Ch. 0 – Viticulture Flashcards

1
Q

Most common species of vine

A

Vitis Vinifera

Vitis Lambrusca

Vitis Riparia

Vitis Berlandieri

Vitis Rupestris

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2
Q

Name parts of vine

A

Tendril

Lateral Shot

Inflorescence

Leaf

Compound bud

Main Shoot

Cane

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3
Q

What is the lenght of stem between nods called?

A

Internod

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4
Q

What does stem transport?

A

Water and solutes (substances dissolved in liquid - minerals and sugars)

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5
Q

Explain compound bud

A

Also called latent bud

Form in one growing season and break open in the next one

Primary bud opens first (followed by secondary or tertiary if necessary)

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6
Q

Explain prompt bud

A

Form and break in the same season and produce lateral shoots

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7
Q

Main functions of lateral shoots

A

Back up if main shoot is damaged.

Additional source of leaves for photosythesis

May have inflorescences (second crop) those ripen later or may be removed.

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8
Q

Explain photosythesis

A

Stomata (pores) open on underside of the leaves letting water diffuse out and carbon dioxide to enter.

Transpiration - transport of water from soil and roots back to leaves

Stomata closes if vine has water stress

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9
Q

Describe composition of grape berry

A

Pulp - water, sugars, acids and some aroma compounds and aroma precursors

Skin - high concentration of aroma compounds and precursors, tannins and colour compounds

Seeds - oils, tannins and embryo for new plant

Bloom - waxy coating of skin

Stem

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10
Q

2 kinds of vine propagations - explain

A

Cuttings - section of vine that is planted and grows as new plant. Can be grafted on selected rootstock and treated in nursery against deseases.

Layering - Establish neighbouring vine’s shoot is buried in the ground. New vine grows on its own roots.

Both methods are geneticaly identical to the parent (vines from seeds are not)

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11
Q

Explain clonal selection

A

Vines with favourable characteristics are propagated in nurseries by cuttings.

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12
Q

Explain mass selection (Selection Massale)

A

Grower takes cuttings from best performing vines in his vineyard and propagate them by cuttings (may graft them on rootstock)

Own unique planting material

Increases diversity

Costly in terms of time and labour

Possible spread of diseases (from parent)

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13
Q

New vines from seeds

Cross X Hybrid

A

Cross - parents from the same species

Hybrid - parents from different species

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14
Q

Dormancy (temperatures, hazards, management)

A

Below 10 degrees

Below -15 degrees hazard of damage or killing vine

Unusual warm can trigger budburst

Winter pruning

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15
Q

Budburst (temperatures, factors, hazards)

A

Temperature above 10 degrees

Continental climate advantageous with large winter/summer difference - uniform budburst

Maritime climate caìn be less synchronized

Other factors: temperature of soil (sand warms up quickly) and grape variety

Hazard of frost and cold days

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16
Q

Reasons of low carbohydrate levels in roots from previous season

A

Excessive leaf removal

Water stress

Mildew infections

High crop loads

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17
Q

Shoot and leaf growth stage (needs)

A

Stored carbohydrates from previous season

Warmth, sunshine, nutrients and water

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18
Q

Petioles

A

Base of leaf stalks where new buds develop

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19
Q

Fruitfullness

A

Number of inflorescenses

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20
Q

Describe pollination

A

Pollen-lade stamens (consisting of anther and filament) are exposed.

The pollen grains are shed and land on the moistened stigma surface

They germinate, each producing pollen tube

Pollen tubes penetrate stigma and then the ovule in the ovary.

Pollen tube delivers the sperm cells which fertilizes the egg in the ovule

Ovule forms up to 4 seeds

The wall of ovary enlarges to form the skin and pulp of the grape

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21
Q

Conditions for successful flowering

(timing, temperatures

A

8 weeks from budburst (temperature dependent)

min 17 degrees

sunlight, nutrients, water

adverse conditions: rain, clouds, cold temperatures

Pollen germination needs temperature of 26-32 degrees

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22
Q

Coulure

A

Grape bunch in which fruit set has failed for high proportion of flowers

Imbalance of carbohydrate levels (low rates of photosythesis - cold, cloudy, hot weather, water stress OR vigorous shoot growth)

Grenache, Malbec, Merlot, Cabernet Sauvignon are the most susceptible

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23
Q

Millerandage

A

High proportion of seedless grapes in bunch - smaller grapes

lower volume of wine or unequal ripeness

Usually from cold, wet, windy weather at pollination and fruit set

Chardonnay, Merlot are susceptible

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24
Q

Methoxypyrazines

A

contribute to herbaceous aromas/flavours

Sauvignon Blanc, Cabernet Sauvignon, Cabernet Franc

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25
Xilem
Transport tissue which gets water and nutrients from roots to other parts of plant
26
Grape berry formation | what is created, what is needed
Tartaric and malic acid Aroma compounds and precursors (Methoxypyrazines) Tannins Water intake is high (too much water can triger leaf growth) Mid water stress speeds up this stage and reduces size of grapes (better quality)
27
Veraison
Colour change growth slows down for few days (lag phase) Chlorophyll in skin cells is broken down and grapes start to change colour Due to the systhesis of anthocyanins
28
Factors influencing ripening stage
Grape variety Climatic conditions Management of vine and vineyard (heavy crop loads, excessive shading) Time of harvest
29
Ripening stage
Sugar and water accumulate Acid levels fall (tartaric acid is the same, malic acid drops due to use for respiration during ripening - respiration is slower in cooler regions -higher acidity) Tannins, colour and aroma compounds and precursors develop Methoxypyrazines levels drops (unless it is cloudy or grapes are too shaded) Tannins polymerise - soften Anthocyanins increase with sunshine and temperatures between 15 and 25
30
Conditions for photosynthesis
18-33 degrees sunlight levels that are above one third of full sunshine Water stress can lead to stop of photosynthesis
31
Phloem
Tissue which transports sugars from the leaves to other parts of the vine Transportation by xylem slows down at ripening
32
Optimal ripeness
Balance of sugar, tannin and aroma ripeness
33
Geen shoot lignification
Becoming woody and rigid - from one-year-wood to cane
34
Optimum temperature for fruit set
26-32 degrees
35
Anthocyanin synthesis | definition and temperatures
development of colour optimum temperature 15-25 degrees
36
The effects of sunshine
Needed for photosynthesis reduction of methoxypyrazines accumulation of tannin before veraison and polymerization after creation of aroma compounds and precursors increased use of malic acid for respiration - lower acidity levels
37
terpenes
Fruity and floral aromas Grapey aromas in Muscat
38
Polymerisation of tannins
softening, less bitterness
39
Influence of latitude
Lower lattitudes - more and stronger solar radiation radiation travels through less atmosphere and falls on larger angle (stronger) Hours of sunshine during the year are more stable higher sugar, lowe acidity, riper aromas, higher but riper tannins, more colour intensity
40
Lattitude for growing grapes
Between 30 and 50 on each side of Equator
41
How much temperature falls each 100m?
by 0.6 degrees
42
Diurnal range
difference between day and night temperatures
43
Effect of altitude
Cooling influence in high altitude Sunshine is more intense in high altitude Ultraviolet radiation is also greater (promotin anthocyanins and tannin synthesis) High diurnal range
44
Effect of diurnal range in high altitude
Air absorbs some energy and warmth from the soil and some heat is retained at night. At high altitude air is thinner and holds less moisture, therefore heat rapidly escapes leading to cool nights.
45
Slope aspects with the most sun exposure
South for nothern hemisphere North for southern hemisphere
46
Importance of aspect and steepness of slope
Increased importance in higher latitudes because solar radiation hits Earth in low angle. The slope increases the angle therefore increasing the intensity of heat and light Extention of growing season In warm climates it may be desirable to limit the heat - planting on slopes which face away from sun East facing vineyards benefit from morning sunshine (less moisture, longer hours of vine growth) Shallower and better drained soils with less nutrients Shelter from winds, rain and frost Danger of soil erosion
47
Effect of proximity of water
Water heats up and cools down slower than dry land Day - water remains relatively cool and lowers the temperature in the area. Cool air from above water is drawn to the land to replace the warm air as it raises, resulting in cool humid afternoon breezes Night - water retains the warmth and keeps local area warmer Cold/warm ocean currents Radiation reflection from the water surface (especially high latitude vineyards)
48
El Nino
Climatic cycle which occurs every 3-7 years Pacific Ocean becomes warmer and causes a lot of rainfall and risk of hurricanes in South America and California Pacific Northwest (Washinghton, Oregon) get warmer than average conditions and drought Australia and Western side of Pacific - warm and drought La Nina is the oposite
49
Effect of wind
cooling or warming influence Cooling breezes near to body of water (moderating diurnal range) Valleys - stronger winds (possibility of funnelling between mountain ranges) Warm breezes from winds travelling over hot land Reduction of humidity (fungal diseases) Increase of evaporation rate (increse of need of water) Hazard of damage by wind (rows of trees as windbreakers on sides of vineyards)
50
Soil and temperature
Free draining soils (sand, stones) warms up quick in spring - encouraging early budburst and longer growing season (spring frost hazard) Warm soils encourage root growth (ability to absorb more water and nutrients) Light coloured soils (chalk) reflect some of energy from solar radiation Dark coloured soils absorb more energy and re-radiate it when temperatures are cooler (at night)
51
Mist, fog and clouds
Mist is formed by tiny drops of water colecting in the air above ground or water. It is formed when warm air is rapidly cooled, causing water vapour in the air to condense Regular cloudy weather can slow down sugar accumulation and acid degradation (beneficial in warm climate for early ripening varieties) Increase humidity - fungal diseases or noble rot
52
Annual water need for vine
500mm in cool climate 750mm in warm climate
53
What is water in vine needed for
For turgidity (so it does not wilt) Photosynthesis Regulating temperature Solvent for nutrients from soil Healthy growth and ripening
54
Explain transpiration
Water vapour diffuses out of the stomata (pores underside of leafs) The water loss causes water to be pulled from the soil
55
Stomata
Little pores underside of the leaves which vapour water Lets carbon dioxide an oxyget diffuse in and out
56
Over supply or under supply of water
Under-supply stomata closes to save water. Photosynthesis stops, growth stops Grape shrivelling before harvest (or under-ripe grapes) Over-supply - vigour (good in spring) Problem in mid summer as it prolongs and compromise ripening Excessive shading Diluting of sugar in grapes before harvest (or even grape splitting) reduced formation of anthocyanins, tannins and aroma compounds, less tannin polymerisation and higher level of methoxypyrazines Humid conditions due to poor ventilation
57
Problems of excessive vegetative growth
vigour (good in spring) Problem in mid summer as it prolongs and compromise ripening Excessive shading Reduced formation of anthocyanins, tannins and aroma compounds, less tannin polymerisation and higher level of methoxypyrazines Humid conditions due to poor ventilation
58
Water and soil
Soil drainage and water retention depends on structure and texture of soil water logged soils are harmful to wine (reducing the amount of oxigen for roots which slows growth) Warm soils speed up bud burst (longer season) Slopes - shalower soil with less nutrients, less water due to run off from the slope, problem with erosion
59
What is evaporation rate and what does it depend on
Amount of traspiration from the wine combined with the evaporation of water from the soil Depends on temperature, humidity and wind
60
Nutrients
Nitrogen Potassium Phosphorus Calcium Magnesium Sulfur, manganese, boron, copper, iron, zinc
61
Nitrogen
Component of proteins and chlorophyll (essential for photosynthesis) essential for vine growth, impact on vigour and grape quality High levels - excessive vegetative growth (hindering ripening, fruit shading, poor ventilation) Low levels - reduced vigour (yellowing of leaves) grapes can be difficult to ferment Restricted supply procudes higher quality grapes
62
Potassium
Essential for vine growth and water flow High levels - problems with uptake of magnesium (reduced yields and poor ripening) high potassium in grapes (high pH in wine) Low levels - low sugar accumulation, reduced yields and poor growth
63
Phosphorus
Important for photosynthesis (only needed small amount and usually sufficient) Low levels - poorly developed root system (poor water intake, low yields, reduced growth)
64
Calcium
Important for structure of plant cells and in photosynthesis Low levels - negative influence on fruit set
65
Magnesium
Found in chlorophyll, key role in photosynthesis Low level - (rare) reduced yields and poor ripening
66
Soil and nutrient availability
Nutrients for vine dissolve in water which is then taken up by the roots Different nutrients are available at different pH levels Soil texture and nutrient holding capacity (clay - high, sand - low) Slopes have more shallow soil with less nutrients Fertilizers, manure, compost
67
Chlorosis
Lack of iron Condition in which leaves turn yellow and photosynthesis stops
68
Explain mineralization
Vine cannot take up organic nutrient compounds (manure, compost) but needs inorganic ones. Soil organisms are feeding on organic material and converting it into inorganic material
69
Texture and structure of soil
Texture - proportion of the mineral particles of sand, silt and clay. Clay - fine texture, effective water holding capacity Sand - good drainage, poor water retention, easy for roots to grow through Silt - intermediate size Loam - moderate proportion of sand, clay and silt Rocks and pebbles - improve drainage but lower water holding capacity Structure - how the mineral particles in the soil form aggregates (crumbs) The size, shape and stability is important for drainage, root growth and workability of soil
70
Definition of climate
Annual pattern of temperature, sunlight, rainfall, humidity and wind averaged out over several years (generally 30)
71
Climate models
Growing degree days (GDD) The Huglin Index Mean temperature of the warmest month (MJT) Growing season temperature (GST) Koppen's Classification
72
Growing degree days climate classification
Amerine and Winkler (1944) Substract 10 (temperature below vine cannot grow) from average mean temperature of a month in the growing season. Multiply by number of days in the month Make same calculation for each month in the growing season Add together to get GDD (any months with negative value do not count) Grouped into 5 zones Winkler Zone I is the coolest
73
The Huglin Index
Similar to GDD but the calculation takes into account both mean and maximum temperature and the increased day lenght experienced at higher latitudes Split into ranges with the most suitable varieties Widely used in Europe
74
Mean temperature of the warmetst month (MJT)
Smart and Dry (1980) Uses mean temperature of July (or January) as well as measures of continentality, humidity and hours of sunshine. Divided into 6 bands
75
Growing season temperature (GST) climate classification
Mean temperature of the whole growing season Split into bands Close to GDD but easier to calculate
76
Koppen's Classification (climate classification)
(1900) Considers both temperature and rainfall patterns (only for temperate zones and not tropics) Maritime - low difference between summer and winter temperature, even spread of rainfall (Bordeaux) Mediterranean - low difference between summer and winter temperature, dry summers, wet winters (Napa, Coonawarra) Continental - extreme difference between summer and winter temperatures, short summers, cold winters, rapidly changing temperatures in spring and autumn (Burgundy, Alsace) Cool climate - average GST 16.5 or below Moderate climate - 16.5 - 18.5 Warm climate - 18.5 - 21 Hot climate - more than 21
77
Monoculture advantages and diasdvantages
Advantages: Ability to mechanize Reduction of competition between other plants Ability to tend to specific needs of the grape variety planted (irrigation, nutrition level...) to increase yields while reducing costs Disdavantages More prone to diseases and pestes - more treatments of protection Nutrients can be depleated - no ecosystem to replenish them Residual chemicals - environmental damage
78
Conventional Viticulture
Raising production levels Reducing labour requirements Mechanization Chemical inputs Irrigation Clonal selection Monoculture
79
Sustainable viticulture
Ecomonic, social and environmental sustainability Aims to promote natural ecosystems, maintain biodiversity, manage waste, minimise applications of chemicals and energy use, and reduce impact of viticulture on environment. Encourages in-depth understanding of lifecycle of vine and pests and monitoring weather. Prevent and predict pest or diseases (fewer applications of chemicals needed) Integrated Pest Management
80
Integrated Pest Management (IP) Lutte Raisonee
Insights of organic viticulture, but prepared to spray when necessary. Identifying and monitoring pests, setting preventative measures, evaluating and implementing control options (if prevention was not effective and treshold levels were exceeded) Reduces cost and vine's resistance to treatments
81
Sustainable viticulture advantages and diadvantages
``` Advantages: Attention to economic social and Environmental impact Scientific understanding of threats minimalisation of interventions Cost saving ``` Disadvantages Term is not protected and can be used to promote wine without any standards Nationwide standards can be set too low
82
What is biomass in the soil
The total quantity of organisms in a given area or volume
83
Organic Viticulture
Seeks to improve soil and range of microbes and animals within it. Therefore increase the health and disease resistane of the vine. Rejects use of synthetic fertilizers, fungicides, herbicides and pesticides. Application of compost (slow release of nutrients, improved structure, increase of biomass) Cover crops to combat erosion, improvement of life of the soil, biodiversity, green manure (ploughing them in soil) Natural fertilizers (animal dung, natural calcium carbonate etc.) restoring natural balance of soil Monoculture is reduced by cover crops, pranting hedges and islands of biodiversity Monitoring weather and using copper sulfate and sulfur to combat mildew Natural predator introduction (Bacillus Subtilis can compete with Botrytis on leaf space) Sexual confusion - pheromone tags which disrupt mating patterns of insects
84
All certification bodies for Organic viticulture need to be certified by:
IFOAM International Federation of Organic Agriculture Movements
85
% of Organicaly grown vineyards in Europe
10% in Europe, accounting for 85% in the world
86
Organic viticulture Advantages and disadvantages
Advantages Central aim of grape grower is health of soil and disease-resistance of vine Reduction in number of chemical treatments Saving on cost of synthetic chemicals Diadvantages Small reduction in yield Significant redustion of yield in difficult vintages Increased reliance on copper sprays - heavy metal build-up in soil Cost and time expended on certification
87
Biodynamic viticulture
Based on Rudolf Steiner and Maria Thun Organic practises with philosophy and cosmology. Adaptation of practises to coincide with the cycles of planets, moon and stars Calendar which advise growers on root, leaf, flower, or fruit days to indicate best days for certain activities Homeopatic remedies 'preparations' are used Increased labour costs
88
Preparations in Biodynamic viticulture
500 (horn manure) - stuffing cow manure into horn and burying the horn in soil over winter. Then dug up and content is dynamised (stirring the content into water - creating vortex and then reversing it) so the water memorises the power of the preparation which can then be strayed into soil as homeopatic compost 501 (horn silica) - filling cow horn with silica (quartz) and burying it for 6mths. Then dug up dynamised and strayed into soil 502-507 (compost) - Series of starters which are added to compost to activate it (yarrow, chamomile, nettle, oak bark, dandelion, valerian prepared in different ways - yarrow in deer's bladder). This assists to the decomposition of compost Ashing - Spreading ashes of weed seeds or harmful animals to ward off these hazards Traditional chemicals to spray such as sulfur and copper are also used.
89
Certification body for Biodynamic viticulture
Demeter Organic certification is a baseline
90
Precision VIticulture
Makes use of data colleced from the vineyard (soil, vigour, topography, plant growth) to respond to changed from plot to plot. Data are collected by sensors by plane (remote) or by tractor or harvester (proximal) use of GPS or GIS presents it visualy in form of map. Interventions in the vineyard such as pruning, treatments, irrigation and harvesting are carried out precisely with the aim of producing best quality and yield, reducing environmental impact and lower cost on treatments. Large scale viticulture only Can also identify quality zones
91
Advantages and diadvantages of Precision Viticulture
Advantages Detailed understanding of variations in the vineyard Ability to tailor a wide range of interventions Disadvantages Initial cost and investment Cost of software and consultancy of trained staff to interpret the data
92
Site selection
Question of style, price and quality Price of land Implication of topography and location - labour availability, mechanization, access to the vineyard, proximity to towns
93
Soil preparation
Checking soil drainage, structure, mineral composition and presence of pests and weeds Plough pan breaking (impervious layer of soil caused by years of ploughing at the same depth) has to be broken down (subsoiling) Old roots have to be removed (and burned to avoid deseases) Farmyard manure, compost and fertilizers may be applied. pH can be adjusted (too acidic soils are adjusted by Lime - calcium based)
94
Choice of grape variety for establishing vineyard depends on:
``` Suitability to climate: Time of budding Duration of annual life-cycle (time of ripening) Tolerance of drought Resistance to disease Winter hardiness Vigour ``` ``` Other factors: Style of wine Yield Cost (ex. Pinot Noir is prone to disease and difficult to grow) Law (specific grapes allowed) Availability Market demand ```
95
Choice of rootstock
Usually hybrids to take advantage of both species Mainly against Phylloxera Criteria: Pests (against nematodes) Water tolerance (drought, water logged soils, salinity) Soil pH Vigour (to take advance on ripening etc.)
96
Rootstock against root-knot nematodes
Ramsey and Dog Ridge (Vitis Champini)
97
Rootstock for drought tolerance
Hybrids of V. rupestris and V. berlandieri
98
Rootstock for water logged soils
Riparia Gloire (V. Riparia
99
Rootstock for high salinity
V. berlandieri 1103 Paulsen
100
Rootstock for acidic soils
Hybrids of V ruperstris and V. berlandieri 99R and 110R
101
Rootstock for soils with high lime content (high pH)
V. berlandieri 41B
102
Low vigour rootstock
V riparia 420A and 3309C advance ripening
103
High vigour rootstock
V. rupestris 140R for unfertile and dry soils
104
Soil health (factors)
Structure of the soil (drainage, water-holding capacity, sufficient oxygen, resistance to erosion, ability to allow roots to penetrate to sufficient depth) Amount of organic matter and humus Number of living organisms Amount of available nutrients
105
Nutrition management techniques
Fertilizers (organic x mineral) Soil cultivation Herbicides (pre-emergence x contact x systemic) Animal grazing Cover crops Mulching
106
2 types of fertilizers
Organic from flesh or composted plant or animal material Cover crops can be plought in (green manure) Cheap or free High in hummus - good for structure and water retention Organic form provides nutrients for soil organisms which turn it into inorganic form Requires a lot of labour Nutrients are available gradually Expensive to transport and spread Mineral Extracted from the ground or chemically manufactured Single nutrient or package (more tailored) Already inorganic form (immediately available) No benefit for soil organisms or soil structure More expensive but cheaper to transport and spread
107
Explain soil cultivation +advantages and disadvantages
Method of weed control that involves ploughing the soil to cut or disturb the weeds' root systems Advantages: No chemicals Crops are incorporated into the soils at the same time as removing weeds Diadvantages: Repatedly it can damage soil's structure and ecology by destruction of habitats It can increase wine vigour as there is no competititon
108
Types of herbicides and their advantages and disadvantages
Pre-emergence herbicides Contact herbicides (kill green parts) Systemic herbicides (taken in by the leaves and kill the whole plant) Advantages: Cheap in terms of labour and machinery highly effective less damaging to soil structure than cultivation Disadvantages: Risk of poisoning of operator, consumer and environment Do not encourage vineyard ecosystems Weeds can become resistant Can increase vine vigour (no competition) Not allowed in organic viticulture
109
Advantages and diadvantages of animal grazing
Advantages: No chemicals used Provide manure Source of meat Disadvantages: Vines must be trained high (risk of eating plant and fruit) Labour for taking care of animals Often susceptible to pesticides
110
Cover crops
Specificaly planted or allowed to grow to have beneficial effect on the vineyard ``` Surpress weeds Improve soil structure Compete with vine for nutrients and water Enhance biodiversity Provide surface to drive on Can be used as green manure Must be managed too No use of chemicals Not suitable for steep vineyards as slopes are becoming slippery ``` Usually legumes or cereals
111
Mulching - explain and elaborate on advantages and diasdvantages
Spreading of matter onto the vinyard soil to suppress the growth of weeds Usually straw or bark chips Advantages: No use of chemicals Can reduce water evaporation Can be ultimately cource of nutrients and hummus (promotes biological activity and structure) Diasdvantages: Bulky - expensive to transport and spread Only effective as thick layer Can increase vigour too much as there is no competition for water
112
Water sustainability in the vineyard
Water efficient irrigation systems and techniques Monitoring of water levels Drought resistant varieties and rootstocks Reducing evaporation (mulching) Reducing competition (removing weeds) Increasing humus levels to improve water retention Promoting growth of roots deep into soil (through cultivation)
113
Types of irrigation
Drip irrigation Positioned far enough from vines to enourage the roots to grow and seek water. Economic use of water Possible control to individual rows Possible to use for fertilizer (fertigation) Possible on slopes Installation is relatively expensive Clean water required Blocking with algae, minerals, salts, bacteria Cannot be used as frost protection Flood irrigation cheap to instal and maintain Not so efficient Channel irrigation Similar as flood but the water flows in furrows between vine more effective Overhead sprinklers Expensive to instal and maintain (high pressure) but can be used against frost (but not so water efficient)
114
Regulated deficit irrigation (RDI)
System of timing and regulating the amount of irrigation so the wine is put under mild to moderate water stress for a specified time within growing season. Reduces size of berries, better quality, lower yield
115
Canopy management Explanation and aims
Organisation of shoots, leaves and gruit of the vine in order to maximase grape yield and quality Maximise light interception Reduce shade within the canopy Ensure that the microclimate for the grapes is as uniform as possible (even ripening) Promote balance between vegetative and reproductive functions Ease mechanisation or manual labour Promote air circulation (reduce disease)
116
Canopy management and quality
Increased sugar levels Increased tannin levels and greater polymerisation (less bitterness) Enhanced anthocyanins Decreased malic acid Favourable aroma precursors and compounds Decreased methoxypyraxines (herbaceous character)
117
Effect of under-cropping
Vigour of the vine continues during the vine cycle because there is not much fruit to ripen. Growing shoots compete with grapes for sugar and nutriens which negatively affects ripening, resulting in lower quality fruit. Next year will have low yield because of reduced bud fruitfulness. - vegetative cycle
118
Effect of over-cropping
Vine will source carbohydrates from the trunk, cordons and roots (those which are needed for winter), which weakens the vine in future years
119
Other influences of vigour of vine
Specific grape varieties Choice of rootstock Viruses Age of vine
120
Explain yield
Measure of the amount of fruit produced. Per vine (kg per vine) Over area (kg per hectare or tons per acre)
121
Canopy management techniques
Site assessment to determine ideal grape variety rootstock vigour, planting density, row orientation Vine training Winter pruning Vine trellising Overall plant vigour management (nitrogen fertilization, irrigation, cover cropping) Summer pruning (Shoot removal, shoot positioning, pinching, shoot trimming, leaf removal, crop thinning/green harvesting)
122
Vine density
Number of vines that are planted per hectare of vineyard Influenced by: Vigour of vine (grape variety, rootstock) Type of trellising system used What access is needed between rows Vines high in vigour need greater within-row spacing to grow and be in balance Vines grown in dry conditions will need low density so the roots can spread out to search for water Between-row spacing considered for shading and machinery
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Row orientation
Depends on climatic and logistical factors North-south provides the most evn sunlight exposure (but west side facing grapes need some extra shading from afternoon sun) Wind has influence (usually 90' angle) Slopes greater than 10' need to be planted up and down the slope to prevent machinery from slipping
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What does vine training and trellising depend on
Vine vigour - natural resources (water, temperature, nutrients), planting material (rootstock, clone, variety), and presence of disease (viruses lower vigour) The site's topography (many trellising systems cannot be used on slopes) The need for mechanisation
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Vine training
The shape of permanent wood Cordon - usually spur pruned, takes longer to establish Head-trained - relatively little permanent wood, spur-pruned or replacement cane-pruned low trained (to benefit from heat, protection from wind) or high trained (avoid frost, ease labour)
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Pruning
Removal of unwanted parts of the vine Winter pruning determins the number and location of buds that will form fhoots in the coming season Spur-pruning - short sections of lignified one year old wood that have been cut to only two or three buds Easier to carry than replacement cane and can be mechanized Replacement cane-pruning - longer section of one year old wood with between 8 and 20 buds. Typically laid down horizontally and trellised for support. More complex and requires skilled labour Number of buds depends on vigour (adjusts balance of growing cycle)
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Trellising
Permanent structures of posts and wires that help to support and position the vine's shoots Untrellised vineyards - head trained spur-pruned (bush wines) Simple, easy and inexpensive. Suitable in hot climates for extra shading. Not suitable for mechanization and wet climates (high vigour with thick canopy, too much shade and risk of diseases) Trellised vineyards A) Vertical Shoot Positioning (VSP) - most common type, most simple. Cordon or head trained. Guyot - replacement cane-pruned wines. (Single or Double Guyot) for wine with low or medium vigour. B) Complex training systems for vigorous vines. Splitting canopy to reduce shade and maximise light exposure. Horizontally (Geneva Double Curtain or Lyre) or vertically (Smart-Dyson or Scott-Henry) Large yields or high quality fruit More difficult to mechanize and manage
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Summer pruning techniques
Enhancing ripening, reducing risk of fungal diseases etc. Disbudding - late in spring to adjust number of buds to bring vine in balance and remove poorly positioned buds Shoot removal - infertile or poorly positioned Shoot positioning - tucking into trellis Pinching - (cannot be mechanized) removing shoot tips at flowering to improve fruitset Shoot trimming - cutting shoots to limit growth and reduce canopy thickness to enhance gruit ripening and reduce competition for carbohydrates Leaf removal - reducing shading and lowering disease risk Crop thinning (green harvesting) - to increase ripeness, if timed near veraison it enhances ripening. Removing grapes which are the least developed. Reducing yield to comply with law
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Weather related hazards
Drought Excess of water Untimely rainfall Freeze Frost Hail Sunburn Smoke taint
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Drought
Vine needs min of 500mm in cool climate and 750mm in warm regions per year Water stress pushes the vine to close stomata to limit water loss. This reduces photosynthesis Unripe grapes, lower yealds Management options: Irrigation Rootstock - V. rupestris and V. berlandieri (110R and 140R) Drought resistant varieties
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Excess of water
Too much vegetative growth - too much shading, less ripeness, fungal diseases Water logging - reducing amount of oxygen available for roots Planting on slopes, on free-draining soils, investing in drainage system
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Untimely rainfall
During pollination and fruit set can cause millerndage or coulure. Mid season can reduce rate of ripening of fruit Around harvest can make the grapes swollen - diluted flavours, splitting, grey rot, difficulty for harvesting Options: monitoring weather, considering early harvest
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Freeze
Temperature below -20 are critical Grafts are the most in danger Management options: Site selection - hillsides rather than valley floors Moderating influence near water bodies Vineyards where snow settles most thickly thick layer protects the vine Resilient varieties such as Riesling and Cabernet Franc Hybrids for extreme conditions Hilling up (building soil around graft) Burrying vines Vines with several trunks to create space for replacement.
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Frost
Cold air collects at ground level, freezing water in the vine's growing buds and shoots. Advective frost - caused by large volumes of cold air moving from cold aread Radiative frosts - result of heat being lost on still cool nights Reducing risk Site selection - avoiding frost pockets Delaying prning postpones budburst into warmer months Late budding varieties High trained vines Bare soil between vines - bare soil collects heat and radiate it back at night Fighting frost Water sprinklers - as water freezes around the plant it releases latent heat, protecting plant Wind machines - pull warm air from above to ground lavel Oil or propane gar burning heaters or wax candles
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Hail
Rockets (seeding clouds with iodide to cause rainfall instead of hail) Netting (but this also causes shading) Number of different plots in other areas to reduce risk Insurance against hail
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Sunburn
Grape transpiration is more limited and less effective than transpiration of leaves. Grapes can reach higher temperatures than leaves and become burnt Leads to scars and splitting, fungal diseases, off flavours, bitter taste ``` Management options: Row orientation and aspect Canopy management to provide shading Additional irrigation during heatwaves to reduce water stress Agricultural suncreen spray Shading with cloth or net ```
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Smoke taint
Smoky or plastic aromas in wine Increases in period after veraison Compounds of smoke bind with sugars and are released with fermentation then increase with maturation and ageing in bottle Management option: Analysis Hand harvesting, gentle pressing, lower fermentation temperatures, reduced maceration reduce uptake of these compounds Flash detente and reverse osmosis can help but not remove it completely Blending with unaffected grapes to dilute it
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Pests
Phylloxera Nematodes Grape moths Spider mites Birds Mammals
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Phylloxera
Identified in 1863 and destroyed two-thirds of Europe vineyards Small insect which feeds on and lays eggs on the roots of vines. It weakens vine roots and causes swellings and cracks, which then lead to rot. It can spread by crawling and flying and is commonly transported by humans on roots of young vines, in soil, on equipment Symptoms: Vines die of drought in patches which increase in size each year Roots are covered with insects surrounded by yellow eggs Swellings on older roots Pale green leaf galls on under the surface Slow stunted shoot growth ad leaf yellowing appears in around 3 years, the plant dies after around 5 years Management options: Does not survive on sandy soils American species such as V. berlandieri, V. riparia, V. rupestris form hard corky layers that surround te eggs, sealing the wounds and preventing invasion by bacteria or fungi European vines grafted on American rootstocks American rootstock has low tolerance to lime which lead to creating of hybrids of more species
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Nematodes
Tiny worms, very common in soil but too small to be seen by naked eye. Feeding on vine roots, significantly reducing yield and vigour. Transmit viral diseases. Most common root-knot nematode and dagger nematode Spread by unclean nursery stock, irrigation, vehicles. Once present, they can only be managed not eliminated Management options: Soil analysis in laboratory Leaving the soil fallow for number of years Fumigate soil Plough in a cover crop of mustard plant which works as biofumigant, killing nematodes Nematode-resistant rootstock
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Grape moths
Feeding on flowers and grapes. Many species have several generations per season The wounds created are vulnerable to further attack from bacteria and fungi including botrytis Light brown apple moth (Australia) European grapevine moth Grape berry moth Management options: Introduction of bacteria Bacillus thuringiensis which produces substance that is toxic to moths Use of pheromone capsules to disrupt mating Natural predators (parasitic wasps, green lacewings, some spider species) Insecticides
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Spider mites
Pacific spider mite (California) Red Spider mite and yellow spider mite (Europe) feed on surface sells of leaves, which leads to discoloration of leaves and reduction in photosynthesis, delayed ripening, reduction in yields. They thrive in dusty conditions Management option: Use of sprinklers, cover crops, mulches to reduce dust Encourage predatory mites Pesticides
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Birds
Physical damage to grapes and threat of bacteria and fungi which can lead to rot Netting Bird scarers and noises Falcons
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Fungal diseases
Powdery mildew Downy mildew Grey rot Eutypa dieback Phomopsis cane and leaf spot Esca
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Powdery mildew
Introduced in Europe in mid 1800. Caused by fungus Erysiphe necator (Oidium tuckeri) American species are less vulnerable Common for Chardonnay and Cabernet Sauvignon (Pinot Noir and Riesling are less prone) Overwinters in buds and on canes. Then attacks young green parts of vine, which starts with dull grey patches and become black patches. Reducing yield. Grapes can laso split at veraison and become target for other infections Optimum temperatures are around 25 degrees and shade. Does not require high humidity so can spread in dry conditions as well. Management options: Keeping open canopy Application of sulfur Fungicides (but fungus can become resistant)
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Downy mildew
Caused by Peronospora, a water mould that lives within vine tissue not on the surface. Introduced from America in late 1800 Attacks especially young green parts and reduces yield by defoliating Needs rainfall and warm temperatures around 20 degrees Yellow circular oil spots and then white downy fungal growth on the underside of leaves Management options: Bordeaux mixture (sopper sulfate and lime) Other fungicides Good drainage and open canopy
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Grey rot
Botrytis cinera, loss of yield and quality. Affcted fruit should be selected out at harvest. Grapes are vulnerable if there is any point of entry The most susceptible are tight bunch varieties such as Semillon, Sauvignon Blanc, Pinot Noir Managing options: Selecting varieties with small grapes and thick skins Keeping open canopy and removing leaves around bunches Traditonal sulfur and copper sprays are ineffective Other fungicides (but develops resistance) Antagonistic bacteria - Bacillus subtilis
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Eutypa dieback
Dead arm Fungal trunk disease that leads to rotten wood and can affect whole vineyards. Kills vines over 10 years. Spores are spread by wind. Infection occures through pruning wounds especially during rain. Most susceptible varieties: Grenache, Cabernet Sauvignon, Sauvignon Blanc Management options: Puning late and applying fungicide to pruning wounds Affected trunk can be cut back 5-10cm beyond visible symptoms and treated with fungicide. Dead wood must be burt Biological control - Bacillus subtilis If the trunk is badly affected the options are to retrain from sucker (sprout at the base of the trunk) or replanting.
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Phomopsis cane and leaf spot
Infected canes whiten and break off easily. Grenache is very susceptible Management options: Fungicides Diseased wood should be burnt Pruning early or late and not in rainy weather
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Esca
Complex fungal disease caused by group of oranisms prevalent in warmer and drier climates. Enters the vine through pruning wounds. Symptoms are tiger-striping of leaves and spotting inside the wood. Reduces yield and leads to death within few years Management options: No chemical control Prevention - disease-free stock, not pruning in the rain, desinfecting pruning wounds.
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Bacterial and virus diseases
Bacterial diseases Pierce's disease Grapevine yellows Viruse diseases Fanleaf virus Leafroll virus
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Pierce's disease
Originated in America Spread by sharpshooter insect Quickly kills vines. Lives in sap channels of vines which it clogs, leaging to shrivelling and dropping leaves and death within one to five years Chardonnay and Pinot Noir especially vulnerable ``` Management options: No chemical control Reducing number of vectors Introducing predators - wasps Strict quarantine rules Developing Pierce's disease resistant vines ```
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Grapevine yellow
Group of diseases spread by vectors (leafhoppers) and untreated stock from nurseries. Symptoms: delayed budburst, drooping posture because new shoots fail to become woody, canopy turning yellow or red (in black varieties). Can live in cover crops as well Chardonnay and Riesling the most vulnerable Reduced yields and lower quality (high acidity and low sugar) Management options: No control Controlling vector Best practise in nursery
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Fanleaf virus
Group of diseases. Early leaf growth is stunted canes grow in distorted ways and leaves are very pale and malformed. Caused by dagger nematode Cabernet Sauvignon most suceptible Management options: No cure, affected vines have to be removed and soil tested
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Leafroll virus
Group of diseases Does not kill vines but reduses yield and quality (high acidity, less colour and lower sugar) Slows down growth of shoots and roots. Management options: Vines have to be tested in lab No cure - removing unproductive vines Open canopies to reduce pest
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Measurig ripeness before harvest
Sugar levels - handheld refractometer (harvested between 19 and 25 Brix which converts to 11-15% abv) Aroma and tannin ripeness - determined by taste Titration can be used to calculate acid levels pH of the juice
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Machine harvesting
Quality can be raised by: Selecting undesirable fruit by hand before machine harvesting Optical sorting devices and cruishing system with SO2 already on the harvester Sorting at arrival to winery Advantages: Faster and cheaper Avoids issues with availability of workers Can be harvested in night - preventing microbial spoilage and oxidation Saves cost of refrigeration Timing of the harvest is flexible Disadvantages: Less gentle (some juice is released and berries crushed) Not economic for small scale Not suitable on slopes Competition for rental of harvester in the best time to pick Substantial initial investment in harvester
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Hand harvesting
Advantages: Pickers can be highly selective Possible on steep slopes, irregular rows and mixed plantings Crushing grapes is avoided if handled gently Disadvantages: More expensive Carried in day light - risk of microbial spoilage and oxidation Labour availability Not suitable for whole bunch fermentation and sparkling wine or botrytised wine