Volume 8 Article informations Dynamics of soil organic and inorganic carbon in southern Tunisia Hatem Ibrahim , Nadhem Brahim, Abdessatar Hatira Abstract SOC (Soil Organic Carbon) and SIC (Soil Inorganic Carbon) are important carbon stocks in arid and semi-arid regions. However, previous studies have mainly focused on the SOC, while limited information has been provided about the rate of carbon sequestration as secondary carbonates (SC). The aim of the study is to understand the vertical distribution of SIC and assess its role in carbon sequestration in the cropland of the South Tunisia. Eighty soil samples were collected from 16 profiles, from two oases: Guettaya continental oasis and Cheneni coastal oasis. The study was based on the measurements of SOC, SIC, soluble Ca2+ and Mg2+ contents. Our results showed that the mean SOC content averaged over 80 soil samples decreased from 10.25 g.kg-1 near the surface to 5.63 g.kg-1 in 80- 100 cm whereas the mean SIC content is 15.13 g.kg-1 in 0-20 cm, then it showed little vertical increase from 12.22 to 14.33 g.kg-1 in the subsoil. There was a significantly positive correlation between SOC and SIC in the two oases Cheneni and Guettaya (r = 0.89 and r = 0.77, p < 0.01 respectively). Our results suggests that increasing SOC might lead to an increase in SIC stocks in the Tunisian oases. Key words: Soil organic carbon, soil inorganic carbon, stock, oases, Tunisia.