Five years of oxen grazing enhances soil carbon and structure in alpine vineyards

Integrating livestock with crop farming can greatly enhance agricultural sustainability and accelerate the agroecological transition. This study investigated the five-year effects of oxen grazing in a vineyard in South-Tyrol (Italy). Grazing occurred from autumn to spring over five consecutive years at a density of 5–7 oxen ha− 1. An adjacent site remained ungrazed. Soil samples were collected and analyzed for soil carbon pools (elemental analyzer), compaction (bulk density), soil structure (micro–water-stable aggregates, µWSA < 63 μm; macro-water-stable-aggregates, MWSA < 250 μm), plant available elements (ICP-MS), total microbial biomass (fumigation and extraction) and microbial abundance (qPCR). The results showed that, despite both fields being pedogenically similar, oxen grazing improved soil C. Oxen grazing increased total organic carbon (+ 14%), total nitrogen (+ 12%), carbon/nitrogen ratio (+ 2%), dissolved organic carbon (+ 11%) and dissolved carbon (+ 11%). Available elements and soil bulk density did not change, while soil structure even improved as evidenced by the increase of µWSA (+ 14%) in the oxen-grazed site. This observation is supported by the increase in bacterial abundance (+ 1%) as they are typically present in µWSA, while MWSA and fungal abundance together with microbial biomass remained stable across the two sites. Our findings highlight the potential of combining viticulture with pasture as a strategy to enhance soil health and C, with no evident negative effects. Strengthening the integration and cooperation between viticulture and livestock farming could play a key role in advancing sustainable agriculture for the agroecological transition.