人类活动引起的土壤侵蚀 ,一直被认为是对人类自养能力的威胁。人们采取各种措施来降低风与水引起的土壤侵蚀 ,本身就说明了侵蚀已威胁到土壤生产力。至于威胁的程度是否属实 ,则很少有人确定过。全球还几乎没有进行过多少关于侵蚀对土壤生产力影响的实地观测。在这不多的观测? Soil erosion caused by human activities has long been considered a threat to human self-sustainment. Various measures have been taken to reduce wind and water-induced soil erosion, which in itself demonstrates that erosion has threatened soil productivity. Few people have identified the extent of the threat. There is little or no global observation of the impact of erosion on soil productivity. In this few observations?