中喜马拉雅山区土地利用的空间分布特征

Spatial Distribution Characteristics of Land Use in the Mid. Himalaya Mountain Area

基于Google Earth卫星地图,采集中喜马拉雅4条典型高山峡谷带遥感影像,利用ArcGIS空间分析技术,按山地垂直带的5级海拔指标和青藏高原土地种的4级坡度指标,分析研究区耕地和草地空间分布特征。研究结果表明：①海拔2200m以下无耕地,坡度影响强烈,海拔2500～3800m的宜农坡度带（〈5°、5～15°）,是耕地利用方式、程度和潜力的核心区域;②草地优势海拔为38004800m,坡度影响较弱,4个谷地在宜牧坡度带（〈5°、5～15°、15～35°）的草地数量差异性小;③横向比较发现,吉隆谷地可利用土地最多,其次为朋曲谷地、波曲谷地、绒辖谷地,但受海拔和坡度限制,不宜农、牧坡度带也有不同程度的农业生产活动,极不利于生态环境保护和土地资源合理利用。研究结果具有代表性地反映了中喜马拉雅山区土地利用现状和结构。

Land use/cover change has increasingly become a core issue in both land resources research and management. The Mid. Himalaya mountain area involves several discontinuous valleys,The problems of land use in this area are closely related to living level promotion of local habitants as well as social economic development. being short of accurate land resource material. Satellite images covering four typical valleys located in the Mid. Himalaya mountain area were collected from Google Earth Planet Map. The four valleys from the east to the west are： Pengqu Valley, Rongxia Valley, Boqu Valley, and Gyrong Valley. The authors investigated mountain altitudinal belts and slope gradients of soil types of the Qinghai-Tibet Plateau, with the objective to obtain the spatial distribution characteristics of farmland and grassland across the study area. The altitude index was divided into five categories, i.e., 〈2500 m, 25003800 m, 38004800 m, 48005200 m, 〉5200 m of the mountain altitudinal belts; and the slope gradient index was divided into four ranges, i.e.,〈5°, 515°, 1535°, and 〉35° of soil types of the Qinghai-Tibet Plateau. Conclusions were drawn that 1） there is no farmland below 2200 m altitude. The land use is determined primarily by the slope gradient in the altitude range of 〈2500 m. 2） It is in the altitude range of 25003800 m and on the two belts of the farming suitable slope gradient （〈5°, 515°） that the very focus zone has relatively larger potential, suitability, and yield of farming utilization. 3） It is in the altitude range of 38004800 m that grasslands dominate and the slope gradient plays an insignificant role. 4） On three belts of the grazing suitable slope gradient （〈5°, 515°, and 1535°）, respective fodder quantities for the four valleys have small differences. 5） Comparison among the four valleys indicates that the Gyrong Valley has the most available lands, followed by the Pengqu Valley, Boqu Valley, and Rongxia Valley. In addition, the land use of the four valleys are significantly determined by altitude and slope gradient so that cultivation and grazing activities take place widely on the belts of the farming unsuitable slope gradient （1535°, 〉35°） and the belt of the grazing unsuitable slope gradient （〉35°）, which seems to be disadvantageous to environmental protection and reasonable utilization of land resources. The conclusions unravel current situations of land resources utilization and configuration in the Mid. Himalaya mountain area, which is of importance to explore the relationships among resources, environment, and society