Soil wettability, runoff and erodibility of major dry‐Mediterranean land use types on calcareous soils

Abstract

AbstractThis study examines six land uses (pine woodland, long unburnt scrubland, recently burnt scrubland, orange grove, olive grove and cereal crop), typical for calcareous soils in a dry‐Mediterranean region such as eastern Spain, with regard to soil surface water repellency occurrence, hydrological response and erodibility. For each land use, we performed water drop penetration time (WDPT) tests and rainfall simulations respectively on in situ soils at ten replicate plots for extremely dry antecedent conditions in summer 2002 and for wet winter conditions, in early 2003 in the Canyoles river valley. In contrasts to what might have been expected, water repellency was absent or subcritical (WDPT < 5 s) under all land uses except pine, where slight repellency was found during summer (avg. WDPT 17 s). Higher levels of water repellency have been reported from some other Mediterranean type regions particularly after burning, and it appears that for some of the land uses examined here, the calcareous nature of the soils may restrict the development of water repellency. However, even the slight repellency observed under pine had a substantial effect on infiltration rates, generating more runoff on dry soil in summer than on moist soil in winter. Apart from water repellency, ground cover had a strong influence on soil hydrological response and was overall the most important factor influencing soil erodibility. The results suggest that, although the planting of pine woodland has been a favoured land management strategy in many parts of the Mediterranean basin, scrubland appears to be the more appropriate land cover type with regard to water use efficiency and soil conservation measures. Copyright © 2007 John Wiley & Sons, Ltd.