SPRING AND SUMMER MANAGEMENT PRACTICES FOR TABLE GRAPES Andrew Teubes Viticultural Consultant
In this presentation Importance of shoot thinning Importance of sunlight penetration into the vine canopy Summer shoot management practices Effects of poor canopy management
Importance of sunlight penetration Fruitfulness (grape yield potential) is dependent on Sunlight penetration into canopy during spring and early summer Temperature during early spring and summer Reserve status of the vine (health and vigour) Nitrogen supply Nutrient status Cane maturation during late summer and autumn
Bud fruitfulness of Thompson Seedless (White Kishmish) canes as a function of bud position Number of clusters per node 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 SUN SHADE 1 2 3 4 5 6 7 8 9 10 11 12 Node position on cane
Importance of correct pruning Creates optimal spacing of spurs and canes Adequate area for growth of shoots Balance the bud load for the vigour of the plants
CORRECT SPACING: SPUR PRUNING 12-15 cm
CORRECT SPACING: CANE PRUNING
Shoot thinning Removal of excessive green shoots from the canes/spurs after bud break Canes: Single shoots 10-12 cm apart Spurs: 2-3 shoots 12-15 cm apart Shoot length 15-20 cm long ideal Remove any double shoots Shoot removal/thinning must be done early in the season Saves valuable time Very important for long term fruitfulness
SPUR PRUNING Shoot thinning by hand
Suckering of excessive shoots to maintain adequate sunlight penetration SPUR PRUNING Shoots removed No shoots removed XX
Spacing between spurs result in good sunlight penetration and spacing of clusters 12-15 cm
CANE PRUNING Shoot thinning at 15-20 cm shoot length Before thinning Ideal spacing is 12 cm Between shoots on the cane After thinning
Before thinning CANE PRUNING Shoot thinning at 15-20 cm shoot length Remove double shoots After thinning
Effects of spring suckering on certain measured parameters of Chenin blanc (1977/78 and 1978/79 seasons) (Stellenbosch, South Africa) (2.5 x 1.2 m spacing) Measured parameters Control (no sucker) Sucker all shoots without clusters Sucker to 3 shoots per spur Sucker to 2 shoots per spur Clusters per vine before sucker 33 37 46 49 Clusters removed per vine 0 0 14 24 Shoots per vine before sucker 49 55 51 51 Shoots removed per vine 0 27 31 35 Yield (kg/plant) 6.72 6.36 6.24 6.42 Yield (gram/shoot) 204 227 312 401 Shoot mass (kg/ha) 3390 2750 2870 3070 Harvest tempo (man hours/ha) Pruning tempo (man hours/ha) 209.6 216.7 198.9 186 103.5 77.4 61.2 48.2
Sunlight penetration ideal after early season shoot thinning
Shoot receiving enough sunlight Poor sunlight exposure resulting in leaf orientation towards light Healthy canopy Canopy too dense
Removal of lateral shoots and leaves around clusters Strong lateral shoot development Clusters hanging freely
Tipping and topping of shoots Ideal shoot length 110-120 cm Canopy before tipping Canopy after tipping
1 Management of the I-trellis 2 3 4 Shoot tipping 40 cm above top wire
Use of shade patterns to evaluate density of canopy Too dense Ideal Shade patterns reflect canopy density (30% sun spots ideal)
Canopy formation Bunch zone Good spacing of shoots
Cluster position on I-trellis
Results of poor canopy management of I-trellis Yellow leaves develop due to too dense canopy Shoots falling over because it was not tipped early enough Leaves shaded, no activity
Which system is properly managed?
Clusters well spaced, not touching each other on spurs Note complete lignification of shoots
Well spaced clusters on canes
Well spaced clusters on canes on T-trellis Good sunlight penetration
Good sunlight penetration on T-trellis Note sunlight penetration
Results of poor sunlight into canopy Poor spacing of spurs = No sunlight in canopy Low yield Poor quality
Effects of poor pruning and canopy management Unproductive leaves Poor ripening of shoots Poor maturation of canes Small crop Dead canes in winter
Too dense canopy cut open too late result in sunburn Clusters very sensitive too direct sunlight
Effect of canopy density on crop yield Treatment Canopy density** Radiant energy µε m -2 s -1 Berry mass (g) Bunch mass (g) Yield per vine (kg) Ideal sunlight 3,36 40,7 1,09 125,4 4,62 Dense canopy 7,20 24,7 0,81 104,7 3,47 Very dense canopy 9,58 3,6 0,63 77,2 2,44 ** Canopy density: Number of leaves between cluster and outside of canopy Increase in canopy density and corresponding shade stress: Decrease in radiant energy in bunch zone Decrease in berry mass Decrease in bunch mass Decrease in yield per vine.
Effects of canopy density on cluster size Bunch in high density canopy Bunch in medium density canopy Bunch in ideal density canopy
Summary of viticultural practices from bud break to harvest Physiological stage Viticultural practice 10-20 cm shoot length Shoot thinning 10 cm between new shoots on canes 12-15 cm between shoots on spurs Remove any double shoots Before bloom Removal of lateral shoots in cluster zone Removal of leaves around clusters After fruit set Before berry softening Tipping of longest shoots at 110 cm shoot length Crop control if required (25-30 clusters maximum/vine) Remove all shoots with clusters on inferior shoots Removal of any new leaves around clusters Before harvest Tipping of shoots again at 110-120 cm shoot length to maintain adequate sunlight
Summary Importance of early season shoot thinning Shoot orientation for maximum sunlight interception Removal of lateral shoots and leaves around bunches on T-trellis Removal of lateral shoots and leaves on I- trellis depends on canopy density Top shoots before they become too long