黄土残塬沟壑区人工林小流域土壤水分时空变化特征.

[Objective] Soil moisture plays a vital role in influencing vegetation recovery, particularly in the loess plateau gully erosion region, where hydrological processes are highly responsive to the combined effects of climate, vegetation, and topography. The aims of this study are to understand the spatiotemporal distribution characteristics of soil moisture at the watershed scale, and to advance ecological construction efforts. [Methods] This research investigated the artificial afforestation watershed in Caijiachuan, Jixian County, Shanxi Province, based on the soil moisture positioning monitoring platform. By conducting watershed-scale field positioning monitoring and employing various geostatistical analysis methods, we systematically gathered soil moisture datasets of growing season in the afforested watershed in 2023. Employing diverse interpolation techniques, we analyzed the spatiotemporal variations of soil moisture at the small watershed scale. [Results] The small watershed-scale soil moisture changes were highly responsive to rainfall, showcasing distinct vertical stratification characteristics. The soil moisture content in the Caijiachuan afforestation watershed was categorized into three layers: the active soil moisture layer (0-10 cm), the sub-active soil moisture layer (10-80 cm), and the soil moisture regulation layer (80-180 cm). The sub-active soil moisture layer exhibited the highest coefficient of variation, while the soil moisture regulation layer had the lowest variation coefficient. The active soil moisture layer was predominantly influenced by climate, the sub-active layer served as the primary layer for vegetation water absorption, and the regulation layer primarily functions as a water storage layer. In terms of interpolation method selection, the inverse distance weighting method yielded the most accurate results for the spatial distribution of soil moisture within the watershed, with a Nash coefficient of 0.64 and a root mean square error of 3.22, establishing it as the preferred interpolation method among the four considered. Upon stratifying the soil in the Caijiachuan afforestation watershed into three layers and conducting interpolation analysis, It was observed that the sub-active soil moisture layer had the highest water content, while the active soil moisture layer had the lowest water content. [Conclusion] The spatial distribution of water in the study area is influenced by many factors such as topography, precipitation and vegetation, and the spatial distribution of water is generally characterized by high in the southeast and low in the northwest. [ABSTRACT FROM AUTHOR]