毛乌素沙地典型地形断面土壤水分动态

基于毛乌素沙地的野外观测资料,对毛乌素沙地典型地形断面土壤水分动态进行分析。结果表明,土壤水分季节变化可划分为土壤水积聚期、消耗期和稳定期;根据土壤水分垂直变化可把土壤剖面划分为土壤水分易变层、利用层和调节层;沿着坡度减小的方向,各地形断面对应层次的土壤水分含量逐渐升高,丘间地土壤水分含量明显高于该断面上其余各点。

Dynamic Trend of Soil Moisture Content at a Typical Profile in the Mu Us Desert

The study area is located in the ecotone between the arid grasslands and desert grasslands in the Mu Us Sandland on the Ordos Plateau. The ground surface here is loose, the vegetation coverage is low, the wind erosion, land desertification and soil erosion are serious, and the study area is one of the regions with the most serious desertification in China. The annual precipitation in the area varies in a range of 250-400 mm, and the precipitation during the period from July to September occupies 60% -70% of the annual one. In the study area the annual evaporation is as high as 2 600 mm, the maximum and average wind speeds are 19. 5 m/s and 2. 9 m/s respectively, and the prevailing wind direction is N-NW. The soils are dominated by aeolian soil, brown soil, meadow soil and saline or alkaline soil. In this paper, the dynamic trend of soil moisture content at a typical section in the Mu Us Sandland is analyzed based on the field investigation. The results show that the seasonal change of soil moisture content can be divided into the soil moisture accumulation period, consumption period and stable period. According to the vertical change of soil moisture content, the easily change layer, utilization layer and regulation layer can be divided. The soil moisture content is increased with the reduction of slope. The soil moisture content in the lands between sand dunes is obviously higher than that at other measuring sites.