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 systems using the Life Cycle Assessment (LCA) methodology. However, considering additional related factors can provide a broader perspective and more comprehensive contextualisation of the results. Net food production is a crucial aspect that adds valuable insights to the discussion on sustainable farming practices. Moreover, few studies have focused on mountain dairy farming systems, which differ significantly in structure and management from large-scale dairy operations in the lowlands. This study aims to provide a comprehensive comparison between conventionally and organically managed mountain dairy farms, specifically focusing on dual-purpose Simmental cattle. Six impact categories, Global Warming Potential (GWP(100)), Marine Eutrophication Potential (ME), Terrestrial Acidification Potential (TA), Land Use (LU), and Water Use (WU), were quantified via the LCA approach and attributed to one kilogram of Energy Corrected Milk (ECM) and one m(2) of on-farm agricultural area. To determine the individual farm's efficiency to provide human edible food, two additional indicators were calculated: milk yield deriving from roughage and net protein provision, based on the amount of human edible protein in the animal diet vs. the amount of human edible protein inside the milk. Further, carbon sequestration by permanent grassland was calculated for each farm. Results showed lower impacts 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 m(3) kg ECM-1), while no significant differences could be found for GWP(100) 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 overall higher efficiency (0.023 vs. -0.016 NP kg ECM-1), mainly due to maize silage input. No significant difference was found in the C sequestration of permanent grassland between the two groups. This study analysed diverse mountain dairy farms using a single cattle breed, focusing on management, environmental impact, food efficiency, and carbon sequestration. Enhancing sustainability in these systems requires considering not only emissions but also their role in converting non-edible feed into food, maintaining low local environmental impact, preserving grasslands, and supporting ecosystem services.

Freie Universität Bozen
University of Basilicata