D1 Canopy management

Question 1

Canopy management

Answer 1

Involves the organisation of the shoots, leaves and fruit to maximise grape yields and quality.

The aim is to
- maximise light interception
- provide shading
- ensure grapes ripen evenly
- Promote balance between vigour and yield of fruit
- ease mechanisation and manual labour
- promote air circulation to reduce pressure disease

Greater exposure to sunlight has different effect on style and quality:
1. greater bud fruitfulness (number of inflorescence developing inside a latent bud), key factor for next year yield.
1. increase sugar level through greater photosynthesis
2. decrease Tartaric and Malic acid
3. greater tannins accumulation and polymerisation (reducing bitterness),
4. breakdown Methoxypyrazine,
4. increase level of aroma precursor and compounds (such us terpenes, fruity floral aroma),
5. enhancing anthocyanin synthesis (development of colour)

Canopy management amend balance between vine’s vigour and its yields of fruit.
The balance depends on the vine’s growing environment (warmth, water, fertile soils)

If the vigour is too high compare to the yields of fruit, leads to vegetative status:
- green parts are favoured, hindering grape ripening.
- a dense, shady canopy increase pressure disease and hinder ripening.
- it reduces bud fruitfulness for the next year, leading to under cropping.

If the vigour is too low compare to the yield of fruit:
- the vine may use sugar from the carbohydrates stored in the trunk and roots, weakening the vine for the future years.

Question 2

Canopy management in vineyard establishment - Vine density, row orientation

Answer 2

When establishing a new vineyard the grower determine grape variety, rootstock vigour, planting density and row orientation.

The vine density is influenced by the vigour (influenced by the growing environment).
This influences the within-row spacing and the type of trellising system.

Between-row spacing also need to be considered, to prevent shading and allow machinery.

Row orientation:
- north-south provides the most sunlight exposure.
- The west side (exposed to the afternoon sun) may require more shading to avoid sunburn.
- Rows at a 90 degrees angle benefits from wind protection.
- Vineyard on slopes greater than 10% need to be planted up and down the slope or machinery may slip.

Question 3

Canopy management in vineyard establishment - Vine training, pruning

Answer 3

The method of vine training must be decided at vineyard establishment . This will depend on:
- The vine vigour
- The topography of the site: Slopes or windy sites vines are trained on individual stakes, rather than a wired trellis.
- The need for mechanisation: Trellis system and VSP are best suited for mechanisation as fruit tends to be in the same area. This is much more difficult in individual stake and bush vines.

Question 4

Canopy management in vineyard establishment - Pruning

Answer 4

Vine pruning is the removal of the unwanted part of the vine:

1. Winter pruning sets the number and location of buds that will form shoots, impacting yields.
   There are two types of winter pruning:
   - Spur pruning: Cane is cut back to only two or three buds. Apply to Cordon and Head trained vines. It’s easy and can be mechanised.
   - Replacement cane pruning: Cane is laid horizontally, has between 8 and 20 buds (needs tying to a trellis for support). Its require more trained labour.
2. Summer pruning keep the canopy well maintained, enhancing grape ripening, reducing chance of fungal disease.
   Technique include:
   - Disbudding: removal of buds, to manage vine balance and yields
   - shoots removal: to maintain an open canopy.
   - shoots positioning: to facilitate mechanisation.
   - Pinching: remove shoots tips at flowering to prioritise fruit set.
   - shoots trimming: to reduce competition between shoots and fruit, lower disease pressure through better air circulation and better spray penetration.
   - Leaf removal: to reduce shading and hence ripening. also lower disease pressure through better air circulation and better spray penetration.
   - Crop Thinning or green harvesting: removal of grape bunches to increase ripeness of those grape left (done when fruit ripening is uneven). Hence enhanced quality

Question 5

Canopy management in vineyard establishment - Trellising

Answer 5

Trellises are wires that support the vine’s shoots.

Untrellised vineyards (bush vines), usually head trained and spur pruned.
It is simple and inexpensive.
The shoots drops providing shade.
It is not suitable for mechanisation.
If the vigour is too high the canopy can become too dense and shade the fruit too much.
Humid and wet condition increase promote diseases.

Trellised vineyards maximise light interception, increase air flow (reducing risk of fungal disease), allow mechanisation. However is expensive to establish and need maintaining.
- VSP: shoots are trained vertically. Called Guyot trained when done on replacement cane pruned vines. Best for low to moderate vigour vines.
- Complex training systems: Optimum for high vigour vines. Split the canopy to reduce shade and maximise light. Geneva (split horizontally), Schott-Henry or lyre (split vertically)