Anisotropy of Soil Hydraulic Properties Along Arable Slopes  

作　　者：JING Yuan-Shu ZHANG Bin A. THIMM H. ZEPP 

机构地区：[1]Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 （China） [2]Geographical Institute, Ruhr-University Bochum, D-44780 Bochum （Germany）

出　　处：《Pedosphere》2008年第3期353-362,共10页土壤圈（英文版）

基　　金：the National Natural Science Foundation of China (NSFC) (No40071044);the Deutsche Forschungsgemeinschaft (DFG) (NoZE 254/4)

摘　　要：The spatial variations of the soil hydraulic properties were mainly considered in vertical direction. The objectives of this study were to measure water-retention curves, θ（ψ）, and unsaturated hydraulic conductivity functions, K（ψ）, of the soils sampled at different slope positions in three directions, namely, in vertical direction, along the slope and along the contour, and to determine the effects of sampling direction and slope position of two soil catenas. At the upper slope positions, the surface soils （0-10 cm） sampled in the vertical direction had a lower soil water content, 0, at a certain soil water potential （-1 500 kPa 〈 ψ 〈 -10 kPa） and had the greatest unsaturated hydraulic conductivity, K, at ψ 〉 -10 kPa. At the lower slope positions, K at ψ〉 -10 kPa was smaller in the vertical direction than in the direction along the slope. The deep soils （100 110 cm） had similar soil hydraulic properties in all the three directions. The anisotropic variations of the hydraulic properties of the surface soils were ascribed to the effects of natural wetting and drying cycles on the structural heterogeneity. These results suggested that the anisotropy of soil hydraulic properties might be significant in influencing soil water movement along the slope and need to be considered in modeling.The spatial variations of the soil hydraulic properties were mainly considered in vertical direction.The objectives of this study were to measure water-retention curves,θ(ψ),and unsaturated hydraulic conductivity functions,K(ψ),of the soils sampled at different slope positions in three directions,namely,in vertical direction,along the slope and along the contour,and to determine the effects of sampling direction and slope position of two soil catenas.At the upper slope positions,the surface soils(0-10 cm) sampled in the vertical direction had a lower soil water content,θ,at a certain soil water potential(-1500 kPa < ψ <-10 kPa) and had the greatest unsaturated hydraulic conductivity,K,at ψ > -10 kPa.At the lower slope positions,K at ψ > -10 kPa was smaller in the vertical direction than in the direction along the slope.The deep soils(100-110 cm) had similar soil hydraulic properties in all the three directions.The anisotropic variations of the hydraulic properties of the surface soils were ascribed to the effects of natural wetting and drying cycles on the structural heterogeneity.These results suggested that the anisotropy of soil hydraulic properties might be significant in inffuencing soil water movement along the slope and need to be considered in modeling.

关 键 词：slope hydrology spatial variation unsaturated hydraulic conductivity water-retention curve 

分 类 号：P64[天文地球—地质矿产勘探]