The DSCATT project proposes to explore the potential for sequestering C in cultivated soils, taking into account the sustainability of agricultural practices in the context of global changes. It operates at 4 sites (in Senegal, Zimbabwe, Kenya, and France). The project addresses 3 interrelated scales, i.e field, farm and territory or village scale. At field level, research focuses on how biomass production and soil C sequestration relate, in different soil and climate conditions. Two approaches complement each other. One studies at the soil-plant interface the processes regulating the forms and residence time of C in soils. It includes the analysis of interactions between nutrients and C storage, the role of deep roots and in soils with contrasting storage potentials. The other approach determines the C balances under different practices. Farms will be characterized in order to propose practices likely to improve complementarities amongst the activities of rural households. At this scale, DSCATT research will focus on farmers' practices (for crops, livestock, forestry…) and assess the impacts of farmers' practices on their objectives (income, food security…), taking into account their main constraints (cash, labour…). At the territory (or farmers' network) level, the different compartments of agroecosystems and the organic matter flows will be studied. The project will analyze the role of the socio-economic and biophysical contexts and will test several possible changes and their impacts on soil C sequestration dynamics, economic performance of farms and food security. This scientific knowledge and the viewpoints of the farmers involved will be shared and used for a transdisciplinary assessment of several C sequestration strategies in agricultural soils. Considering changes and uncertainties, a multi-criteria and prospective evaluation approach is proposed. It will allow iterations between evaluation and redefinition of strategies to cope with global changes in agriculture.