NH - Unit 2 - Vineyard management - Pruning and training Flashcards
What happens in un-pruned vines?
- they produce many short shoots further and further away from thee trunk
- these shoots provide irregular yields with many small bunches of high-acid, sugar-low berries
What are desirable objectives of pruning?
- To overcome the vine’s natural tendencies, and force it to produce more suitable fruit
- To help organise the plant on the trellis
- Heavily pruned vines => fewer shoots => fewer leaves => reduced photosynthetic capacity => reduced vine vigour
- young vines => prune lightly, flower removal
- older vines => lightly pruned vines decrease in vigour by increasing fruit production
To achieve quality fruit, there must be :
- an appropriate balance between the level of crop and the leaf area on each shoot
- The number of flowers (later bunches - level of crop) on the vine shoot is determined in the previous year according to conditions at flower initiation
- The size of each shoot (leaf area) is determined at pruning => the more buds left on, the weaker their individual vigour
- more shoots have to share the limited amount of winter reserves and the capacity of the plant’s root system
What is the effect of a heavy of too low crop on the quality of the fruit?
- a heavy crop on short shoots will lead to over-cropping
- high yields of low quality fruit
- weekens the vine the following year
- shoots that have a disproportional low crop will be over-vigourous
- cary on growing after véraison
- detriment of the quality of fruit
- large leaves and laterals
- canopy shading
What is the advantage of helping to orgnanise the plant on the trellis by pruning?
- plant can capture the maximum amount of light (important in cool climates)
- Leaf bunching is avoided
- reduces disease risk
- increase yield and quality
- Bunch ripening is better synchronised
- personel and machines can pass along the alleys without causing damage
- mechanical operations such as spraying and harvesting are more efficient ande effective
What is an ideal canopy?
Ideal canopy is homogenous along the row (15 shoots per metre) with an average leaf thickness of 1-1.5 leaves
How is vine vigour measured?
vine vigour is measured by weight of wood produced each year
What is a the “ideal” balance between fruit and leaf
- a shoot with moderate yiel
- a pencil thick shoot
- 12-15 nodes long with
- inter nodal length of 60mm.
- This should weight approx 30-40g in winter
What is the charge?
The number of buds to be left during winter pruning
How do you calculate the charge?
Count the number of ideal shoots produced in the previous growing season (small shoots may count as half, larger as 2 of 3)
Or
Remove the canes, weigh them then divide the weight by 30-40
How can the charge be affected by vine age?
- In vines less than 8 years old the charge is increased significantly
- in older vines it is increased by 5-15%
- to compensate for non breaking buds caused by winter injury
What is canapy management and what is the aim?
The organisation of the shoots, leaves and fruit of the grapevine to maximise the quality of the macroclimate of the leaves and fruit.
The aim is to improve quality and yield and to minimise disease risk.
Where is canopy management in particular important?
- In cool-climate regions and in the New World
- improvements in vine management
- planting of the vines on fertile soils
- => have exacerbated the problem of high vine vigour in fertile soils
What are the main aims of canopy management?
- to maximise the effectiveness of light interception
- to reduce canopy shading, particularly in the fruiting cluster / renewal zone
- to produce a uniform microclimate for fruit
- to achieve an appropriate distribution of the products of photosynthesis
- to arrange the locations of individual organs in restricted zones in space
How does canopy management maximise the effectiveness of light interception in vine canopies?
- By presenting a large canopy surface to the sun
- Encouraging early development of that canopy in the spring
- avoiding inter-row shading by having a maximum ratio of canopy height to alley width of 1:1
Wjy is the reduction of shading in the fruiting cluster / renawal zone important in canopy management?
In highly shaded leaves, the rate of respiration outstrips that of photosynthesis => the leaf consumes rather than produces energy.
Shade reduses the viability and succes of floral initiation in dormant buds => causing an imbalance between leaf area and fruit weight
Shaded flowers have lower rates of successful fertilisation and fruit set
Shaded berries keep cooler and so do not ripen as well as in cool climates
Shaded fruit has lower quality flavours and colours (some of the biochemical reactions that produce these are stimulated by sunlight
Shaded fruit and leaves have far greater risks of contracting fungal diseases, espacially powdery mildew and grey rot.
What are the benefits of uniform microclimate for fruit produced by canopy management?
- it leads to more synchronised ripening
- it also leads to a greater chance of picking at the optimum period
Why is the appropriate distributionof the products of photosynthesis achieved by canopy management so important?
- too much fruit and not enough leaves (overcropping) will generate poor quality fruit and reduce vine vigour
- conversely, too many leaves and not enough fruit will cause over-vigour growth, which will also produce poor quality fruit
Why is the arangement of the locations of individual organs (trunk, canes, shoots, leaves and fruit) achieved by canopy management so important?
- this facilitates mechanisation, particularly in pruning, pesticide application and harvesting
How is diagnosis done in canopy management?
- By measuring the quality of vine canopies when the grapes are ripening
- look out for :
- the leaf layer number (roughly, the thickness of the canopy)
- the percentage of exposed grape clusters
- leaf size and colour
- the presence of lateral shoots
- the percentage of shoot tips that are still actively growing
Who is Dr. Richard Smart?
a leading Australian viticulturist
how and what should be assessed before prescribing a canopy management technique
* the potential fertility of the site by digging up a soil profile
- Water supply
- Soil fertility tests
- Performance of vines on similar soils
* the vigour of the vine
How does Smart class the sites?
In 3 categories :
- high potential
- medium potential
- low potential
Describe a high potential site :
High vigour
deep soils usually 1m+
Fertile
Good water supply
High nutrient levels
What are the different views for planting density on high potential sites?
View 1 :
- Low density planting (> 3000 vines / hectare)
- complex big vine trellis systems suggested (Ruakura twin two tier or Geneva Double Curtain)
View 2 :
- High density planting (e.g. Mount Etna, Adelaide Hills)
- to promote competition to reduce vigour
- if not dense enough => vigour not restricted sufficiently => large canopies that tangle and shade neighbouring vines
Describe a medium potential site :
Medium vigour
Soils 0.5 m-1 m deep
Adequate water supply
Average fertility
require average plant density 3000 - 5000 vines/ha
large VSP, Lyre, Scott-Henry recommended
Describe a low potential site
Low vigour
Soils less then 0.5m deep
Poor water availability in the season
Low fertility
High planting density 5000+ vines/ha
Ordinary VSP (single or double guyot or cordon)
- if there is sufficient water to meet the vine’s needs
- In arid condition water availability will be limiting factor of vine vigour over soil fertility => thus very low density planting
Excessively low vigour is genarally due to :
How can it be solved?
- Drought stress (solved by irrigation)
- Low soil fertility (solved by increased fertilisation, drainage, addition of soil organic matter etc.
- Disease (solved by diagnosis and treatment)
How can excessive vigour be controlled
- selection of low vigour rootstock
- Increase water stress
- cover cropping (dekgewas)
- High density planting
- Removal of alternate vines increasing vine length and reducing shoot vigour and canopy density
- Root pruning
- Retro fitting a more complex trellis system
- Pinching (removal of shoot tips around flowering)
- Shoot positioning, trimming
- Leaf stripping
- Crop Thinning
- Green harvest
Explain root pruning
- a sub-soiling tine is passed through the vineyard at 30 - 50 cm from the vine row after harvest or pre-burst
- difficult to predict the response => pruning will stimulate root growth
Explain pinching :
- a strategy for excessively high vigour
- the selective removal of shoot tips around flowering
- usually done manually
- aims to make uniform shoot growth
- improve berry set
- In vigourous vines, this leads to an increase in the development in lateral shoots => have to be removed
What is the second most costly manual intervention in the vineyard
Winter pruning
What are the two common forms of pruning?
- replacement-cane (guyot)
- spur pruning (cordon)
Explain minimal or zero pruning :
- used for Thompson seedless table grapes (Australia)
- have reduced shoot growth and begin to self regulate
- the produce higher yields => suited to warmer climates
- a large amount of permanent woord develops over a number of years => has te removed now and then
Explain replacement cane system
- Popularised in the 1860’s by Jules Guyot
- a cane pruned system with one or more spurs
- Cane buds grow into shoots that produce the yield in the following season
- Spur buds produce next years canes
- preventing the vine frow sprawling too far along the trellis
- Choice of single or double Guyot
- choice is usually down to vigour or laws
- Has to be carefully pruned
- straight trunk
- crown wel positioned in relation to the fruiting wire
- remove badly positioned shoots when they grow
- all flowers should be removed from the least vigourous young vines untill they establish themselves
What are the advantages of replacement-cane pruning?
- By limiting the carbohydrate reserves, the vine’s vigour is kept under control
What is the disadvantage of replacement-cane pruning?
- winter pruning requires great skills
- can not be mechanised
When pruning replacement cane vines, how do you select the spur and cane?
- The spur should be selected first
- not too low under the crown
- nearer the roots than the cane
- pointing allong the row, not the alley
- the cane selected so that
- further from the roots than the spur
- should be able to be tied down (bowed)
- so it doesn’t protrude into the alley
- so it does not invade the neighbouring vine’s trellis space
- buds should be spread evenly along the trellis
What is “pendelbogen” and why is it used?
- Canes that are tied down in the shape of an arch
- to regulate shoot vigour along their length
- vines will grow more vigorously at their extrimities
- buds at the ends of canes furthest from the crown wil tend to break first and produce the most vigourous shoots
- the longer the cane, the greater the difference in vigour between shoots
- leading to uneven canopies
Explain spur pruning without a cordon
- head pruned: spurs that are distributed around the head
- bush vines or gobelet vines (if shoots are tied together at the top)
What are cordon / spur systems?
- Systems where the cane is left permanently attached to the fruiting wire so that it becomes a permanent cordon
- The canes coming of these cordons are then spur-pruned
- The shoots arising from these spurs can be trained either upwards or downwards
What is the most common cordon system?
Cordon the Royat
- a single or double horizontal cordon
- shoots then vertically trained
Give examples of cordon / spur pruned systems
- Cordon de Royat
- Sylvoz, Lenz - Moser systems
- “big vines” trellising systems (Geneva Double Curtain)
What are the advantages of cordon systems?
- Easier to prune
- can be pre-pruned mechanically
- retain a larger volume of permanent wood than replacement-cane systems
- Can help provide necessary carbohydrate systems
- => is important if bud breaks occurs while frost is still a risk
What are the disadvantages of cordon / spur pruning?
- larger carbohydrate reserves also enable the vines to be more vigorous than in replacement cane systems
- the loss of growing points along the cordon
- can be minimised by keeping cordons shorts, pruning according to charge
- If this fails => cordon will have to be replaced
- the lenghtening of growing points
What points should be considered when pruning concerning wood?
- wood retained should be in good state of health
- look out for spotting due to botrytis, powdery mildew, phomopsis, poorly ripened woord
- Canes with deformities shouldbe eliminate
What points should be considered when pruning buds?
- buds on canes formed in the previous year are the most fruitful
- if vine is pruned severely, old buds on the trunk will break
- the embyonic flowers within these will have degenerated
- will produce little fruit
What points should be considered when pruning concerning pruning cuts?
- if large cuts have to be made
- leave a stump that can be cut back the following winter
- unwanted canes must be cut back to old wood
- => surviving basal buds will turn into watershoots
What points should be considered when pruning concerning timing?
- earlier pruning ecourages earlier budburst
- increases risk of spring frost damage
- delayed pruning delays budburst
- avoids spring frost risk
- when left too late
- => when buds start breaking => takes longer to tie down the canes => many young shoots may be damaged
What do you do with pruning waste?
- can be collected and used as fuel or mulched in the alleys
- can increase the humus levels in the soil
- diseases (eutypa, blackrot) can overwinter on canes
- then burn pruning waste
What are the aims of summer training (Trimming off shoot extrimities)
- to control excessive shoot growth
- facilitate the passage of manpower and machinery
- reduce inter-row shading and winddamage
- Reduces canopy thickness to improve the micro-climate and spray penetration
- encourage the onset of maturity
- descouraging shoot growth
- stimulate berry development
- Aesthetics of the vineyard
What is the timing of summer training?
starts in July (northern hemisphere)
not too early, not too severely
What is shoot positioning?
Shoot removal
Bud rubbing
Tucking in
When should shoots be removed?
If they are:
Badly positioned (and would have to be removed at winter pruning anyway)
In contact or close to the ground
Rootstock shoots
Causing too much canopy shade (especially in the renewal zone)
When do you carry out shoot removal?
Summer trimming should take place after spring frosts but before flowering
What is the target shoots per metre in summer trimming
15 shoots per metre
How long does shoot removal take when done by hand?
17 - 50 hours / ha
What is bud rubbing?
Bud rubbing is the removal of the shoot before it has had chance to grow
What does the act of tucking in do?
- Aims to organise the canopy
- Helps to facilitate mechanisation
- important in upright canopies
- without it => shoots bunch together => flop to the ground => preventing the passage of machinery
- also important in downward-growing canopies
- shoots will resist growing downwards and form irregular canopies
- can be done by hand, using moveable wires
- can be done by machine
Explain the process of leaf stripping
- removal of leaves around the fruit zone
- done between véraison and harvest
- manually or by machine
- to improve the canopy microclimate
- improves fruit quality
- improves fruit health
- to improve spray penetration
- increase the speed of manual harvesting
- can take up to 70 hours / ha
