Seasonal soil water repellency and evaporation in a Mediterranean climate

Shallow soil water repellency is a common natural phenomenon of organic origin, but its significance to native environments is not well understood. Using laboratory experiments, we demonstrate how water repellency serves to channel and conserve moisture against evaporative loss. By comparing 4 years of field data to 1D model predictions, we demonstrate how water repellency varies seasonally, breaking down with progressive rainfall in winter. Results suggest that seasonal variations may be predicted to some degree of accuracy with rainfall data alone, and that water repellency likely produces real adaptive benefits to the originating vegetation.