Influence of pyroclastic soil on epikarst formation: a test study in southern Italy

Epikarst formation in the southern Apennines (Italy) was hypothesized to be significantly influenced by diffuse rainwater infiltration through soil of pyroclastic origin. Multidisciplinary investigations were carried out at an experimental field site to test this hypothesis. At this site, other factors influencing epikarst formation can be assumed invariant. A direct relationship was observed between soil thickness and epikarst thickness. This relationship supports the hypothesis that the pyroclastic soil plays a significant role in governing epikarst evolution and thickening. The sandy loam texture and the high hydraulic conductivity of the soil allow easy rainwater infiltration, therefore causing a diffuse interaction between percolation water and the soil medium, and spatially homogeneous recharge within the aquifer system. The soil contains a large accumulation of organic carbon and considerable CO2 production results from the activity of autochthonous microorganisms belonging to different genera