Could mobile viti-photovoltaic panels shading mitigate worst climate change effect on wine quality? Example of Merlot vineyard located in the Bordeaux winegrowing area

Abstract

The consequences of climate change represent a real challenge for viticulture. Analysis of past and recent shifts in climate conditions, along with future projections of wine production, highlights the risks faced by the industry on several levels. On the one hand, we observe an advancement of the phenological cycle, leading to an earlier ripening stage (Garcia de Cortázar-Atauri et al., 2016). Rising atmospheric temperatures and increased water stress during ripening lead to organoleptic quality loss in berries, with lower acidity and higher sugar content (Lecourieux et al., 2019; Mira de Orduña, 2010). In addition, yield loss may result from increasingly extreme weather events, such as spring frost, hail, heat waves, or torrential rains. These non-optimal conditions can severely disrupt vine functioning (altered nutrient dynamics, incomplete storage, disease development) and could impact the harvest through increased sanitary pressure from cryptogamic or aerial pathogens, as well as sunburn damage on berries. Furthermore, wine quality is increasingly destabilized by the imbalance in grape composition due to the discrepancy between technological, phenolic, aromatic, and textural ripeness. This complicates the harvest date decisions, which could lead to low acidity and premature development of aging markers (Allamy et al., 2023; Bindo et al., 2013).

The concrete effects of climate change are already observed with early-ripening grape varieties such as Merlot. In this context, the Vitisolar project, funded by the Nouvelle-Aquitaine Region and EDF Power Solutions, aims to evaluate the effects of a viti-photovoltaic system on the overall functioning of an existing Merlot vineyard planted in 2012. Its main objectives are to assess the effects on the vineyard agro-system: at the agricultural and oenological levels (soil-plant-grape-wine); on pests and biodiversity (fauna-flora); and to assess compatibility with existing viticultural practices. To study oenological aspects, healthy mature grapes were harvested and vinified for “control” and “under panels” modalities. Then, aromatic and phenolic composition were assessed, together with sensory analysis, on young wines and wines after one year of aging. This work aims to present the initial results regarding the effects of the viti-photovoltaic system on the overall wine quality (WP2.6 of the project).

References

Allamy, L., van Leeuwen, C., & Pons, A. (2023). Impact of harvest date on aroma compound composition of Merlot and Cabernet-Sauvignon must and wine in a context of climate change: a focus on cooked fruit molecular markers. OENO One, 57(3), 99–112. https://doi.org/10.20870/oeno-one.2023.57.3.7458

Bindo, K., Varela, C., Kennedy, J., Holt, H. & Herderich, M. (2013). Relationships between harvest time and wine composition in Vitis vinifera L. cv. Cabernet Sauvignon 1. Grape and wine chemistry. Food Chemistry, 138 (2), 1696-1705. https://doi.org/10.1016/j.foodchem.2012.09.146

García de Cortázar-Atauri, I., Duchêne, E., Destrac-Irvine, A., Barbeau, G., de Rességuier, L., Lacombe, T., … van Leeuwen, C. (2017). Grapevine phenology in France: from past observations to future evolutions in the context of climate change. OENO One, 51(2), 115–126. https://doi.org/10.20870/oeno-one.2017.51.2.1622

Lecourieux, D., Kappel, C., Claverol, S., Pieri, P., Feil, R., Lunn, J.E., Bonneu, M., Wang, L., Gomès, E., Delrot, S. & Lecourieux, F. (2019). Journal of Intégrative Plant Biology, 62 (8), 1132-1158. https://doi.org/10.1111/jipb.12894

Mira de Orduña, (2010). Climate change associated effects on grape and wine quality and production, Food Research International, 43(7). https://doi.org/10.1016/j.foodres.2010.05.001

Acknowledgements

This project was supported by EDF Power Solutions, the Nouvelle-Aquitaine Region, the European Union, and the French Environment and Energy Management Agency (ADEME).