Impacts of environmental variability and viticultural practices on grapevine behaviour at terroir scales

Climate change poses several challenges for the wine-industry in the 21st century. Adaptation of viticultural and winemaking practices are therefore essential to preserve wine quality and typicity. Given the complex interactions between physical, biological and human factors at terroir scales, studies conducted at these fine scales allow to better define the local environment and its influences on grapevine growth and berry ripening. Accordingly, they lead to a greater understanding of the potential future impacts of climate change and adaptation strategies necessary at different spatial and temporal scales. Within the context of climate change, this paper presents the impacts of the local environment and viticultural practices on grapevine behaviour in the mid-Loire Valley winegrowing region, France, namely in the AOP Coteaux du Layon (variety: Chenin) and the AOP Saumur Champigny (variety: Cabernet franc). Both areas were equipped with climatic instruments (weather stations, temperature sensors and rain gauges) and during the growing season, phenological observations and berry composition analyses were effectuated. A strong spatial variability in temperatures and bioclimatic indices was observed within the vineyards. This variability, related to altitude, aspect and nearness to river, was even more evident during extreme events, such as risk of spring frost. Overall, the local climate variability in relation with soil characteristics, notably water holding capacity, was related to grapevine growth and berry composition. Vineyard plots with greater heat accumulation had earlier phenological stages and higher maturity indices. These results illustrate that adaptation solutions to climate change do exist at local scales, in terms of spatial temperature variability, soil properties and viticultural practices, particularly those related to soil management strategies. As adaptation to climate change is essential, these results show that it is necessary to conduct studies at fine terroir scales in order to better understand the spatial variability of local climate and its influences on grapevine behaviour.