Abstract
Regenerative agriculture aims to produce food while simultaneously improving soil health, supporting biodiversity, reducing input costs and enhancing climate resilience. Evidence on its environmental and socio-economic impacts across different systems and climates remains limited, with few studies measuring multiple outcomes following whole farming system transition. To be impactful, regenerative agriculture research must address farmers' knowledge needs and provide practically feasible, economically viable solutions. This can be achieved through action-based research, co-designed with farmer stakeholders in real-world settings. Such research is time-consuming and involves potential risk for farmers adopting new practice combinations. Here, we describe two UK research projects gathering evidence on regenerative agriculture in partnership with farmers, at different scales. One is a replicated large-plot trial that stacks regenerative principles, the other a farmer-led quasi-experiment, following the transition in active farm businesses and using a flexible scoring system based on regenerative principles. We highlight benefits, challenges and future research directions emerging from these projects, including: challenges defining regenerative agriculture; co-design and maximizing knowledge exchange; generalizing results beyond study sites, when practices and outcomes are context-dependent; the need for interdisciplinarity; and generating evidence on long-term transitions with time lags between system change and outcomes, in an environment of short-term funding.This article is part of the theme issue 'Transforming terrestrial food systems for human and planetary health'.