Khairallah W., Bahri H., Coulouma G., Annabi M., Raclot Damien. (2025). Role of topography and physico-chemical properties on organic carbon distribution in semi-arid calcareous soils. Euro-Mediterranean Journal for Environmental Integration, 10 (4), 2851-2861. ISSN 2365-6433.
Titre du document
Role of topography and physico-chemical properties on organic carbon distribution in semi-arid calcareous soils
Soil represents a significant reservoir of organic carbon within terrestrial ecosystems. Despite considerable research efforts, the factors that control the distribution of soil organic carbon (SOC) remain insufficiently understood, particularly in calcareous soils where recent studies have indicated potential interactions between inorganic and organic carbon pools. The objective of this study was to evaluate the influence of topography and physico-chemical soil properties on the distribution of soil organic carbon (SOC) in a small calcareous catchment cultivated with annual crops under a semi-arid Mediterranean climate (Kamech, Cape Bon, Northeast Tunisia). Soil samples were gathered from all horizons of ten soil profiles, selected to encompass the three primary soil types identified within the study catchment. As anticipated, the SOC contents were found to be low and to decrease significantly with increasing soil depth. It is noteworthy that significantly higher SOC levels were observed in Vertisols in comparison to Cambisols and Calcisols. The results indicated that clay content was the primary factor influencing SOC distribution in the studied soils. In addition, the topographical location of the profile was identified as a secondary factor in explaining lateral SOC distribution within the catchment. Furthermore, the study demonstrated a negative correlation between SOC and soil inorganic carbon (SIC), which is an unexpected result for semi-arid environments and requires further investigation.
