Biological and chemical factors controlling the patchy distribution of soil water repellency among plant species in a Mediterranean semiarid forest

Natural soil water repellency is a property that has already been observed in forest soils and is characterized by its patchy distribution. There are many factors involved in its development. In this work, we have studied a large number of chemical and biological factors under the influence of different plant species (Pinus halepensis, Quercus rotundifolia, Cistus albidus and Rosmarinus officinalis) to learn which has the greatest responsibility for its presence and persistence in the top-soil layer. We observed strong and significant correlations between ergosterol, glomalin related soil protein (GRSP), extractable lipids, soil organic matter (SUM) content and water repellency (WR). Our results suggested lipid fraction as the principal factor. Moreover, apart from Pinus, fungal biomass seems to be also related to the SUM content. Soil WR found under Pinus appears to be the most influenced by fungi. Quality of SUM, to be precise, lipid fraction could be responsible for WR and its relationship with fungal activity. (C) 2013 Elsevier B.V. All rights reserved.