Résumé
CONTEXT: Smallholder farmers in sub-Saharan Africa seek to improve their livelihoods by investing in new assets. These investments and their effectiveness are constrained by current capital and management practices. Therefore, to understand farm trajectories, the combined effects of different management practices and the timing of investments and losses must be considered. OBJECTIVE: The present study aimed to determine, under 128 distinct scenarios, which ones enable a poorly endowed farm to develop and maintain a sustainable agropastoralism in southwestern Burkina Faso. METHODS: For this purpose, we used the Ecological Discrete-Event Network (EDEN) modelling framework. This framework includes a formalism based on if-then rules describing economic and ecological events (e.g. investments and losses) that affect qualitative variables. The model rules were built from a literature review, expert interviews, and direct observations. Based on this model, the software then computes all trajectories the farm can take. Based on empirically-reported farm types and trajectories, we then attempted to falsify the modelled dynamics using model-checking techniques. RESULTS AND CONCLUSIONS: Model predictions matched all observed farm types and trajectories, thus not falsifying the model. Results highlighted that, for this system, livelihood improvement relied on the ability of the farm to to increase its cultivated area, workforce, livestock and fodder resources, all while producing and applying organic inputs to maintain or recover soil fertility. Although qualitative, model predictions are consistent with available observations and provide explanations about farm trajectories in southwestern Burkina Faso. SIGNIFICANCE: The EDEN modelling framework, through its qualitative — yet rigorous — exploration of all possible trajectories, can help the decision-making process by highlighting the far-reaching consequences of management actions.