Study On Mechanism Of Desertification And Evaluation Of Ecologic Environment In Bashang, Hebei Province

Bashang Area of Heibei Province is on the southern edge of Mongolian Plateau and in the north of Hebei Province, and this area is one typical mixed zone of agriculture and animal husbandry in China, which is also a typical fragile and weak ecological and environmental belt in North China. The research on the ecological environment of this area is of great practical and theoretical significance. As regards such a fact, the Hebei Science Committee established a project of "Study of origin mechanism of land desertification in Bashang Area of Heibei Province and countermeasures"in 2002. The paper is part outcome of the project. Based on the regional geological, meteorologic, forest, vegetation, land utilization and human culture data from the field work, remote sensing and the landforms'feature conditions of the focus area, the comprehensive research on the Bashang Area of Hebei Province has been carried out in this paper. And the research mainly focused on the typical areas. During the research, the Landsat TM remote sensing images of 1987 and 1999 were used as the data resource, under the support of processing software of remote sensing image, ERDAS 8.4 and the geographical information system of ARCUNFO 8.02, a classification system of remote sensing image for land utilization and vegetation cover was established; at the same time, one image classification and abstraction scheme with the computer-controlled automatic classification and manual interpretation error correction functions was materialized in the research; as a result, the two phases of high-precision land utilization/vegetation cover maps have been achieved, which is the powerful effective data support to the accurate analysis of the desertification of lands in Bashang Area. Based on the comprehensive information of a great deal of geological, remote sensing, geographical, meteorologic, hydrographic, social and human culture of the study area, this dissertation has systematically analyzed the relation between land desertification and land disaster, and discussed the mechanism of land desertification of this area. The research results indicate that the geological factors, meteorologic factors, vegetation, hydrology and other natural factors are the key factors of land desertification. Due to the controlling factors of landform features, the salinization predominates was the main type of desertification in the western part of Bashang Area. The sand desertification predominates on the edge of Bashang Area, and the middle is a transition zone. Through the study to the distribution of strata in Bashang Area and the distribution characteristics of desertification, it is found that the Quaternary loose accretion is the basic material source of the desertification of this area. The slope and gully density among the factors of land features is...