长江上游典型样区土地利用现状初步分析

Actualities of Land Use in Upper Yangtze River Basin Typical Spots

为了掌握土地利用现状,以长江上游水土流失重点区域为对象,首先采用抽样调查方法确定4个典型样区,然后在各样区内以单幅1∶10000地形图覆盖范围为调查对象,进行土地利用现状的野外现场勾绘和室内各种土地利用面积的统计分析。结果表明:长江上游地区土地利用以农用地为主,其中主要类型是耕地和林地,而耕地中又以水土流失最易发生的坡耕地比例最大,接近耕地总面积的一半,同时,由于地理位置的不同,不同典型样区的土地利用也存在较大的空间差异,其中金沙江干热河谷区与其余3个样区的差异较大。

For understanding the present situation of land use in upper Yangtze River basin, four typical spots where soil and water loss are serious were first confirmed by using spot check survey. In every typical spot, taking one 1 ： 10 000 topographic map cover area as the investigation target, the land use survey in field, statistics and comparison analysis were implemented. The results show as follows： The agricultural land is the major land use type in upper Yangtze River basin, in which cropland and forest land are main sorts. Among the cultivated lands, sloping field is mostly threatened land which can cause soil loss easily, and its percent of soil loss is the highest, near one half of whole area of farmland, so soil and water conservation in upper Yangtze River basin is one difficult task. Meantime, investigated data indicate that there exist spatial differences in the four typical spots.