土壤流失的速率可能要比一般想象的更快一些.在经营管理条件很差的情况下,每年每公顷的土壤流失量可达270吨,常见的是每年每公顷流失土壤20—50吨.土壤的流失,大多是由风蚀和水蚀所引起的;同时,由于土壤的流失,也使土地的肥力和生产能力随之下降.在土壤没有扰动的自然状态下,形成25毫米的表土层可能需要约300年时间. The rate of soil loss may be faster than generally thought, and in very poorly managed conditions, annual soil loss per hectare can reach 270 tons, often 20-50 tons of soil is lost per hectare per year. Are mostly caused by wind erosion and water erosion, and at the same time, the fertility and productivity of the land are also reduced due to the loss of soil. In a natural state where the soil is not disturbed, it may take about 25 millimeters of topsoil formation 300 years time.