D1.C3. The Growing Environment Flashcards
Temperature under what degree ensure dormancy in the vine?
10°C
Temperature under what degree can cause winter freeze and damage the vine?
–20°C
What is the optimum temperature range for photosynthesis?
18–33°C
What is the ideal temperature for uniform flowering?
17°C
What is the optimum temperature range for fruit set?
26–32°C
Warm temperatures above which degree, promote bud fruitfulness in the next year?
Above 25°C
What is the ideal temperature range for acidity?
15–21°C
Over 21°C, the acidity drops quickly, below 15°C acidity levels are too high
In black grapes, anthocyanin synthesis is optimum at between which temperatures?
15–25°C
Name two early-ripening varieties that need less heat in total and will ripen very early in warm climates
Pinot Noir and Chardonnay
Under which light level, the amount of light becomes the limiting factor to the rate of photosynthesis?
If light levels drop below one third of full sunshine
What are the main effects of sunlight on grapes?
- Development of anthrocyanins
- Reduction of methoxypyrazines
- Increase in aroma precursors and compounds such as terpenes
- Increase in malic acid usage leading to lower acidity levels
What is the effect of prolonged periods of sunshine and hot temperatures on the grapes?
It leads to sunburn, which has a negative effect on grape quality and yields
What is the effect of latitude on solar radiation? Why?
Lower altitude regions receive more solar radiation. The curvature of the Earth means that nearer the poles solar radiation must travel through a larger section of atmosphere to reach the Earth’s surface. Solar radiation is adsorbed (held by water droplets, dust and ozone) and scattered as it travels through the Earth’s atmosphere, decreasing its intensity
Compare the properties of a grape grown in higher latitude with one grown in lower latitude, if all other factors are equal
Grapes grown at lower latitudes can have higher levels of sugar, lower levels of acidity, riper aromas and, in black grapes, higher but riper tannins and more colour intensity than those at higher latitudes
What is the advantage of the high latitude regions in terms of grape ripening process?
High latitude regions have longer daylight hours in the summer and shorter daylight hours in the winter. This permits a longer duration of time over which photosynthesis can take place in the growing season.
What is the effect of altitude on temperature?
Temperature falls by approximately 0.6°C over every 100 m increase in altitude
What is the relation between latitude with altitude?
In low latitude areas, high altitude is favourable, that would otherwise be too hot and in high latitude areas, low altitude is favourable, that would otherwise be too cold
Why is sunshine more intense at higher altitudes?
Because the solar radiation travels through less atmosphere before it reaches these sites
What is the effect of intense sunlight on grape development?
It promotes anthrocyanin and tannin synthesis
Why do the high-altitude sites have a high diurnal range?
At high altitudes the air is thinner and holds less moisture and therefore heat rapidly escapes, leading to relatively cool night-time temperatures
What is “aspect”?
Vineyards planted on slopes will face a particular direction, which is called aspect.
Why is the importance of aspect and the steepness of the slope increases at high latitudes?
The slope increases the angle (nearer to perpendicular) at which the solar radiation hits the Earth’s surface, hence increasing the intensity of heat and light
In the cool climate regions like Burgundy and Alsace, the Grand Cru sites that give wines with greater ripeness and concentration are usually positioned on slopes facing which direction?
South-east facing slopes
What are the advantages of the east facing slopes?
- Slopes facing east benefit from morning sunshine that can heat up the atmosphere when air and soil temperatures are at their lowest. This can extend the hours of vine growth and grape ripening each day, especially in cool climates
- The grape canopy, which can be covered with dew in the morning, also dries out earlier in east-facing vineyards, reducing the spread of fungal disease, which is beneficial for grape quality and yields
What is the disadvantage of west facing slopes in warm climates
Slopes that face west receive the afternoon sun and may become too hot, especially in warm climates, and risk of sunburnt grapes is increased
What are the advantages of slopes other than aspect?
- Shallower, poorer soils
- Better drainage
- Provide shelter from rain and wind
- Protection from frost
What are the disadvantages of slopes?
- Erosion
- Inability to use machinary
How does a large body of water cools nearby vineyards?
Air directly above dry land heats up more quickly than that above the water, and this warm air rises. Cool air from above the water is drawn to the land to replace the warm air as it rises, resulting in cool, humid afternoon breezes
What are the effects of Finger Lakes on nearby vineyards?
The wind reduces the severity of winter freeze and protect against spring frost
In California, why are the early-ripening grape varieties like Chardonnay and Pinot Noir are grown in areas in close proximity to San Pablo Bay?
Due to moderating influence of cooling afternoon breezes
What is effect of Gulf Stream on Bordeaux?
It creates a warmer climate in Bordeaux (average growing season temperature 17.7°C )
What is effect of California Current on west coast of North America including Oregon?
It cools the climate
Name another advantage of large bodies of water on moderating the cool climates especially prominent in higher latitudes?
Radiation reflected from the water surface
What are the effects of El Niño on:
- California
- More northerly states like Washington and Oregon
- Australia?
- California: High levels of rainfall and risk of hurricanes. The rainfall can disrupt pollination and fruit set and lead to excessive water availability, which can increase vegetative growth and hinder ripening
- Washington and Oregon: It brings warmer than average temperatures and drier conditions
- Australia: It tends to cause warmer temperatures and drought conditions, which can cause extreme vine stress and vine damage
What are the effects of La Niña?
- Cooler, wetter conditions in Washington and Oregon
- Warmer, drier conditions in California and South America.
- Wetter and cooler conditions in Australia
What are the effects of valleys on the wind
- Valleys that face the coast or other areas of low land (e.g. the Petaluma Gap in California) can mean that winds are felt even relatively far inland
- Valleys can also lead to stronger winds as the moving air is funnelled
What is “Zonda wind”?
It is a warm wind seen in Mendoza, which heats the vineyard area, caused by the wind traveling over hot land masses
What are the effects of the wind other than moderating the climate?
- Winds reduce the occurrence of humid, stagnant air in the vine canopy that encourages the development of fungal diseases
- They also increase evapotranspiration from the vine, meaning that vines’ water needs may be higher than in non-windy areas
- Strong winds can cause damage to vines and vineyard trellising
Name one measure to protect the vineyard from strong winds
Rows of trees can be planted at the edges of vineyards to act as windbreaks. However, care must be taken as they can compete with the nearest vines for water and nutrients
Which properties of the soil influence the warmth of the soil and the air directly above it?
- Drainage
- Texture
- Colour
What are the advantages of freely draining soils especially in cool-climate vineyards?
- They warm up more quickly in the spring than damp soils, rising soil temperature encourages the breakdown of starch in the roots, which stimulates budburst and shoot growth which result in a longer growing season
- Warm soils also encourage root growth, which means the vine can absorb more water and nutrients
What is the disadvantage of freely draining soils especially in cool-climate vineyards?
- Early budburst increases the risk of spring frost
What is the advantage of light-coloured soils?
They reflect the energy from solar radiation into the lower parts of the canopy, which may receive less sunlight from above, can be beneficial to increase photosynthesis and grape ripening in cool and cloudy climates (Sancerre and Champagne) or where late-ripening grapes are used
What is the advantage of dark-coloured soils?
They absorb more energy and re-radiate most of it when temperatures are cooler, for example at night. This can be useful, especially in cool climates or for late-ripening grapes, allowing the development of colour and degradation of acid to continue during the night
What is the effect of stony soils on grape development?
Stony soils, especially if the underlying soil is slightly damp, are also very effective at absorbing heat and releasing it at night. This is because stone and water are good conductors compared to air
Name 4 wine areas in which morning mist is common
- Sonoma
- Napa
- Layda Valley
- Sauternes
In which conditions, mist can be beneficial for grape development?
In warm regions and when growing early-ripening grape varieties, mist can be beneficial by slowing down sugar accumulation and acid degradation in the grapes
What is the risk of fog in terms of grape growing?
Due to increased humidity, fungal infection risk increases
Name two wine regions with warm or hot climates with a large diurnal range and explain why this is favourable for grape growing in these areas?
- Mendoza and Ribera del Duero
- A relatively cool period during the night can slow the respiration of malic acid and be beneficial for the formation of anthocyanins
Name two wine regions with cool and moderate climates with a low diurnal range and explain why this is favourable for grape growing in these areas?
- Mornington Peninsula and Mosel
- Night- time temperatures still allow ripening (e.g. acid degradation, anthocyanin synthesis) to continue
What is the effect of night-time temperatures on aroma compounds?
- Warmer night temperatures are associated with a greater breakdown of methoxypyrazines
- Cooler temperatures are associated with a greater retention of some other compounds, such as rotundone
What are the minimum amount of rainfall that the vine needs for cool and warm climates?
- 500 mm for cool climates
- 750 mm for warm climates
The vine needs water for:
- Turgidity
- Photosynthesis
- Temperature regulation
- Uptake of nutrients from the soil by acting as a solvent
What is transpiration?
The upward movement of water from soil, driven by the negative pressure created by the loss of water through stomata
What are the functions of stomata?
- Free exchange of water vapour out of the vine
- Diffusion of CO2 and oxygen in and out of the leaves
What are the results of partial closure of stomata?
- Water conservation
- Reduction or sometimes cessation of photosynthesis
What is the solution when lack of rainfall during the growing season is an issue?
Irrigation
What happens if water is too easily available in late spring and early summer?
Vegetative growth is promoted so mild water stress before véraison is beneficial as it inhibits further vegetative growth
What are the adverse effects of vegetative growth?
- Too much shading leading to reduced formation of anthocyanins, tannins and aroma compounds, less tannin polymerisation and higher levels of methoxypyrazines
- Poor ventilation encouraging fungal disease
What are the results of too much water availability during ripening period?
- Dilution of sugars in the grapes
- Grape splitting encouraging botrytis
What are the results of water deficit during ripening period?
- Early onset of grape shrivel
- Reduced ability of the grapes to reach the desired level of ripeness
What are the other impacts of water on growing environment other than direct influence of water availability on the vine?
- Damp soils can delay budburst
- Hail can damage the vine
- Rainfall at pollination and fruit set can negatively affect these important stages of the vine growth cycle
- Rain creates a humid environment which promotes fungal diseases like downy mildew and botrytis
- Large bodies of water moderate both diurnal and seasonal temperatures but proximity to water also increase humidity, encouraging fungal infections
What are the natural factors that affect water availability?
- Rainfall
- Characteristics of soil and land
- Evapotranspiration rate
How does topography have an influence on the patterns of rainfall?
Mountain ranges can force winds of warm moist air upwards over high altitudes. This causes the water vapour to cool, this can mean that the regions on one side of the mountain experience greater rainfall
What is the difference between the two sides of Cascade mountains in regard to rainfall pattern and viticulture practices?
On the west of the Cascade Mountains the AVA of Puget Sound is cooler and much wetter than the warmer, drier AVAs to the east of the mountains, for example Columbia Valley. Plentiful rainfall in the winter and early spring mean that grape growers in Puget Sound can dry farm whereas irrigation is needed in Columbia Valley for vines to survive
Compare the soil structure and viticultural practices of Hawke’s Bay with Jeres.
- Hawke’s Bay in New Zealand receives around 1,000 mm rainfall annually, however, the extremely free draining nature of the gravel soils in the Gimblett Gravels area mean that irrigation is often required
- Jerez in Spain receives 650 mm with virtually no rainfall in the summer months. Here, the main soil type is albariza, a clay soil that has good water retention and which releases water slowly to the vines. This soil also forms a crust when dry, which reduces evaporation
What are the advantages and disadvantages of slopes in regions with high rainfall?
Advantage: There will be greater surface run-off, meaning less penetration of water
Disadvantage: Surface run-off causes erosion of the soil and leaching of nutrients
What is evapotranspiration rate?
Evapotranspiration rate is the amount of transpiration from the vine, combined with the evaporation of water from the soil surface, it is therefore the rate at which water is no longer available
Evapotranspiration rate depends on which factors?
- Temperature
- Humidity
- Wind
What are most important nutrients in the soil for the vine?
- Nitrogen
- Potassium
- Phosphorus
- Calcium
- Magnesium
What are their functions of nitrogen and what happens when the levels are high and low in the soil?
- It is a component of proteins and chlorophyll.
- Too much nitrogen in the soil causes excessive vegetative growth.
- Too little nitrogen results in reduced vigour and yellowing of vine leaves. Grapes that have low nitrogen levels can also be problematic for fermentation
What are the functions of potassium and what happens when the levels are high and low in the soil?
- It helps regulate the flow of water in the vine.
- Very high potassium levels in soils can cause problems in the uptake of magnesium, and this may lead to reduced yields and poor ripening. High levels of potassium in the grape must are linked to high pH.
- Low levels of potassium can lead to low sugar accumulation in the grapes, reduced grape yields and poor vine growth in general
What are the functions of phosphorus and what happens when the levels are low in the soil?
- It is important for photosynthesis. Vines need only a small amount, and usually there is enough phosphorus naturally present in the soil
- Deficiency of it leads to poorly developed root systems (and hence a diminished ability to take up water and nutrients), reduced vine growth and lower yields
What are their functions of magnesium and what happens when the levels are low in the soil?
- Magnesium is found in chlorophyll and has a key role in photosynthesis
- Deficiency can result in reduced grape yields and poor ripening.
What are the natural factors that affect nutrient availability?
- Water availability
- pH: Iron is poorly available in soils with high pH (limestone) , whereas phosphorus take up is low in low pH soils
- Organisms that perform mineralization process
- Texture of the soil: Soils with high proportion of clay and humus are good at holding nutrients, whereas, sandy soils are poor at it
- Topography: Soils on slopes are often thinner and less fertile than those on plains or valley floors
What are the most important physical elements of a soil?
- Texture
- Structure
What does “texture of the soil” describe?
It describes the proportions of the mineral particles of sand, silt and clay
Finely textured soils have high proportion of which mineral particle?
Clay
Which mineral particle is poor in retaining nutrients?
Sand
What is the size of slit in comparison with clay and sand
It is just in between
What is “loam”?
‘Loam’ describes a soil that has moderate proportions of clay, silt and sand
What are the effects of larger rock fragments such as gravels or pebbles on viticulture?
These larger particles improve water drainage but lower water- and nutrient-holding capacity
What does “ structure of the soil” describe?
It describes how the mineral particles in the soil form aggregates (crumbs)
The size, shape and stability of aggregates in the soil are important for:
- Water drainage
- Root growth
- Workability of the soil
What is “humus”?
It is organic matter in the soil that is formed by the partial decomposition of plant material by soil microbes and earthworms
What are the properties of humus?
It has a spongey texture, large surface area and is able to adsorb water and nutrients. It helps to bind soils together and can help soils to retain water and nutrients
How can the climate affect the suitability of soil for viticulture?
Free draining soils can be beneficial for avoiding excess water in rainy climates (e.g. the gravelly soils in the Haut-Médoc)
What is climate?
It is the annual pattern of temperature, sunlight, rainfall, humidity and wind averaged out over several years (30 years is the timescale generally agreed)
To date most climate classifications focused on:
Patterns of temperature (often considered the most important influence on the vine cycle) and sometimes rainfall
Name the climate classification systems which use calculations
- Growing degree days (GDD)
- The Hughlin Index
- Mean temperature of the warmest month (MJT)
- Growing season temperature (GST)
In viticulture, in very broad terms the majority of the world’s wine regions can be categorised under three headings:
- Maritime
- Mediterranean
- Continental
What are the temperature ranges for cool, moderate, warm and hot climates?
Cool climates – regions with an average GST of 16.5°C (62°F) or below.
Moderate climates – regions with an average GST of 16.5–18.5°C (62–65°F).
Warm climates – regions with an average GST of 18.5–21°C (65–70°F).
Hot climates – regions with an average GST in excess of 21°C
What is continentality?
It is the difference between the annual mean temperatures of the hottest and coldest months
What is the effect of large bodies of water on continentality?
Large bodies of water, such as oceans, seas or large lakes, heat up and cool down more slowly than landmasses. Therefore, in winter they have a warming effect on the surrounding air and in summer they have a cooling effect, therefore they decrease continentality
What is weather?
It is the annual variation that happens relative to climatic average
What is vintage variation?
The influence of weather on the style and the quality of the wines produced in that year
In which style of wines, vintage variation is not desirable?
- Non vintage sparkling wines
- High volume, inexpensive wines
How can weather can reduce the yields?
- Fungal diseases due to too much rain
- Spring frosts
Why the yields that are substantially larger than normal can also be problematic?
- The winery may not have the capacity for the increased volume of fruit
- Finding routes to market/customers for all the wine (at a profit) may be difficult
What are the adverse effects of global warming on viticulture?
- The increased temperatures speed up the rate of sugar accumulation and reduction of acidity, but do not quicken the ripening of most aroma and tannin compounds leading to higher alcohol levels in wines and lower levels of acidity
- The grapes from certain vineyard regions may no longer exhibit the same aroma profiles as they do now (like Syrah in Northern Rhone)
- Drought ( California and South Africa)
- The increased frequency of extreme and erratic weather events is problematic for all regions
What is the function of Calcium. What happens when there is Ca deficiency?
- Calcium has an important role in the structure of plant cells and in photosynthesis
- Calcium deficiency is rare but can have a negative influence on fruit set
