Conventional viticulture relies on herbicides to prevent the growth of competing vegetation under the vines. There is a drive within the industry, particularly in New Zealand, to increase sustainability, and therefore a nonchemical option to deal with under-vine vegetation would be of great benefit. A very limited number of studies have considered the impact of under-vine management practices on the aroma profiles of wine. The effect of three different under-vine management approaches (mowing, cultivation and herbicide) on vine performance, soil properties and aromas of Sauvignon blanc and Pinot noir grapes and wines were considered in a commercial vineyard in Blenheim, New Zealand. A full factorial randomised block design was developed and vine performance (i.e., trunk circumference, leaf area, point quadrant analysis (PQA), midday stem water potential, petiole analysis, and leaf gas-exchange), basic fruit compositional parameters (pH, TSS, TA and berry weights) and wine aroma profiles were compared in the three treatments. There were few differences in vine physiological parameters and canopy measurements, suggesting that the mowing and cultivation do not lead to under-vine weeds greatly competing for either water or mineral nutrients. Yield and fruit composition were not significantly affected by the treatments, indicating that ripening was not impaired by the nonchemical options. Wines made from mowed treatments showed lower pyrazine concentrations and lower 3MH and 3MHA concentrations in the Sauvignon blanc wines. These data show that nonchemical methods to control under-vine vegetation are a viable option, as they do not negatively affect the vines and are able to affect the flavor and aroma of the resulting wines. This adds a tool for viticulturists looking for a sustainable under-vine management option and allows them to tailor the composition of the fruit as it develops in the vineyard.

Under-vine management to modulate wine chemical profile

248th National Meeting (2014)

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