Impact of foliar nanocalcium fertilization on yield and wine characteristics of 'Vranac' wine grapes

This study investigates the impact of foliar application of calcium nanofertilizer (Fitosmart®) on the yield and quality of Vitis vinifera L. (cv. 'Vranac') grapes. The experiment was conducted during the 2023 growing season at a commercial vineyard in Montenegro, where vines were treated with a 0.5% calcium nanofertilizer solution at three critical phenological stages: pre-bloom, post-bloom, and veraison. The results showed a significant increase in grapevine yield, primarily driven by an enhanced number of clusters per vine, while cluster weight exhibited only a minor increase. Chemical analysis revealed delayed sugar accumulation in treated grapes, which impacted must and wine composition by slightly reducing total soluble solids and final alcohol content. Treated wines demonstrated increased levels of total polyphenols and anthocyanins, factors that contribute to the sensory quality of red wines, including aroma authenticity, harmony, and overall impression. These findings suggest that the foliar application of nanocalcium fertilizers can enhance both grape yield and wine quality, making it a promising, sustainable alternative to conventional mineral fertilizers. However, further research is needed to explore its broader applicability across diverse climatic conditions and grapevine varieties.