持的土壤保持活动的水平，以适应这种情况。
