以防沙治沙为目标的土地利用方式调整——以内蒙古自治区多伦县为例

风沙现象的发生与作用力(风力)大小和下垫面特征密切相关,土地利用方式反下垫面的特性,从而影响风沙现象的发生和发展。本文以地处半干旱地区的内蒙古多伦县为例,在充分查明原有每个土地利用地块抗风蚀特性,和生态安全性的基础上,根据下列原则:(1)依照大的地貌类型或地貌区域的差异,进行宏观尺度上土地利用格局配置;(2)不再沙化条件下维持生态安全;和(3)充分考虑目前现实状况,进行以防沙治沙为目标的土地利用方式调整。调整结果反映在两县市的1∶250000土地利用图上。另外,对多伦县的土地利用格局也作了初步探讨。

Adjustment of land use types for desertification control and prevention:Taking Duolun County of Inner Mongolia as a typical case

The formation and development of desertification always depend on two of factors: wind power and characteristics of the underlying surface Pattern sand types of land use are parts of reflections of the latter,which would certainly influence the formation and its development desertification.With Duolun County located on the Inner Mongolia Plateau in semi arid climate region as a typical representation, this paper deals with how to adjust land use types so as to improve the characteristics of the underlying surface and to control desertification The following steps are adopted for accomplishingthis objective:1) Compiling current situation map of present land use of this countyby using Landsat TM image data 2) Considering thegoal is desertification control and prevention, the following three factors like material composition of the earth surface vegetation cover degree of the earth surface and content of organic matter are used as indexes to assess ecologic safety Four grades of safety, semi safety, semi non safety and non safety are distinguished Each land use unit corresponds to a certain grade of safety, so that a map of the county level ecologic safety assessment is obtained 3)Identifying three principles for adjusting land use types:(a) collocation of macroscopic land use pattern should consist with large scale geomorphologic types or large regional geomorphologic difference, (b) ecological safety under condition of free from redesertification; and (c)actual present land use condition should well be considered 4) Adjusting land use pattern and types respectively in semi non safety and non sefety areas Land use types involved in the adjustment include farmland, grassland, open forest, sandy land, saline alkali land etc accounting for 25 8% of the county's total land area. All of the adjusted land use units are shown on the map at a scale of 1∶250,000 Besides, a primarily study on pattern of land use of this county before and after adjustment is also done