Vine spacing of <i>Vitis vinifera</i> cv. Shiraz/101-14 Mgt II. Establishment, and vegetative and reproductive growth

Abstract

Knowledge of vine growth reaction to plant spacing under relatively high potential soil conditions is limited. This study aimed to determine the effects of vine spacing (with fixed row spacing) of Shiraz (clone SH 9C)/101-14 Mgt on a relatively high potential soil in the Breede River Valley, Robertson, South Africa on establishment and training labour, aboveground growth, and yield. The vineyard was planted in 2008 to a Vertical Shoot Positioning trellis, a fixed row spacing of 2.2 m and row orientation of approximately NNE-SSW (30 °). The 15 in-row vine spacing treatments changed from 0.3 - 4.5 m with increments of 30 cm (from 15151 – 1010 vines/ha). Results were generated over six seasons after cordon development was completed. Grapes were harvested at two ripeness levels. Clear groupings were evident for establishment and further training management. Total costs showed trends with an optimal of around 1.8 m vine spacing, but were markedly higher for closer spacing. Canopies developed uniformly with cordon extension. General vegetative growth (over treatments) varied according to seasonal conditions. Individual leaf size was higher for more closely spaced vines. Total vegetative growth parameters mostly showed increasing and decreasing trends on a /vine and /ha basis, respectively, with an increase in spacing. Yields showed a general increase with wider spacing on a /vine and /ha basis. Yield:cane mass ratios displayed an increasing trend from narrow to wide vine spacing, as did fertility and bunch mass. The bunches from the narrowly spaced treatments seemed more compact. Growth and yield parameters showed very clear trends reaching an optimal at around 1.8 m vine spacing. The results of this study can be applied in vine spacing selection and sustainability strategies for different terroirs. Comprehensive guidelines for extrapolation to different growth conditions and terroirs are provided.