黄土高原上黄小流域土地利用类型的坡度分析

Distributions of Land Use Types by Slope Category in Shnaghuang Small Watershed on the Loess Plateau,China

以上黄小流域1∶1万DEM和1982-2008年6期土地利用数据库为基础,运用RS/GIS技术提取不同坡度下各土地利用类型的面积分布数据,研究黄土高原小流域尺度下的土地利用类型坡度组成状况及其变化趋势。结果表明:(1)近30 a来,上黄小流域各土地利用类型均发生了剧烈的变化。其中,耕地呈现先增加后锐减的变化趋势,林地一直呈现递增趋势,而草地变化趋势与林地相反;(2)目前各土地利用类型的坡度分布较为合理,基本体现了因地制宜,合理配置资源的原则;(3)该流域仍有约6.81 hm2的土地需要退耕还林还草,但该面积还占不到全试区总面积的1%,说明该试区基本完成国家退耕还林还草任务的要求。

Based on the DEM at 1∶10 000 scale and the land use data base from 1982 to 2008,the distribution and change conditions of land use type at different slope category were analyzed by using RS and GIS.The results showed that（1） the land use changed dramatically in the past 30 years in Shanghuang small watershed,where the areas of arable land increased first and then decreased sharply from 2002 to 2008,the areas of woodland increased continuously,and the areas of grassland decreased continuously.（2） Now the distributions of land use area at different slope were more reasonable,which basically reflects the principles of rational allocation of resources.（3） 6.81 hm2 of land in this basin still should be convert to forest land/grassland,but this area accounts for less than 1% of the total area of this basin.Therefore,the task of conversion of cropland to forest land or grassland was basically completed in the Shanghuang small watershed.