子午岭植被恢复对土壤饱和导水率的影响

通过对子午岭林区不同植被的土壤性质进行实验室测定和野外调查,对饱和土壤水分运动的重要参数之一土壤饱和导水率(Ks)及其相关因子进行了多元分析和通径分析,揭示了植被恢复提高土壤水分传输性能的机理,主要结论如下:土壤有机质是子午岭林区九种植被下土壤饱和导水率提高的主要驱动因子.不同植被下的土壤饱和导水率均随深度的增加而迅速降低,尽管草地和先锋草地在5～10cm深度有一强透水层.土壤饱和导水率在剖面上的平均值,从辽东栎、早期森林、灌丛、先锋草地、弃耕地到草地依次降低.灌丛与草地、弃耕地的差异达到显著水平,辽东栎顶级群落的饱和导水率最高,植被的恢复明显提高了土壤饱和导水率.土壤容重、毛管孔隙度、>0.25mm团聚体含量及粘粒含量直接影响土壤饱和导水率.土壤有机质含量的提高能够改善容重、毛管孔隙度、团聚体含量等物理性质.

Effects of vegetation rehabilitation on soil saturated hydraulic conductivity in Ziwuling Forest Area

Soil organic matter was the major driving force for improvement of soil saturated hydraulic conductivity (Ks) in nine stands of the secondary zone of Ziwuling Forest in the Loess Plateau. Values of soil saturated hydraulic conductivity quickly reduced with depth under different communities, though at 5-10 cm depth both Bothriochloa ischaemum and Vanward grassland had a permeable layer. The average Ks for each soil profile progressively declined from that for Quercus liaotungensis to early forest, to shrub, to Pioneer grass and to farmland abandoned to Bothriochloa ischaemum, respectively. Values for shrub land were significantly higher than for Vanward grassland and abandoned farmland. Quercus liaotungensis supported the highest values under the nine stands, with vegetative restoration notability improving Ks. Soil saturated hydraulic conductivity was directly affected by soil bulk density, capillary porosity, > 0.25mm aggregate content and clay content. Soil physical properties such as soil bulk density, capillary porosity and aggregate content were all improved by soil organic matter content.