Grapegrowing soils

La composition du raisin de la variété Muscat d’Alexandrie a été étudiée dans trois terroirs différents au Nord-Est de la Tunisie (RafRaf, Baddar et Kelibia).
Des échantillons de raisins ont été récoltés à maturité industrielle durant les saisons 2001 et 2002 dans les trois régions citées. Les paramètres pomologiques (poids moyen de la grappe et de la baie) et physico-chimiques

Sustainability is a key focus in viticulture, where managing abiotic and biotic stress presents a major challenge.

In wine growing regions around the world, climate change has the potential to affect vine transpiration and overall vineyard water use due to related changes in atmospheric demand and soil water deficits. Grapevines control their transpiration in response to a changing environment by regulating conductance of water through the soil-plant-atmosphere continuum. Most vineyard water use models currently estimate vine transpiration by applying generic crop coefficients to estimates of reference evapotranspiration, but this does not account for changes in vine conductance associated with water stress, nor differences thought to exist between varieties. The response of bulk stomatal conductance to daily weather variability and seasonal drought stress was studied on Cabernet-Sauvignon, Merlot, Tempranillo, Ugni blanc, and Semillon vines in a non-irrigated vineyard in Bordeaux France. Whole vine sap flow, temperature and humidity in the vine canopy, and net radiation absorbed by the vine canopy were measured on 15-minute intervals from early July through mid-September 2020, together with periodic measurement of leaf area, canopy porosity, and predawn leaf water potential. From this data, bulk stomatal conductance was calculated on 15-minute intervals, and multiple regression analysis was performed to identify key variables and their relative effect on conductance. Attention was focused on addressing multicollinearity and time-dependency in the explanatory variables and developing regression models that were readily interpretable. Variability of vapor pressure deficit over the day, and predawn water potential over the season explained much of the variability in conductance, with relative differences in response coefficients observed across the five varieties. By characterizing this conductance response, the dynamics of vine transpiration can be better parameterized in vineyard water use modeling of current and future climate scenarios.

The wine spoilage yeast Brettanomyces bruxellensis can be found at several steps in the winemaking process due to its resistance to multiple stress conditions. Among the resistance strategies, one could be the formation of biofilm, a lifestyle known to enhance persistence of microorganisms. In this study, we propose to characterize biofilm of B. bruxellensis in wine, especially through several microscopic analyses.

Oxidative stability is a critical factor in wine shelf-life. SO₂ is commonly added to wine due to its strong antioxidant activity, although there is a general push to reduce SO₂ use in vinification.