西藏茶巴朗流域的土壤侵蚀及防治对策

Soil Erosion and Countermeasures for Prevention and Control of Chabalang Watershed in Tibet

为探讨西藏地区水土流失特点及防治途径,以茶巴朗小流域为研究对象,对其遥感影像进行了解译和信息提取。结果表明:与西藏地区主要侵蚀类型为冻融侵蚀不同,水力侵蚀是茶巴朗小流域水土流失的主要类型,面积为51.80km2,占流域面积的66.05%;其次是冻融侵蚀、风力侵蚀,分别占流域面积的5.74%、3.66%,且侵蚀强度以中度为主,并依海拔梯度呈现出条带状分布特征。茶巴朗小流域土壤侵蚀模数为4 087 t/(km2.a),主要分布在流域内的中山区和河谷区。针对该流域水土流失特点,提出了"开展生态移民,控制牲畜规模"、"调整土地利用结构,实施退耕还林还草"、"科学布局小水电站开发项目,构建以电代柴生态补偿机制"、"加强土壤侵蚀动态监测研究,完善工程项目水土保持管理"的防治对策。

In order to examine characteristics of soil and water loss and ways of prevention and control of Tibet area,the paper interpreted imagesof remote sensing and collected information by taking Chabalang small watershed as an object of study.The outcomes show that the main typeof erosion of the small watershed is hydraulic erosion which is different from freezing and thawing erosion,the main type erosion of Tibet area.The hydraulic erosion area is 51.80 km2,making up 66.05% of the catchment area.The next is freezing and thawing erosion and winderosion,making up 5.74% and 3.66% of the catchment area respectively,mainly moderate erosion intensity and showing the characteristicof zonal distribution along with the elevation.The soil erosion modulus of the small watershed is 4 087 t /(km2·a) and mainly distributes inhilly and valley regions of the catchment area.According to the characteristics of soil and water loss of the watershed,it puts forward preventionand control countermeasures of'carry out ecological migration project and control the scale of livestock','adjust the structure of landuse and carry out the project of conversion of cropland to forest and grassland','scientifically layout small hydro-power projects and establishecological compensation mechanism of using power instead of firewood'and'strengthen soil erosion dynamic monitoring study and improvesoil and water conservation management of engineering projects'.