Spatiotemporal dynamics of soil moisture in a watershed in the Loess Plateau during vegetation restoration

Understanding the stability of soil moisture distribution is essential for hydrological processes in degraded ecosystems; however, it is frequently neglected in watershed management and restoration efforts. In this study, the influence of vegetation restoration on the distribution of soil moisture at the watershed scale was analyzed through field in situ monitoring for two consecutive years (2023-2024), and on this basis, the time stability of soil moisture was examined. The study found clear seasonal patterns in soil moisture, with the highest mean value of 18.04% in May and the lowest of 13.11% in September. The CV (coefficient of variation) ranged from 12 to 27%. Soil moisture was higher in the southeast and lower in the northwest, showing strong spatial autocorrelation, with surface soil moisture showing greater spatial heterogeneity than deeper soil moisture. S25 was identified as the most temporally stable, with a mean relative difference of 0.002 and a temporal stability index of 0.990, establishing it as the representative point for temporal stability analysis. This study advances the comprehension of vegetation restoration's role in soil moisture stability and offers empirical evidence supporting ecological restoration initiatives on the Loess Plateau, thereby contributing to the region's sustainable development.