石灰岩与白云岩坡地土壤饱和导水率对比研究

目的]对比研究不同下垫面特征和土地利用方式对两类坡地表层土壤性质及其土壤饱和导水率(Ks)的影响。方法]以喀斯特地区不同岩性下垫面的石灰岩和白云岩两类坡地表层土壤为研究对象,采用Guleph稳定入渗仪和土壤分析的方法。结果](1)石灰岩和白云岩表层土壤在受到放牧作用影响后,土壤均呈现显著退化趋势,其容重、黏粒含量增大,孔隙度、有机质含量降低。(2)石灰岩和白云岩两类坡地表层土壤在未受到人为干扰的自然植被条件下,由于表层岩溶带的发育,Ks都很高,平均值分别为328.6和257.2mm/h。其中,石灰岩坡地相比白云岩坡地,Ks具有更高的空间变异性,二者Ks变异系数变化范围分别为90.71%~95.62%和59.60%~67.32%。(3)受到放牧作用影响后,石灰岩和白云岩坡地表层土壤Ks相比自然植被状态下呈显著降低趋势,Ks分别降低52.2%和86.7%,白云岩坡地Ks降低程度大,高于石灰岩坡地。

Comparative Study on Saturated Hydraulic Conductivity of Limestone and Dolomite Slope

Objective] To analyze the influence of land use and lithology on soil properties and saturated hydraulic conductivities (K_s).Methods] The surface soil from limestone and dolomite slopes in karst region was took as the study objective, and Guelph parameter and soil laboratory analysis were used.Results] (1) Under over grazing condition, soil bulk density and clay content increased and porosity and organic matter content decreased significantly on both of limestone and dolomite slopes. (2) Under undistured land use condition, K_s of limestone and dolomite soil was very high, the average value was 328.6 mm/h and 257.2 mm/h respectively. Compared to dolomite slope, the spatial distribution of K_s on limestone slope was more heterogeneities that coefficients of variations (C_v%), which changed between 90.71% and 95.62%. (3) Under the influence of over grazing, the K_s of limestone and dolomite soil decreased by 52.2% and 86.7% respectively, significantly lower than average values.