Terroir 2004 banner
IVES 9 IVES Conference Series 9 The relationship between wind exposure and viticultural performance of Vitis vinifera L. cv. Merlot in a coastal vineyard (South Africa)

The relationship between wind exposure and viticultural performance of Vitis vinifera L. cv. Merlot in a coastal vineyard (South Africa)

Abstract

The South Western Cape of South Africa is exposed to strong southerly and south easterly synoptic winds during the growth period of the grapevine. The development of sea breezes in the afternoon is also a phenomenon associated with the ripening period of grapes cultivated in this coastal area. Wind is one of the environmental variables having the greatest spatial variation but the implications of regular exposure to wind for the performance of the grapevine has not yet been determined for vineyards in the South Western Cape. This study was initiated to meet this need.
The study was conducted in a hedge-trellised vineyard of Vitis vinifera L. cv Merlot with north east – south west row direction. Thirty experimental sites, each consisting of 14 vines, were identified as being exposed to wind or sheltered based on hand-held anemometer readings during the 2001/2002 season. Four stationary anemometers were strategically positioned between the thirty sites. Stomatal conductance and leaf temperature were measured with a PP systems porometer. Vegetative and yield measurements were performed during the 2002/2003 season. The t-test of equal variance was used to determine significant differences in measured parameters between exposed and sheltered grapevines.
Stomatal conductance and leaf area were significantly reduced by exposure to wind. This was associated with a significant reduction in the leaf area of primary shoots, related to shorter shoots, but a significant augmentation of secondary shoot leaf number and area. The number of bunches per vine and yield were also reduced for exposed vines. The berry potassium content was significantly increased for exposed grapevines.
This demonstrates that exposure to wind can result in significant within-vineyard, and potentially between-vineyard, variability in grapevine physiology, vegetative growth, yield and berry composition, with implications for wine style and quality.

Download the PDF

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

J.W. Pienaar (1, 2), V.A. Carey (1) & E. Archer (1, 3)

1) Department of Viticulture and Oenology, Stellenbosch University, Private Bag X1, 7602 Matieland, South Africa.
2) J.C. Le Roux, P.O. Box 184, 7599 Stellenbosch, South Africa.
3) Lusan Premium Wines, P.O. Box 104, 7599 Stellenbosch, South Africa

Contact the author

;

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

Spectral characterisation of fungal diseases on Vitis vinifera leaves

Aims: The aims of this study were to (1) detect alterations in the reflectance spectra of vines with fungal diseases, (2) map these alterations, and (3) determine the best wavelengths which may be used as early indicators of fungal diseases in vines.
Read More

Étude des potentialités des terroirs viticoles: une démarche globale en zone A.O.C. L’exemple des Côtes du Rhône

Depuis près d’une quinzaine d’années, l’Appellation d’Origine Contrôlée (A.O.C.) Côtes du Rhône a engagé un vaste programme afin de mieux connaître et valoriser les potentialités des différents terroirs qui la composent.

Read More

A fine-scale approach to map bioclimatic indices using and comparing dynamical and geostatistical methods

Climate, especially temperature, plays a major role in grapevine development. Several bioclimaticindices have been created to relate temperature to grapevine phenology (e.g. Winkler Index, Huglin Index, Grapevine Flowering Véraison model [GFV]).

Read More

IDENTIFYING POTENTIAL CHEMICAL MARKERS RESPONSIBLE FOR THE PERMISSIVENESS OF BORDEAUX RED WINES AGAINST BRETTANOMYCES BRUXELLENSIS USING UNTARGETED METABOLOMICS

All along the red winemaking process, many microorganisms develop in wine, some being beneficial and essential, others being feared spoilers. One of the most feared microbial enemy of wine all around the world is Brettanomyces bruxellensis. Indeed, in red wines, this yeast produces volatile phenols, molecules associated with a flavor described as “horse sweat”, “burnt plastic” or “leather”. To produce significant and detectable concentrations of these undesired molecules, the yeasts should first grow and become numerous enough. Even if the genetic group of the strain present and the cellar temperature may modulate the yeast growth rate¹ and thus the risk of spoilage, the main factor seems to be the wines themselves, some being much more permissive to B. bruxellensis development than others.

Read More

Global warming effects on grape growing climate zones within the Rioja Appllation (DOCa Rioja) in north Spain

Aims: The aims of this work were (1) to assess the changes in some of the main bioclimatic indices used for climate viticultural zoning within the Rioja Appellation area in the north of Spain between 1950-2014 (60 years), and (2) to carry out a comprehensive sociological evaluation among grapegrowers and winemakers of this region, to better understand the impact of climate change on their activity, their degree of concern about it and the potential adaptation measures they would be willing to adopt to cope with it in future years.

Read More