岩石对喀斯特峰丛山体土壤水分布特征的影响

Influences of Rock on Soil Moisture Distribution in the Karst Cluster-Peach Mountains

喀斯特峰丛山体土壤水是喀斯特地区水文循环及生态环境重要的影响因素。该地区各类岩体碎石类型较多,对土壤水运移及分布影响各不相同。研究岩石对土壤水的影响,对研究该地区水动力过程及水文生态效应具有重要意义。选取贵州省普定县岩溶区内典型的喀斯特峰丛山体,利用TDR测定不同类型岩石影响下的土壤含水率,分析了岩石对土壤含水率空间分布规律的影响。结果表明,由于对土壤水的阻碍作用,岩层下部土壤含水率较低,岩层上部土壤含水率较高;但岩层上部土层浅薄时,土壤含水率偏低。破碎岩块阻碍土壤水运动,土壤水在土壤与岩块表面溶蚀接触区域得到雨水集中补给,含水率较高。土壤中砾石增加了土壤透水性能,使土壤含水率较高,影响作用随埋深增加而减小。

Soil moisture content in the karst cluster-peach mountains is a key factor to control hydrology and environment of the area. The wide distribution of rock has the profound impacts on soil moisture movement and its distribution. Study of soil moisture distribution plays an important role in hydrologic dynamic and eco-hydrology. In this study, soil moisture contents in the typical karst cluster-peach mountains in Puding County, Guizhou Province were measured by TDR. The influences of rock are then revealed based on the observed data. Results show that soil moisture content is lower in underlying strata and higher in soil layers above strata due to thicker soil layers, and however, it is lower if soil layer becomes thin. Soil moisture content is found to be higher near the dissolved stone because of the recharge from precipitation. Soil moisture content in the soil layers with gravel is higher because gravel within soil may increase water infiltration into soil. However, the influence is reduced with increasing depth.