北方农牧交错带东段土地水蚀荒漠化监测——以扎鲁特旗为例

Monitoring waterpower desertified land in the east part of the agro-pasture zigzag zone in north China-the case of Zhalot Banner

以20世纪80年代末和2000年TM影像作为信息源,经合成、增强、几何纠正、镶嵌和人机交互判读并结合野外调查提取土地水蚀荒漠化信息,建立土地水蚀荒漠化空间数据库,结果表明:研究区水蚀荒漠化率为10.64%,以轻度侵蚀为主。水蚀荒漠化空间分异明显,在北部中山区形成三个集中分布区。研究期内土地水蚀荒漠化动态为整体扩展,局部逆转,程度加强;中度、强烈和严重水蚀面积增加,轻度的减少;发生逆转的主要为轻度水蚀土地。人类不合理的经济和社会活动与脆弱的自然条件耦合是研究区土地水蚀荒漠化发生并扩展的全部原因。因此要从控制人口增长,调整不合理的土地利用方式和强度,加强生态环境管理入手,高度重视农牧交错带东段退化土地的综合防治,为区域可持续发展提供良好的生态环境。

Using TM imagm of the end of 1980s and 2000 （The resolving power are 30 and 15m ） of Zhalot Banner as information source, the statistics of waterpower desertified lands area in 2000 and the conversion of waterpower desertified land areas and the proportions from the end of 1980s to 2000 were gained and the databank were upbuilt by synthesizing, reinforcing,correcting, inlaying, judging of man and computer tcgether and field seeing about, then the status quo and changes of waterpower desertified lands were analyzed. The results show that： The waterpower desertification of land is very severe and the amount of waterpower desertified land occupim 10.64 % of the total land area. Mcst of the waterpower desertified land is of light- grade and the proportion of waterpower desertified lands is 44.10% , 27.40% , 25.09% and 3.41% from the light-grade to the severe-grade , respectively. The waterpower desertification of land took place mostly in the north of Zhalot Banner where the landform is middle- altitude mountains and the area of waterpower deserffied lands is less in the middle of Zhalot Banner where the landform is low mountains and hills and there is no waterpower desertifed lands in the south plain. There are 3 great scaled areas of waterpowter desertified land in the north of Zhalot Banner. The first lcvates in the Arkhundleng river drainage area and most of the lands are the violentgrade ;the second in Aileen ,Dalleen and Ubukhundleng river drainage areas and most of them the middle- grade; the third in the upriver of Kholeen river drainage area and most of them the light - grade. The trend of waterpower desertification of land in Zhalot Banner has been expanded on the whole（The proportion of increasing is 21.37% ） and has been reversed on some parts（It has been took place on the middle part mostly） and the degree of erosion has been strengthened. The areas of the middle- grade , the violent- grade and the severe- grade waterpower desertified lands have been increasing and it has been decresing of the light - grade from 1980s to 2000. Most of reversed lands are the light- grade of waterpower desertified lands. The fragile weather, the steep - landform and high - physiognomy, the matter of the ground and the degraded vegetation are the natural condition that result in the waterpower desertification of land,while the factors that bring and accelerate the process are the land use pattern and intensity of over-assarting,over - grazing, over - woodcutting and over- collecting. But the land use pattern and intensity are usually bringed as a result of population increasing,unconstant policy and bad management. It is imperative of that pay attention to the waterpower desertification of land, especially the light- grade degraded land in the agro- pasture zigzag zone in north China by controlling population,adjusting the structure of land use and intensity and enhancing the management of environment.