云雾山封育草原对表土持水性的影响

应用离心机法测定土壤水分特征,研究黄土高原典型草原带退耕地植被恢复演替过程中土壤持水性能的变化特点及趋势。结果表明:土壤含水量与土壤水吸力之间符合幂函数θ=aS^b,参数a的变化随着植被的演替呈增加趋势;由于植被的影响,在同一吸力范围内的土壤含水量不同,植被为顶级长芒草(Stipabungeana)群落时,土壤在各吸力段的含水量最高,坡耕地最低;其它群落土壤含水量随着水吸力的增加变化趋于一致;退耕地植被在演替过程中通过提高土壤有机质含量改善结构,降低容重并增加毛管孔隙度,对土壤的储水和持水性能产生作用。

Study on Water-Holding Capacity of the Top Soil of a Steppe Reserve in the Yunwu Mountains, Guyuan, Ningxia Hui Autonomous Region

The study was undertaken to determine the tendency and variation of the soil-water holding capacity during the restored vegetation community succession in a plot of former cropland bordering a typical steppe zone on the Loess Plateau. The curves of soil water characteristics measured by centrifugation showed: there was a high power function correlation between the soil moisture and the potential of soil water, which could be represented by θ=aS^b. Following the succession of the vegetations, the value a increased gradually. Soil water contents of various vegetations are different at the same range of soil water potential. The data indicated that the water content of soil covered with Stipa bungeana was the highest, while the land was the lowest in the slope, though at the same range of soil water potential. The soil water contents of other plant community successions reached the same level with the increase of soil water potentials. The vegetation succession lessened the soil bulk density and enhanced the soil porosity by increasing the soil organic matter and improving the soil construction; thus, affecting the soil-water holding capacity.