Environmental efficiency and carbon sequestration potential of organic vs. conventional simmental dairy farming systems in Mountain regions: a case study

Numerous studies have investigated the environmental impacts of dairy cattle farming systemsusing the Life Cycle Assessment (LCA) methodology. However, considering additional relatedfactors can provide a broader perspective and more comprehensive contextualisation of theresults. Net food production is a crucial aspect that adds valuable insights to the discussion onsustainable farming practices. Moreover, few studies have focused on mountain dairy farmingsystems, which differ significantly in structure and management from large-scale dairy opera-tions in the lowlands. This study aims to provide a comprehensive comparison between conven-tionally and organically managed mountain dairy farms, specifically focusing on dual-purposeSimmental cattle. Six impact categories, Global Warming Potential (GWP100), MarineEutrophication Potential (ME), Terrestrial Acidification Potential (TA), Land Use (LU), and WaterUse (WU), were quantified via the LCA approach and attributed to one kilogram of EnergyCorrected Milk (ECM) and one m2 of on-farm agricultural area. To determine the individualfarm’s efficiency to provide human edible food, two additional indicators were calculated: milkyield deriving from roughage and net protein provision, based on the amount of human edibleprotein in the animal diet vs. the amount of human edible protein inside the milk. Further, car-bon sequestration by permanent grassland was calculated for each farm. Results showed lowerimpacts of the organically managed farms (ORG group) for the categories ME (0.0009 vs.0.0017 kg N eq) and WU (0.02 vs. 0.08 m3 kg ECM−1), while no significant differences could befound for GWP100 and TA, and the conventional farms (CON group) were more efficient in LU(0.97 vs. 1.54 m2a crop eq). In the case of net food production, the CON group showed an over-all higher efficiency (0.023 vs. −0.016 NP kg ECM−1), mainly due to maize silage input. No signifi-cant difference was found in the C sequestration of permanent grassland between the twogroups. This study analysed diverse mountain dairy farms using a single cattle breed, focusingon management, environmental impact, food efficiency, and carbon sequestration. Enhancingsustainability in these systems requires considering not only emissions but also their role in con-verting non-edible feed into food, maintaining low local environmental impact, preserving grass-lands, and supporting ecosystem services.