D1 Wine Production - 2020 Flashcards
What are the most important North American vine species?
Vitis labrusca
Vitis riparia
Vitis Berlandieri
Vitis rupestris
What are the four sections of the vine structure?
The main shoots,
One-year-old wood
Permanent wood
Roots
What is the canopy?
The main shoots and all of their major structures:
- stem
- buds
- leaves
- lateral shoots
- tendrils
- inflorenscences/grape bunches
What is the function of the stem?
The stem transports water and solutes to and from the different structures. It is also a store of carbohydrates. The little swellings along the stemare called nodes. the lengths of stem in between the nodes are called internodes
What types of buds are there?
Compound buds (latent buds): form in one growings season and break open in the next growing season. They produce the main shoots in the next growing season. Within a compound bud there is a primary bud and smaller secondary and tertiairy buds. Those only grow if damage has occured to the primary bud
Prompt buds: They form and break open in the same growing season. They form on the main shoot and produce lateral shoots.
What is lignify?
When in fall the green shoots become woody and rigid
What is the petiole?
The leaf stalk
What is a lateral shoot?
Lateral shoots grow from buds formed in the current year (prompt buds). They have sometimes inflorescences. The main function is to allow the plat to carry on growing if the tip of the main shoot has been damaged or eaten. It can provide an additional source of leaves for photosynthesis (extra sugar). Lateral shoots that are near the ends of the main shoot are okay, at the base they are undesirable as they impede flow and can shade the fruit too much.
What is second crop?
If a lateral shoot produces inflorescences. These bunches often ripe later than those on the main stem. If harvested at the same time, the bunches on the second crop will be higher in acidity, lower in potential alcohol, may have unripe tannins and aromas/flavours and, in black grapes, less colour development. If the second crop is removed during growing season it is called green harvesting.
Tell me about photosynthesis in the leaves
The sugars produced in photosynthesis are used for vine growth and metabolism. Stomata (pores) open on the underside of the leaves, letting water diffuse out and carbondioxide to enter. As water diffuses from the leaf, a process called transpiration draws water and nutrients from the soil up through the vines to the leaves. These stomata partially close if the vine is water stressed. This can help conserve water, but limits photosynthesis preventing carbon dioxide from entering the vine.
What are bunches?
A bunch of grapes is a fertilised inflorescence.
What are the elements of a grape?
Pulp: it contains water, sugars, acids and some aroma compounds and aroma precursors. Of most grapes the pulp is colourless, exceptions include teinturier varieties (e.g. Alicante Bouschet)
Skin: it contains a high concentration of aroma compounds and aroma precursors, tannins and colour compounds. The powdery waxy coating is called bloom.
Seeds: they mature inside the grape. They contain oils, tannins and the embryo.
What is one-your-old wood?
It refers to the main shoots from the last growing season that were kept at pruning. Depending on pruning, the one-year-old wood will either be called a cane or a spur
What is permanent wood?
The trunk and the parts of the vine that are older than one year. A trunk can have one or more horizontal arms of permanent wood: cordons.
What is the function of the roots?
They anchor the vine and take up water and nutrients. The store carbohydrates and produce hormones that have important functions within vine growth and grape ripening.
How are vines propagated?
Through:
Cutting: a section of a vine shoot that is planted an then grows as a new plant. The advantage is that it permits the use of rootstocks by grafting and many small cuttings can be taken from a vine and propagated at the same time.
Layering: using shoots from an established neighbouring vine to produce a new vine. This is done by bending down a cane and a section is buried in the ground. The disadvantage of this technique is that the new vine is not resistent against phylloxera or have the qualities that a choice of rootstocks offers
What is clonal selection?
When vines with particularly favourable characteristics are selected by vine nurseries or grape grower for propagation by cuttings in order to grow new vines with these favourable characteristics. Each of the clones is a slightly different vine.
What is mass selection?
When the best-performing vines are selected after several years of monitoring and recording their performance after cultivating cuttings.
What are advantages and disadvantages of mass selection
Advantages:
- it increases the diversity of planting material in the vineyard and troughout the region
- vineyard owner is using their own unique planting material
Disadvantage:
- costly in time and labour
- if the parent vine is infected by disease, this is likely to be passed onto the new vines, so this technique can increase the spread of vine diseases
How are new grape varieties produced?
The pollen from the stamens of the flowers of one vine is transferred to the stigmas of the flowers of another vine and fertilisation occurs, this is called cross fertilisation. When the grapes develop, the seeds are planted and grown, with all different characteristics (eg siblings).
A new grape variety must be registered on the OIV catalogue.
When the two parents are from the same species, offspring is called a cross. When the two parents are from different species, the offspring is called a hybrid (eg Vidal Blanc from ugni blanc (v.vinifera) and a member of the seibel family (american parentage))
What are the stages of the vine growth cycle?
- Dormancy 1-3
- Budburst 3-4
- Shoot and leaf growth 3-7
- Flowering and fruit set 5-6
- Grape development 6-10
- Harvest 9-10
- Leaf fall and dormancy 11-12
What does the vine require for photosynthesis?
Acces to adequate water, sunlight, warmth and nitrogen. Carbon dioxed is also required, it becomes the limiting factor as it is out of control of the grape grower.
Warmth is needed for respiration, the proces in which energy is released from food substances, in this case, sugar.
Nutrients are important for cell structure and function and therefore vine growth and reproduction
What does the vine needs during the dormancy stage?
Dormancy is from november to march (NH) or may to september (SH). The vine needs temperatures below 10 degrees celcius, then the vine does not grow.
Without leaves, no photosynthesis. The vine supports its growth by using stores of carbohydrates.
Adverse conditions in this period:
- extremely cold temperatures (-15). When the temperature is -25, v. vinifera will be dead
- unusually mild temperatures
When is budburst and what factors does it depend on?
Budburst is from march to april (NH) and september to october (SH). It depends on these factors
- air temperature: above 10 degrees celcius . In continental climates budburst is relatively uniform and it has positive implications for homogeneity of later stages in the growing season. In maritime climates, budburst can be less synchonised. A few unusually mild winter days cause early budburst, any cold days and frosts that follow can potentially harm the newly budburst.
- Soil temperatures: higher soil temperatures encourage early budburst. Sandy soils warm up more quickly
- Grape variety: Early budding (<10): Chardonnay, Pinot Noir, Merlot and Grenache. Late budding (>10): Sauvignon Blanc, Cabernet Sauvignon and Syrah
- Human factors: carrying out winter pruning late in the dormant period can postpone budburst (used in regions with spring frosts)
When do shoots and leaves grow and what does the vine need at this stage?
March to July (NH) and september to January (SH)
The vine needs stored carbohydrates, warmth, sunlight, nutrients (nitrogen, potassium and phosphorus) and water.
Adverse conditions include low carbohydrate levels (caused by conditions in the precious growing season) and water stress
When does flowering and fruit set occur?
May to June (NH) and November-December (SH)
What is the process of flowering and fruit set?
The opening of the individual flowers within and inflorescence. Within this process, the pollen-laden stamens are exposed. The pollen grains are shed and land on the moistened stigma surface, a process called polination. Here, they germinate, with each pollen grain producing a pollen tube. These pollen tube delivers the sperm cells, which fertilise the eggs in the ovule. This leads to the formation of a grape berry. The fertilised ovules form seeds, with up to four per grape. The wall of the ovary enlargers to form the skin and pulp of the grape.
Fruit set is the term used to describe this transition from flower to grape.
What are conditions for successful flowering?
Flowering typically takes place within eight weeks of budburst, but the timing is temperature dependent. Warm conditions (>17) are favourable for successful flowering
What are the conditions for successful fruit set?
Typically 30 percent of the flowers will become grapes. Pollen germination requires warm temperatures (26-32 degrees). Pollen tube growth is negatively affected by cold, rainy and/or windy conditions. But very hot conditions lead to water stress
Name the two common forms of irregular fruit set
- Coulure: fruit set has failed for a high proportion of flowers. It is caused by an imbalance in carbohydrate levels, this leads to low rates of photosynthesis. This can be the result of either cold or hot weather, vigorous shoot growth, very fertile soils, heavy application of fertilisers, vigorous rootstocks. Susceptible grape varieties are Grenache, Cabernet Sauvignon, Merlot and Malbec
- Millerandage: a high proportion of seedless grapes, these grapes are often smaller
What are the four stages of grape development?
Grape development occurs from June to october (NH) and december to april (SH)
- Grape berry formation
- Véraison
- Ripening
- Extra ripening
What happens during grape berry formation?
Grape berry formation is the first stage in grape development. The grapes grow in size and tartaric and malic acids accumulate. Aroma compounds and precursors develop, such as methoxypyrazine. This contributes to the herbaceous aromas/flavours. The tannins are very bitter at this time. Sugar levels are low. Water flow into the grape is high and is mainly tranported by the xylem (transport tissue for water and some nutrients).
Too much water and nitrogen can prolong this stage, mild water stress can speed up this stage.
What happens during véraison?
This is the second stage in grape development. Grape growth slows down for a few days (lag phase). Grape cell walls become stretchy and supple and becomes red in colour due to the synthesis of compounds called anthocyanins.
What happens during ripening?
Ripening is the third stage in grape development. Cells in the grape expand rapidly, sugar and water accumulate and acid levels fall. Tannins, colour and a number of aroma precursors and aroma compounds develop.
What happens with sugars during the ripening stage?
Sugar accumulation is very rapid at the start of the ripening stage and then slows towards the end. It is produced by photosynthesis at 18-33 degrees celcius and sunshine levels above one third of full sunshine.
Water flow via the xylem slows down and a sugar solution is transported by the phloem into the grape (phloem is a transport tissue that transfers sugar from the leaves to other parts of the vine). The sugar accumulation within the grape is correlated to the rate of grape transpiration. Grapes can transpire a small amount of water through the skin.
What about the acids during the ripening stage?
The total amount of tartaric acid does not change, but by diluting as sugar and water accumulate in the grape, the concentration falls. The concentration of malic acid falls even further because this type of acid can be used in respiration during the ripening stage.
Mean temp above 21 degrees can lead to rapid loss of acidity whereas mean temp below 15 degrees can reduce acid loss. Cool night time temp means that less malic acid is lost (in climates with high diurnal range)
What happens to aroma compounds and aroma precursors in the ripening stage?
Methoxypyrazine levels fall. but cool temp en limited sunlight can hinder this decrease.
The range of different aroma compounds and precursors that can be found in grapes is huge, and the synthesis, degradation or retention of each of these compounds may be influenced by heat and light in a different way.
What happens to tannins in the ripening stage?
In black grapes, level of tannings are high at véraison and decrease slightly throughout ripening. The tannins polymerise and this causes them to become less bitter. Sunshine on the grapes promotes tannin accumulation pre-véraison and greater polymerisation post-véraison.
On what factors does the length of the ripening stage depend?
- Grape variety
- Climate conditions
- Management of the vine and vineyard
- Time of harvest
What happens during extra-ripening?
If the grapes are left on the vine, they shrivel. So, water loss in the grape trough grape transpiration means that sugars are concentrated.
What is the definition of ripeness?
Ripeness of the grapes depend of several parameters. The most important are:
- Level of sugar
- Profile of the aromas/flavours
- Tannin ripeness
It is easier to adjust sugar, alcohol or acid levels than to work with grapes that have unripe tannins and/or aromas. Therefore, many grapegrowers will focus on attaining the desired level of tannin and aroma ripeness.
Other parameters are acidity levels, pH levels, colour development.
What are the key resources needed by the vine and how does the growing environment influence these sources?
- Temperature and sunlight
- Water
- Nutrients
Climate, weather and climate change influence the growing environment
What are the effects of temperature?
- <10: ensure dormancy. 10: stimulate budburst, warm soil also promotes budburst.
- 18-33: photosynthesis
- > 17: flowering
- 26-32: fruit set
- warm temperatures influence grape ripening, sugar accumulation in the grapes is faster due to optimum rate of photosynthesis and increased grape transpiration
- Malic acid degradation is increased at warm temperatures.
The effect of temperature on the formation of aroma compounds and aroma precursors is very complex. Generally riper aroma/flavours are associated with grapes grown in warmer climates. Cool conditions may hinder the breakdown of methoxypyrazine. In black grapes anthocyanin synthesis is optimum at 15-25 degrees.
Extreme heat can cause photosynthesis to slow down or stop.
Wat are the effects of sunlight?
The vine needs sunlight for photosynthesis.
Grape exposure to sunshine has a number of effects:
- enhancing the development of anthocyanins
- reduction of mothoxypyrazine
- greater accumulation of tannins pre-véraison
- promoting tannin polymerisation post-véraison
What are natural factors that effect temperature and sunlight?
- Latitude (between 30 and 50)
- Altitude: temperature falls by apporximately 0,6 degrees over every 100m increase in altitude.
Sunshine is more intense at high altitude and the ultraviolet radiation promote anthocyanin and tannin synthesis. - Slopes and aspect: extra warmth and light during spring and autumn extend the viable growing season for vines grown on slopes that face towards the sun.
- Proximity to water: water heats up and cools down more slowly than dry land. During the day, the water and the air above a body of water remains relatively cool, and lowers the average temperature in the local area. The opposite happens at night. The water retains the warmth gained during the day, whereas, without solar radiation, the land loses heat relatively quickly. The warmth of the body of water keeps the local area warmer. Also the radiation reflected from the water surface can benefit the vineyard.
Ocean currents do also have an effect on temperature
- Gulf stream (from gulf of mexico and warms up many European wine regions)
- California current (from the northern pacific and cools the west coast of north america) - Winds
- Characteristics of soil: drainage, structure and colour
- Mist, fog and clouds
What is ENSO
El Nino Southern Oscillation is a climatic cycle in the pacific ocean.
- El Nino starts when warm water in the western pacific ocean moves eastwards along the equator towards the Caribbean. The eastern pacific ocean becomes warmer than average ant his tends to cause high levels of rainfall and risk of hurricanes in south america and California. However, it brings warmer than average temperatures an drier conditions in the pacific northwest. On the westers side of the pacific ocean in Australia, el Nino tends to cause warmer temperatures and drought conditions
- La Nina is caused when the eastern pacific ocean is cooler than average. It tends to result in cooler, wetter conditions in the pacific northwest, but warmer, drier conditions in California and south america. It also causes wetter and cooler conditions in Australia.
What is diurnal range?
The average difference between daytime and nighttime temperature. Continental climes or at high altitude tend to have higher diurnal range.
Cool night time in hot regions can slow the respiration of malic acid en be beneficial for the formation of anthocyanins.
Warmer night time in cool regions can allow ripening to continue
There are also exceptions: Wachau in Austria: cool climate with cold nights. The exact reasons behind diurnal range are unknown.
What are the effects of water on the growing environment?
The vine needs a minimum of 500 mm rainfall a year in a cool climate and at least 750 mm in warm regions. The vine needs water for turgidity, photosynthesis and regulating its temperature. Water is a solvent for nutrients and acts as a medium in which all of the vine’s biochemical and physiological mechanisms take place..
Water vapour diffuses out of the stomata, it causes water to be pulled upwards from the soil, through the roots and the above-ground parts of the vine (transpiration).
Open stomata let carbon dioxide and oxygen diffuse in and out. A lack of water causes the vine to partially close its stomata - sometimes irrigation is needed
If water is too available vegetative growth is promoted and thus compromising ripening. It can lead to reduced formation of anthocyanins, tannins and aroma compounds, less tannin polymerisation and higher levels of methoxypyrazines.
What are natural factors that effect water availability?
- Rainfall: is caused by water vapour condensing and precipitating. Mountain ranges can force winds of warm moist air upwards over high altitudes, this causes the water vapour to cool, condense and precipitate. The other side of the mountain is called ‘rain shadow’.
- Characteristics of soil and land: soils that retain some water can be advantageous, water-logged soils are harmful to the vine. It reduces the amount of oxygen to the roots of the vine.
- Evapotranspiration rate: the amount of transpiration from the vine, combined with the evaporation of water from the soil surface. Or, the rate at which water is no longer available, either because it has been taken up by the vine or because it has been lost to the atmosphere. It depends on temperature, humidity and wind.
Why does a vine need nutrients for?
The vine acquires the nutrients it needs from the soil. Nutrients are important for healthy vine growth and can have an influence on yield and grape composition.
What are the most important nutrients + their function?
- Nitrogen: Vine growth and has influence on vine vigour and grape quality. It is a component of proteins and chlorophyll (required for photosynthesis). Too much: excessive vegetative growth. Too little: reduced vigour and yellowing of vine leaves. Grapes with low nitrogen can be problematic for fermentation.
- Potassium: vine growth and helps regulate the flow of water in the vine. Too much: hinders the uptake of magnesium. Also gives high pH in the grape must. Too little: low sugar accumulation in the grape.
- Phosporus: photosynthesis. Too little: poorly developed root system, reduced vine growth and lower yields.
- Calcium: structure of plant cells and photosynthesis. Too little: negative effect on fruit set
- Magnesium: found in chlorophyll (photosynthesis). Too little: reduced grape yields, poor ripening.
What are other nutrients the vine might need?
Sulfur, Manganese, Boron, Copper, Iron and Zinc
What are natural factors that effect nutrient availability?
Vine nutrients dissolve in soil water, so the soil factors that influence water availability alsof impact nutrient availability.
- Soil pH: e.g. high pH can cause chlorosis (leaves turn yellow and photosynthesis stops)
- The vine needs the nutrients in inorganic form. Organisms that live in the soil are important in the process of mineralisation: feeding on organic matter and converting it into available forms
- Soils with high proportion of clay are good at holding nutrients
What are the most important physical elements of a soil?
- Texture: proportions of the mineral particles of sand, silt and clay. Soils with high proportion of clay are finely textured.
- Structure: how the mineral particles in the soil form aggregates (crumbs). The size, shape and stability of these aggregates are also important for determining water drainage, root growth and workability of the soil.
The suitability of the soil for viticulture will depend on the texture and structure of the soil combined with how far the roots are able to penetrate.
What is a climate?
A region’s climate is defined as the annual pattern of temperature, sunlight, rainfall, humidity and wind averaged out over several years (generally 30 years)
Name the different climate classifications
- Growing Degree Days (GDD): ~temp of a month in the growing season-10 C x days in that month. Add all months for the GDD.
5 Groups: Winkler Zone 1 - Winkler Zone 5 - Huglin Index: Similar formular to GDD. But includes mean and maximum temp and increased day length at higher latitudes.
Ranges with grape varieties to each range. - Mean July/Januari Temperature (MJT): + measures of continentality, humidity and hours of sunshine. Six bands cold-hot
- Growing Season Temperature (GST): Mean temp of the whole growing season.
- Köppen’s Classification:
- Maritime - Mediterranean - Continental
- Cool - Moderate - Warm - Hot
Tell me more about Köppen’s Climate Classification?
First, the world’s wine regions are categorised under three headings:
- Maritime: low annual differences summer-winter. Rainfall is evenly spread
- Mediterranean: low annual differences summer-winter. Rainfall in the winter
- Continental: more extreme differences summer-winter. Short summers and cold winters.
Next, the categories are qualified with a temperature categorisation:
- Cool: ~<16.5
- Moderate: ~16.5-18.5
- Warm: ~18.5-21
- Hot: ~>21
What is continentality?
A measure of the difference between the annual meant temperatures of the hottest and coldest months.
What is the definition of weather?
A region’s weather is the annual variation that happens relative to the climatic average.
Weather can have a significant influence on the wines produced in that year and this is often termed vintage variation.
What are the effects of climate change?
The main measurable effect of climate change is a rise in temperatures. It also has the consequent effect of greater evapotranspiration and therefore likelihood of water stress. Other effects include changes in the geographical distribution of rainfall, greater weather variability and a greater frequency of extreme weather events.
What are the factors considering in approaches to grape growing?
- World view and ethical issues
- Desired level of production
- Intended wine quality
- return on investment
- Cost
- Availability of labour
- Environmental impact
What are the aims of conventional viticulture and how are these aims achieved?
The aims include raising production levels and reducing labour requirements. This is achieved by mechanisation, chemical inputs, irrigation and clonal selection.
What are the advantages and disadvantages of conventional viticulture?
Advantages:
- ability to mechanise the work in the vineyard
- reduction of competition by other plants
- ability to tend the specific needs of the grape variety planted and increase yield while reducing costs
Disadvantages
- Plants in monoculture are more prone to disease and pests
- Nutrients can be depleted
- Residual chemicals can find their way into ground water.
What are other approaches to viticulture?
- Sustainable
- Organic
- Bio-dynamic
- Precision viticulture
What are the three themes to sustainable viticulture?
- economic
- social
- environmental
For WSET is primarily environmental sustainability important. It aims to promote the natural ecosystems in the vineyard, maintain biodiversity, manage waste, minimise applications of chemicals and energy use, and reduce the impact of viticulture on the wider environment.
What is lutte raisonée?
IPM or integrated pest management
It includes setting thresholds at which action needs to be taken, identifying and monitoring pests, setting up preventive measures and evaluating and implementing control options
Can you name any examples of the guidelines for sustainable viticulture?
LODI rules (Lodi California)
Sustainable winegrowing NZ
Sustainable winegrowing South Africa
What are the advantages and disadvantages of sustainable viticulture?
Advantages
- more thoughtful approach to grape growing
- scientific understanding of the threats to successful grape growing
- reduction in the spraying of synthetic and traditional treatments
- consequent cost saving
Disadvantages
- term is not protected and can be used by anyone
- standards can be set too low a bar for sustainable certification
What are the aims of organic viticulture and what are the key features?
Organic viticulture seeks to improve the soil of the vineyard and the range of microbes and animals, and thereby increase the health and disease resistance of the vine. Use of man-made fertilisers, fungicides, herbicides and pests is rejected, instead sulfur and copper sulfate are used to combat mildew.
Key features are
- application of compost
- cover crops are also often used to prevent erosion of the soil
- natural fertilisers may also be used
- monoculture of vineyards can be reduced by growing cover crops, planting hedges and establishing ‘islands’ of biodiversity
What natural predators or ecosystems can be used in organic viticulture?
To defend against grey rot > bacillus sibtillis: it competes with botrytis cinerea for space on the grape
Sexual confusion: a technique involves the use of pheromone tags or capsules to disrupt the mating patterns of insects such as moths and mealy bugs
What is IFOAM
International Federation of Organic Agriculture Movements. All certification bodies for organic viticulture must meet their standards.
Each vineyard must undergo a period of conversion.
How many vineyards are farmed organically?
In Europe it is 10%. Europe accounts for 85% of organic viticulture in the world. Fastest growing is Spain (Castilla- La Mancha)
6% in New Zealand
4% in USA
<2% in Chile and Argentina
What are the advantages and disadvantages of organic viticulture?
Advantages:
- making the health and disease-resistance of the vine and the heath of the soil central aims of the grape grower
- the reduction in the number of chemical treatments in the vineyard and the elimination of spraying synthetic chemicals
- saving on the cost of synthetic chemicals
Disadvantages
- possible small reduction in yield
- possibility of significant reductions in yield in difficult years
- increased reliance on copper sprays
- the cost and time expended on certification
How does biodynamic viticulture use ‘preparations’?
Preparations are used to fertilise the soil, treat diseases and ward off pests. For example:
- Preparation 500: cow manure stuffed into a cow’s horn, this is buried in the soil through the winter. Then its dug up and the content is dynamised and then sprayed over the vineyard. It aims to catalyse humus formation.
- Preparation 501: ground quartz (silica) into a cow’s horn, burying it for 6 months, dug up dynamised and sprayed onto the soil. It aims to encourage plant growth.
- Compost: it is believed that it has to be activated first by adding a series of starters (yarrow, chamomile, nettle, oak bark, dandelion, valerion) These are called preparations 502-507. It aims to assist with decomposition of the compost.
What is the most common certification body for biodynamic grape growers?
Demeter. It sets international standards for farming and animal husbandry.
What is the most famous domaine that uses biodynamic grape growing?
Romanée Conti in Burgundy
Also in the Loire Valley this approach is popular
What is precision viticulture?
It makes use of data collected from the vineyard (soil, vigour, topography, plant growth) to respond to changes from plot to plot and from row to row. The data is collected by sensors either on aircraft (remote) of mounted on a tractor or harvester in the field (proximal).
GPS and GIS allows the data to be presented visually
What is variable-rate application technology?
Interventions in the vineyard that are targeted in the light of the data collected. For all key interventions, pruning, leaf removal, treatments, irrigation, crop thinning and harvesting, is van be carried out precisely with the aim of producing the best quality and yield, reducing environmental impact and reducing costs on treatment.
What are the advantages and disadvantages of precision viticulture?
Advantages:
- detailed understanding of variations in the vineyard
- ability to tailor a wide range of interventions to individual blocks of vines
Disadvantages:
- initial cost of remote data collection
- Cost of sensors and software and of consultancy
What are the considerations in site selection?
- Price of the land
- Location, layout and topography
- Steep slopes
- Source of irrigation water
- Ease of acces to the vineyard site
- Proximity of the vineyard and winery to towns and cities
What are in general stipulations a grape grower has to account for?
Wines with a PDO will be subject to rules that stipulate
- what grape varieties can be used
- maximum yield
- viticultural practices
- winemaking practices
What is the function of the structure of the soil?
- Root penetration
- Water drainage
- Nutrient holding capacity
- Workability
What are considerations in choosing grape varieties, climactic wise?
- Time of budding
- Duration of annual life-cycle
- Tolerance of drought
- Resistance to disease
- Winter hardiness
- Vigour
What are considerations in choosing grape varieties, other than climactic considerations?
- Style of wine
- Yield
- Cost
- Law
- Availability
- Market demand
What can a grape grower do to quickly capitalise on trends?
A grape grower can cut the original vine at the trunk and graft a bud from a new vine variety on top. This is called head grafting or top grafting. The benefit is that, with and established root system, the new vine variety can product fruit suitable for wine much more quickly than a brand-new planting. A disadvantage is that the rootstock will have been selected based on the characteristics of the original grape variety, and may not be equally suited to the new grape variety.
What considerations can a grape grower think over when choosing rootstocks?
- pests
- water
- soil pH
- Vigour
Managing nutrients and water is by managing…?
structure and texture of the soil and the organisms that live within it
What attributes to soil health?
- Structure of the soil
- Amount of organic matter and humus in the soil
- Number of living organisms in the soil
- Total amount of available nutrients that the vine needs to grow successfully
Fertilisers may be used to correct any detected nutrient deficiencies. What kind of fertilisers are there?
- Organic fertilisers: are derived from fresh or composted plant or animal material. Organic nutrients need to be broken down into inorganic nutrients by the living organisms, these fertilisers require incorporation into the soil, which requires labour.
- Mineral fertilisers: are extracted from the ground or chemically manufactured. They can provide a single nutrient or several nutrients and thus can be more tailored. These are more expensive, more concentrated
Cultivation is a method of weed control that involves ploughing the soil to cut or disturb the weeds’ root systems. Wat are the advantages and disadvantages?
Advantages - not use any chemicals - enables fertiliser and mow cover crops to be incorporated into the soil at the same time as removing weeds. Disadvantages - repeated cultivation can damage the soil's structure - costly in labour and machinery - disturbing the soil buries seeds - it can encourage vine vigour too much
What types of herbicides do you know?
- Pre-emergence herbicides
- Contact herbicides
- Systemic herbicides
What are the advantages and disadvantages of using herbicides?
Advantages - cheap in labour and machinery - highly effective - less damaging than cultivation Disadvantages - risks of poisoning - Weeds can become resistant - They can increase vine vigour - Not allowed in organic and biodynamic viticulture
What are the advantages and disadvantages of animal grazing?
Advantages - No use of any chemicals - The animals can provide manure - Animals can be a source of meat Disadvantages - animals may eat leaves and/or grapes - animals need caring for - animals are susceptible to vineyard pesticides
What is the aim in the use of cover crops?
Cover crops may be grown to suppress weeds. The may also be planted to improve soil structure, compete with the vine for nutrient and water availability in fertile sites, manage soil erosion, enhance biodiversity and provide a surface to drive on
Examples include legumes (beans and clover), cereals (ryegrass and oats)
What is mulching?
Mulching is the spreading of matter onto the vineyard soil to suppress the growth of weeds. They are usually made of biodegradable materials, such as straw or bark chips.
What are steps that can be taken in the vineyard to increase the efficiency of water use?
- use of certain water-efficient irrigations systems combined with better monitoring of water take-up by the vine
- use of drought-tolerant grape varieties (grenache) and rootstocks (140R)
- reducing evaporation (by applying mulch)
- reducing competition
- increasing humus levels in the soil to improve water retention
- promoting the growth of vine roots deep into the soil
What is the most common type of irrigation and wat are the advantages and disadvantages?
Drip irrigation
Advantages:
- economic use of water
- control water supply to individual rows or blocks of vines
- used to supply fertiliser (fertigation)
- can be used on slopes
Disadvantages
- installation costs are high
- clean water is required
- maintenance work is required
- cannot be used in frost protection (aspersion)
What are other types of irrigation that can be used?
Flood irrigation
Channel irrigation
Overhead sprinklers
Wat is RDI?
Regulated Deficit Irrigation: is a system of timing and regulating the amount of irrigation so that the vine is put under mild to moderate water stress for a specified time within the growing season. It is scheduled between fruit set and véraison.
Vine growth and grape development can be better controlled and less water can be used.
What is canopy management?
The organisation of the shoots, leaves and fruit of the vine in order to maximise grape yield and quality
What are the key 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
How can canopy management enhance yield?
Canopy management can help maximise the leaf surface area that is exposed to sunlight. this increases the vine’s photosynthetic capacity and means it can ripen larger yields.
It can also influence yield (and grape quality) by reducing fungal disease pressure.
What are the effects of canopy management on grape quality?
- increased sugar levels in grapes
- increased tanning levels and greater polymerisation
- enhanced antocyanin development
- decreased malic acid
- increased levels of some aroma precursors and aroma compounds (e.g. terpenes)
- decreased methoxypyrazines
Why is canopy management important in vine balance?
Canopy management can improve vine balance by achieving a suitable balance between the vine’s vigour and crop load.
What is the definition of yield?
Yield is a measure of the amount of fruit produced. It can be measured per vine (kg per vine) of over a set area (kg per hectare or tons per acre).
Yield over a set area will depend on the yield per vine and the planting density. The higher the yield within a set area, the more wine can be made and sold.
What are techniques used in canopy management?
- site assessment
- vine training
- winter pruning
- vine trellising
- overall plant vigour management
- summer pruning
- –shoot removal
- –shoot positioning
- –pinching
- –shoot trimming
- –leaf removal
- –crop thinning/green harvesting
What are the influences on optimum vine density?
- vigour of the vine
- type of trellising
- access between the vines
What are considerations in row positioning?
north south orientation provides the most even sunlight exposure through the canopy. Prevailing winds may also be a factor in decisions on row orientation, with grape growers choosing to orient the rows at a 90 degree angle to the direction of the wind to provide most protection.
General considerations:
- rows parallel to the longest side of the vineyard
- slopes >10%: rows planted up
On what does appropriate training and trellising method depend on?
- vigour of the vine
- topography of the site
- need for mechanisation
What are the two categories of vine training?
- Head training: little permanent wood. Can be spur-pruned or replacement cane-pruned.
- Cordon training: with one or more permanent horizontal arms (cordons). Usually spur-pruned.
Either can be low-trained: to benefit from heat retained by the soil or provide greater protection from wind.
Or either can be high-trained: to better avoid frosts or make manual interventions such as harvesting easier.
What is spur-pruning?
Spurs are short sections of one-year-old-wood that have been cut back to only two or three buds. Spurs can either be distributed along a cordon or around the top of the trunk. This method can be mechanised. Form of winter-pruning
What is replacement cane-pruning?
Canes are longer sections of one-year-old-wood an can have from 8-20 buds. They are laid down horizontally and need a trellis. This method is more complex and requires a skilled labour force. More buds ar left on the vine with more vigorous vines. It is a form of winter-pruning
What are the characteristics of an untrellised vineyard?
Vines are head trained and spur-pruned and are called bush vines. Simple and easy and inexpensive. Usually planted in hot and sunny regions. It is not suitable for mechanisation.
Why would you choose for a trellised vineyard?
Shoots can be spread out to maximise light interception, increase air flow and aid mechanisation. However, it is expensive to establish and needs maintaining.
What types of trellis system do you know?
- Vertical shoot positioning (VSP)
2. Complex training systems
