Identification of Key Factors Influencing Soil Infiltration in Semi-Arid Watershed

Soil infiltration dynamics in arid and semi-arid regions are crucial for understanding water resource management and ecosystem sustainability. This study investigates the interplay between vegetation restoration, topographic characteristics, and soil physicochemical properties in influencing soil infiltration in a semi-arid Iranian watershed. Comparative analysis of a restored watershed and a control watershed revealed that restoration significantly improved soil properties, including a 35% increase in organic matter, a 22% decrease in bulk density, and enhanced porosity and aggregate stability. Vegetation restoration also elevated infiltration rates, particularly in high-TWI zones, and mitigated the adverse effects of compacted soils and surface crusting observed in degraded areas. Slope aspect strongly influenced hydrological performance, with north-facing slopes displaying higher infiltration rates and water retention capacity due to cooler microclimates and greater organic matter accumulation. Conversely, south-facing slopes experienced reduced hydrological functionality, highlighting the need for slope-specific restoration approaches. Topographic Wetness Index (TWI) emerged as a critical driver of soil-water interactions, with high-TWI zones supporting enhanced infiltration and soil moisture retention. These findings underscore the importance of aligning restoration strategies with local soil characteristics and topographic conditions. To optimise infiltration and bolster ecosystem resilience, adaptive management practices integrating native vegetation, targeted soil amendments, and enhanced hydrological connectivity are recommended.