腾格里沙漠沙丘固定后土壤的斥水性特征研究

Characteristics of Soil Water Repellency in Stabilized Sand Dunes in the Tengger Desert

土壤斥水性是重要的土壤物理属性,对土壤水文过程和地貌过程有重要的影响。利用毛细上升法研究了腾格里沙漠东南缘沙丘固定后土壤的斥水性特征,分析了不同小地形、不同土壤深度和不同土壤粒径土壤的斥水性差异。结果表明,固沙植被建立后显著地改变了沙丘的土壤斥水性,且随沙丘固定时间增加而呈增强的趋势。丘间地和迎风坡的土壤斥水性大于丘顶和背风坡的斥水性。0～3cm土层的土壤斥水性显著大于3～6cm。随着粒径的不断增大,土壤斥水性呈减小趋势,不同粒径段土壤斥水性差异显著;且土壤斥水性与粒径分别为0～0.05mm、0.05～0.01mm、0.01～0.15mm的土壤呈极显著正相关线性关系,与粒径大于0.15mm的土壤呈显著负相关线性关系。植被区土壤斥水性的增加可能与大气降尘在固定沙丘表面不断沉积、生物土壤结皮形成,尤其是藻类和地衣的形成有关,斥水性的增强将影响到植物种在沙丘上的有效水分利用。

Soil water repellency （SWR） is one of the important physical properties of soils, which has signifi- cant effects on soil hydrological process and geomorphological process. In this study, the Capillary Rise Method was used to measure the SWR in the afforestation area in the Shapotou region, southeast of the Tengger Desert, China. Variations of soil water repellency in different micro landforms, different soil depths and different particle sizes were analyzed. Results indicate that the soil SWR is markedly changed by vegetation restoration, and it increases with the dune stabilization duration. In the same vegetation area, the SWR in inter-dune depression and windward slope is greater than that in crest and leeward slope, but no significant difference is found. The SWR of 0-3 cm topsoil is significantly greater than that in the soil layer of 3-6 cm. The soil SWR decreases with the increase of grain size, and the differences of SWR between dif- ferent sieved soil fractions are found to be significant. There are significantly positive correlations between the SWR and the content of soil grain size at 0-0.05 mm, 0. 0540.01 mm and 0.01-0.15 mm, and a sig- nificantly negative correlation between the SWR and the content of soil grain size exceeding 0.15 mm. The increase of SWR at afforestation areas may depend on atmospheric dust on the stabilized dune surface and the formation of biological soil crusts, especially the formation of algal crust and lichen crust. Enhanced SWR will affect the effective water use of plants in the sand dunes.