Soil organic carbon (SOC) is important for soil health and climate change mitigation through carbon sequestration. This study assesses the spatial distribution, composition, and stabilization mechanisms of SOC in the Corleone region of western Sicily, an area proposed for UNESCO Geopark status. Focus is placed on the influence of glauconite-rich Corleone Calcarenites on soil development and SOC dynamics. Nine soil profiles representing diverse land uses and soil types were analyzed for organic and inorganic carbon content. SOC was fractionated into particulate organic carbon (POC) and mineral-associated organic carbon (MOC) using density and aggregate-size fractionation. To analyze carbon sequestration mechanisms, oxalate extractable contents of Al and Fe, elemental composition and general soil characteristics (grain size, pH, C/N ratio, bulk density, soil skeleton content) were examined. SOC stocks ranged from 6.24 kg C/m² in erosion-prone Cambisols to 24.7 kg C/m² in Vertisols and forested areas. While no significant differences were found between aggregate-size fractions, SOC content correlated positively with oxalate-extractable Fe (R² = 0.32, p < 0.05). Weathering degree showed a positive correlation with well-crystallized iron oxides and clay content, suggesting a more stable carbon pool in weathered soils. Profiles developed on Corleone Calcarenites exhibited higher SOC stocks in deeper horizons compared to those on Numidian Flysch, suggesting that glauconite supports SOC stabilization via mineral-organic complex formation and increased oxyhydroxide content. Overall, the Corleone region demonstrates strong potential for long-term SOC sequestration. Sustainable land management practices are recommended to enhance this capacity and support climate resilience through improved soil carbon retention.
Annette den Boer (Fri,) studied this question.