Canopy Management

Question 1

Key aims of canopy management (6)

Answer 1

• Maximise the effect of light interception by the vine canopy
• Reduce the shade within the canopy
• Ensure that the microclimate for the grape is as uniform as possible so that grapes ripen evenly
• Promote balance between the vegetative and reproductive functions of the vine
• Arrange the vine canopy to ease mechanization and/or hand manual labour
• Promote air circulation through the canopy to reduce incidence of disease

Question 2

The impact of canopy management on yield

Answer 2

• A vine canopy that is well exposed to sunlight has positive implications for grape yields in the next growing season, promoting a greater number of inflorescences developing inside the latent bud (bud fruitfulness)
• Maximizes the leaf surface area that is exposed to sunlight, increasing the vines photosynthetic capacity (compared to a dense and shaded canopy) and means it can ripen larger yields
• Good canopy management can also influence yield (and quality) by reducing fungal disease pressure. Due to poor air circulation, dense, shaded canopies dry out more slowly after rainfall or morning dew and provide suitable conditions for fungal diseases to develop

Question 3

The impact of canopy management on quality

Answer 3

• Increased sugar levels in grapes through greater overall photosynthesis in the vine
• Increased tannin levels and greater polymerization of those tannins, leading to less bitterness
• Enhanced anthocyanin (colour) development in black grapes
• Decreased Malic acid - warmer grape temp lead to more Malic acid broken down. Otherwise acidity levels would be unpleasantly high
• Increased levels of some favorable aroma precursors and aroma compounds (terpenes)
• Decreased methoxypyrazines, which give herbaceous characters in grapes, such as Cab Sauv.
• Reduce incidence of fungal disease and therefore has a implications for grape quality

Question 4

Impact of canopy management on black grapes

Answer 4

Without full ripeness, grapes would be unpleasantly high in acidity, hars tannins and unripe fruit will reduce the quality

By contrast, fully ripen grapes can produce wines with a good depth of clout, ripe fruit aromas and balancing acidity and ripe tannins

Question 5

Impact of canopy management on vine balance

Answer 5

Achieving a suitable balance between the vines vigour and crop loads is essential for successful grape ripening and sustained production over future growing seasons.

The optimum crop load is one that allows the grape grower to grow the maximum yield of grapes that have the required composition for the desired wine style and quality

Question 6

Canopy management techniques (6)

Answer 6

Canopy management should be a key consideration when establishing a vineyard. Choices regarding vine density will affect the vine training and trellising, and therefore these all need to be decided before vine planting.

• Site assessment to determine the ideal variety, rootstock, planting density and row orientation
• Vine training
• Winter pruning
• Vine trellising
• Overall plant vigour management (nitrogen fertilization, irrigation, cover cropping)
• Summer pruning

Question 7

Summer pruning techniques (6)

Answer 7

• Shoot removal
• Shoot positioning
• Pinching
• Shoot trimming
• Leaf removal
• Crop thinning / green harvesting

Question 8

Vine density (in row spacing)

Answer 8

The number of vines that are planted per hectare of vineyard.

The optimum vine density is influenced by:

• The vigour of the vine (influence by natural resources and planting materials)
• Type of trellising system used and what access is needed between the vines

Vines that are low in vigour and VSP trained can be planted very close together within the row as the individual vines are relatively small.

Vines that are high in vigour would need greater within row spacing to grow an be in balance. Planting these vines too close tighter could lead to overlapping canopies and increased shading, reducing ripeness and quality

Vines grown in dry climates without irrigation may also be plated a low density, so that the roots can spread out, without competition from otters vines, in search for as much water as possible

Question 9

Vine density (between row spacing)

Answer 9

Vine rows should be planted far enough apart so that one row does not shade the next. Therefore, vigorous vines that are high-trained and trellised need greater spacing between the rows.

The width of any machinery that might be used should also be considered wen planning between row spacing

Question 10

Row orientation

Answer 10

Depends on climatic and logistical factors

Generally considered that a north-south orientation provides the most even sunlight exposure through the canopy. However, because conditions in the afternoon are usually warmer than those in the morning, grape bunches on the west side of the canopy may require more shading from leaves to protect them from sunburn.

From a logistical standpoint, vineyards on slopes at an angle of greater than 10% need to be planted up and down the slope rather than across. Otherwise machinery may slip, unless the vineyard is terraced

Question 11

Vine training and trellising method will depend on:

Answer 11

Vigour of the vine:
Depends on natural resources, planting material and the presence of any diseases

The topography of the site:
Many trellising systems can not be used on steep slopes or windy sites

The need for mechanization:
Certain training and trellising systems are more suited to mechanisation than others

Question 12

Vine training

Answer 12

Refers to the shape of the permanent wood of the vine, there are two types; head training or cordon training

Either system can be low-trained or high-trained:

Low trained vines benefit form heat retained by the soil and provide greater protection from wind

High trained vines better avoid firsts or make manual interventions such as harvesting easier

Question 13

Head training

Answer 13

These vines have relatively little permanent wood, permanent wood consist of the trunk, and sometimes with a few short subs growing from the top of the trunk.

They can either be spur pruned or replacement cane-pruned

Question 14

Cordon training

Answer 14

These vines have typically have a trunk and one or more permanent horizontal arms of permanent wood (cordons)

Usually spur pruned

Cordon training takes longer to establish than head training due to the amount of permanent wood

Question 15

Vine pruning

Answer 15

The removal of unwanted part of the vine. Takes place in the winter and summer. Winter pruning is very important as it determines the number and location of buds that will form shoots in the next growing season.

Two types of pruning

• Spur pruning
• Replacement cane pruning

Question 16

Spur pruning

Answer 16

Spurs are short sections of one year old wood (from the last growing season) that have been cut back to only two or three buds.

They can either be distributed along a cordon (cordon training) or around the top of the trunk (head training).

Spur pruning is easier to carry out than replacement cane pruning and can often be mechanized

Question 17

Replacement cane pruning

Answer 17

Canes are longer section of one year old wood and can have anything between 8 to 20 buds.

They are laid down horizontally and need tying to a trellis for support and positioning. Its complexes than spur pruning and requires skilled labour

The number of buds left on the vine will depend on the vigour of the vine, with more buds left on for more vigoures vines. Thin influences the number and size of shoots in the next growing season.

Question 18

Trellising

Answer 18

Trellises are permanent structures that help to support and piston the vines shoots

The vines tendril will naturally curl around the trellis and help to keep the canopy in place. The grape grower will also tie in branches and shoots to the trellis as necessary

Question 19

Untrellised vineyards

Answer 19

In some regions vines may not have a trellis.

In most cases these vines are head trained, spur pruned and called bush vines.

The benefit is that this system is simple, easy and inexpensive to develop. The shoots may also droop down providing shade for the grapes.

Usually planted in hot and sunny regions, such as La Mancha in Spain, so the shade can be beneficial to avoid sunburnt grapes.

A potential disadvantage is that it is not suitable for mechanization.

Best suitable to vineyards with dry condiments, which restricts the vigour. If the vine is too vigoures, the canopy may become too dense and shade the fruit too much. Wet conditions could also promote the development of disease in a dense canopy.

Question 20

Trellised vineyards

Answer 20

Trellised vineyards are very common

Advantages:

• Shoots can be spread out to maximize light interception
• Increase air flow, reducing risk of fungal disease
• Allows mechanization

Disadvantages;
- Expensive to establish and need maintaining

Question 21

Vertical shoot positioning (VSP)

Answer 21

Most common trellising system

Can be used on both head-trained, replacement cane-pruned vins and cordon-trained spur-pruned vines.

When used on replacement cane-pruned vines it is typically called Guyot training (single/double). Soots are trained vertically and are held in place onto the trellis forming a single narrow canopy. Best suited to vines with low word moderate vigour.

Question 22

Complex training systems

Answer 22

Vines that are vigors can produce a lot of shoots and ripen high yields of fruit. If trellised VSP the canopy can be too dense, resulting in too much shading of the fruit

Complex training systems have been invited to split the canopy to reduce the Sade and maximise light interceptions:

Geneva Double Curtain (GDC) or Lyre; The canopy is split horizontally

Scott-Henry: The canopy is split vertically

These systems make it possible to make best use of vineyard space and resources to produce larger yields or high-quality fruit, but they are more difficult to mange and mechanise

Question 23

Summer pruning

Answer 23

Includes a variety of technique to keep the canopy of the vine maintained.

Aimed to enhance grape ripening, reducing chance of fungal disease or making the vineyard easier to mange.

Except for pinching, these techniques can all be mechanized if the vineyard is appropriately set up, and this is becoming more common in areas where skilled labour is difficult to find

Question 24

Disbudding

Answer 24

The removal of buds to manage vine balance and yields, and to remove buds that are poorly positioned.

Growers will often leave a high number of buds on the vines at winter pruning in case buds are damaged early in the growing season (spring frost)

Disbudding in the late spring an be sued to adjust the number of buds to bring the vine into balance, and where necessary comply with grape growing regulations.

Also a chance to remove poorly positioned buds (those facing downwards or too close together) and to remove buds of non fruit baring shoots, which may compete with the grapes for sugar and other resources

Question 25

Shoot removal

Answer 25

The removal of shoots, often laterals, that are infertile or poorly positioned will help to maintain a well organized, open canopy

Question 26

Shoot positioning

Answer 26

Shoots are tucked into the trellis wires to better organize the canopy and facilitate mechanization

Question 27

Pinching

Answer 27

The removal of shoot tips at flowering to improve fruit set

Question 28

Shoot trimming

Answer 28

Cutting shoots to most growth and reduce canopy thickness enhance fruit ripening by reducing competition for carbohydrates between the shoot tips and fruit, and lowers disease pressure through better air circulation

Question 29

Leaf removal

Answer 29

Removing leafs to reduce shading of fruit and hence enhance ripening, will also lower disease pressure through better air circulation and improves spray penetration.

However, in warm dan hot climates, excessive removal of leaves can expose the grapes to too much sunshine and heat and lead to sunburn

Question 30

Crop thinning or green harvesting

Answer 30

The removal of bunches of grapes to increase ripeness of those grapes left on the vine. If this process is timed near veraison, it can enhance ripening.

If fruit ripening is uneven (uneven budburst, frost) the least ripe grapes bunches may be removed to improve uniformity of ripening, and hence enhance quality