Spatial Variation in Soil Water Content Over Hillslopes Engineered by Fish-scale Pits in Taihang Mountainous Region

【Objective】 Fish-scale pit is a common technology used to engineering earth slopes in arid and semi-arid regions to improve water infiltration and reduce soil erosion. The objective of this paper is to investigate how implementation of this technology reshapes soil water distribution in the slopes. 【Method】 The experiments were carried out at slopes on the south face of Taihang mountainous region with slope without pits taken as the control. Across each experimental slope, we measured soil water content in the top 0~20 cm soil across the slope at different seasons and analyzed its spatial variation. 【Result】 ①Engineering earth slopes with the fish-scale pits could improve soil water content by 7%~41% depending on seasons and locations in the slope; it also made soil water distribution less spatially heterogeneous and increased the proportion of structural variation in the total variation by 20%~88%.②Under natural conditions, soil water content in non-pitted slopes decreases from the top to the toe, while engineering the slopes with the pits made soil water distribution patchy, especially in drought seasons. ③Redundancy analysis revealed that for the engineered slopes, environmental factors that affected spatial variation in soil water content and their associated contribution scores (the numbers in the bracket) were ranked in the order of gravel content (22.7%)>sand content (2.9%)>silt content (2.3%)>altitude (1%)>bulk density (1.3%)>gravel coverage (0.02%), while for the natural slopes the factors were ranked in the order of altitude (25%)>gravel content (13.9%)>silt content (8.1%)>bulk density (2.9%)>sand content (1.2%)>gravel coverage of soil surface (0.4%). 【Conclusion】 Engineering earth slopes using fish-scale pits can reduce the influence of topography on spatial distribution in soil moisture, with the gravel content affecting spatial variation in soil water content the most. It also reduced spatial variation in soil moisture and increased soil water content. These combine to improve the bioavailability of soil water to plants and crops.