Stability of mediterranean burnt soils under different plant covers

In Mediterranean areas, fires are accelerators of soil degradation and the definition of the time extent to re-establish the soil community is a great challenge. The aims of the research were to evaluate, during two years after a fire: i) the potential recover of the soil abiotic properties; ii) the stability (resistance or resilience) of the soil microbial community; iii) the potential role of different plant covers on soil recover capability. To reach the aims, soil properties as organic matter content, C and N concentrations, microbial (MB) and fungal (FB) biomasses, respiration (Resp) and coefficient of endogenous mineralization (CEM) were measured twelve, fifteen, eighteen and twenty-four months after fire, and were compared to those in pre-fire soils. The results showed that the MB was less resistant in soils under herbs and black locust, and more resilient under pine and holm oak; FB showed low resistance till one year after fire regardless to the plant cover, and high resilience at two years after fire, especially under holm oak and pine; Resp greatly slowed down and did not recover the initial values regardless to the plant cover; CEM resisted to fire in soils under different plant covers. In conclusion, the soil abiotic properties were strongly affected by plant covers, whereas the biotic ones also by the time since fire. Finally, soils under holm oak were the most fire resistant.