Effect of two doses of urea foliar application on leaves and grape nitrogen composition during two vintages

[Background] Nitrogen affects grapevine growth and also yeast metabolism, which have a direct influence on fermentation kinetics and the formation of different volatile compounds. Throughout the grapevine cycle, soil nitrogen availability and grape nitrogen composition can vary because of different factors. Nitrogen foliar applications can contribute toward enhancing grapevine nitrogen status and minimize the problem of leaching that traditional nitrogen‐soil applications can provoke. The present study aimed to evaluate the influence of urea foliar applications on grapevine nitrogen status and grape amino acid content. Accordingly, two different doses of urea were applied over the leaves of a ‘Tempranillo’ vineyard. [Results] The highest urea doses affected nitrogen content on blade leaf tissues after veraison. Must amino acid profiles were modified by urea application and some of the compounds increased their concentrations. The effect of year on the increase of must total amino acid concentrations was more important than the effect of the doses applied. [Conclusion] Urea foliar applications can be an interesting tool for decreasing grapevine nitrogen deficiencies. This method of nitrogen implementation in the vineyard could avoid sluggish fermentation problems during winemaking, enhance must nitrogen composition, and contribute to improving wine quality. © 2016 Society of Chemical Industry
We thank the Gobierno de La Rioja for financial support provided to the project P.R. 03/14‐07/15. E. P. Pérez‐Álvarez and T. Garde‐Cerdán thank the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) for predoctoral and doctoral support. We also express our gratitude to Ricardo Leza for providing the vineyard site in which the present study was conducted.