This study was carried out to determine an optimal irrigation and canopy management strategy to mitigate the effects of climate change on grape quality parameters and yield components in Mediterranean vineyards, mainly to avoid the imbalance between sugars and organic acids in the must. The experiment was carried out during 2021 and 2022 in a commercial vineyard located in Consell (Bodega Ribas, S.A.T., Mallorca, Spain). Two deficit irrigation treatments, moderate deficit irrigation (MDI) and severe deficit irrigation (SDI), were applied in combination with three canopy management treatments (control (C), leaf removal (L), and leaf removal with shading (L+S)). Cluster temperature and radiation, water stress level and leaf area index were measured during the growing seasons. Berry weight, total soluble solids, pH, total titratable acidity, tartaric acid, malic acid and potassium concentration were measured at different berry development stages. Yield components were determined at harvest. The application of the L+S treatment generated natural shading on the clusters reduced the temperature excess compared to the L treatment which resulted in greater exposure. The reduction in temperature combined with the maintenance of moderate water stress delayed grape ripening, mainly by delaying the accumulation of sugars and slowing the degradation of malic acid in the berries. The combination of moderate water stress and shading of clusters after plant defoliation maintained a higher cluster weight, with no significant yield losses compared to the control treatment. The combined strategy of moderate water stress and natural shading of the clusters on defoliated vines has been shown to reduce extreme high temperature in the cluster zone and consequently avoid berry quality and yield losses at harvest.
Puigserver et al. (Thu,) studied this question.