WSET D1 The Vines and Vinification Flashcards
The anatomy of the vines, vineyard management and wine making
The stucture of the vine
four sections:
- the shoots,
- one-year-old wood,
- permanent wood and
- the roots.
What is the canopy?
The shoots and all of their major structures – buds, leaves, lateral shoots, tendrils and inflorescences/grape bunches.
What is the structure of the shoots?
They grow in spring from buds retained from the previous year.
Structure:
- buds,
- leaves,
- tendrils,
- lateral shoots
- inflorescences or grape bunches
What is the main role of the shoot?
To transport water and solutes from the other structures of the vine. It also stores carbohydrates.
What are solutes?
Substances that dissolve in a liquid to fomr a solution. It includes sugars and minerals.
What is a node?
A swelling along the shoot, where the other structures are attached.
What is an internode?
The length between two nodes.
What are canes?
The shoots that lignify in autumn (become woodey, rigid and brown)
What is petiole?
The name of the leaf stalk.
Where do buds form?
Between the leaf stalk (petiole) and the stem.
What are buds?
Buds as they mature they contain all the structures that will become the green parts of the vine.
- stem,
- buds
- tendrils
- leaves
- often inflorescences
Types of buds?
Two types.
- Compound buds or latent buds
They form in one growing season and break open in the next one. They produce the shoots in the next growing season. It usually contains a primary bud and smaller secondary and tertiary buds that only grow in case of damage to primary, eg. spring frost. - Prompt buds
Form and break open in the same growing season on the primary shoot. That shoot has just grown from a compound bud. It produces lateral shoots.
What is a lateral shoot?
They grow from buds that are formed in the current year. They contain stem, buds, tendrils and sometimes inflorescences. They allow the plant to carry on growing if something happens to the tip of the primary shoot.
They also provide extra leaves for photosynthesis.
If growns close to the base, they can cause too much shade.
Pinot Noir often produces inflorescence on lateral shoots. The grapes from these ripen later. (They might be removes by green harvest) If not it has to be harvested separately.
What are tendrils?
Support the vine. Attach themselves to the trellis, keeping the canopy in place.
Leaves, their parts and role
Responsible for photosynthesis.
They let water diffuse and take up CO2 through the stomata.
Stomata
Pores on the underside of the leaves.
Transpiration
Water diffuses from the leave, that causes the vine to draw water ad nutrients from the soil to the leaves.
What happenes is waterstress?
The stomata partially close. This helps to conserve the water but limits photosynthesis as the closes stomata doesn’t take up CO2.
What is inflorescence?
Cluster of flowers on the stem. They will become bunches of grapes. There are usually one to tree per shoot.
What is fruit set?
Inflorescence becoming bunches of grapes.
What are bunches?
Infertilizes inflorescences. It depends on the variety of the how many flowers turn into grapes.
Parts of the grape?
- Stem
- Pulp - Most of the weight of the grape. Contains water, sugars, acids and aroma compounds and precursors. Mostly colourless. (Alicante Bouschet is red)
- Skin - contains aroma compounds and precursors, tannins, colour compounds
- Seeds They turn brown from yellow as they mature. they contain oils, tannins and the ebryo fo the growth of a new plant.
What is the one year old wood?
The shoot of the previous growing season. Kept for they new growing season when pruning. It contains the compound buds for the new shoots of the new growing season. It will be a cane or a spur by pruning.
Permanent wood
is the woody part of the vine. It is more than a year old, including the trunk.
What is a cordon?
Horizontal arms of the permanent wood. They store carbohydrates and transport water and solutes to other parts.
What is the role of roots?
- Anchor the vine.
- Take up water and nutrients though the root tips
- Store carbohydrates in winter
- Produce hormones that are important for growing and ripening.
They grow 50cm - 6m under the ground.
Types of propagation
- cuttings (section of a vine that is planted and will grow a new plant, can be grafted on rootstocks)
- layering (filling gaps in the vineyard by bending a cane down and bury a section under the ground.) (as not grafted on a rootstock in doesn’t protect from phylloxera)
Both methods create genetically identical plants to the parent plant.
Though seeds they are not genetically identical.
Clones are…
If plants from cuttings or layering show different characteristics, they will be propagated by cuttings to grow new vines with these characteritics. This in Clonal Selection.
Pinot Noir Clones
115 - low yield
521 - high yield
Precose - early ripening
Mutation
Sometimes the mutation is so significant thatthe new vine will be considered/classified as a new variety.
For example Pinot Noir, Pinot Blanc, Pinot Gris, Meunier
Mass selection
is a clonal selection. They select the best performing vines and take their cuttings for propagation.
If the parent vine has a disease, the cutting will have too.
How to produce new grape varieties?
They come from seeds. The pollen from one vine is transferred to the stigma of another vine. After this cross fertilisation grapes develop and the seeds from these vines are planted for new growth. If they have the characeristis they were looking for, they will be propagated by cuttings.
Registered in the OIV catalogue if it is worth for commercial sales.
What is crossing?
When two the parents are from the same spicies. eg. Pintotage (Pinot Noir x Cinsault (Hermitate in SA) Muller Thurgau ( Rielsing x Madelein Royale) Cabernet Sauvignon (Cabernet Franc x Sauvignon Blanc)
What is hybrid?
Parent vines from different species.
eg. Vidal Blanc = Ugni Blanc (vitis vinifera) x Seibel (American paretage)
Vine growth cycle
- Dormancy (temp. below 10°C) (-15°C damages the vine, -20°C kills the vine) (bad: extremely low or high temperature)
NH: Nov-March SH: May-Sept - Budburst (green shoots start to emerge)(above 10°C)
NH: March-April, SH: Sept-Oct (Bad: frost, cold soils)
Higher soil temperature (sandy soils rather than clay soils encourage earlier budbrurst.
Depends on grape variety as well.
Later pruning = delay budburst - Shoot and leaf growth
(bad: Low carbohzdrate levels, water stress)
NH: March-July, SH: Sept-January - Flowering and Fruit Set (see parts of vine flower)
(bad: rainy, coudy, windy, cold)
NH: May-June, SH: Nov-Dec - Grape development (needs sunlight, warmth, mild water stress, bad: too much water and nutrients, excessive shading very cold or very hot) NH: June-October SH: December-April
- Harvest
- Leaf fall, dormancy
Early budding varieties
Chardonnay, Pinot Noir, Merlot, Grenache.
Late budding varieties
Cabernet Sauvignon, Sauvignon Blanc, Syrah
Vigour
The speed of shoot growth, including the growth of shoots, leaves and lateral shoots, effecting yield and ripening.
eg. high vigour = long shoots, large leaves, lots of lateral shoots.
Conditions for sucessful flowering
Usually 8 weeks from budburst
- Min 17°C
Parts of the vine flower
Successful fruit set?
30% of flowers becume grapes, can range up to 60%.
Optimal temp. 26-32 °C
Forms of irregular fruit set and their cause
Coulure:
The fruit seet fails for a proportion of flowers. Ovule fertilisation in unsuccessful, and no grapes develop. Some is normal but it can reduce yield.
Cause: inbalance of carbohydrates becauce of low photosynthesis because of cold, couldy, hot, arid weather conditions, or too fertile soils = vigour = diverting carbohydrates.
Millerandage:
A high proportion of seedless grapes, that are smaller than normally. It reduces volume. Some small grapes can stay small and unripe. Uneven bunches.
Cause: cold, wet, windy weather.
More susceptibel: Chardonnay and Merlot
Stages of Grape Development, what the vine needs and what conditions are bad at these stages?
June-October/December-April
Vine needs: sunlight, warmth and mild water stress
Adverse contitions: too much water and nutrients, exessive shading, very cold or very hot weather
Stages:
- Early grape growth
Hard green grapes start to grow, tartaric and malic acids accumulate. Some aroma compounds and precursors, eg Methoxypyrazines. Tannins accumulate and are very bitter at this stage. Water gets transported to the grape by the xylem.
Too much water and nitrogen can prolong this stage and encourage shoot growth. Delays the ripening stage. Shoot growth continues during this stage but slower than before.
- Veraison
The Grape growth slows down for a few days (lag phase) The grape cell walls become more stretchy, green-coloured chlorophyll in skin cells breaks down and the grapes start to change colour. Black varieties beome red du to the synthesis of anthocyanins, white grapes start becoming yellow.
- Ripening
Cells expand, sugar and water accumulates, acid levels fall. Tannins, colour and aroma precursors and compounds develop. Water flow through xylem slows down, transport of sugar solution by phloem starts.
- Extra ripening
Grapes left on the vine start to shrivel. Loss of water, concentrated sugar. Extra ripe aromas.
What is lag phase?
Those few days during veraison when the grape growth slowes down.
Aroma compounds and precursors and their contribution
Methoxypyrazine - herbaceous aromas and flavours in wines, Sauvignon Blanc, Cabernet Sauvignon, Cabernet Franc
Anthocyanine - colour of black grapes
Terpenes
What is ideal temperature and sunlight for max rate photosynthesis?
18-33 Celsius degrees (64-91 degrees F), sunlight levels with above one third of full sunshine
What are xylem and phloem?
Plants have tissues to transport water, nutrients and minerals. Xylem transports water and mineral salts from the roots up to other parts of the plant, while phloem transports sucrose and amino acids between the leaves and other parts of the plant.
How do tartaric, malic acid and other aroma compounds change during ripening?
Tartaric acid level doesn’t change, only gets dilluted as sugar and water accumulates.
Malic acid level falls quickly, as it can be metabolized in respiration.
Respiration is slower at cool temperatures, so less malic acid is lost during respiration.
Methoxypyrazine level falls.
Other aroma compounds and precursors increase. eg terpenes (give floral, citrus and grapey aromas)
Tannin slightly decrease by polymerisation, become less bitter.
Anthocyanins increase, most rapidly between 15 and 25 celsius degrees
Effects of temperature
Dormancy - under 10°C
Winter freeze, damage wine - -20°C
Kill the vine - -25°C
Budburst - above 10°C
New shoots and leaves development - optimum - 18-33°C
Optimum flowering temp - above 17°C
Pollen germination optimum 26-32°C =
= Fruit set - 26-32°C
Bud fruitfulness above 25°C (During flower set and fruit set time)
Final month of ripening mean temp above 21°C + rapid acidity loss, under 15°C too much acid
Anthocyanin synthesis optimum 15-25°C (tannin too)
Photosynthesis at maximum rate 18-33°C
Key resources needed by the vine and the natural factors that affect them:
- Temperature and sunlight:
- Latitude
- Altitude
- Slopes and Aspect
- Proximity to Water
- Winds
- Soil characteristics
- Mist, Fog and Clouds
- Diurnal range
- Water:
- Rainfall
- Characteristics of Soil and Land
- Evapotraspiration Rate
- Nutrients
- Soil factors that influence water availability
- Soil pH eg. iron poorly available in high pH (limestone) - leads to chlorosis, or vines struggle to take up phosphorus in highly acidic soils.
- Organic/inorganic nutrient compounds
- Soil textures (high proportion of clay holds nutrients, sandy soils don’t
- Topography (slopes = less nutrients as thinner, less fertile soils)
Macronutrients in soil and their role
- Nitrogen (N) - component of cell proteins, chlorophyll, hormones and nucleic acids. Vine growth, vigour and grape quality. Low level problematic for fermentation.
- Potassium (K) - vine growth, regulate flow of water and sugar in the vine. High: problem of taking up magnesium, poor yields and ripening. High (K) in grapes = high pH) Low: low sugar accumulation.
- Phosphorus (P) - photosynthesis, energy, root growth. Only small amount, naturally present in soil.
- Calcium (Ca) - cell acidity, component of cell walls, structure of the plant, photosynthesis. Deficiency is rare = poor fruit set.
- Sulphur (S) - essential constituent of amino acids and enzymes.
- Magnesium (Mg) - found in chlorophyll, regulates internal acidity, sugar metabolism, photosynthesis. Encourages ripening.
What are the micronutrients?
- Boron
- Manganese
- Copper
- Iron
- Molybdenum
- Zinc
- Cobalt
- Chlorine
- Silicon
What is pH?
Soil acidity is mesured by the pH scale. This measres the concentration of hydrogen ions in the soil.
- Acid pH 4 - 6.9
- Neutral pH 7
- Alkaline pH 7.1 - 8.5
Grapevines cannot tolerate soil pH below 5. In these soils aluminium becomes available to the root system, which poisons the plant.
Limestone-rich soils tend to have high pH (alkaline). This inhibits the uptake of iron and other micronutrients, increasing the risk of chlorosis.
Soils then to become more acidic with culitvation due to the release of organic acids on the breakdown of organic material.
What influences soil fertility?
- Soil texture
- Soiil structure
- Organic matter content
- Mineral content
- Availability of water and air
- level orf acidity/alkalinity
Soil texture
Soil texture is described by the size of particles that make up a soil. Particles are graded according to their diameter iin millimetres.
- Clay < 0.002mm
- Silt < 0.02mm
- Find sand < 0.2mm
- Sand < 2mm
- Gravel > 2mm
Clay is finely textured, particles are very small. They have large surface area compared to their volume, so they are effective at holding water and nutrients.
Sand are relatively large and have small surface area to their volume. Water can drain though them easily.
What is soil?
The upper layer of the earth, made up of geologiacal sediment.
Geological sediment comes from the weathering of the bedrock.
Soil structure
Describes how the soil particles form lumps or crumbs (aggregates).
Size affects:
- water drainage
- root growth
- workability of the soil
Influenced by:
- Organic matter content
- Earthworms and other soil organisms
- Wetting and drying
- Freezing and thawing
- Presence of plant roots
- Texture
- Drainage
- Compaction
Why is humus important?
Soils that are high in sand or gravels and pebbles need some clay or humus to bind them together.
Humus is organic matter that originates from plant and animal remains, animal excreta. It is partially decomposed by soil microbes and earthworms. Its texture is spongy and absorbs water and nutrients well.
What is climate?
The annual pattern of temperature, sunlight, rainfall, humidity and wind averaged out over usually 30 years.
Climate classifications
Models to help to group vineyard areas into different climatic bands.
- GDD (Growing Degree Days) - Amerine and Winkler (1944) Originally created for California. Calculation: Average mean temperature of the month - 10°C x Number of days in that month. Make same calculation for each month and add them together = GDD
- Category I-V.*
- I. Cool: eg Chablis, Mosel, Champagne*
- II. Moderate: Napa, Bordeaux, Northern Rhone*
- III. Warm: Barossa Valley, Stellenbosch, Southern Rhone*
- IV. Hot: Best for fortified wine.*
- V. Tropical: Table grapes, raisins.*
- Huglin Index - GDD but takes into account hte mean and maximum temperatures and the increased day length at higher latitudes. Designed for Europe. Bands: A, B, C1a, C1b, C2, C3a, C3b.
- A. Germany excl. Baden*
- B. Loire, Champagne, Alsace, Austria*
- C 1a Bordeaux, South West France, Rhone, Vinho Verde*
- C 1b Hungary, Trentino-Alto Adige*
- C 2 Languedoc-Roussillon, Provence, Northern Spain (exc. Atlantic coast), most of Italy*
- C 3a Parts of Greece*
- C 3b Portugal (exc Vinho Verde), Southern Spain, Puglia, Sicily, most of Greece*
- MJT (Mean Temperature of the Warmest Month) July/January - 6 bands from cold to very hot - Measures continentality, humidity and hours of sunshine.
-
GST (Growing Season Temperature) - Mean temperature of the whole growing season. Similar to GDD, bands from cool to hot. WSET uses this.
- Cool climates - 16.5°C or below
- Moderate climates - 16.5°C - 18.5°C
- Warm climates - 18.5°C - 21°C
- Hot climates - above 21°C
-
By temperature and rainfall patterns in temperate zones:
- Maritime
- Mediterranean
- Continental
*
What is continetality?
The difference between the annual mean termeprature of the hottest and coldest month.
Inland: Protected from ocean influences = high continentality.
By large bodies of water: cooling and warming effect. Milder winter, cooler summes. Lower continentality. Maritime, mediterranean.
What is weather and its effects?
Annual variation that happens realitve to the climatic average. eg. amount and timing of rainfall.
- style and quality of wine
- vintage variations
- yield
- sugar and acid levels
- tannin and aroma ripeness
Effects of climate change?
- Rise in temperature
- greater evapotranspiration =estreme water stress = potosyntheis to stop (California, South Africa)
- speed up rate of sugar accumulation + reduction of acidity, but do not quicken ripening of tannin and aroma compounds = grapes may be picked with higher levels of sugar = higher alcohol levels = lower acidity levels = higher pH levels
- aroma profiles/hallmark aromas change: eg. Moderate climate Syrah shows black pepper characteristics in the Northern Rhone. This may not develop with rising temperatures.
- Greater weather viariability
- Extreme weather events
Different approaches to grape growing (Types of viticulture) and their pros and cons
-
Conventional Viticulture - production orientated farming
- mechanisation
- chemical inputs
- irrigation
- clonal selection
- using herbicides, agrochemicals to control pests
- mineral fertilisers
- Pros:Ability to mechanise
- Reduction of competition from other plants
- Increase yields and minimising cost
- Cons:
- Depleted nutrients, need of more feritlizers
- Residual chemicals (hazard for environment, workers and consumers)
- Pros:Ability to mechanise
-
Sustainable Viticulture (economic, social and environmental sustainability)
- promote natural ecosystems
- maintain biodiversity
- manage waste
- minimise applications of chemicals and energy use
- reduce impact on hte wider environment
- in/depth knowledge of life-cycles of vine and vineyard pests, monitor weather
- predict and prevention
- integrated pest management (IPM) (lutte raisoné) similar to orgainc, but uses chemicals interventions when necessary
- Pros:
- more thoughtful approace
- minimize interventions
- reduction of spraying
- cost saving
- Cons:
- term is not protected, no clear standards
- standards can be set too low
- Pros:
-
Orgainc Viticulture
- Aims to improve the soil and the range of microbes and animals (eg earthworms), increase the health and disease/resistance of the vine by it.
- Rejects manufactured fertilisers, fungicides, herbicides and pesticides.
- Key features are:
- Application of compost that breaks down in the soil. Structure, nutrients.
- Natural fertilisers (animal dung, natural CaCO3)
- Cultivation of cover crops. Erosion, life of the soil.
- Reduction of monoculture (planting hedges, biodiversity)
- They use traditional remedies usch as sulfur and copper sulfate.
- Use of natural predators eg grey rot Bacillus subtilis competes with Botrytis cinerea
- IFOAM (International Federation of Organic Agriculture Movements)
- Pros:
- Improvement of health and disease-resistance of the vine
- Health of soil
- elimination of synthetic chemicals
- saving cost of synthetic chemicals
- Cons:
- Smaller yields
- increased reliance on copper sprays, build-up in soil
- cost and time on certification
- Pros:
-
Biodynamic Viticulture
- Rudolf Steiner, Maria Thun
- Organic practices but also philosophy and cosmology.
- Vineyard soil is the part of a connected system with the Earth, other planets and the air. Cycles of planets, moon and starts.
- Homeopathic remedies called ‘preparations’ are used.
- 500 (horn manure)
- 501 (horn silica)
- 502-507 (compost activation by starters, such as yarrow, chamomile, nettle, oak bark, dandelion, etc.)
- traditional chemicals so spray against disease, including sulfur and copper. Ashing
- DEMETER certification body
- Pros and cons same as organic
-
Precision Viticulture
- makes use of date collected from the vineyard (soil, vine vigour, topography, etc.) to respond to changes
- Data is collected by sensors. Remote: aircraft, proximal: mounted on a tractor or harvester. use of GPS (Global Positioning Systems) and GIS (Geographical Information Systems) Presented in maps.
- Data collected can be eg. composition of soil, growth of canopy.
- Variable-rate application technology: interventions are targeted in the light of the data collected.
- Pros:
- affects yield and quality within vineyard
- ability to tailor interventions to individual blocks or rows of vine
- Cons:
- costs of data collection
- cost of sensors and software, consultancy, trained staff
- Pros:
What to consider when establishing a vineyard?
- Style, quality and price of wine
- Price of land
- Location and topography
- Irrigation
- Vineyard site and distance from winery
- Proximity to towns, cities for labour, supplies
- Local and national laws
- landscaping (steep slopes=terraces)
Soil preparation
Assess and rectify:
- drainage,
- structure,
- mineral composition
- pests
- unwanted plants
- topography
- manure, fertilizers, compost
What to use for acidic soil?
lime, (calcium based substance) spread and ploughed in
What to consider when choosing grape variety?
- time of budding
- duration of annual life-cycle
- tolerance of drought
- resistance to disease
- winter hardiness
- vigour
- style of wine
- yield
- cost
- law
- availability
- market demand
What to consider when selecting rootstocks?
Tolerance to
- phylloxera
- nematodes
- lime
- acidity
- caliinity
- drought
- waterlog
Vigour
Preferred soil type
What are the principal vine species and characteristics?
Vitis vinefera (Europe)
- vigour and ripening variable
- resistance to phylloxera and nematodes is poor
Vitis riparia (central and eastern North America)
- low vigour
- early ripening
- resistance to phylloxera
- suffers from cholorsis (iron deficiency) in chalky soils
- USE: high fertile soils
Vitis rupestris (Southern centre of USA)
- vigorous with deep rooting
- good resistance to phylloxera
- suseptible to chlorosis
- USE: poor soils with limited water availability
Vitis berlandieri (Southern USA and Mexico)
- vigorous, deep rooting
- high resistance to chlorosis
- cuttings hard to root so usually used as hybrid with riparia or rupestris
- hybrids are lime-resistant
Vitis labrusca (North eastern USA)
- parent in hybrids such as Concord
- not often used as a parent for rootstock production
Choice of rootstock based on different criteria
-
PESTS
- phylloxera
- Riparia Gloire de Montpellier (Vitis riparia)
- 420A - Millardet et de Grasset (V. rip x V. berl)
- 99R Richeter (V. berl x V. rup)
- nematodes
- Dog Ridge (Vitis champini)
- Ramsey (Vitis champini)
- phylloxera
- WATER
- drought
- 110R - Richter or 140R - Ruggieri) (V. berl x V. rup)
- water-logged soil
- Riparia Gloire de Montpellier
- salinity
- 1103P - Paulsen (V. berl x V. rup)
- drought
- SOIL pH
- Acidic soils
- 99R Richeter (V. berl x V. rup)
- 110R - Richter or 140R - Ruggieri) (V. berl x V. rup)
- High pH - high lime content
- 41B - Millardet et de Grasset (V. berl x V. vinifera) (used in Champagne)
- Acidic soils
- VIGOUR
- Low (advance ripening, great for cool climate)
- 420A - Millardet et de Grasset (V. rip x V. berl)
- 3309C - Couderc (V. rip x V. rup)
- High
- 140R - Ruggieri (V. berl x V. rup) to boost vine growth in unfertile soils and dry conditions
- Low (advance ripening, great for cool climate)
Consider style of wine:
eg. High vigour rootstock for sparkling wine where high yields of grapes with delicate aromas and high acidity is prefered to lower yields with more concentrated aromas, colours and/or tannins.
Types of nutrient management
Application of fertilisers
Cultivation - weed control
Herbicides
Animal grazing
Cover crops
Mulching
Types of fertilizers
- Organic: Derived from fresh or composted plant or animal materials (manure, slurry, green manure)
- pros
- fertilizers are cheap or even free
- some are high in humus that is good for the soil structure as well
- nutriens become available gradually (needs breaking down)
- cons
- organic nutrients need to break them down, so needs incorporation into soil, that needs labour.
- bulky, expensive to transport
- pros
- Inorganic - syntethic: manufactured from minerals extracted from the ground or synthetic chemicals
- pros
- can provide a single nutient or several so can be tailored
- already inorganic so more readily available for the vines
- cheaper transport, as more concentrated
- cons
- more expensive
- pros
Cultivation
Weed control by ploughing the soil to cut or disturb the weeds’ root systems
Pros: no chemicals (organic, biodynamic use) enables fertilisers
Cons:
- if repeated, can damage the soil structure and ecology,
- costly as needs skills and machinery,
- buries weed seeds that grow back,
- no competition for water, so can increase vigour
Herbicides
3 types of chemical sprays
- Pre-emergence herbicides: before weeds establish. Inhibits germinations of seedlings.
- Contact herbicides: sprayed on established weeds. kills the green parts that they contact, plant dies.
- Systemic herbicides: sprayed on established weeds, taken in by the leaves and then travels up and down in the sap, killing the whole plant.
Pros: cheap, highly effctive, less damage to soil structure.
Cons: risks of poisoning operator, consumer, environment, vineyard ecosystem, increase vigour, resistans of plants
Animal grazing
Pros: no chemicals, vineyard manure, source of meat for humans
Cons: training vines high, caring for animals that are suseptible to vineyard pesticides
Cover crops
For: suppress weeds, improve soil sturcture, manage soil erosion, enhance biodiversity, surface to drive on.
Beans, clover, ryegrass, oats
If ploughed in, provides organic matter.
Pros: no chemicals, infuence vigour, good surface for machinery
Cons: In poor soils reduction of vine vigour is not good, diffuculty of mowing under rows, unsuitable for sloping vineyards as they are slippery.
Mulching
Biodegradable materials, such as straw or bark chip.
Pros: no chemicals, reduce water evaporation from the soil (dry climates), source of nutrients and humus
Cons: very bulky, expensive to transport, needs thick layer, increase vigour as no competition for vine.
Water management
Irrigation/drainage
Source of water: river, lake, reservoir, bore-hole
Effective use of water (sustainability)
- water-efficient systems + better monitoring
- drought tolerant varieties (eg. Grenache)
- reducing evaporation by mulching
- reducing competition (weeds)
- increase humus level for water retention
- promoting the growth of vine roots deeper
Types of irrigation
- drip irrigation
-
pros:
- economic
- supply individual rows or blocks
- supply fertiliser
- can be used on slopes
- cons:
- costs
- clean water (mud blocks, algea, bacteria)
- no use for frost protection
-
pros:
- flood irrigation (behind a sluice)
- pros: cheap to install and maintain
- cons: inefficient
- channel irrigation (water flows down furrows)
- increased efficiency
- overhead sprinklers
- pros: used for frost protection
- cons: expensive to install, needs high water pressure, uses large amount of water
Amount and timing of irrigation: RDI (Regulated Deficit Irrigation)
Aims of canopy management
- maximise the effectiveness of light interception by the vine canopy
- reduce the shade within the canopy
- ensure that the microclimate for the grapes is as uniform as possible so that grapes ripen evenly
- promote balance between the vegetative and reproductive functions of the vine
- arrange the vine canopy to ease mechanisation and/or manual labour
- promote air circulation through the canopy to reduce incidence of disease.
Effects of sunlight exposure in the canopy
- increased sugar levels in grapes through greater overall photosynthesis in the vine
- increased tannin levels and greater polymerisation of those tannins, leading to less bitterness
- enhanced anthocyanin (colour) development in black grapes
- decreased malic acid – warmer grape temperatures lead to more malic acid being broken down in cellular respiration, otherwise, especially in cool climates, acidity levels in the wine could be unpleasantly high (tartaric acid remains)
- increased levels of some favourable aroma precursors and aroma compounds (such as terpenes)
- decreased methoxypyrazines, which give herbaceous characters in grape varieties such as Cabernet Sauvignon, Cabernet Franc, Sauvignon Blanc
Canopy management techniques
- vine training
- winter pruning
- vine trellising
- overall plant vigour management (nitrogen fertilisation, irrigation, cover cropping etc.)
- summer pruning
- – disbudding
- – shoot removal
- – shoot positioning
- – pinching
- – shoot trimming
- – leaf removal
- – crop thinning/green harvesting.
What does trellising and training depend on?
- vigour of the vine
- topography of site
- need for mechanisation
Types of trainig
- head training: relatively little permanent wood. The permanent wood = trunk, sometimes with a few short stubs growing from the top. These vines can either be spur-pruned or replacement cane-pruned.
- cordon training: trunk and one or more permanent horizontal arms of permanent wood, typically called ‘cordons’. They are usually spur-pruned. (longer to establish)
Types of pruning
Spur pruning – short sections of one-year-old wood that have been cut back to only two or three buds. (cordon training) or around the top of the trunk (head training). can be mechanised.
Replacement cane pruning – Canes are longer sections of one-year-old wood and can have anything between 8 and 20 buds. They are typically laid down horizontally and need tying
to a trellis for support and positioning.
Trellising
- Untrellised vineyards: head-trained and spur- pruned, and are called bush vines. They are easy and inexpensive to develop. The shoots may also droop down, providing shade for the grapes. These vines are usually planted in hot and sunny regions, such as La Mancha in Spain, so some shade can be beneficial to avoid the grapes becoming sunburnt.
- VSP - vertical shoot positioning: The vine’s shoots are trained vertically and are held in place onto the trellis forming a single narrow canopy. It can be used on both head-trained, replacement cane-pruned vines and cordon-trained, spur-pruned vines. When used on replacement cane-pruned vines, it is typically called Guyot training: one cane is retained in Single Guyot; two in Double Guyot.
- Complex trellising systems: for more vigorous vines.The canopy can either be split horizontally, in the case of Geneva Double Curtain (GDC) or Lyre, or vertically, as in the case of Smart-Dyson or Scott-Henry. Using these systems, it is possible to make best use of vineyard space and resources to produce large yields of high-quality fruit, but they are more difficult to manage and mechanise.
