Improvement of the Tempranillo phenolic profile through foliar urea application

Abstract

Phenolic compounds are essential to many sensory and health-related properties of grapes and wine. This two-year study evaluated foliar urea as an agronomic tool for improving the phenolic profile of Tempranillo grapes in a DOCa Rioja vineyard. Treatments were arranged in randomised blocks with three replicates. Urea was applied at two phenological stages and at different doses, and grape phenolic compounds were subsequently analysed. In 2018, only the high-dose pre-veraison treatment increased total flavanols relative to the control. By contrast, the low-dose veraison treatment significantly increased total stilbenes, hydroxycinnamic acids and flavonols, while the high-dose veraison treatment also enhanced several phenolic groups. Overall, although both veraison applications improved the concentration of selected compounds, the low-dose treatment at veraison was the most effective for enhancing the Tempranillo phenolic profile because it increased a broader range of phenolic families. Foliar nitrogen management can therefore modulate grape phenolic composition, but its effectiveness depends strongly on dose and application timing.

References

1. Garde Cerdán, T. Improvement of the Tempranillo Phenolic Profile through Foliar Urea Application. Recording of the presentation delivered at Enoforum Spain 2026, Zaragoza, 20–21 May 2026. Available soon on Infowine Premium: https://vinidea.it/es/brand/infowine/

Acknowledgements

This work was supported by projects PR-03-18 and PR-03-19, co-funded by the Government of La Rioja and ERDF funds (EU). R. M.-P. acknowledges a predoctoral contract from the National Institute for Agricultural and Food Research and Technology (INIA) and the Government of La Rioja.