Global warming and soil management impact on organic carbon stocks and dynamics in vineyard soils

Climate change significantly affects soil organic carbon (SOC) stock and vulnerability, as well as microbial biodiversity, across different agro-ecosystems including vineyards. Due to the wide cultivation of wine grapes, the wine sector is now called upon to reconcile environmental protection, competitiveness, and resilience to global warming. The SUSTAIN project aims at determining the potential of vineyards, characterized by different pedoclimatic conditions and cultivars, on SOC accumulation in the context of climate change scenarios. A randomized block design, consisting of 3 blocks composed of 8 plots each, and 2 factors, i.e., land management practice (amendment with digestate, cover crop, bare soil) and climate manipulation (ambient temperature, warming), was set up in three study areas within the Veneto region (North of Italy). Open top chambers (OTC) were used to obtain a temperature increase of ~2 °C (SSP2-4.5). Soil samples have been collected at four times (after 0, 6, 12, and 18 months from the OTC placement) and at 3 depths (0-15, 15-30, and 30-45 cm) and characterized from the physical, chemical and microbiological point of view. From each sample, particulate and mineral-associated organic matter (POM and MAOM, respectively) were isolated and characterized by elemental and thermal analysis. DNA was extracted from topsoils, and metagenomic analyses and enzymatic assay were carried out. The preliminary results indicated no significant differences in SOC stocks following short-term warming. On the opposite, a general and slight increase in SOC concentration already occurred after 6 months in plots with cover crops, where POM played a greater role in SOC accrual. Thermal analysis, which was used to evaluate SOC stability, underlined that, regardless of vineyard and agronomic management, POM is the more labile fraction, while MAOM showed an increase of stability with depth. On the other hand, no significant differences were observed among treatments and climate manipulations. It is expected that results obtained at the end of experiment will help to better understand the SOC and microbial dynamics in vineyards as a function of future climate change scenarios. In addition, Life Cycle Assessment (ISO14040), which integrates experimental data and company inventories, will estimate the carbon footprint of the vineyards management. Ultimately, these outcomes will enable the identification of soil-management strategies that strengthen long-term carbon storage while substantially reducing the environmental impact of viticulture.