Water repellency of air-dried and sieved samples from limestone soils in central Portugal collected before and after prescribed fire

Abstract

Soil water repellency (SWR) in Mediterranean sub-humid environments is poorly studied in soils derived from basic bedrock. This study addressed this gap by comparing SWR in soil samples collected before/after a prescribed burning in a Mediterranean shrubland overlaying limestone. Sampling was performed on two adjacent slopes (NE/SW) underneath Quercus coccifera, Pistacia lentiscus, Arbutus unedo shrubs, and on bare inter-patches, at two depths (0–2 and 2–5 cm). Samples were sieved at SW) and the four patches (Arbutus unedo > Pistacia lentiscus ≈ Quercus coccifera > Bare). The low-severity fire slightly increased SWR but did not affect the above-mentioned pre-fire differences. The wax and resins from different shrub species have implications for SWR persistence on the finer soil fractions. Prescribed fire increased the severity of SWR at surface but also its frequency at the subsurface layer.