Trade-offs among environmental impacts for organic vegetable farms with contrasting input levels

French organic vegetable farms vary from complex biodiversity-based systems with diverse crops to simpler input-based systems with fewer crops, leading to different environmental impacts. We conducted a life cycle assessment (LCA) of three contrasting farms: a large farm in open-field production (OP), a microfarm combining open-field and sheltered production (MF), and a medium-sized farm in sheltered production (SP).Due to MF’s complexity (high crop diversity and biodiversity-based approach), we applied a system-level LCA instead of a traditional crop-based LCA, assessing farm inputs and vegetable outputs over one year. Using functional units based on output mass, area, and economic value, we evaluated six key impacts: climate change, energy demand, land competition, marine eutrophication, on-farm biodiversity, and plastic use.The choice of functional unit strongly influenced the ranking of the systems. Energy demand per ha increased from OP to MF to SP. Per ha, SP had the highest climate impact, while OP had the lowest. Per kg and per €, climate impacts varied less, with different rankings. OP used considerably less plastic but performed worse for biodiversity and land competition. Despite higher yields, SP did not outperform OP or MF in climate change, energy demand, or plastic use.Biodiversity results highlighted the critical role of semi-natural habitats, emphasizing the need for clear farm boundary definitions in system-level LCA. Plastic use quantification echoed concerns over agricultural microplastic pollution. Estimating nitrate leaching remained challenging due to the limitations of the IPCC Tier 1 model, leading to high uncertainty in marine eutrophication impact assessments.The novelty of this study lies in 1) assessing environmental impacts of three contrasting organic vegetable farms, including a complex microfarm; 2) quantifying impacts of crops, semi-natural habitats, and farming practices on biodiversity; and 3) quantifying plastic use.