Foliar application of urea improved the nitrogen composition of Chenin grapes
The nitrogen composition of the grapes directly affects the developments of alcoholic fermentation and influences the final aromatic composition of the wines. The aim of this study was to determine the effect and efficiency of foliar applications of urea on the nitrogen composition of grapes. This study was carried out during 2023 vintage and in the Chenin vineyard located in Estacion Experimental Mendoza (Argentina). Three urea concentrations 3, 6 and 9 Kg N/ha (C1, C2, and C3, respectively) and control (T) were applied in this vineyard at veraison. In all solutions were added 1ml/l of Tween 80 ® surfactant. In addition, the experimental design was a randomized block design with three. Also, each treatment was repeated one week later. The grapes were harvest at optimum maturity (20º Brix), harvested by hand and transported in separate boxes for each treatment and control. Subsequently, grapes samples were analysed to determine the oenological parameters (official methods), and the nitrogen composition, ammonium and amino nitrogen (OenoFoss™ autoanalyzer). In addition, the yeast assimilable nitrogen (YAN) content was calculated as the sum of ammonium and amino nitrogen. Finally, the results were studied statistically by analysis of variance (ANOVA) and differences between samples were compared by Duncan’s test (p-value ≤ 0,05). In 2023 vintage, C1 and C3 treatments improved the amino nitrogen content. In addition, ammonium nitrogen content was increased by C2 and C3 treatments. And YAN content was increased by all urea treatments and C3 treatment was the one that most increased the YAN concentration in must samples. Consequently, foliar applications of urea, applied at veraison, could be an agronomic practice to improve the nitrogen concentration in Chenin grapes.
Acknowledgements: Many thanks to the collaboration with researchers from Estación Experimental Mendoza. R. M.-P. thanks National Institute for Agricultural and Food Research and Technology (INIA) and Government of La Rioja for the predoctoral contract.
Issue: ICGWS 2023
1Instituto de Ciencias de la Vid y del Vino (Gobierno de La Rioja, CSIC, Universidad de La Rioja) Ctra. de Burgos, Km. 6. CP 26007 Logroño, La Rioja, España
2Universidad Juan Agustín Maza. Centro de Estudios Vitícolas y Agroindustriales. Lateral Sur del Acceso Este 2245.CP 5519 Guaymallén, Mendoza, Argentina
3Instituto Nacional de Tecnología Agropecuaria. Estación Experimental Mendoza. San Martín 3853. CP 5507EVY, Luján de Cuyo, Mendoza, Argentina
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yeast assimilable nitrogen, veraison, Vitis vinifera L