| Summary: | A conceptual model of the spatio-temporal dynamics of Shifting Agricultural Systems (SAS) in the rainforest region of Southern Cameroon made it possible to identify five different cultivation cycles, which enabled the quantification of soil dynamics and carbon stocks. Carbon stocks in each pool were evaluated using all chronosequences for land use types, including Virgin forest (PF), Secondary forest (SF), Forest fallow (FF), Chromolaena fallow (CF), Mixed crop field (MC) and Old cocoa plantations (OCP). Under each treatment, biomass measures were conducted on trees, undergrowth, litter and plant roots. Soil samples were analysed for physicochemical determinations. The total carbon (in TC/ha-1) varies in the following decreasing order: VF (305), SF (251), OCP (184), FF (180), CF (101), and MC (67). Although the average soil carbon stock represents 93% and 78% under the MC and CF systems, respectively, it represents only 26% of total carbon for the VF system. When a PF system is converted into MC, there is a total carbon loss of 97% from aerial biomass and 17% from soil. Fallowing and reconversion to SF lead to a carbon re-accumulation of 3.9 TC/ha-1.year-1 (r2= 0.83, p= 0.001). Several soil parameters have shown major variability within the system. This study has produced quantified data, which can be used to evaluate soil quality according to land use and the cost of the carbon sequestered by these agricultural systems.
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