D1 the growing environment - warmth & temperature Flashcards
The growing environment
Include the natural resources available that affect the vine’s growth.
Warmth/temperature, sunlight, water and nutrients/soil.
The effect of warmth/temperature
Grape variety or clone has different temperature needs.
The effects of temperature are various:
- Under 10C the vine may freeze.
- Above 10C bud burst are stimulated.
- Above 15C acids drops.
- above 17C optimum for uniform flowering
- 18-33C optimum for photosynthesis. Above 33C may cause water stress.
- 26-32C optimum for fruit set and bud fruitfulness
The effect of sunlight
Sunlight influence wine style and quality.
Fog and clouds can slow sunshine.
Sunlight influence dub fruitfulness, fruit set and grape ripening through higher photosynthesis rate and higher transpiration rate. leading to:
1. increase sugar
2. decrease Tartaric and Malic acid
3. greater tannins accumulation and polymerisation (reducing bitterness), 4. breakdown Methoxypyrazine,
4. increase level of aroma precursor and compounds (such us terpenes, fruity floral aroma),
5. enhancing anthocyanin synthesis (development of colour)
Natural factor that affect temperature and sunlight - Latitude
Grapes can grow between 30 and 50 degree latitude.
The lower the latitude, near the Equator, the more intense the solar radiation is. as it travels for shorter distance and spreads through a shorter section.
Therefore grapes grown in lower latitude has higher level of sugar, lower acidity, higher but riper tannins, riper aroma, and more colour intensity than those at higher latitude.
At low latitude the transpiration rate may be too high (vine regulate their temperature) causing water stress.
Grapes can also suffer from sunburn.
At higher latitude, it may be not warm enough for grapes to accumulate enough sugar. (despite the longer daylight hours)
Natural factor that affect temperature and sunlight - Altitude
Temperature falls of 0.6C every 100m increase of altitude.
High altitude sites are beneficial, in very hot places, for the retention of acidity due to the high diurnal range (high difference between day and night temperature).
At high altitudes, night are cooler because the heat accumulated during the day and released at night, is not retained in the atmosphere because the air is thinner than at lower altitude.
Natural factor that affect temperature and sunlight - Slope and aspect
Vineyards planted on slopes (south NH; north SH) can provide various benefit:
1. better drainage
2. reduce risk of fungal disease
3. protection from wind, rain, frost, excess sunlight
4. receive more intense solar radiation because of the increased angle
5. vineyards facing east may, in NH, benefit from extra morning sunlight.
Vineyards facing west is exposed to afternoon sun which can increase the risk of sunburn.
Natural factor that affect temperature and sunlight - Water bodies
Large bodies of water may mitigate the climate.
Because, water heats up and cools down more slowly than land it can provide cooling breezes during the day and warm air during the night (to mitigate the winter freezes and spring frosts)
Natural factor that affect temperature and sunlight - Soil
The warmth of the soil and the air above it is influenced by the soil drainage, texture and color.
- Free drain soil (sandy and gravel) warms up quickly, stimulating bud burst, shoots and roots growth, therefore extending the growing season and leading to greater ripeness.
However, due to an early bud burst, there is risk of spring frost. - Light colored soil (chalky) reflects sunlight to the vine for extra solar radiation, increasing photosynthesis rate. Therefore, leading to greater ripeness
- Dark colored soil and dump condition (vulcanic and stony) absorb more heat and releases it at night, providing greater development of anthocyanin and further decrease of acids.
Natural factor that affect temperature and sunlight - Mists, fogs, clouds
Warm air rapidly cooled cause water vapor to condense. It is common close to the river or mountains.
Mists, fogs and clouds can slower photosynthesis due to the shading provided. May be beneficial in too hot, sunny climates.
However, it may increase humidity increasing the risk of fungal disease (dry, sunny condition can encourage noble rot).
Natural factor that affect temperature and sunlight - Winds
Winds can have warming or cooling influence (even far inland).
Winds and breezes can reduce humidity, therefore reducing risk of fungal disease.
However, strong winds can disrupt flowering, lowering yields.
Rows of threes can act as windbreaks, however they can compete for water and nutrients
