目前,世界耕地面积约为15亿公顷,占陆地总面积的10—11%.个别地区的耕地面积已达70%.由于森林资源日趋枯竭,生态系统受到了严重破坏,土壤侵蚀和尘暴等自然灾害频频发生.迄今为止,世界土壤风蚀面积已达陆地面积的34%,水蚀面积已达31%.每年约有600亿吨肥沃的表土被冲刷流入海洋.这样继续下去,本世纪未,全世界的土壤侵蚀面积将达10亿公顷. At present, the world’s arable land is about 1.5 billion hectares, accounting for 10-11% of the total land area, and the cultivated area has reached 70% in some areas. Due to the depletion of forest resources, the ecosystem has been severely damaged, and soil erosion and dust storms and other natural So far, the world’s soil wind erosion area has reached 34% of the land area, water erosion area has reached 31% .About 600 tons of fertile top soil is washed into the ocean each year .To continue this century, the world The soil erosion area will reach 1 billion hectares.