Effect of prescribed fire on soil properties and soil erosion in a Mediterranean mountain area

Prescribed fires are a common management practice in the Mediterranean region and can be an alternative to reduce the quantity of fuel and hence decrease the wildfire risk. This research focused on effects of a prescribed fire, which was applied in Montesinho Natural Park (PNM), in soil properties and on soil erosion processes. Chemical soil properties were assessed before, two, six and thirty-six months after the fire. Despite low fire intensity, soil chemical changes were observed. Thirty-six months after the fire it turned out that the soil organic matter, pH values and electrical conductivity were similar to those seen before the fire. However, the same was not verified with the values of the exchangeable bases, extractable potassium and phosphorus and exchangeable acidity that differ from the observed ones before the fire. Runoff and soil loss were monitored in a set of 4 m2 paired plots installed in the study area, during 14 months after the fire and summed annual losses equivalent to 10.3 mm runoff and 1.3 Mg ha−1 soil loss. Although corresponding to a short monitoring period, these results may add to a better knowledge of the potential susceptibility of burnt shrublands to soil degradation and their natural recovery rates.