Circularity in agri-food systems (AFS) has gained popularity as a concept promoted to decrease negative environmental impacts of agriculture and value chains, from the perspective of either nutrient cycling or a circular economy. However, at the global scale, evidence of increased circularity in AFS remains scarce. Research has been critical of the concept of a circular economy, especially socio-metabolic research. Yet, the latter provides a comprehensive framework for analyzing AFS in relation to planetary boundaries through the quantification of material and energy flows. The present review aimed to understand how socio-metabolic research addresses circularity in AFS, renders circularity operational and supports the transition towards strong sustainability. A total of 78 case studies were selected and characterized in terms of their (i) key methodological features, especially whether they addressed circularity as a context, purpose or means, and (ii) their pathways to action through the place of stakeholders and the key drivers of changes related to livestock production. We discuss knowledge gaps for acting on AFS and identify three priorities for transformative socio-metabolic research of AFS: (i) reveal hidden flows, identify system and compartment diversity (ii) assess trade-offs of transitioning to a circular system, including external impacts beyond the territorial scale (iii) strengthen methods for engaging local stakeholders in the design and implementation of the transition.

摘要

从养分循环或循环经济的角度来看，农业食品系统（AFS）的循环性作为一个旨在减少农业和价值链对环境的负面影响的概念而受到欢迎。然而，在全球范围内，AFS 循环性增加的证据仍然很少。研究一直对循环经济的概念持批评态度，尤其是社会代谢研究。然而，后者提供了一个全面的框架，用于通过量化物质和能量流来分析与行星边界相关的 AFS。本综述旨在了解社会代谢研究如何解决 AFS 中的循环性、使循环性可操作并支持向强大可持续性的过渡。总共选择了 78 个案例研究，并根据其 (i) 关键方法论特征，特别是它们是否将循环性视为背景、目的或手段，以及 (ii) 通过利益相关者和关键点采取行动的途径进行了表征。与畜牧业生产相关的变化的驱动因素。我们讨论了针对 AFS 采取行动的知识差距，并确定了 AFS 变革性社会代谢研究的三个优先事项：（i）揭示隐藏的流动，识别系统和区室多样性（ii）评估向循环系统过渡的权衡，包括外部影响超越领土范围 (iii) 加强让当地利益相关者参与过渡设计和实施的方法。