Study on Vertical Distribution Characteristics and Influencing Factors of Soil Moisture on Slopes in Loess Tableland Beam Area—Based on Long‐Term Observation Data

ABSTRACT Soil moisture content (SMC) is a major constraint on land use and vegetation growth in semi‐arid regions. Understanding changes in SMC is essential for the recovery and reconstruction of vegetation on the Loess Plateau. However, fewer studies have analyzed the characteristics and influencing factors of soil moisture changes through long‐term observation data. Based on the rainfall observation data and SMC data from 1954 to 2010 in Nanxiaohegou watershed, this study analyzed the variation of SMC on slopes in the gully region of the Loess Tableland. Characterization and correlation analyses of SMC changes were based on three factors: rainfall intensity, slope, and land use pattern. The following key results were obtained: (1) excessive rainfall intensity provided a weak recharge of SMC, while insufficient rainfall provided an inadequate recharge of SMC; (2) vegetation on gentle slopes of 0°–5° and steeper slopes of 25°–30° led to higher SMC; (3) compared to other land uses, the SMC infiltration process in agricultural land exhibited a lag in response to rainfall; (4) higher correlation between deep SMC. The SMC was most significantly influenced by environmental factors in grassland. The results provide new information on land use in the Loess Tableland gully region. When implementing projects such as reforestation in this region, grassland, and agricultural land with good SMC retention capacity should be selected when possible and laid down on steeper slopes.