Soil surface water dynamics in different units under dehesa landuse system

Abstract

The main goal of this paper is to study the soil surface hydrological behaviour corresponding to different degradation levels in the dehesa ecosystem. During a complete hydrological year soil moisture measurements were taken of the surface and it was observed their dependence on climatic variables, as rainfall and ETP, and topographic and soil factors. A set of physical and hydrodynamic soil parameters and variables was analysed. The results demonstrate that the maximum water holding capacity depends of the surface degradation levels related to silty-clay textural fraction and organic matter content. Nevertheless, certain homogeneity in the available soil water content was observed at the different spatial units. The soil water content shows a high sensitivity to rainfall distribution and the evolution of ETP over time. The hydrological consequences of the seasonal soil behaviour are important in this type of ecosystem. That is a key factor which affects runoff generation mechanisms at the slopes, and explains the flow volume, the characteristics of the hydrographs and the type flow at the catchment scale.