关键词: 沙漠化, 土壤环境, 植被逆行演替, 生物过程

Abstract: Features of soil environment and vegetation in four types of desertified land were investigated and their changes laws and causes and mutual relation were analyzed. Results showed: desertification caused a rapid deterioration of soil environment and vegetation, of which soil organic matter and quick-acting N and water content declined by 66.2%, 69.0%, 74.8% respectively, and soil temperature raised by 0.9 ℃ in seriously desertified land compared with no desertified land, specially soil water content is 2.3% in dry period and can not meet the needs for crop growth. The plant diversity decreased by 85.5%~88.3%,saturation index of plant spices dropped from 20~40 n·m^-2 to 1~5 n·m^-2,primary productivity declined by 80.6%~96.7% in seriously deteriorated grassland compared with normal grassland. Meanwhile, contrary succession displayed and dominant spices changed in the vegetation. Though management measures as fertilizing and inter-tilling were practiced, photosynthetic efficiency and biomass decreased by 56.7% and 57.4% in dry cropland. Desertification process caused by vegetation deterioration was slower than that by wind drifting sand.

Key words: desertification, soil environment, vegetation succession, bio-process