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