Effect of hedge shape for mechanical pruning of vinifera vines
The effect of hedge pruning Cabernet Sauvignon and Doradillo grapevines was examined for five years. The mature vines had previously been spur pruned on bilateral cordons and were hedged to square, offset rectangular or triangular shapes.
The yield and the capacity of hedged vines were equal to or greater than the manually pruned vines except in 1976, when the hedged Doradillo vines had lower yields than those manually pruned. Hedging increased yields compared to the control vines mainly through increases in the numbers of clusters.
Hedging had different effects on each variety. With Cabernet Sauvignon a triangular hedge initially had lower yields but in later years yielded more than the square and offset hedges. The increase in yield was due to an increase in the size of the bunches, as a result of an increase in berry number, compared to the other hedge shapes. The effect of shape on bud selection is discussed.
Machine pruning can increase the efficiency of pruning 40-fold so that one man can prune up to 400 ha (4 x 106 m2) of grapevines. Mechanical pruning of vineyards is rapidly expanding in Australia and in 1979 about 1000 ha (10 x 106 m2) were pruned by machines.