科尔沁沙地坨甸交错区土壤水分的空间变异规律

科尔沁沙地沙丘-草甸相间地区，地貌形态多样、土地利用类型众多，从而导致土壤水分空间分布的复杂性。通过对科尔沁沙地典型沙丘-草甸相间地区的调查取样与试验分析，运用统计学理论和方法，研究土壤水分的空间变异性及其空间分布规律。结果表明：水平方向上，土壤水分总体表现为草甸地大于沙丘地，过渡带介于两者之间。就草甸地而言，植物生长越好，其土壤水分越高，保水持水性能也越好；沙丘地则与之相反，植被最稀疏的流动沙丘，其土壤含水量大于半流动半固定沙丘与固定沙丘，且有良好的储水条件。垂向上，高覆盖草甸、低覆盖草甸和农田（草甸）土壤含水量在地表下0～40 cm波动最大，40～160 cm随深度增加而递增；流动沙丘、半流动沙丘和固定沙丘土壤含水量随深度增加呈微弱加大趋势。林地、撂荒地、农田（沙丘）变化程度居中。从空间分布看,研究区中东部土壤水分偏大，且向南北两侧区域递减。

Spatial Variation of Soil Moisture Content in the Dune-meadow Ecotone in the Horqin Sandy Land

The spatial distribution of soil moisture content is complex in the Horqin Sandy Land with dune meadow landscape features, because of various landforms and different types of land use. The statistic theory and methods were used to study the spatial variation and distribution of soil moisture content through careful investigation, sampling and test analysis. The results showed that, at horizontal direction of the study area, soil moisture content in meadows was much higher than that in sand dunes. As for the meadows, the better the vegetation grew, the higher the soil moisture content and water retention capacity would be. It was contrary in the areas with sand dunes, soil moisture content and soil water retention in mobile dunes covered by sparse vegetation was higher than that in semi-fixed and semi-mobile dunes or fixed dunes. Vertically, there was a high fluctuation of soil moisture content in soil layer of 0-40 cm in depth in meadows with high and low vegetation coverage or in cropland, and soil moisture content in soil layer of 40-160 cm in depth was increased with the increase of soil depth. Soil moisture content was slightly increased with the increase of soil depth in mobile dunes, semi-mobile dunes and fixed dunes. In woodland, fallow land and cropland (in sandy land), the variation of soil moisture content was moderate. Spatially, soil moisture content was high in the central and eastern parts of the study area and decreased southward and northward.