Soil physico-chemical indicators for ecosystem services: a focus on water regulation

Abstract. This study investigates the intricate relationship between soil properties and water-related processes, with a focus on their collective impact on ecosystem service provision, particularly water regulation. Conducted in three diverse regions Marchfeld (Austria), Bologna (North Italy) and Rmel (Tunisia), the research aims to identify key soil properties that influence water infiltration (INF), groundwater recharge (GWR), and crop water stress indexes (CWSI). Key soil characteristics such as saturated hydraulic conductivity (K_S ), available water content (AWC), bulk density (BD), saturated water content (θ_s ), organic matter (OM), clay content and soil depth were analyzed for their role in regulating water movement and the overall hydrological balance. Pairwise correlation and multiple linear regression analyses were used to assess the interactions among soil water balance processes and soil properties. The results reveal significant variations between regions in terms of the factors that control infiltration, groundwater recharge, and CWSI. For example, in Marchfeld infiltration showed a strong positive correlation with BD (r = 0.74, p < 0.001), while CWSI had the most significant negative correlation with soil depth (r = -0.35, p < 0.001). Futhermore, multiple linear regression models were developed to assess the relevance of the different soil properties and of their interactions on the components of the soil water balance. As an example, in Marchfeld, the model for infiltration (r = 0.79, p < 0.001) was highly predictive, incorporating Clay, OM and soil depth. These results emphasize the critical role of key soil properties K_S , AWC, BD, OM, clay content, θ_s and soil depth in controlling soil water processes. The study highlights the value of using these properties in predictive models to inform water management practices to optimize crop performance and soil conservation in different agricultural settings.