In interaction with climate and genetic or human factors, the soil is a major component of the viticulture terroir. The mineral composition of the soil influences vine performance and wine sensory attributes. Among the elements that vines take from the soil, nitrogen is the one that has the strongest impact on vine physiology, vigor and grape composition. In addition to its major effect on primary metabolites in berries, nitrogen plays also a decisive role in the secondary metabolism, especially in the production of key compounds for berries quality, like volatile thiols, methoxypyrazines and glutathione (GSH).
To study the effect of nitrogen on these target metabolites, an experiment on Sauvignon blanc vines was performed in Bordeaux and Sancerre areas (France). Four nitrogen treatments were applied: control, soil application of 50kg N/ha, soil application of 100kg N/ha and foliar application of 15kg N/ha. Secondary metabolites were measured in grape berries and in wines produced through small scale vinifications.
Yeast Assimilable Nitrogen and N-tester measurements showed a significant difference in vine nitrogen status among the four treatments. The analysis of volatile compounds showed an increase in the content of 3-sulfanylhexan-1-ol precursors (P-3SH) and GSH in berries from vines with high N status. Similar effect of nitrogen was observed on the concentration of 3SH and GSH in wine.
This study will allow better management of vine nitrogen status in vineyards allowing a quantitative and qualitative control of grape berries.
Authors: Pierre Helwi (1), (3), Sabine Guillaumie (1), Cécile Thibon (2), Philippe Darriet (2), Cornelis van Leeuwen (1), (3)
(1) Univ. Bordeaux, ISVV, UMR 1287 EGFV, INRA, 33882 Villenave d’Ornon France
(2) Univ. Bordeaux, ISVV, Unité de recherche OEnologie EA4577, USC1366, INRA, 33882 Villenave d’Ornon France
(3) Bordeaux Sciences Agro, ISVV, UMR 1287 EGFV, INRA, 33882 Villenave d’Ornon France
Email: pierre.helwi@bordeaux.inra.fr
Keywords: terroir, nitrogen, Sauvignon blanc, berry, wine, volatile thiols, methoxypyrazines, glutathione