Since the 1950s, intensive and specialized agricultural systems using a few select species and relying heavily on agrochemical inputs have enabled a huge increase in food production. However, in parallel, drawbacks appeared including biodiversity loss, greenhouse gas emission, erosion, and water pollution. Today shifting farming systems to mitigate soil degradation trends is indispensable. Using viability theory, we propose a dynamic model of the sequence of agricultural productions and practices that can be implemented in the long term to restore soil quality while respecting a set of agronomic and economic constraints. The paths to soil restoration vary depending on agronomic and economic constraints, the time available for restoration, the initial soil conditions, and investment capacities. Economic valuation of the minimum cost of restoration shows that the agroecological transition may be costly and that farmers can have difficulty meeting the costs, thus raising the question of how the cost of agroecological transition is to be shared. Recommendations for Resource Managers The mathematical viability theory is used to design a new model of farm management to assess possibilities and cost of the agroecological transition more precisely the successive choices of crops and agricultural practices intended to restore topsoil quality. This discrete dynamical model has an irregular time step corresponding to agricultural cycles and to dates of parcel release retrieved by using an inverse approach. The agronomic and economic constraints are mixed depending both on states and controls. The economic constraints are imposed on a monthly time step while states and controls variables evolve with the agricultural cycles what best fit the economic situation farmers must face. The trajectory selection criteria is the minimum cost of restoration. Optimal viable strategies depend on initial soil quality and available capital, time of exercise, constraints, and of crops and practices diversification. Computations were made with a software specially developed for this study using data sets collected in the French West Indies.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020]
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Pédologie [068]
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Sciences du monde végétal [076]
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Economie et sociologie rurale [098]
