鄂尔多斯高原北部沙区生长季土壤水分特征分析

Characteristics of Soil Moisture for Sandy Region in North of Ordos Plateau During Growing Season

土壤水分是沙地植被稳定性的决定因素之一。在鄂尔多斯高原北部沙区选择地形或植被类型各异的24块样地进行生长季土壤水分监测与分析。结果表明,研究区土壤水分具有极高的时空异质性,不同样地、不同层之间的土壤体积含水量在0.7%～39.4%之间变化,且多数样地存在0～10cm厚的干土层;0～70cm厚度土层的平均水分含量大于10%的样地的等值线图具有极大的相似性,小于10%的样地差异较大却分布了研究区的主要植被类型;土壤水分对降水有明显的响应作用,在三维等值线图上表现出典型的凹陷(干季)和凸起(雨季)。进一步探究该区域以土壤水分为主的自然植被分布格局、人工植被配置、生态水文过程转变、人工生态系统的演替等问题,将有助于完善该区域的生态安全格局。

Soil moisture is one of the determinants of sandy vegetation stability. About 24 sample plots were selected for monitoring and analyzing soil moisture in the sandy region in north of Ordos Plateau for different topographies or vegetation types during growing season in 2004. The results showed that the soil moisture distribution had high temporal and spatial heterogeneity. The soil volumetric moisture content changed from 0.7% to 39.4% for different plots and different layers, and most plots had a dry soil layer about 0-10cm. The isolines were quite similar for plots with averaged soil moisture more than 10% in 0-70cm, while, which showed largely different for those with averaged soil moisture lower than 10% and the primary vegetation types in our study area. The soil moisture showed apparent response to precipitation, with distinct concave or convex during the dry or rainy season respectively in the three-dimensional isolines. Based on soil moisture, further study on the distribution of natural vegetation pattern, the configuration of artificial vegetation, the transformation of eco-hydrological process and the succession of artificial ecosystem would help to perfect the regional pattern of ecological security.