This study has two aims, the first, to analyze the spatial
distribution of Soil Organic Carbon (SOC) in Tunisia, second, to estimate
carbon stocks for major soil types representative of Mediterranean drylands.
Repartition of SOC stocks at the depth of 0.3 to 1 m were estimated for
Tunisia, using a soil map combined with the results from a soil database.
In addition, the total SOC stocks in the 0-30 cm and 0-100 cm soil depth
were estimated for Tunisia using a digital soil map combined with results
from a soil database. Tunisia contains nine main soil classes. The entire
soil database totaled 1483 soil profiles corresponding to 5024 soil horizons.
This dataset was built from previous analytical results published from
Tunisian soil surveys (1960-2006). Most bulk density values were estimated
using pedotransfer functions. Results showed that the upper soil layer
0-30 cm contains 405.44 TgC (1 Tg = 1012 g), while that in
the 0-100 cm soil depth was estimated to be 1006.71 TgC. Estimates by
soil types showed that the highest SOC stocks was estimated for Luvisols
to 7.16 and 15.92 kgCm-2 for 0-30 cm and 0-100 cm, respectively.
The lowest SOC stocks were estimated for the Lithosols to 1.84 kgCm-2
at 0-30 cm and 4.04 kgCm-2 for 0-100 cm. The soil types most
representative in extension in Tunisia were the Lithosols, Regosols and
the Cambisols and stocks were estimated to 73.22, 119.83 and 100.35 TgC,
respectively. Tunisian SOC density in the surface layer 0-30 cm is 2.612
kgCm-2 and 6.486 kgCm-2 within the 0-100 cm depth.