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
