The cotton zone of West Africa undergoes a progressive saturation of available agricultural space and a difficult economic situation. The produced biomass is often cited as a factor limiting the farming systems intensification and sustainability. ·Thus, to analyze the ecosystem's sustainability, it is necessary to understand the production, transformation and allocation of biomass. The biomass management decisions are taken at the farm level, but depend on processes at the village scale, which must be considered. Scientists of various disciplines developed a conceptual model to represent the biomass flows in two typical villages of the cotton producing area in Southern Mali. The objective was to represent the current situation, and to simulate possible future evolutions. This model consists of four interlinked modules: The first module considers the biomass production at the field scale and the use of transformed biomass in the fields. The second module describes the biomass uses and transformations of the farm types. The third module represents the operation and biomass production of the common assets, including areas not individually owned and the tree production of the farms' fields, in open access. The fourth module describes the economic operation of the farms -stocks, products valuation, margin calculation- and the workforce balance. The model will be formalized in a simple numerical model. Surveys are underway, to estimate its many parameters and compartments sizes, in such a way that it will be able to reproduce the current state. We will then assess its aptitude to simulate the farm functioning and the biomass balance at village scale in the medium term. We want to use the model to consider the introduction of innovations that interfere with biomass management in a village territory.