Comparison of Organic Carbon Stock of Regosols Under Two Different Climates in Tunisia

Abstract

More than half of Tunisian soil is composed of Lithosols and Regosols. These soils, despite their existence in dry climates, are either steppes or farmland. The present work focuses on the state of the carbon stock in the Regosols of Tunisia. Two areas are selected for this study: a Regosol in Gafsa (S1) under arid climate, and another Regosol in Kairouan (S2) under semiarid climate. S1 and S2 are under two olive groves. The findings reveal that the granulometry, the pH, and the bulk density are very close. The difference lies in the content of organic carbon and therefore the carbon stock. The surface layer (0–20 cm) stores almost 3.01 kg/m2 for S1 and 3.6 kg/m2 for S2 while the depth of 0–100 cm S2 stores more than S1 with 10 and 8 kg/m2, respectively.