Are alternatively organized value chains more environmentally sustainable? Evidence from soybean production in Minas Gerais and Paraná states, Brazil

The predominant agro-industrial soybean production in Brazil has led to a significant socio-ecological crisis. Alternative agriculture has been increasingly marketed as a viable solution to the multifaceted challenges engendered by this intensive production system in the Atlantic Forest biome of Brazil and its related global value chains. Accurate evaluation of their true transformative impact on sustainable food system transitions is needed. We conducted a Life Cycle Assessment (LCA) of five different soybean production systems in the States of Minas Gerais and Paraná: conventional GM (genetically modified seeds), and four alternatives [(1) conventional GM inputs-reduced, (2) conventional non-GM, (3) conventional non-GM soybean–coffee intercropped, and (4) organic]. We collected life cycle inventory data through interviews and observations over a 2-year period and assessed environmental impacts on climate change, biodiversity loss, soil quality, acidification, eutrophication, ecotoxicity, human toxicity, particulate matter formation, and energy use. Results obtained showed significant variability in footprints of the studied systems, with alternatives scoring similar or higher impacts in climate change, acidification, eutrophication, and non-renewable energy use compared to conventional production systems. Organic and soybean–coffee intercropped productions had the lowest biodiversity loss, ecotoxicity, and soil quality impacts. Our sensitivity analysis indicated that a 10% reduction in fertilizers and diesel could decrease emissions by 0 to 14.4% across production systems, with most impact categories exhibiting impact reductions below 10%. Alternative productions faced challenges such as weed control, bioinput production, and efficiency, as well as contamination from conventional neighboring farms. Addressing these led to an increased use of diesel and biopesticides. From an LCA perspective, organic and non-GM production did not outperform conventional GM production. However, organic production, followed by soybean–coffee intercropping, achieved significantly higher on-farm agrobiodiversity scores. A diversification of soybean cropping systems and improved management of crop residues would effectively reduce inputs, favor closing nutrient loops locally, and avoid replicating the environmental impacts of intensive monocultures. However, the initial decrease in soybean production volumes might lead to additional land use elsewhere.