Carbon footprint assessment on a mature vineyard

ItIt is recognized that agriculture is the fourth largest contributor to global greenhouse gases (GHGs)emissions by sector (14%) and the wine industry is one of the most important economic sectors in terms of production and distribution worldwide. However, agriculture can also contribute to sequester carbon,so it is important to understand the double role of such systems. Even if the agricultural phase is recognized by several authors to have a strong environmental impact during the wine production, only a few studies estimate GHG emissions related to this stage. In addition, the determination of the carbon footprint (CF) (i.e. the amount of direct and indirect CO2emissions caused by a production process) of the agricultural phase is not a simple task due to the large uncertainty related to local characteristics, climate, land, agricultural practices, grape type, and to a general lack of experimental data. The main goal of this work was to determine the CF of a mature vineyard during the grape production process. The CF analysis was conducted in a typical Mediterranean vineyard located in the South of Sardinia (Italy) using 1 kg of grape yield as functional unit. The system boundary was "from cradle to gate" excluding winemaking processes, distribution, and consumption. In addition, the study was addressed to assess the role of the vineyard to offset carbon emissions at the end of the productive year. The Eddy Covariance technique was used to directly measure the CO2 exchange over the vineyard and the net CO2 budget was computed by combining the measured fluxes and the GHG emissions estimated by the CF analysis. Results showed that the production of 1 kg of grape determined a total amount of GHG emissions of 0.39 kg CO2-eq and most of them derived from external inputs such as fossil fuel combustion and soil management. In addition, ecophysiological processes could contribute to offset the CO2emissions released during the agronomic practices.