Intrinsic soil properties shape water availability under changing land-use in contrasting soil textures

Abstract

Understanding how intrinsic soil properties modulate water retention under land-use change is critical for sustainable soil management in tropical regions. This study investigated how clay and soil organic matter (SOM) contents, along with bulk density (BD), influence the soil water retention curve (SWRC) and plant available water (PAW) following transitions from native forest (NF) to pasture (PAST) and crop-livestock-forestry systems (CLF). The study was conducted across four sites in Goiás State, Brazil, spanning sandy and clayey Ferralsols and Cambisols. Soil samples were collected from 0.0–0.2 and 0.2–0.4 m layers under each land use. SWRCs were modeled using the Van Genuchten equation. Principal component and correlation analyses were performed to evaluate relationships among soil properties and water retention parameters. Results showed that in sandy soils, moderate increases in BD and SOM under CLF and PAST enhanced water retention at field capacity, increasing PAW. In contrast, in highly clayey soils, increased BD and SOM often reduced PAW due to higher water retention at wilting point. Clay content improved water retention, especially in sandy soils, but its effect was more variable in clay-rich soils, where mineralogical differences influenced pore structure. These findings emphasize the context-dependent role of texture, SOM, and BD in regulating PAW. While CLF systems showed potential to restore PAW in sandy soils, their effect in clayey soils was limited by structural and mineralogical constraints. Tailored land management strategies that account for intrinsic soil characteristics are essential to optimize water availability in tropical agroecosystems.