Estimate of Organic Carbon Stocks of Some Soils under Cotton Growing in the North of Côte d’Ivoire: Case of Korhogo department

The present work, initiated in Korhogo, the north department of Côte d’Ivoire, aims to assess the level and the dynamics of the organic stocks of some soils under cotton crops through changes in the total amount of both carbon and nitrogen. For this purpose, we used rural sites under two main modes of soil management: plots of cotton growing and the shrubby savanna left fallow which was considered as the reference site. Tests including morpho-pedological characterizations and physico-chemical analyses were performed on soil samples and the organic carbon stocks were evaluated. The characterized soils are of Cambisol type with amajorpedogenetic phenomenon of reworking. Combination of the organic matter with concretions and ferruginized nodules gives the soils their characteristic brown coloring. The dynamics of the organic matter stock in these soils indicate that their continued cultivation results in an acceleration of the mineralization (C/N = 1.2 to 2.12) and as a result, a decrease in the organic matter stock (2.07 to 2.31 t/ha for soils under cotton growing against 9.42 to 9.81 t/ha for soils under fallow).