Influence of topography on sediment dynamics and soil chemical properties in a Mediterranean forest historically affected by wildfires: NE Iberian Peninsula

Abstract

Wildfires are a major concern in Mediterranean areas and play an important role in the pedogenic process, as they usually increase soil credibility due to the destruction of vegetation cover and soil structure. On top of these factors, slope and aspect also determine the degree of retention and availability of water and nutrients in soils after fire, which in turn influence the recovery of vegetation and its protective effect against erosion. This work aims to describe the effects of slope and aspect on soil development in an area historically affected by wildfires. The study area is located in Ódena (NE Iberian Peninsula) in a Mediterranean forest. Four representative soil profiles were sampled from a south-facing steep slope, north-facing steep slope, south-facing gentle slope and north-facing gentle slope. In each profile 11 samples were sampled. The amount of soil organic matter (SOM), inorganic C (IC) and total N (TN) as well as cation availability, pH, and electrical conductivity (EC) were determined for all the horizons of each profile. Results showed that IC, TN, C/N ratio, pH, EC and K were mainly affected by aspect, whereas organic matter, C/N ratio, pH, EC, Ca and Mg were especially influenced by slope. Slope determined the amount and availability of SOM and nutrients, which highlights the need to prioritise the management of areas susceptible to erosion in order to ensure soil and ecosystem functionality.