Volcanic soil phytotoxicity in a burnt Mediterranean area.

Mediterranean regions, because of climate and vegetation, are affected by high incidence of wildfires that modify soil characteristics. The aims of the present research were to investigate: 1) the phytotoxicity of soils collected before and after fire; ii) the probable variations in phytotoxicity of soils under different pre-existent vegetation covers (black pines, black locusts, holm oaks and herbaceous); iii) the probable variations in phytotoxicity of surface (0–10 cm) and deep (10–20 cm) soils. The impact of fires on soil phytotoxicity was estimated through root elongation, seed germination and germination index of Sorghum saccharatum L. and Lepidium sativum L. The research was performed inside the Vesuvius National Park (Naples, Southern Italy). The results highlighted that S. saccharatum L. was more sensitive to the effects due to fires. In fact, the assays performed by S. saccharatum L. highlighted a transition from inhibitory effects before fire to stimulating effects after fire, lower values for soils under black pines and holm oaks, and higher toxicity in deep than surface layers of soils. • S. saccharatum L. more than L. sativum L. was useful to show toxicity in burned soils. • S. saccharatum L. test showed low toxicity in soils under black pines and holm oaks. • Two of the three endpoints of S. saccharatum L. showed higher toxicity in deep soil. [ABSTRACT FROM AUTHOR]