WINETECH Technical Yearbook 2021

PRACTICAL IN THE VINEYARD | DECEMBER 2021

INTRODUCTION There are basically two types of canopies, divided canopies and non-divided canopies. Non-divided canopies carry their grapes in a single bunch zone while divided canopies carry their grapes in two bunch zones. The purpose of divided canopies is to increase yield without compromising quality. It is however only suitable for more vigorous growing conditions with sufficient water and fertiliser as well as a strong-growing scion and rootstock combination. Where soils have weak growth potential and/or sufficient water is not available for irrigation, it is therefore not recommended. The objective with divided canopies is to prune more bearers per running metre of cordon, exposing more leaves to sunlight by dividing the canopy. The effectiveness of the canopy is thus increased, and the vine can ripen more grapes. Canopies can be divided vertically or horizontally. Examples of horizontally divided canopies include Lyre systems and Geneva Double Curtain. Examples of vertically divided canopies include Smart-Dyson and Ballerina, which will be the focus of this article. TRELLIS SYSTEM The correct trellis system is very important to accommodate the larger canopies. For both the Smart-Dyson and Ballerina

systems, class 3 posts have to be used. At least 2.1-m posts, but preferably 2.4-m posts. The posts have to be planted 60 cm deep and the cordon must be at least 90 cm above the ground to accommodate the drooping shoots. A minimum of two sets of foliage wires is required. The Ballerina system’s shoots sprawl downward and no wires are required under the cordon. For the Smart-Dyson, a foliage wire is required 30 cm under the cordon to keep the sprawling shoots in position. It is advisable to position this wire on the other side of the cordon wire on the post (as indicated in the illustration), so that the shoots that are positioned downward, do not snap easily when the wire is tucked in. A wider row width (2.7 m) is needed for cultivars that grow upright (for example Colombar) in the case of the Ballerina system. For the Smart-Dyson, the normal row width of the farm can be used. PRUNING Pruning also has to be adjusted for both systems: • Smart-Dyson – prune to approxi- mately 15 two-bud bearers per run- ning metre cordon. Ballerina – prune to approximately 20 two-bud bearers per running metre cordon. •

Shiraz Smart- Dyson – note

the good bunch distribution and canopy density.

HENNIE VISSER: Vinpro, Robertson and Klein Karoo KEYWORDS: Vertically divided canopies, yield optimisation. Divided canopies – Smart-Dyson and Ballerina

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