Fostering local crop-livestock integration via legume exchanges using an innovative integrated assessment and modelling approach based on the MAELIA platform

CONTEXT: Crop diversification is now well-recognised as a strong lever to address the environmental challenges currently faced by agriculture. Connecting and fostering local exchanges between specialised arable crop and livestock farms can support the diversification of crops and relocate animal feeding with local protein (vs. soya supplements). However, the trade-offs and synergies between individual and collective objectives and perfor-mances generated by this system are still largely unknown. Innovative tools that consider the spatiotemporal heterogeneity underpinning the daily functioning of farms are needed to explore the implications of exchange scenarios. OBJECTIVES: To assess self-sufficiency, sustainability and vulnerability at the farm, group (arable vs. livestock) and territorial levels considering the baseline situation and scenarios that increase synergy between arable and livestock farms. METHODS: We demonstrated the utility of using MAELIA, a spatial agent-based integrated modelling framework, to support iterative design and assessment of self-sufficiency, sustainability and vulnerability of such scenarios. MAELIA was applied to model a collective of five arable and two livestock farmers in western France. In a participatory approach, scientists, agricultural advisers and the farmers co-designed three possible scenarios of legume exchanges. RESULTS AND CONCLUSIONS: Only the most ambitious scenario based on strong collaboration allowed farmers to reach local protein self-sufficiency while reducing the variability in five of the seven indicators used to assess farm performances. Meeting livestock farms' demand for legumes had a positive influence on socio-economic performance at the territorial level, including an increase in the mean gross margin (of 71 (sic)/ha; 4% higher), decrease in the use of nitrogen fertiliser (of ca. 21 kg N/ha; 11% lower) and decrease in labour time (of ca. 12 min/ha; 5% lower). No major trade-offs between self-sufficiency and vulnerability were observed. However, there were distinct individual performances related to the degree of changes imposed on each farm. SIGNIFICANCE: We show that by reducing the dependence to external inputs, these systems are promising al-ternatives to an environmentally sustainable, resilient and economically viable agroecological transition. The development of dedicated institutional support for direct bilateral or multilateral agreements, and specific financial and technical support would encourage farmers to join such initiatives and redesign their farming systems.

Automated summary

Crop diversification is recognized as a solution to current environmental challenges in agriculture. Enhancing local exchanges between arable crop and livestock farms can support diversity and improve farm performances. Collaboration scenarios have shown potential for achieving local protein self-sufficiency and reducing external input dependence.