The Effect of Vine Spacing and Trellising on Yield and Fruit Quality of Shiraz Grapevines

The inter-relationship between vine spacing (1.5 to 4.55 m row and 1.5 to 3.05 m vine spacing) and trellis width (up to 2.25 m T trellis) was examined using vigorous Shiraz grapevines. This experiment showed that vine spacing and trellis can be manipulated to produce similar vineyard yields. The question arises whether vineyard yield is best achieved by greater numbers of less productive shoots at high vine densities or by fewer, more productive shoots at lower densities. High density plantings produced the greatest yield per hectare in the early years; however, within six years vines grown in wide rows with wide trellises were producing more yield per hectare. After six cropping years, there was only a 20% and 7% difference in cumulative yield between row width — trellis and vine spacing treatments respectively. Wider spaced vines required larger trellises for their increased capacity to be expressed. Close, evenly spaced vine canopies (1.5 to 2.25 m apart) produced the best yields per hectare. Reduced canopy congestion improved vine bud burst and yield per shoot. Vineyard systems to improve productivity are discussed.