Effect of vine nitrogen status on grape and wine quality: Terroir study in the Vaud vineyard (Switzerland)

Barrel ageing is a transformative process that alters a wine’s organoleptic properties and consequently its price. Even though it is considered beneficial mostly for red wines, ageing can also be used for white wines but for shorter time periods. Due to barrel costs, space requirements and the markets’ demands for fast release of each new vintage, new products such as oak chips or shavings have been developed to help minimize the time needed for the extraction of essential wood compounds.

Today winegrowers involved in mechanical winter pruning are applying this viticultural technique on two main training systems, the free cordon, appearing to be the more efficient, and the trellised vertical shoot positioning (VSP) system. The main reasons for maintaining the trellis are generally due to common habits in vineyard management, risk of wind damage for the shoots, or risk of decrease in photosynthesis potential. The aim of the study was to assess the effects of the two training systems on vine. In addition, different nitrogen fertilization levels were applied on the two systems to evaluate the best combination to achieve yield and grape quality.

Polyphenols are common in human diets, primarily in plant-derived food and beverages. They influence multiple sensory properties such as aroma, flavour, colour, and taste, such as astringency and bitterness [1]. The major phenolic compounds in grapes and wines are anthocyanins and tannins (proanthocyanidins or condensed tannins).

Context and purpose of the study ‐ Vine balance is a concept describing the relationship between carbon assimilation (usually estimated using a measure of vine vigour, e.g. pruning weight) and its utilisation for fruit production (usually estimated using harvest yield). Manipulating vine balance through leaf area or crop load adjustments affects the proportion of the vine’s total carbohydrate production required to mature the fruit. It is commonly considered that composition of the berry, and resulting wine, is strongly affected by vine balance.

L’étude préliminaire, réalisée sur les principaux cépages de la région Midi-Pyrénées, a montré que le Cot N possédait des teneurs en acide tartrique dans les moûts et les vins plus élevées que celles des cépages Négrette N, Tannat N, Duras N et Fer Servadou N.