黄土高原水土流失造成的危害及其综合治理措施

黄土高原地区的面积为64.27万km2,其中,水土流失面积达45万km2,占总面积的70.9%,每年向下游输沙量约达12.8亿t,占黄河向下游输沙量的80%。其主要产沙区在六盘山以东地区,东部侵蚀度北强南弱,西部北弱南强;黄土高原存在几个高强度侵蚀中心,水蚀风蚀形成侵蚀强烈地区。水土流失的主要危害是破坏土地资源,生产能力降低;农田破坏严重,削弱土壤肥力;降水少而平均,干旱灾害不断加剧;林草地比例严重下降,形成恶性循环。总结黄土高原水土保持的历史经验与教训,要通过加强宏观控制、推进小流域综合治理、建设基本农田、逐步退耕造林种草、坚持治理与开发相结合、严格控制人口增长等措施解决水土流失问题。

Caused Harm of Soil Erosion in the Loess Plateau and Its Comprehensive Control Measures

The area of the Loess Plateau is 642 000 km2 and soil loss area of the Loess Plateau reaches 450 000 km2,which accounts for 70.9% of total area.The sediment discharge to lower reaches every year reaches about 1 280 000 000 t,which occupies 80% of total sediment discharge to lower reaches for the Yellow River.The main areas of producing sediment are located in east of Liupanshan,the north erodibility in east areas was stronger than south and that was opposite in west areas.The Loess Plateau has several high-intensity erosion centers and the water erosion and wind erosion formed the intense erosion area.The main harms of soil erosion includes the followings:destroying the land re-source,reducing productivity,reducing the soil fertility,serious destruction of farmland,less but even precipitation,constantly increase of drought,serious drop of the proportion of woodland and grassland,forming the vicious circle.The historical development experience and lessons of the water and soil conservation in Loess Plateau were sum up.The problem of water and soil loss should be resolved by advancing the comprehensive control of small basins,constructing the basic farmland,returning farmland to woodland and grassland gradually,combining government and development,controling population growth strictly,strengthening the macro-control.