Ch 6 - Vineyard Management Flashcards
(37 cards)
What is vine training?
Typically refers to the shape of the permanent wood of the vine. 2 categories: head training or cordon training. Either can be low-trained to benefit from heat retained by soil or high trained to avoid frost.
What is low training used for?
To benefit from heat retained by the soil.
What is high training used for?
To avoid frosts.
What is head training?
Vines that have relatively little permanent wood - some only have a trunk and some have short arms growing from top of the trunk. Can be spur pruned or replacement cane pruned.
What is cordon training?
Typically vines have a trunk with one or more permanent horizontal arms or cordons. Usually spur pruned. Takes longer to establish because of greater amount of permanent wood but sturdy permanent cordon with shoots positioned along its length makes mechanisation in vineyard like machine harvesting easier. Vines usually have 1 or 2 cordons but cordon trellising can be used to create big vine structures where shoots may grow from four or more cordons.
Why is pruning undertaken?
Removes unwanted leaves, canes and permanent wood. Shapes vine and limits size. Also aides canopy management. Takes place every winter and summer.
When is pruning particularly important and why?
Important in winter to determine number and location of the buds that will form shoots in the growing season. Important to make sure they aren’t close together. Helps with canopy management.
What are they types of winter pruning?
2 types of winter pruning: spur and replacement cane.
What is Spur pruning?
Spurs are short sections of 1 year old wood that have been cut down to two or three buds. They are either distributed along a cordon of permanent wood (cordon training) or around top or the trunk (head training).
What is replacement cane pruning?
Canes are longer sections of 1 year old wood - can have between 8 and 20 buds. Typically only 1 or 2 canes are retain and each is tied horizontally to the trellis for support. Mostly seen on head-trained vines. More complex than spur and requires large skilled labour force to choose suitable canes and train them. Aka guyot. One can is Single Guyot, 2 is Double.
What is Summer pruning used for?
Trimming the canopy to restrict vegetative growth and direct sugar production to the grape rather than the growth of shoots and leaves. Can involve leaf stripping to optimise grape exposure to sun.
What are untrellised vineyards and what regions are they best suited to? Why is it not suited to other regions?
Shoots hang down often as far as the ground aka bush vines. Typically head trained and spur pruned. Best in warm or hot, dry, sunny regions e.g. Southern Rhone and Barossa where extra shade helps protect the grapes. In cool or wet regions this shade can impede ripening and lack of airflow can promote disease. Not suited to mechanical harvesting.
What is Gobelet?
Like bush vines but the shoots of head-trained, spur pruned vines are tied together instead of allowed to fall to ground which helps expose the bunches to air and sunlight.
How does trellising work?
Each row of vines has a line of posts joined by horizontal wires - the canes and shoots are tied to the trellis aka canopy management.
Why might a vineyard use trellising?
The arrangement of young shoots can control amount of sunlight that gets into the canopy. IN regions with less light, keeping shoots apart opens the canopy to maximise exposure and aide ripening. IN those with intense light, keeping grapes shaded may reduce sunburn which could lead to off-flavours.
Open canopy can improve air circulation, important in wet climates because damp stagnant air can promote fungal diseases.
Finally, can aid mechanisation by positioning grapes in one area of the vines and leaves in another. Spraying of insecticides and fungicides is also more effective.
What is the most widely used canopy management system and how does it work?
Vertical Shoot Positioning (VSP) - can be used with replacement cane or spur pruned vines. Shoots are trained vertically and tied in place onto the trellis forming a single narrow canopy. Keeping shoots apart keeps the canopy open, well aerated and as shade free as possible. In hot regions with lots of sun, VSP can be adapted so the tops of shoots aren’t tied, but flop over to create some shade and protect the fruit.
Why might a producer choose VSP rather than untrellised bush vine?
Because mechanical harvesting can be used with VSP.
What might a grower do if the vineyard has limited water availability?
Limited water availability - areas with little water may benefit from low density so each roots can take up water from large volume of soil without competing against neighbouring vines.
What factors may impact the choice regarding yields in the vineyard? How are yields managed and measured?
Yields - there may be legal requirements limiting or proscribing yields. May have contractual obligations to winemaker. May predict yields from the number of buds left on vine after winter pruning but frost, poor fruit set, pests etc could reduce this. If yields are too high then can remove immature grapes shortly after veraison - aka green harvesting but this is risky because if done at the wrong time the vine will compensate by increasing size of the grapes left. Can dilute flavours in remaining grapes.
What might a grower do if the vineyard sees sufficient rainfall and has high nutrient content?
Many New World regions in particular offer the vine more nutrients than classic European regions - high density planting is not enough to limit the growth of vines so they use low density planting using vines with multiple cordons or canes. Often can produce good quality grapes at high yields - common in NZ.
What might a grower do if the vineyard sees sufficient rainfall and has low nutrient content?
Provided the vine has access to sufficient water it can thrive even in barely fertile soil. Left unchecked it could produce too much vegetation so vines should be planted at high density to provide competition for resources and restrict vegetative growth. Also important to ensure the vine has correct number of buds after winter pruning because if there are too few each will have access to too much energy - iff there are too many though they won’t get enough energy to ripen. If managed correctly, the combination of density and pruning makes open canopy easier to maintain with advantages it confers on fruit quality and disease control. Very common in many European Vineyards.
What are the main pests in vineyards? Describe how each may impact vines. What can be done to avoid/control each?
Phylloxera - attacks the foots underground and infects the vine which slowly weakens and dies. Use of american rootstocks which are resistant to phylloxera is common.
Nematodes - microscopic worms that attack roots of vines interfering with nutrient and water uptake. Can give viruses. Sanitising soil before replanting and using resistant rootstocks are helpful.
Birds and mammals - both consume grapes and half eaten ones can increase risk of fungal dsieas. Netting best option against birds - fencing against mammals like rabbits.
Insects - feed on grapes and leaves. May use insecticides or integrated pest management.
Describe downy and powdery mildew and their impact on the grapes.
Downy and powdery mildew - thrive in warm, humid environments and can affect all of the green parts of the vine including leaves and grapes. Causes loss of fruity flavours and can give mouldy, bitter taint.
Describe grey rot and its impact on grapes.
Caused by Botrytis cinerea and thrives in damp conditions. Attacks grapes and can taint flavours and lead to loss in colour of black grapes. For some white grapes this rot is good and can help produce sweet wines (noble rot).
