关键词: 土地利用结构优化, 中国生态地理区域系统, 因子分析, 北方沙漠化地区

Abstract: North China has been seriously influenced by sandy desertification,which is closely related to the land use structure.According to the county level detailed investigation data on land use,factor analysis was used to do integrated evaluation on land use structure for each evaluated unit (including county and county-level city).Based on the integrated score for each evaluated unit and the newly completed eco-geographical system of China,the evaluated units were united by using the GIS technique.Thus,the combined division method of from-top-to-bottom and from-bottom-to-top was successfully used.The sandy desertification affected North China was therefore divided into 12 regions.Typical regions with data of remote sensing investigation and evaluation of land resources were selected from the aforesaid 12 regions.The achievements of remote sensing investigation and evaluation of land resources in typical regions were reorganized to analyze the land quality and land suitability according to the need of ecological construction. Optimization of land use structure was established in typical regions and extended to the 12 divided regions.Directions for land use optimization were suggested based on the comparison between calculated optimization of land use structure and detailed investigation land use structure.The authors emphasize that returning cropland to shrubbery or grassland is more important and the optimization of land use structure should be carried out step by step.

Key words: optimization of land use structure, eco-geological system of China, factor analysis, sandy desertification region in North China