S15 - Session O4 - Assessing carbon sequestration and its within-vine allocation in the vineyard

Authors: Leonardo Montagnani, Torben Oliver Callesen, Carina Veronica Gonzales, Flàvio Bastos Campos, Massimo Tagliavini *

Vineyards represent a relevant land-use type in the Mediterranean region. They present perennial woody plants (vines) and often herbaceous vegetation in the alleys. To which extent these features are posing the vineyards in terms of carbon balance is still unclear. While some studies suggest they could act as large carbon sinks, others indicate a minimal capacity to sequester carbon. To elucidate the specific features of carbon allocation and potential carbon sequestration in a mountain vineyard, we applied a complete assessment approach to quantify the overall carbon balance and its components. To this end, we established an eddy covariance tower in an organic, grassed and irrigated vineyard in Caldaro, South Tyrol, Italy, where two vine varieties, Chardonnay and Sauvignon blanc, are cultivated. In addition, we regularly assessed the net primary productivity in the different vine organs and alleys. We also concurrently assessed the soil respiration of the rows and inter-rows, as well as the heterotrophic component of soil respiration. Results showed a large gross primary productivity (GPP): from mid-April to the end of October, the overall photosynthesis estimated after flux partitioning was 2580 g C m -2 , which is at the upper end of the photosynthetic capacities of broadleaves forests in temperate regions, and it is also higher than grasslands in the same climate conditions. The overall respiration was also high and overpassed GPP starting from September on, leading to an overall net ecosystem production of 215 g C m -2 during the growing season. We found that the different plant organs considered (leaves, canes, bunches and grasses) accommodated most of the sequestered carbon. The ongoing research will show how the winter period will affect the carbon balance and what is the contribution of belowground plant organs and the soil to the potential carbon sequestration of the experimental vineyard.