Integrated crop-ruminant livestock systems as a strategy to increase energy, carbon and nutrient circularity: Exploring scenarios in dairy production systems across the southern hemisphere

Abstract

CONTEXT: This study investigates the integration potential of crop-livestock systems within dairy production in Uruguay, New Zealand, and Argentina, addressing the dual challenges of increasing food production and enhancing environmental sustainability. OBJECTIVE: The objective is to explore integration strategies for dairy farm systems in order to increase food output and circularity, reduce GHG-e, nutrient losses and improve production system resiliency. METHODS: We developed a framework and modeled four progressive scenarios for each country's dairy systems, focusing on energy flows, carbon emissions, and nitrogen balance. RESULTS AND CONCLUSIONS: The results indicate that higher levels of integration significantly reduce environmental impacts and increase resilience. Specifically, as integration increases, the Energy Return on Investment (EROI) improves due to enhanced self-sufficiency and reduced reliance on external feed sources. For instance, the transition from conventional to ecosystem-based practices led to notable reductions in greenhouse gas (GHG) emissions, achieving lower carbon footprint through increased diversification and the incorporation of agroforestry. Nitrogen use efficiency also showed marked improvements as nitrogen surpluses decreased across scenarios, primarily due to better management of animal excretions and the integration of crops. Despite the promising outcomes, challenges remain, including farmers' capacity to diversify and the substantial investments in infrastructure and management required to facilitate such transitions. SIGNIFICANCE: Ultimately, this study underscores the importance of integrating crop-livestock systems to address the complexities of sustainable dairy production, while also urging further exploration into practical strategies that can support farmers in adapting to environmental and economic pressures.