基于RS/GIS的生态脆弱区土地利用适宜性评价

 以加快水土保持步伐、提高土地生产力、改善生态环境为目的,以黄土高原水蚀风蚀生态脆弱区典型流域为例,以航片为基本信息源,通过实地调查,获得1990年和2002年土地利用数据。根据统计时期内土地利用变化,计算土地利用合理性指数,采用限制性影响因素法,评价研究区土地资源,并与2002年土地利用进行比较。结果表明:1990—2002年,基本农田、林草地类增加,坡旱地减少。1990年,土地利用合理性指数为0.55,2002年为0.67。2002年,农地类土地资源呈两级趋势,具备灌溉条件的水浇地为Ⅰ等适宜性,旱梯田与坡旱地为Ⅲ等适宜性。林地类土地资源有90.32%属Ⅱ等适宜性。牧草地类土地资源属于Ⅰ等适宜性和Ⅱ等适宜性。通过分析,Ⅲ等适宜性农地更适合草类生长。保持现有水浇地和旱梯田面积,将Ⅲ等适宜性农地退为草场,研究区农林牧用地结构将达到1.0∶2.5∶4.8。

Evaluation of Land Use Suitability at the Vulnerable Ecological Area Based on RS/GIS

Land use planning is crucial to the areas that are under severing soil erosion. Land evaluation is an important basis for landscape and land use planning. A framework was developed for land evaluation in Liudaogou watershed with typical characteristics of water-wind erosion crisscross region, in the loess plateau, focusing on integrative, process and ecological analysis. Landuse data in 1990 and 2002 were collected from RS data and GIS was used for data storage and analysis. The landuse rational index from the point of land slope degree for two periods was calculated and four limiting factors (the section of landform, slope degree, soil type and soil erosion intensity) were selected and their ranking and weighted contribution were given to evaluate the suitability of current land source for farmland, grassland and forest separately in 2002. By comparing the different suitability of current farmland, grassland and woodland, measures for better land use and conservation are suggested.