Temporal and spatial patterns of soil moisture in semiarid badlands of SE Spain

Temporal and spatial patterns of soil water content (theta) have been studied in badlands in Tabernas (Almeria, SE Spain). theta was measured on a detailed time scale for 18 months under different conditions of soil surface cover, soil properties and topography. theta was found to be highly spatially heterogeneous within small areas, controlled primarily by soil surface cover and soil properties. The role of lichen crusts in theta conservation has been demonstrated even when the properties of the soil beneath do not favour water storage. Differences in soil moisture regimes have been found below inter-shrub (open) areas and below shrubs. The influence of most terrain attributes (slope gradient and aspect, specific catchment area, slope curvature, wetness index, slope length factor and distance to channels on theta is masked by the influence of soil cover properties. The simultaneous monitoring of rainfall, soil moisture and runoff at short intervals shows the different responses of soil surfaces to rainfall and the influence of rainfall partitioning on soil moisture patterns. This work contributes to an understanding of several aspects of spatial and temporal variability of theta in semiarid areas and the factors controlling it, and provides key information for their management. (C) 2003 Elsevier B.V. All rights reserved.