Adjustment of land use types for desertification control and prevention:Taking Duolun County of Inner Mongolia as a typical case
Adjustment of land use types for desertification control and prevention:Taking Duolun County of Inner Mongolia as a typical case
复制标题
作者：
Y. Lian
沙漠化的形成和发展总是取决于两个因素：风力、下垫面特征、土地利用类型沙型是后者的部分反映，必然影响荒漠化的形成和发展，以地处内蒙古高原半干旱气候区的多伦县为典型代表，本文就如何调整土地利用类型，改善下垫面特征，防治荒漠化问题进行了探讨。1）利用Landsat TM影像数据编制该县土地利用现状图。2）以荒漠化防治为目标，以地表物质组成、地表植被覆盖度、有机质含量三个因子作为生态安全评价指标，将生态安全分为安全、半安全、区分半不安全和不安全，每个土地利用单元对应一定的安全等级，从而得到县级生态安全评价图。3）确定土地利用类型调整的三个原则：（a）宏观土地利用格局配置应与大尺度地貌类型或大区域地貌差异相一致;（B）生态安全不受再荒漠化影响;（3）充分考虑土地利用现状。（4）在半不安全区和非安全区分别调整土地利用格局和类型。桑迪、盐碱地等占全县土地总面积的25.8%。调整后的土地利用单元均在1∶ 25万比例尺的土地利用图上显示出来，并对调整前后该县土地利用格局进行了初步研究
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