This paper presents an agent-based model, which is developed to support decision-makers in the selection of best biowastes management scenarios. The model simulates biowastes transfers between the production points to farmland and analyses supply/demand balance of organic matter (transformed biowastes) as a complementary organic resources for crops. The system describes the biowastes chain management and contains five main agents: (1) producer agents that generate biowastes, (2) treatment plant agents that transform biowastes into compost or sludge, (3) vehicle agents that collect biowastes from producers to treatment unit and deliver organic matter after transformation by treatment unit to farmland, (4) agricultural sites that need organic matter, and (5) administrative agents that plan schedules of vehicle agents and orders of organic matter. Our aim is to test organizational alternatives at a territory scale to manage this new matter (biowastes transformed) on the economic market. The proposed model is used on a french overseas department in the Indian Ocean: La Réunion island.