绿洲荒漠化及其评价指标体系的初步探讨

针对目前荒漠化评价指标体系中存在的问题，在大量前人工作的基础上，选取位于极端干旱区的民勤绿洲作为研究样区，在对绿洲荒漠化特点及其发生的自然与人为原因分析的基础上，对绿洲沙质荒漠化发生的边界范围，荒漠化评价指标选取原则等问题进行了探讨，最后从灌丛沙堆发育程度，土壤、植被、人为因素，地貌形态及其发育程度等5个方面，提出了一套以地面工作为基础的绿洲沙质荒漠化评价指标体系。

The Desertification of oasis and ITS Assessment Indicators

Desertification is one of important environmental problem in the world. In this paper, the Minqin oasis were selected as an example to discuss the oasis desertification assessment indicators. According to our research result, the sandy desertification always occurs in the edges of oasis periphery which distance is 1-2km. Its obvious symbol is the reactivition of fixation and semifixation dune on which grows the shrubs. In this study, the surface investigation assessment indicators were proposed. The assessment indicators include 5 aspects. First is the developing status of shrub sand dune which include soil crust, dune density, dune height, percent of sand dune occupied the total area, the percent of the areas which were uncovered by plants on sand dune. The second are the soil physical, chemistry and biological characteristics. The third is the vegetation coverage, composition and regeneration. The forth is the landforms shape and its developing status. The last one is the human factors which include social and economic factors.