Early post-fire changes in properties of Andosols within a Mediterranean area

The increasing frequency and extent of forest fires cause severe temporal effects on soil properties, which knowledge about is controversial or lacking. So, the research aimed to evaluate changes in Mediterranean Andosol properties (pH, water and organic matter contents, C and N concentrations) and total and available Ca, Cu, Fe, K, Mg, Na, Ni and Pb concentrations 1 and 2 years after fire occurrence, comparing them to the pre-fire ones. The results underline that, in the investigated Mediterranean Andosols, fire caused significant decrease in water and organic matter contents, C, Fe and Mg total concentrations as well as significant increase in pH, total Ca, K, Fe, Na concentrations and available Cu and Pb fractions. After fire, temporal changes of soil element concentrations occurred at different speeds, as Ca, Cu, Fe, Mg and Ni total concentrations changed already 1 year after fire occurrence; whereas, K and Na total concentrations changed only after two years. Finally, 2 years after fire none of the investigated soil properties reached the pre-fire values, suggesting a whole worsening of soil conditions. The early responses of soils to fire are useful to predict the evolution of the system, the relationships between below and above ground and to provide useful tools for management practices.