Impact of innovative canopy management techniques on grape and wine quality under Mediterranean summer conditions

Abstract

The recent effects on temperature and rainfall caused by global warming pose a serious threat to the wine industry worldwide, mainly in terms of a loss of quality in the wines produced. The main effects on grape quality include an imbalance between the sugars and organic acids accumulated in the berries, which leads to a deficient winemaking process and lower-quality wines. To mitigate these effects on grape quality, a study was carried out to evaluate new vineyard management techniques on white berries compared to traditional models. During the 2024 summer season, this study was conducted with plants of ′Prensal Blanc′ and Giró Ros′ cultivars at commercial vineyard Bodega Son Juliana, located in one of the main wine-growing regions of Mallorca. Two leaf cover management treatments were applied: the first being a winery control called leaf thinning (L), and the second, called leaf thinning and shading (L+S), in which where the vine shoots were released to shade the bunches of grapes. During the grape ripening months, temperature and radiation conditions were monitored at the bunch level, in addition to tracking the main grape quality parameters (sugar content and acidity). At harvest, yield, disease impact, and berry quality were analyzed for each variety-treatment combination. The remaining material was used to vinify the grapes with commercial yeast. Once finished, the wines were bottled, wine samples were sent for analysis, and a tasting was conducted. The results from the monitoring during the ripening months showed that the L+S treatment delayed sugar accumulation and acid degradation by 1 to 2 weeks in both varieties, thus delaying the harvest date. The final grape quality results showed that the application of the treatment had positive effects in preventing acid degradation and regulating the must’s pH. The wines resulting from the winemaking process showed positive effects from the L+S treatment compared to the S treatment, with more balanced wines, as well as better ratings in the tasting.