Long term influence of a cover crop in the agronomic and oenological performance of CV. Chardonnay

Abstract

Context and purpose of the study- Cover crops are acknowledged to be an interesting tool to produce higher quality grapes in red varieties, as they generally reduce vine vigour and yield. However, their incidence in white wine quality is not clear, since higher nitrogen availability can play an important positive role, and cover crops may compete for this nutrient. The possible reduction in available nitrogen can also modify the fermentation processes, as well as the synthesis of aromas in the wine. The aim of this work was to evaluate the long-term effect of a grass cover crop on grape and wine quality.

Material and methods – The study was conducted in a cv. Chardonnay vineyard located in Otazu (Navarra, Spain). During the 10 years prior to the experiment, the vineyard had been managed with a Festuca arundinacea and Lolium rigidum cover crop. In order to evaluate its incidence, at the beginning of the experiment, part of the rows were tilled, and the agronomic and oenological performance of both soil management strategies compared, with a detailed evaluation of the effects on must and wine amino acids.

Results – After 5 years of evaluation, the presence of the cover crop was shown not to affect yield, cluster number or berry weight, but it decreased pruning wood weight and leaf nitrogen content. Regarding grape composition, no differences were observed in terms of sugar content, pH and titratable acidity but covercropped vines produced grapes with lower yeast assimilable nitrogen and amino acid