毛乌素沙地南缘生态过渡带植被和土壤的特性

对毛乌素沙地南缘生态过渡带流动半流动沙丘、固定半固定沙地、盐化丘间低地和缓坡丘陵梁地4种不同生境植被和土壤特性进行了研究，以探讨毛乌素沙地南缘沙漠化现状。结果表明，从缓坡丘陵梁地，经盐化丘间低地、固定半固定沙地到流动半流动沙丘，植被总盖度、草本植物盖度、物种丰富度均呈下降趋势；植被组成中多年生草本植物逐渐减少，一年生草本植物及沙生灌木、半灌木逐渐增加。土壤含水量为流动半流动沙丘〈固定半固定沙地〈缓坡丘陵梁地〈盐化丘间低地。土壤黏、粉粒及有机质、全氮等养分含量总体为由缓坡丘陵梁地到流动半流动沙丘逐渐降低，砂粒含量逐渐增加。pH和可溶性盐含量无明显变化规律。总体上看，该地区植物群落多以耐瘠薄性强的植物组成，一年生植物比例较高，植被不稳定，土壤组成主要以砂粒为主。土壤含水量低，养分贫瘠，环境脆弱，易产生风蚀、沙化。

Vegetation Characteristics and Soil Properties in the Transitional Zone in South Fringe of Mu Us Sandy Land

An experiment was conducted to reveal vegetation characteristics and soil properties under four different habitats in the transitional zone in south fringe of Mu Us sandy land and to explore sandy desertification status in the region.Results showed that total vegetation coverage,herbaceous coverage,and species richness were all decreased,and perennial species gradually gave place to psammophyte annuals,shrubs,and semi-shrubs from gentle slope hilly ridge,through saline bottomland and fixed and semi-fixed du...