To support sustainable development, several researchers in ergonomics propose a comprehensive approach to work situations or the systems in which they are embedded. This article empirically instantiates one of the proposed models - the Sustainable System of Systems (SSoS) model - in the case of the work of farmers engaged in agroecological transitions. It thus explores complexity regarding sustainability, and to highlight its contributions and limits. Based on a case study, our results illustrate how the macro, meso and micro levels of SSoS are finely articulated in workers' concerns, decisions, and trajectories to sustainability. We enrich this approach with a diachronic method to support the actors involved in such transitions as they navigate the complexities of sustainable transition.Practitioner summary: The research proposes insights into how farmers manage their transition to more sustainable practices, by revealing the various systems influencing that transition. It highlights: (1) farmers' development of a systemic and temporal approach to this transition, and the impacts that the different levels of the system have on one another; and (2) methodological issues related to the development of long-term ergonomic actions to support navigation and copying within the complexity of sustainable transition.
Keywords: Sustainable development; agriculture; long-term ergonomic actions; systemic approach; transition.