The Spatial Variation and Impact Factors of Soil Saturated Hydraulic Conductivity in Shalehills(CZO).

Understanding water movement in the vadose zone is critical for accurate climate and crop modeling, precision agriculture, and contamination mitigation. A better understanding of the spatial variability soil hydraulic properties and underlying processes responsible for this variability could lead to a more accurate modeling. The soil field saturated hydraulic conductivity (Ks) at 29 sites in a forested and steep slope catchment was measured by using the double-ring infiltrometer. The goal of this study is to investigate the spatial distribution of Ks and the influences of several factors, such as location on the slope, facing of slope, and slope type on the Ks. Results showed that the influence of the location on a slope is greater than that of the slope aspect and slope type. There was statistically significant difference for the Ks on the ridge and on valley. The Ks on the planar slope was somewhat higher than that on the swale slope. The effect of slope type is likely caused by differences in soil type on the planar- and swale-slope. However, there was no evidently impact of slope aspect on the Ks distribution. This suggests that location on a slope plays an important role and should be considered more often in hydrologic model parameterization. Moreover, the high variation of Ks in ShaleHills at both the local scale and catchment scale also should be a major concern in soil water movement related modeling and field experimental designing.