D1: Viticulture - from PS Hill Flashcards

1
Q

What are the key vine species, their origin and their primary use?

A

Eurasian, predominantly for grape production:
- Vitis vinifera

North America varieties, predominantly for rootstock:

  • Vitis labrusca
  • Vitis riparia
  • Vitis berlandieri
  • Vitis rupestris
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2
Q

Name the main structural groups in a vine

A

4 main groups:

  • main shoots/stems
  • one year old wood
  • permanent wood
  • roots
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3
Q

Name the main structure of vine shoots

A
  • stem with nodes
  • buds
  • leaves
  • tendrils
  • lateral shoots
  • leaves
  • inflorescences/grape bunches
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4
Q

List the primary purposes of the stem

A
  • primary support structure
  • transport of water and solutes
  • carbohydrate store
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5
Q

Lignifying is the process by which _____ become _____

A

Lignifying is the process by which SHOOTS become CANES

NB, lignifying turns wood from green to brown

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6
Q

______ is the process by which shoots become canes

A

LIGNIFYING is the process by which shoots become canes

NB, lignifying turns wood from green to brown

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7
Q

What are the types of buds?

A

Compound buds (or latent buds) form in one season and break open the next. They are supported by secondary and tertiary buds in case of frost/damage

Prompt buds form and break open in the same season and produce lateral shoots

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8
Q

What are lateral shoots?
What is the impact of lateral shoots?
Name a grape variety which typically has them?
How are they typically managed?

A

Lateral shoots are from buds that formed that season.

They can give rise to too much shade/vegetation, and potentially a secondary crop with later ripening.

Pinot Noir

They are often summer pruned to focus ripening on primary shoot structures

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9
Q

_____ is a cluster of flowers that becomes grapes during the process of ________

A

An INFLORESCENCE is a cluster of flowers that becomes grapes during the process of FRUIT SET

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10
Q

Name the key parts of a grape and the attributes they can bring to wine

A

Pulp - bulk of the juice (water, sugar), some aroma compounds and aroma precursors

Seed - tannins

Skin - aroma compounds, aroma precursors, tannins, colour

Bloom - naturally occurring yeasts

Stem - tannin

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11
Q

What structures are one year old wood pruned into?

A

cane: 8-20 buds
spur: 2-3 buds

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12
Q

What structures can permanent wood be shaped into?

A

Trunk - vertical

Cordons - horizontal

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13
Q

What are the key attributes of roots?

A
  • Anchor vine
  • uptake of water and nutrients
  • hormone production
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14
Q

What are main methods of vine selection and propagation within a single variety?

A

Layering - no selection, adjacent vines are used to plug gaps in vineyard

Clonal selection - typically cutting

Mass selection- typically cutting

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15
Q

What are the main methods of selection and propagation of new grape varieties? Give an example of each

A

Cross fertilisation - pollen from one vine is transferred to stamen of a different vine.

e.g. Pinotage from Pinot Noir and Cinsault

Cab. Sav. from Sauvignon Blanc and Cab. Franc

Müller-Thurgau from Riesling and Madeleine Royale

Hybridisation - pollen from one species is transferred to stamen of a different species. e.g. Vidal Blanc from Ugni Blanc (vinifera) and Seibel

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16
Q

List the phases of vine growth, starting in winter

A
  1. Dormancy
  2. Budburst
  3. Shoot and leaf growth
  4. Flowering and fruit set (8 weeks after budburst)
  5. Grape Development
  6. Harvest
    7/1. Leaf fall/ dormancy
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17
Q

What resources does a vine need to survive?

A
  1. Water
  2. Sunlight
  3. Warmth
  4. Nutrients
  5. Carbon Dioxide (rarely a factor for growers)
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18
Q

What average temperature gives rise to dormancy?

A

<10°C

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19
Q

What temperature kills most vines?

A

Vitis vinifera is killed below -25°C

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20
Q

What average temperature gives rise to new growth in the spring?

A

Budburst is triggered >10°C

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21
Q

Compare the impact of a continental climate over maritime on budburst

A

Sharper changes in temperature in continental systems, typically give rise to uniform budburst and ultimately ripening. There is a lower risk of frost damage from a cold spell after budburst

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22
Q

Compare the impact of soil water retention on temperature and vine growth

A

Free draining soils hold less water, and heat up quicker encouraging earlier ripening

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23
Q

How and why do growers delay budburst?

A

Late winter pruning can delay budburst, to help avoid spring frost damage

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24
Q

What does a vine need during its ‘shoot and leaf growth’ phase?

A

You do not want early growth limited. Ensure leaves form to photosynthesise. You can always prune leaves, you can’t add them!

Warmth - temp >10°C

Access to carbohydrates - e.g. late winter pruning can reduce these and slow growth. Large harvest in the prior year can reduce storage

Access to nutrients and water

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25
Q

What does a vine need to maximise flowering and fruit set?

A

Warm temperatures in the previous year result in a high inflorescence count in compound buds

Current year needs a minimum temperature of 17°C, and optimal germination is over 25°C, with dry, calm days so that pollen is not washed away from the stigma, and can grow fertilisation tubes

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26
Q

Name and describe the process by which grapes form from flowers?

A

Fruit set

Pollen grains land on the stigma and from there grow a tube into the ovary to deliver sperm cells that fertilise the vines eggs. Fertilised eggs form seeds with grapes, and the walls of the ovary enlarge to form the pulp and the skin.

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27
Q

______ is a condition in which fruit set has failed for a high proportion of flowers.

Describe its causes and name a susceptible variety

A

COULURE is a condition in which fruit set has failed for a high proportion of flowers

It is cause by vine stress (lack of water, or too cold), or too vigorous vegetative growth competing for resources (too much fertiliser)

Grenache, Cabernet Sauvignon, Merlot, Malbec

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28
Q

What is coulure?

A

A high failure rate for fruit set

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29
Q

______ is a condition in which there is a high proportion of seedless grapes.

Describe its causes and name a susceptible variety

A

MILLERANDAGE is a condition in which there is a high proportion of seedless grapes.

It is caused by cold, wet weather at pollination and fruit set disrupting the growth of pollen tubes.

Chardonnay, Merlot

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30
Q

What is millerandage?

A

Millerandage is a term for a high proportion of seedless, smaller grapes.

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31
Q

What are the key stages of grape development?

A
  1. Berry formation
  2. Veraison
  3. Ripening
  4. Extra-ripening
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32
Q

What compounds accumulate during initial berry formation?

A
Tartaric acid
Malic Acid
Aroma compounds/ precursors
Methoxypyrazines (herbaceous flavours)
Bitter tannins
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33
Q

What are methoxypyrazines?

A

Herbaceous flavoured compounds formed in some grape varieties. The levels usually drop in ripening (Cabernet Franc and Gamay both lose vegetal flavours when ripe)

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34
Q

What are anthocyanins?

A

Compounds that give black grapes their colour

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35
Q

What compounds give black grapes their colour?

A

Anthocyanins

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36
Q

What compound levels change during berry ripening?

A
  • Malic acid levels may drop as plants use it as an energy source as sugar is diverted to grapes
  • Anthocyanins accumulate in black grapes
  • Sugar accumulates
  • Water accumulates, diluting acid
  • Methoxypyrazine levels fall
  • tannins can polymerase and reduce bitterness
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37
Q

What are terpenes?

A

Terpenes are aroma compound that gives floral and citrus aromas. e.g. the grapey aroma in Muscat

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38
Q

What is a good temperature range for ripening and why?

A

15°C to 21°C (depends on variety)

Too low and malic acid levels remain high; methoxypyrazine levels remain high. Grapes will be more herbacious and acidic

Too high and lots of acid is lost. Grapes ripen too quickly and do not develop as many aroma compounds. Grapes will be sweeter and blander

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39
Q

What happens during extra-ripening of grapes?

A

Grapes lose water and shrivel. Ripe aromas can develop (potentially good or bad depending on the variety and style of wine)

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40
Q

How can growers maximise latitude at or above 50°?

A

At high latitude, plant vines at a lower altitude, and aspect towards the sun to maximise sun exposure.

Proximity to water can dampen temperature swings, protecting from frost in winter, e.g. finger lakes

Use early ripening grapes - e.g. Chardonnay and Pinot Noir

Free draining soils warm up more quickly and promote early budburst to maximise the growing season

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41
Q

How can growers minimise latitude at or below 30°?

A

Steep slopes may have reduced water and soil quality, slowing growth in warmer climates

Plant at high altitude, and/or on a slope away from the sun (e.g. south facing in southern hemisphere). Each 100m of altitude, drops average temperate by 0.6°C

Proximity to water can dampen temperature swings - limiting overheating in summer

Use late ripening grapes in warmer climates (e.g. Cabernet Sauvignon)

Clay rich soils hold water and delay budburst as they remain cool

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42
Q

What is the minimum annual rainfall for a vine? Give examples of how soil type can increase/decrease these minimums in Hawkes Bay and Jerez respectively

A

500mm in cool climates, 750mm in warm

However, Hawkes bay has to irrigate despite receiving 800mm due to highly drained soil. Jerez copes on 650mm due to albariza, a clay soil with excellent water retention

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43
Q

Which wine growing areas are particularly reliant on irrigation?

A

Argentina, California, South Africa and Australia

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44
Q

What are optimum rain levels at key points during the season for grape development?

A

High rain in early spring to encourage early vegetative growth

Reduced water in late spring and early summer to allow germination and fruit set, and limit competition for carbohydrates as vegetative growth is reduced

Limited rainfall in late ripening to stop dilution and splitting

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45
Q

What are the top 5 vine nutrients and their purpose?

A
  1. Nitrogen is required to form proteins and chlorophyll
  2. Potassium - regulates water
  3. Phosphorus - used in photosynthesis
  4. Calcium - used in cell structure and photosynthesis.
  5. Magnesium - in cholorphyll
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46
Q

What is the impact of too much/ little nitrogen?

A

High levels result in too much vigour - secondary impacts of shading grapes and hindered fruit set and ripening, and encourage fungal disease.

Low levels cause leaf yellowing and reduced vigour. Yeast may be impacted during fermentation.

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47
Q

What is the impact of too much/ little potassium?

A

High levels - can impact magnesium uptake, reducing yields. It may raise also raise the pH in the grape/must as potassium accumulates

Low levels impact sugar accumulation and limit growth

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48
Q

What is the impact of too much/ little phosphorus?

A

High levels are not common

Low levels detrimentally impact root systems, impacting water and nutrient uptake.

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49
Q

_____ is the yellowing of vines in high pH soils (e.g. ____ or ____ soils) that limit uptake of ______

A

CHLOROSIS is the yellowing of vines in high pH soils (e.g. CHALKY or LIMESTONE soils) that limit uptake of IRON

This is common in CHALKY soil

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50
Q

What are the minerals particle types that can make up soil?

A

Sand (large), silt (medium), clay (fine)

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51
Q

_____ describes a soil with moderate proportions of _____, ______ and ______

A

LOAM describes a soil with moderate proportions of SAND, SILT and CLAY

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52
Q

What does GDD stand for? How is it determined?

A

Growing degree days

Average temperature in excess of 10°C in a given month
x
No. of days in month

Calculated for each month in a season

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53
Q

Name at least three climate classifications

A
  • Growing Degree Days
  • Huglin index (widely used in Europe)
  • Mean temperature of warmest month (MJT - used in hot climates where the stress of the warmest month is important)
  • Growing Season Temperature (GST)
  • Köppens classification (maritime, Mediterranean, continental)
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54
Q

What GST bands are used by WSET to categorise climates?

A

Cool <16.5°C

Moderate 16.5°C - 18.5°C

Warm - 18.5°C - 21°C

Hot >21°C

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55
Q

What are the negative implications of climate change on vines and ultimately wine?

A

Careful - very area specific!

Earlier ripening reduces the accumulation of aromas and tannins

Higher sugar levels increase alcohol

Reduced malic acid increases pH

Specific flavour profiles may change (e.g. black pepper in Syrah may not develop)

Increased water stress

Erratic weather events can reduce yields (e.g. storms, hail)

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56
Q

What are the positive implications of climate change on vines and ultimately wine?

A

Careful - very area specific!

Opens up new areas for cultivation

Reduced impact of fungal diseases

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57
Q

List key advantages and disadvantages of monoculture crops

A

Advantages:

  • increased mechanisation
  • reduced competition for resources
  • ability to tailor husbandry to specific varietal requirements (e.g. irrigation)

Disadvantages:

  • crop is more prone to disease
  • depletion of nutrients
  • reliance on chemicals can increase environmental damage
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58
Q

List key advantages and disadvantages of sustainable agriculture

A

Advantages:

  • more thoughtful approach leads to potentially better outcomes through a wider consideration of viticulture impact
  • reduced interventions (spraying, poisons)
  • cost savings

Disadvantages:

  • no clear global definition, national standards are typically set
  • standards can be set too low nationally
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59
Q

List key advantages and disadvantages of organic viticulture

A

Advantages:

  • healthier balanced soil
  • reduced chemical treatments
  • saving cost of synthetic chemicals

Disadvantages:

  • potential yield reduction
  • more volatile yields, especially in bad years
  • reliance on copper sprays
  • increase in cost and time
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60
Q

What are the key features of organic viticulture?

A
  • compost provides nutrients
  • cover crops reduce erosion and provide green manure
  • uses natural fertilisers
  • reduced monoculture - plant hedges, etc
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61
Q

What are the key features of biodynamic viticulture?

A
  • align activities with philosophical and cosmological concepts. e.g. take grafts when the moon in ascending
  • use of homeopathic remedies and certain preparations to fertilise soil and treat pests, e.g. preparation 500 is manure based, 501 is silica based
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62
Q

Who developed the concept of biodynamic viticulture?

A

Rudolf Steiner and Maria Thun

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63
Q

What are the key features of precision viticulture?

A
  • use detailed data to vary interventions/husbandry by plot and row
  • data may include soil composition or growth rates
  • interventions that can be tailored include: choice of rootstock/grape, canopy management, irrigation, harvest timing
64
Q

List key advantages and disadvantages of precision viticulture

A

advantages:
- maximise understanding of yields and/or grape quality

Disadvantage:
- cost of data collection, training and analysis

65
Q

What attributes might you look for in selecting a site for high volume wine?

A
  • flat for mechanisation
  • consistent weather for predictable yields and quality
  • source of water
  • warm conditions to reduce fungal diseases
  • price of the land
  • proximity of labour/transport/winery
66
Q

What attributes might you look for in selecting a site for premium wine, in a cool climate?

A

Focus on quality grape production. e.g. aspect/altitude that maximises ripening potential

Understanding whether the quality of grapes and wine that can be produced will support a profitable business

67
Q

List at least 5 ways you might prepare soil for planting in a new site

A
  • remove large rocks
  • subsoiling to remove impervious plough pan layers
  • remove old roots
  • use of systemic herbicides
  • application of manure/compost
  • pH adjusting (e.g. add lime)
  • landscaping - e.g. terracing
68
Q

List at least 5 ways grape varieties can be selected to match the climate

A
  • budding timing: early to maximise growing season (Chardonnay), late to avoid frost (Riesling)
  • Annual life-cycle: early ripening for cool climates (Chardonnay, Pinot Noir), late for warm (Mourvedre)
  • Drought tolerance: Grenache
  • Disease resistance: Cabernet Sauvignon is less susceptible to grey rot
  • Winter hardiness: Vidal, Riesling and Cabernet Franc are tolerant of cold
  • Vigour: high vigour varieties (Sauv. Blanc) can be planted in less fertile areas, or additional canopy management is required
69
Q

List at least 5 non-climatic factors that influence the choice of grape to plant

A
  • style of wine, e.g. tannic wine needs tannic grape
  • yield: high yield for mass production. e.g. Grenache
  • Management cost: e.g. Pinot Noir needs more attention due to disease susceptibility
  • Law: choice may be restricted
  • availability of cuttings
  • Market demand
70
Q

What rootstock is tolerant of phylloxera?

A

All main North American varieties

71
Q

What rootstock is tolerant of root-knot nematodes?

A

Ramsey or Dog Ridge (both Vitis Champini)

72
Q

What rootstock is tolerant of drought?

A

110R or 140R. Both hybrids of V. rupestris and V. berlandieri

73
Q

What rootstock is tolerant of acidic soil?

A

99R or 110R. . Both hybrids of V. rupestris and V. berlandieri

74
Q

Name a low vigour rootstock, and where/why it is helpful?

A

420A or 3309C - can advance ripening in cool climates

75
Q

Name a high vigour rootstock, and where/why it is helpful?

A

140R can boost growth in infertile soils

76
Q

How many years before a vine produces suitable grapes?

A

PDO wines in the EU are 4 years by law

2-3 years if not required by law

77
Q

How many years until a vine stops producing suitable grapes?

A

10-40 years for maximum yields

Vines over 50 years are typically only retained for making premium wines due to low yields

78
Q

What factors make up soil health?

A

structure (sand/silt/clay mix) - drainage/water holding capacity, ability for roots to penetrate

organic matter - hummus

living organisms - these break down organic matter into inorganic

nutrients

79
Q

What are the two categories of fertilisers?

A

Organic (e.g. compost)

Inorganic - manufactured

80
Q

What are organic fertilisers and how do they get into a plant?

A

Fresh or composted plant or animal waste, that is broken down by organisms in the soil to release inorganic nutrients for uptake by roots

81
Q

What are mineral fertilisers?

A

inorganic nutrients that can be taken up directly by vines

82
Q

______ is a method of weed control that ploughs weed roots back into the soil

A

Cultivation

83
Q

What are the advantages/ disadvantages of cultivation?

A

Advantages:

  • chemical free (organic and biodynamic friendly)
  • fertilises soil

Disadvantages:

  • changes the soil structure
  • buries seeds so weeds can grow back
  • requires heavy machinery
  • can increase vigour if all competition is removed
84
Q

What are the main types of herbicide?

A

Pre-emergence: persist in soil

Contact: sprayed on established weeks and kill parts they make contact with

Systemic: taken up by plants and kills the whole plant

85
Q

What are the advantages/ disadvantages of herbicide?

A

Advantages:

  • cheap labour and machinery
  • effective
  • don’t damage soil structure

Disadvantages:

  • environmental/ operator/ consumer risk
  • resistance can arise
  • increase vigour too much if all competition is eliminated
  • not allowed in organic/biodynamic
86
Q

What are the advantages/ disadvantages of cover crops?

A

Advantages:

  • organic/biodynamic suitable
  • manage vine vigour by competing for water/nutrients
  • surface for machinery

Disadvantages:

  • risk of too much competition
  • hard to mow
  • can be slippery on slopes when wet
87
Q

What are the advantages/ disadvantages of mulching?

A

Advantages:

  • organic/biodynamic suitable
  • reduces water evaporation in hot climates
  • long term release of nutrients

Disadvantages:

  • bulky to transport
  • needs a lot to be effective
  • can increase vigour too much
88
Q

How can a vineyard reduce water usage?

A
  • efficient drip system
  • drought tolerant varieties, e.g. Grenache
  • drought tolerant rootstock, e.g. 140R
  • mulch cover
  • increase water retention with additional humus
  • promote deep root growth
89
Q

What types of irrigation are there?

A

Drip
Flood
Channel
Sprinkler

90
Q

What are the advantages of drip irrigation?

A
  • efficient
  • highly tailored
  • can supply liquid fertiliser
  • used on any terrain
91
Q

What are the disadvantages of drip irrigation?

A
  • high capital cost
  • needs clean water to keep holes clear
  • need maintenance to keep clear
  • unlike sprinklers, cannot protect against frost
92
Q

How is water managed across the growing season?

A

Lots of water at budburst to encourage initial leaf growth

Water deficit may benefit veraison

Careful management at other times

Might want reduced water at harvest time to prevent swelling

93
Q

What are the aims of canopy management?

A
  • Effective light absorption by canopy
  • Reduce shade on grapes
  • Uniform microclimates for grapes
  • Balance between vegetative and reproductive functions in the vine
  • Ease of harvesting
  • Promote air circulation
94
Q

What impact does sunlight have on different compounds in a ripening grape?

A
  • increases sugar through photosynthesis
  • increases tannins
  • increases polymerisation of tannins
  • decreases malic acid
  • increases some aroma compounds
  • decreases methoxypyrazines
95
Q

What happens if a grape gets sunburn?

A

Too high temperatures damage grapes causing browning

96
Q

What are the implications on the following season from a too low yield in a year?

A

The following year can be too vigorous, reducing bud fruitfulness and encouraging vigorous growth

97
Q

What are the implications on the following season from a too high yield in a year?

A

Trunks and roots can be exhausted of carbohydrate, weakening vine growth the following year

98
Q

What is a high planting density and a low planting density?

A

low - 100s of vines per hectare

high - 10,000 vines per hectare

99
Q

How is vine density determined when planting?

A

Vigour of the variety: low vigour can be more closely planted that high vigour

Trellising techniques

Local laws may put limits in place

100
Q

What is considered when choosing a canopy training method?

A
  • Vine vigour
  • Site topography
  • Mechanisation requirements
101
Q

What is vine training?

A

Shaping of permanent wood

102
Q

What are the common types of vine training?

A

Head training - just a trunk

Cordon training - arms on a trunk

Both can be high (avoid frost, easier harvesting) 
or low (benefit from heat retained by soil)
103
Q

What are the common types of pruning?

A

Spur pruning - 2-3 buds

Replacement cane pruning 8-20 buds

104
Q

Why are some vineyards untrellised?

A

Called bush vines - simple and inexpensive. Normally practiced in sunny regions to keep grapes shaded, and in dry regions as vigour is limited (other too much canopy grows)

105
Q

What is the most common trellising system?

A

VSP: Vertical Shoot Positioning - best for low/moderate vigour

106
Q

What trellising is used for vigorous vines?

A

GDC - Geneva Double Curtain

Lyre

Scott-Henry

107
Q

What is the Scott-Henry technique?

A

Double level VSP (vertical shoot positioning) for high vigour vines

108
Q

What is GDC?

A

The Geneva Double Curtain training, splits the canopy horizontally

109
Q

List at least 5 summer pruning techniques

A

Disbudding

Shoot removal

Pinching, during fruit set

Leaf removal

Crop thinning/green harvesting

110
Q

Why carry out summer pruning?

A

Reduce competition between vegetation and grapes

Increase sun/circulation for grapes

Remove grapes ripening out of sync

111
Q

What are the physiological changes in a vine during water stress?

A

Leaf stomata close to reduce transpiration and limit water loss, which also reduces gas exchange.

Photosynthesis is reduced as CO2 levels fall.

Vegetation growth and grape ripening reduce.

Prolonged periods result in leaf loss and death of the vine.

112
Q

How can water stress be managed?

A

Irrigation systems, where laws allow

Drought resistant rootstock (e.g. 110R and 140R)

Drought tolerant grape variety (e.g. Garnacha/Grenache)

113
Q

What does an excess of water cause?

A

Vegetative growth results in shaded grapes, reducing ripeness.

Increased risk of fungal disease.

Waterlogged roots can impact growth and kill the vine, and lead to compacted soil

114
Q

How can an excess of water be managed?

A

Primarily in vineyard selection and design: plant on slopes; plant in free draining soil; construct drainage systems

115
Q

What are the two worst times in the season for heavy rain?

A

During pollination and fruit set - it can result in millerandage and coulure

At harvest grapes can swell and split - diluting must, and potentially causing grey rot and oxidation

116
Q

How can heavy rain at harvest be managed?

A

Trade off from bringing the harvest forward, or risking damage to the crop from rain.

117
Q

What climate types and/or geographical locations are most at risk from vine death in freezing temperatures?

A

Strong continental climates: e.g. Canada, Washington State, parts of China

118
Q

How can vine death from freezing be managed?

A

Hillside planting over valley floors

Plant near bodies of water to benefit from temperature moderation

‘Hilling up’ soil around the vine graft

Burying the vine over winter

Prune multiple trunks to increase chances of survival

119
Q

When is frost the biggest risk to a vine?

A

During budburst, frost can kill the buds and young shoots, leaving growers reliant on secondary buds. These have lower yields and delayed ripening.

120
Q

How can frost risk be minimised?

A

Avoid planting in frost pockets

Late winter pruning can delay budburst

Plant late budding varieties (e.g. Reisling)

Train vines high

Bare soil between vines absorbs more heat in daytime to reflect back overnight

121
Q

When frost is imminent, how can the risk be minimised?

A

Water sprinklers can release latent heat in water, but must be kept on until temperatures rise. There is a risk of sunburn through the ice on a clear day.

Wind machines / helicopters - work if there is an inversion layer. This is typically radiation frost

Burners (smudge pots) - although these are polluting

122
Q

How can the risk of hail be minimised?

A

Mainly netting, although this can shade grapes

Multiple plots spreads risk - hail is often localised

123
Q

How can the risk of fire be minimised?

A

Have water on site, use sprinklers. Have fire breaks in crops. Depends on the size of the fire!

124
Q

What can be done about smoke taint?

A

Smoke taint is thought to be concentrated in the skin:

  • Minimise skin impact in fermentation
  • Whole bunch pressing
  • Lower fermentation temperature
  • Reduce maceration
125
Q

What animal pests can attack vines and what is the primary defence against each?

A

Phylloxera - resistant rootstock

Nematodes - resistant rootstock

Grape moths - chemicals (insecticide, or pheromones)

Spider mites - pesticides

Birds - netting

Mammals - fencing

126
Q

List at least 4 fungal diseases

A

Powdery mildew

Downy mildew

Grey rot

Eutypa Dieback

Phomopsis

ESCA

127
Q

What diseases are the most prevalent vine diseases, which attack young, green parts of the vine

A

Powdery mildew and downy mildew

128
Q

How can powdery mildew be treated?

A

Prune an open canopy to minimise shade

Early spraying of sulphur

Systemic fungicides

129
Q

How can downy mildew be treated?

A

Bordeaux mixture - copper sulphate and lime

130
Q

What fungus attacks fruit and which species are particularly vulnerable?

A

Grey rot

Species with tight bunches or thin skins: Semillon, Sauvignon Blanc, Pinot Noir

131
Q

How can grey rot be treated?

A

Prune an open canopy

Fungicides

Competing bacteria (Bacillus subtilise)

132
Q

________ infects pruning wounds and results in rotten wood

A

Eutypa dieback (also called Dead arm)

133
Q

How can eutypa dieback be treated?

A

Prune late and apply fungicide to wounds

Cut back dead wood 5cm past infection. Burn the wood

Cut away plant and regrow from a sucker

134
Q

What are the 2 main vine bacterial diseases?

A

Pierce’s disease

Grapevine yellows

135
Q

How are bacterial infections spread?

A

They need a vector

Pierce’s disease is the sharpshooter

Grapevine yellows is the leafhopper

136
Q

What are the 2 main vine viruses?

A

Leafroll virus

Fanleaf virus

137
Q

How are viral infections spread?

A

Either with a vector, or grafting infected material

Fanleaf vector is the dagger nematode

Leafroll vector is the mealy bug

138
Q

_____ causes vines to grow twisted and stunted

A

FANLEAF VIRUS causes vines to grow twisted and stunted

139
Q

How would you identify leafroll virus in a vineyard?

A

Slow growth, yields halved and leaves change colour in the autumn (red or yellow)

140
Q

How would you identify fanleaf virus in a vineyard?

A

Stunted, twisted vines

141
Q

What factors influence harvest timing?

A

Climate

Sugar levels - minimum alcohol levels may need to be reached

Forecast rain

Aroma and tannin ripeness (usually determined by taste)

Wine style - e.g. later for botrytis, or off dry styles.

142
Q

What is the typical sugar level in a grape harvested for still wine?

A

19° and 25° Brix, which will convert into 11–15% abv wine

143
Q

What supplementary processes can increase the quality of grapes when machine harvesting is used?

A

Hand selecting undesirable fruit before harvesting

Use a bow-rod machine

Use an optical sorting machine

Sort on arrival

144
Q

What are the advantages of machine harvesting?

A

Faster and cheaper

Consistent availability

Harvesting at night is an option

Can be more flexibly on harvest dates

145
Q

What are the disadvantages of machine harvesting?

A

May rupture grapes

Only supported by large crops - major investment

Needs mono crop

Needs flat slope

146
Q

What are the advantages of hand harvesting?

A

Highly selective grape selection

Flexible for topography

Grapes can be harvested whole, or in whole bunches

147
Q

What are the disadvantages of hand harvesting?

A

Cost

Need a work force

Have to harvest during the day

148
Q

Which wines require grapes to be hand harvested?

A

Whole-bunch pressed wines: e.g. bottle fermented sparkling wines

Carbonic or semi-carbonic wines: e.g. Beaujolais

Botrytis affected grapes

149
Q

Set out the typical viticulture requirements for the best Priorat vineyards

A

Hot enough to plant on north facing slopes to avoid sun

Free draining soils, and no permitted irrigation, limits vine vigour. So vines can be bush trained for shade.

Low density planting to avoid competition for water and nutrients (up to ~3,000 vines per hectare)

Garnacha and Carieñena are drought resistant and late ripening

Drought tolerant rootstock may be used (e.g. 140R)

150
Q

Set out the typical viticulture requirements for the best Pauillac vineyards

A

Variable maritime climates - so different grapes are planted that can be blended, as these spread risk of a deep crop loss.

Poor, free draining soils limit vigour, so planting using VSP as simple and maximises grape exposure to the sun.

Rain and mist risk means canopies are pruned clear of grapes, which increases sun for ripening and reduces fungal disease

Vines are planted at high densities to maximise yield as land is so expensive

151
Q

Set out the typical viticulture requirements for the best Finger Lake vineyards

A

Despite the proximity of water, climates are cool, so Reisling is common as it is late budding to protect against frost, and is winter hardy

Growers may hill up the soil in winter

Soils are nutrient rich and rain is plentiful. Scott-Henry trellising improves light interception, gives circulation to protect against fungal disease, and makes the most of the large vine

Summer pruning can help ripening

Vine densities are low to give vigorous vines space. Wide spacing for mechanical harvesting

152
Q

Set out the typical viticulture requirements for Californian Central Valley vineyards to produce high-volume wine?

A

The climate is warm, and irrigation permitted, so vines grow vigorously. Low density planting reduces upfront costs of vines (1,500 vines per hectare) and vines grow quite large

Varieties are high-yielding

Spur pruning is quicker and lower skilled, reducing cost

Shoots are hung over a single wine to reduce trellis cost, and provide shade from intense sun

Machine harvesting reduces cost and enables night time harvesting to save on refrigeration

Early harvest avoids spoilage risk and reduces rot

153
Q

What can calcium deficiency cause?

A

Detrimental impact on fruit set

154
Q

What can magnesium deficiency cause?

A

Impact chlorophyll reducing photosynthesis. Reduced grape yields and poor ripening

155
Q

Why is a large, well-developed root system beneficial to viticulture?

A

If a root system is large in comparison to the canopy, the more it puts a stress on the vine and produces higher quality grapes.

156
Q

Compare a Mediterranean climate to a maritime climate

A

A Mediterranean climate is warmer, with an extended autumn. It is more suited to late budding, late ripening varieties like Mourvèdre