坡位对土壤水分及植被空间分布的影响

目的]探讨微地形对土壤含水量和生物量的影响,为浑善达克沙地环境建设和合理开发利用提供理论参考。方法]以内蒙古锡林郭勒盟白音锡勒牧场境内的中国科学院内蒙古草原生态系统定位站沙地样地为研究对象,对坡底、坡顶、阴坡和阳坡等坡位的植被和土壤水分等指标的测定,对其进行方差分析和相关性分析。结果]坡底以多年生杂类草占优,阴坡以灌木、半灌木及多年生禾草为主,阳坡以灌木、半灌木、多年生禾草及1,2年生植物为主,坡顶以多年生禾草和1,2年生草本植物为主;0—50cm土壤平均含水量的大小顺序为:坡底阴坡阳坡坡顶,生物量顺序与土壤平均含水量一致;坡顶、坡底、阳坡和阴坡各层土壤水分变异系数由大到小的顺序因土层和坡位的不同而表现出一定的差异性,0—50cm各层平均变异系数坡顶最大,坡底次之,阳坡最低;生物量和各层土壤含水量均呈现正相关关系,其中0—5,5—10和20—30cm土壤含水量与生物量之间表现为极显著线性正相关(p0.01)。结论]微地形对植被种类和土壤含水量具有一定影响,且土壤含水量和植物生物量呈现正相关关系。

Effects of Slope Position on Spatial Distribution of Soil Water and Vegetation in Sandy Land

Objective] To study the impacts of micro-topography on plant functional groups, biomass and soil water content in order to provide theoretical reference for environmental construction and reasonable development in the Hunshadake sandy land area.Methods] The investigations were conducted in sandy land, in Inner Mongolia grassland ecosystem research station(IMGERS). Soil water content, biomass and plant functional groups were investigated under different micro-topographic conditions.Results] The bottom of hill was dominated by perennial grass, while the top of hill was dominated by perennial grasses and annual or biennial herb. Shrub, subshrub and perennial grasses were distributed on the north-facing slopes, while shrub, subshrub, perennial grasses and annual or biennial herb were distributed on the south-facing slopes. The soil water content(0-50 cm) was showed as follows:bottom of the slope >north-facing slope >south-facing slope >top of the slope, and same trend was showed in biomass. Coefficient of variation of soil water content(0-50 cm) was the greatest at the top of the slope, while it was the lowest at the bottom of the slope. Aedbetween biomass and soil water content, and significant linear correlation existed between biomass an soil water content in top soil(0-5 cm), soil at the depth of 5-10 cm and 20-30 cm(p<0.01).Conclusion] Micro-topography influences soil water content and florisitics, and there is a significant positive correlation between soil water content and biomass.