CAMBIAMENTI CLIMATICI E VITICOLTURA NEL NORD ITALIA: PROSPETTIVE DI ADATTAMENTO E MITIGAZIONE

Climate change is leading to warmer temperatures and more erratic and intense precipitation patterns with future increases in frequency and intensity of extreme events, such as heat waves, heavy precipitations, hailstorm and drought spells. This will especially affect viticulture, because wine quality and style are highly dependent on local microclimate. In particular, climate change will impact on acidity to sugar ratio, the key quality parameter for grapes in sparkling wines production. This will have strong repercussions on the wine sector of north-eastern Italy, the production zone of the renowned Prosecco sparkling wine. On the other hand, the relationship is not unidirectional as agriculture influence climate changes with green houses gasses emissions during field management. For this reason, combined with the carbon removal by harvest, agricultural lands are considered a net source of carbon released in the atmosphere. Yet, tree crops have been shown to be a good C sinks in the short and medium term. Moreover, sustainable practices are often proposed as a good strategy for lowering impact of field management. But very low information is available in literature about the effectiveness of vineyard uptake on offset field emissions under sustainable management. The aims of this study followed these two research lines, to reach new information about i) real water requirement of a representative vineyard in the DOC Prosecco, variability of heat and drought stress risk in the extensive and variable Prosecco DOC related to grape quality and productivity in the different areas with a special focus on malic acid; ii) carbon footprint reliability and nitrous oxide emissions factors (EF) for organic fertilization, with a specific long term monitoring that allowed for calculate specific emissions factors, and climate impact of sustainable viticulture, with a multiannual comprehensive GHG budget of the vineyard. The average water consumption during growing season for a representative vineyard in the DOC Prosecco was about 450 mm with significant different values in irrigated and not-irrigated years but very stable inside these periods. The zoning for heat and water stress risk of DOC prosecco was able to discriminate different levels of heat and water stress in the DOC Prosecco, highlighting different features about grape quality and productivity depending on risk levels. This will provide the possibility of planning differentiated management strategies to safeguard the productivity and quality of the grapes for the different DOC areas. The analyses of high-resolution infield monitoring of nitrous oxide emission allowed to have a better picture of nitrous oxide emission in vineyard soil and to calculate robust and specific annual EF for N2O emissions for different soil and fertilizer management. It showed that standard EF included background fluxes, while organic fertilization was responsible for about half of emissions. We presented the first multi-annual study on comprehensive C balance in vineyards that shows net negative C balance of viticultural phase in organic conduction in four years with high variability in its components even for the same site, confirming that soil management is crucial for increasing carbon uptake and soil stock in orchards. Sustainable practices were shown to be potentially effective in helping the field phase to be climate neutral or even positive in tree crops. These kind of study and results are essential to drive management of tree crops trough future climate changes, with a perspective of climate neutrality thanks to low carbon agricultural models.