基于RS和GIS的岷江流域退耕还林还草的初步研究

Closing Land for Forest or Grass in Minjiang Drainage Based on RS and GIS

目前我国西部地区大力开展改善生态环境的退耕还林还草工程。岷江属于长江上游重要的支流之一 ,其水保工作将对整个长江流域的生态环境建设直接产生影响。退耕还林还草的科学问题在于水土保持 ,利用 RS和GIS数据以及通用水土流失模型对岷江上游进行侵蚀强度分级和填图、坡耕地的提取 ,最后统计分析坡耕地和侵蚀强度间的关系 ,确定区域内退耕还林还草的标准 ,并且对退耕还林还草后生态环境的变化和水土流失量进行了初步预测方法。

Closing land for forest or grass is a important project, which was developed in west-China in 2000, in improving environment, water and soil preservin g and reducing natural disaster. Minjiang river is an important branch of Yangt ze river. Its water and soil preserving will affect environment of Yangtze river drainage directly. The essence of closing land for forest or grass lies in wate r and soil preserving. Remote sensing and geography information system (GIS) tec hniques were applied to extract the sloping land information and describe all fa ctors of the USLE model. The universal soil loss equation (USLE) is used to calc ulate the annual soil loss, and characterize the spatial distribution of the ris k of soil erosion by water in Minjiang river drainage. The relationship between sloping land and soil erosion will be analyzed, which is in different slope for determining the criterion of closing land for forest or grass. In the end, the change of environment and soil loss is evaluated before and after closing land for forest or grass in Minjiang drainage.