Study of the vine performance and the wine composition of Tannat on the terroir of Colonia del Sacramento – Uruguay

Grape-growing terroirs were defined according to the method proposed by Falcetti and Asselin (1996) near of Colonia de Sacramento, a city of Uruguay situated on the left of the “Rio de la Plata”. In a second stage, the performance of the plants of Tannat variety implanted in vineyards situated at two UTB, named “Real de Vera” and “Riachuelo”, were analyzed to confirm the suggested delimitation during three years. The studies were realized in three vineyards. The weight of the berries and the pruning weight by plant were determinated. The determination of the leaves water potential was realized after the budburst and the potential exposed leave area was determinated at the veraison. Vinifications of 50 kg of grapes per vineyards were done. The wines were analyzed, determining the classical oenological parameters and the global polyphenolic composition. The index of Ravaz, the ratio SFE p / yield and the water status by plots were determinated. The effect of the year was clearly observed on the total of the vineyards. The yields per plant, the weight of pruning, the potential foliar surface expose and the index of Ravaz presented significant differences between vineyards. The differences between the indicators of physiologic answer, the yields and the wine composition were clearly explained by the characteristics of the soil, the water status and the viticultural practices. The plants submit at stress during the maturation were the most equilibrated.