Ch 7: Canopy Management Flashcards
Bud Fruitfulness
The number of inflorescences inside a latent bud. Shady conditions are associated with reduced bud fruitfulness, with the bud producing more vegetative structures and less reproductive structures.
Canopy management
The organization of the canopy to maximize grape yield and quality. The primary aims are: maximize light and circulation, ensure that the microclimate is uniform so that the grapes ripen evenly, reduce shade, promote balance between vegetative and reproductive functions.
The effects of promoting sunlight within the canopy include
- Higher levels of sugar due to higher leaf surface area for photosynthesis.
- Increased tannin levels which are less bitter because of greater polymerisation
- Enhanced anthocyanin (color) development in black grapes
- Decreased malic acid
- Increased levels of some favorable aroma precursors and compounds (e.g. tarpenes > floral, fruity aromas)
- Decreased methoxypyrazines - responsible for herbaceous characters (Cab)
Vine Balance
Balance between the vine’s vigour (shoots and leaves), and its grapes. Vegetative vs. Balanced.
Vegetative Cycle
Low fruit yields can lead to a vegetative cycle, where too much shade leads to fewer grapes in the current season, as well as reduced fruitfulness of latent buds for next year’s harvest.
Yields
The measure of the amount of fruit produced, per vine or over a set area. The ideal yield is one in which the grape grower can grow the maximum yield of grapes with the structure and components needed for the quality and style of wine desired. Yields from an unbalanced vine, one which is either overcropped or undercropped, can lead to lower quality grapes. However, the yield at which the vine is balanced depends on the growing environment, the vine, and wine style. Therefore, some vines will be balanced at higher yields than others.
Winter pruning influences….
The number of shoots and potential yield for the upcoming growing season
Summer pruning is applied during the growing season to ….
Adjust vine balance and enhance ripening
Vine density
The number of vines per hectare. Consideration needs to be given to between-row spacing and within-row spacing, and depends on the vigour of the vine and trellising system. Wines with low vigour on a VSP trellised system can be planted close together, while wines with higher vigour may overlap if planted too close. In dry environments, vines may be planted with a lot of within-vine spacing so that the roots can expand in their search for water. For between-row spacing, vine height needs to be considered so that the vines do not shade each other, as does mechanization to ensure that farm equipment can fit in between the vines.
Row Orientation
The direction at which the vines are planted. Climactic and logistical concerns influence the decision. Climactically, vineyards planted in a north-south orientation get the most even exposure to sunlight. For wind protection, winegrowers may plant rows at a 90-degree angle to the wind direction. Practically, it is more efficient to plant rows parallel to the length of the vineyard.
Vine Training
Refers to the shape of the permanent wood on a vine. There are generally two types of training: head training and cordon training. In head training, the permanent wood consists of the trunk. In cordon training, the permanent wood consists of the trunk, and one or more horizontal arms, called cordons.
Cordon training
These vines typically have a trunk and one or more arms of permanent wood that grow out horizontally from the trunk. They are usually spur pruned, and take longer to establish than vine training due to the greater amount of permanent wood.
Head training
These vines have a trunk of permanent wood. They can be spur pruned, or replacement cane pruned.
Vine pruning
The removal of unwanted parts of the vine. Winter pruning is particularly important as it determines the number and position of buds in the following year and impacts the potential yield.
Spurs
Short sections of one-year old wood that have been cut back to 2-3 buds.
Spurs can be distributed along a cordon (cordon training) or around the top of the trunk (head training).
Spur pruning
Winter pruning technique that cuts back one-year old wood to 2-3 buds. It is easier than cane pruning and can be mechanized.
Replacement cane pruning
Winter purning technique where sections of one-year old wood is pruned down to about 8 to 20 buds, and tied to a trellis horizonally. It is more complex than spur pruning and requires skilled labor to select suitable canes for training.
Trellises
Permanant posts and wires that help support the position of the shoots.
Bush vines
Head trained, spur pruned vines that are not trellised.
Advantages: simple and easy to develop. Leaves can shade grapes. Often used in hot, sunny growing regions, like Prioriat to avoid sunburn.
Disadvantages: cannot be mechanized. If the vine is too vigorus, the canopy can become too dense and shade the fruit too much. In wet climates, a dense canopy can promote disease.
Vertical shoot positioning (VSP)
Positioning the shoots vertically to a trellis to form a single, narrow canopy. This maximizes sunlight, increases airflow, and helps with mechanization.
It is best suited for vines with low to moderate vigor.
Complex training systems
They split the canopy to reduce shade and maximize light for vigorous vines where the canopy would be too dense for VSP.
Can produce large yields of high quality fruit, but are difficult to manage and mechanize.
Disbudding
Removing buds that are poorly positioned or on non-fruitbearing shoots to manage vine balance and yields.
Summer pruning. Cannot be mechanized.
Shoot removal
Removing shoots that are infertile or poorly positioned (too close together) to maintain an organized, open canopy.
Summer pruning.
Shoot positioning
Tucking shoots into the trellis to organize the canopy and facilitate mechanization.
Summer pruning.
