农牧交错带土地荒漠化及其影响因子研究——以扎鲁特旗为例

Study on Desertification and Its Affecting Factors in Farming-pasturing Ecotone—A Case Study in Zhalot Banner,Inner Mongolia Autonomous Region

以扎鲁特旗2000年TM影像作为信息源,并结合野外考察进行人机交互判读,建立土地荒漠化数据库。结果表明:扎鲁特旗土地荒漠化严重,荒漠化率达28.88%。荒漠化类型有沙质荒漠化、水蚀荒漠化和盐渍化。土地荒漠化空间分异明显,南、北部严重而中部较轻,农牧交错区比纯农区和纯牧区严重。地形地貌、松散的土质以及干旱多风的大陆性季风气候是土地荒漠化的基本条件,过度垦殖、过度放牧和过度樵采是土地荒漠化的直接原因,人口剧增是间接原因,而管理失误才是土地荒漠化的根源。要遏制农牧交错带土地退化的严峻态势,必须加强管理,控制人口,改革土地利用制度,调整土地利用结构,重视环境建设。

By using the TM images of Zhalot Banner in 2000 as the information source, the distribution maps and spatial database of desertified lands in the banner are compiled through synthesizing, reinforcing, geometric correcting, inlaying and man-computer interactional interpretation based on field investigation. The results show that the land desertification in the banner is extremely serious, and the lands in proportion of 28.88 % of the to- tal land area in the region have been desertified. The results reveal that the proportions of the areas of sandy desertified lands, water-eroded desertified lands and salinized soil are 13.54%, 10.64% and 4.70% respectively. The desertification is severer in the south and north of Zhalot Banner than that in the central part, and it is severer in the farming-pasturing ecotone than that in the pure-farming and pure-pasturing zones. The spatial distribution of land desertification is closely related to the terrain. The plain in the south is mainly in sandy desertifi- cation and soil salinization, the mountainous area in the north is mainly in water-eroded desertification, and the hilly area in the central part is a transitional zone. Basic causes of land desertification are topography, loose soil, and relatively arid and windy continental monsoon climate. Excessive reclamation, pasturing and firewood gathering are the direct causes of land desertification, rapid population growth is an indirect cause, and the fault in land resources management is a main factor. In order to restrain and control land degradation in the farming-pasturing ecotone, it is suggested to strengthen the government administration, control population density, reform land use system, regulate land use structure, and give importance to ecological environment regeneration.