Flashcards in Viti 3: Vineyard Management Deck (93)
Sandy soil with lots of rainfall:
Likely deficient in potassium, calcium and sulfur
Frequently cultivated, shallow soils with little rain:
Likely deficient in nitrogen
Calculation for planting density:
(Field of 1 ha) - Planting density = no. of rows x no. of vines in each row
Increasing total canopy area:
Narrow alley widths, maximises capturing of sunshine and serves as windbreak.
Important to remember about alley width:
Should never be narrower than the heights of the row canopy.
Such that you leave a shoot density of roughly 15 shoots per metre.
Vine orientation in cool climates:
N-S to maximise sunlight interception on both sides in autumn. SB theory of E-W (fruit and pyrazine flavour balance).
Main reason for adopting more complex trellising systems:
Vigour and disease control
'Bush vines' or 'gobelets'. Usually spur
-pruned. Can be cane-pruned to form 'baskets' like in Santorini. Offers bunch shading and low maintenance costs. BUT low yields, more prone to disease (air circulation) and all must be done manually.
Can be trained higher to simplify vineyard work, good air circulation. Crown (head) about 20-30cm above ground and 2-4 canes fixed to stake. Can also be spur-pruned without a crown and radiating in a circular shape. Issues: low yields due to lower density. Not suitable for high vigour sites.
Either cordon-trained, spur-pruned or head trained, cane-pruned. Relatively cheap and practical. Cordon: trunk division 15cm below wire. Head: crown below wire and 4 canes max of 10-15 nodes and 2-4 replacement spurs with 2 nodes. Issues: new shoots hang down and risk sunburn.
Called 'California sprawl' in mid-1980s when it was developed. One fruiting wire, one foliage wire above 0.3-0.5m. Machines can prune and harvest. More wires may be needed if canopy is big.
Vertical shoot positioning (VSP):
Canopy is non-divided. Involves moveable foliage wires. Developed for areas with high fungal infection risk, keeping foliage off ground and simplifying spraying and trimming. Can be cane-pruned (e.g. guyot) or spur-pruned (unilateral or bilateral). Shoots are uniformly trained, with all fruit in one zone and all shoot tips in another. Mechanisation possible and easy operations. BUT shoot density often high and risks shading.
1. Scott-Henry (Oregon, trials in NZ and Aus): involves two fruiting wires, one at 1m and one at 1.15m. Top shoots divided over two fruiting wires, bottom shoots one wire. Whole thing 2 meters tall and needs rows of 2m to stop shading. Machine harvestable and cane-pruned. 2. Scott-Dyson/ballerina (overtaken): cordon-trained with spurs pointing up and down with a canopy each. Machine harvestable.
60% more canopy, more photosynthesis. Shoot density halved (more ripening, less disease). Devigorating effect as half of shoots face downwards. BUT, tricky and expensive.
Geneva double curtain (GDC):
Horizontally divided with shoots facing downwards. Curtains at least 1m apart, shoots at least 1m in length. Best in vigorous soils, avoids shading. Spur-pruned by machine and machine-harvested. Devigorating effect. BUT, expensive and tricky.
Developed in France for medium/high vigour sites. Trellis divided horizontally with shoots trained upwards in two curtains. Machine pruning possible, special machines even made. BUT, middle of U must be kept open to expose fruit and leaves. Require constant trimming.
Mainly used in Argentina, Chile and Italy. Trunks about 2m high (tractors pass beneath), cane or spur-pruned. Needs framework, so expensive and rare. If vigour is high, good pruning needed to reduce powdery mildew and botrytis infection.
Planting new vines:
Summer, year 1: remove existing vegetation. Autumn, year 1: corrective fertilisation and deep ploughing. Spring, year 2: deep cultivation, tracing out and planting itself.
Why uproot trees instead of just cutting them down?
Because their roots might harbour fungal diseases. Need to be gathered and set alight. Can also leave field fallow for a year.
Water accumulating in dips can lead to...
Root asphyxiation and problems for passing machinery. Subsoil needs levelling and then topsoil replacing.
Breaking up subsoil:
Reducing erosion risk:
Planting trees/digging ditches above, making paths with guttering or planting along contours.
Using farmyard manure:
Used to lift organic matter level above 2%, to add structure and to contribute to humus.
Used to improve soil structure. Helps surface soil disperse and minimises sub-surface soil swelling.
Lifting soil pH:
Should come up to above 6.5. Calcite (calcium carbonate), magnesite (magnesium carbonate) or dolomite (mixture of both).
Alternative to disinfecting soil:
Leaving it fallow for 5-8 years.
If natural draining isn't sufficient:
Improve soil structure (manure, organic matter etc.), ditches, drainage pipes (perforated plastic), mole drainage (clay subsoil, no stones) and sub-soiling.
Why are vines planted down a slope rather than across it?
Because it aids mechanisation.
Over what percentage incline should terraces be considered?
20% - retaining walls also needed.