Viticultural characterisation of soils from triassic period at Beaumes-de-Venise (Côtes du Rhône, France)

In 2020 one out of  eight wine bottles were filled with a flavoured wine-based beverage.

There is an urgent need in viticulture to adopt alternative herbicide-free soil management strategies to mitigate climate change, increase biodiversity, reduce plant protection products and improve soil quality while minimizing detrimental effects on grapevine’s stress tolerance and fruit quality. To propose sustainable solutions, adapted to different pedoclimatic conditions in Switzerland, we developed a multidisciplinary 4-year project, started in 2020. Objectives of the project are to a) evaluate the impact of green covers (spontaneous flora, winter cover crop and permanent ground cover) on environmental and agronomic parameters and b) develop subsequently innovative strategies for different viticultural contexts of Switzerland. The project is divided into 3 phases: 1) diagnosis, 2) on-farm and 3) on-station experiments. Phase 1) consisted in an assessment of 30 commercial vineyards all over Switzerland, where growers already use different herbicide-free soil management strategies. The most promising practices identified in this exploratory phase will be replicated in commercial vineyards across Switzerland (“on-farm”) as well as in a classical randomized block design in an experimental plot (“on-station”). For phase 1), measurements consisted in evaluation of soil status (compaction, structure, roots development), soil microbial diversity (metagenomics), plant diversity and biomass, vine physiology (water stress, vigor, leaf nitrogen) and berry quality (acidity, sugar, available nitrogen). Interestingly, the permanent ground cover resulted in a higher Shannon index thus a higher biodiversity as compared to the other itineraries. The winter cover crop increased vine nitrogen and vigor while deteriorating soil quality, leaving the soil more exposed and compacted likely due to more frequent tillage. The spontaneous flora led to higher berry sugar accumulation, less nitrogen and higher malic acid concentration putatively due to a higher water retention of the flora in a particularly wet vintage. Phases 2) and 3) are required to confirm those tendencies, over the 3 next vintages and different climatic conditions.

The concept of terroir is defined by a set of natural and human factors. On the slopy vineyards of the Burgundian « Côte », the « Appellations d’Origine Contrôlée (AOC) » spread out according to the slope in their order of quality : « AOC Grand Cru » at the top, « AOC Premier Cru » and « AOC Village » and « Bourgogne » on the piemont. In order to correlate the hierarchy of the vintages with the evolution of the topographic and pedological criteria, two toposequences were studied, in Gevrey Chambertin (« Côte de Nuits ») and Aloxe Corton (« Côte de Beaune »).

Protein instability in wines is challenging, and despite many efforts to find satisfactory alternatives to bentonite, both in terms of stability and quality, the solutions are limited in the wine industry.

A part, at least, of the fruity aroma of red wines is the consequence of perceptive interactions between various aromatic compounds, particularly ethyl esters and acetates, which may contribute to the perception of fruity aromas, specifically thanks to synergistic effects.1,2 The question of the indirect impact of non-fruity compounds on this particular aromatic expression has not yet been widely investigated. Among these compounds higher alcohols (HA) represent the main group, from a quantitative standpoint, of volatiles in many alcoholic beverages. Moreover, some bibliographic data suggested their contribution to the aromatic complexity by either increasing or masking flavors of wine, depending of their concentrations.