D2 & D3: The Vine Growth Cycle and The Growing Environment Flashcards
Effect of Temperature: Under 10 degrees
ensures winter dormancy of vine
Effect of Temperature: minus 20 degrees
can cause winter freeze and can damage the vine
Effect of Temperature: above 10 degrees
Effect:
- stimulates budburst and a significant rise in temps can make ripening more uniform
- warm soils help budburst
Risk:
- cold temps and frost can be harmful and reduce yields
Effect of Temperature: 18 - 33 degrees
- optimum temp for photosyn
- helps new shoots and leaves develop
- creates sugar for energy
Effect of Temperature: above 17 degrees
- successful, uniform flowering
Risk:
- cold, damp conditions cause problems for flowering and fruit set
- impacts yield and quality of grapes and wine
Effect of Temperature: optimum temp of 26 to 32 degrees
- successful, uniform fruit set
Risk:
- cold, damp conditions cause problems for flowering and fruit set
- impacts yield and quality of grapes and wine
Effect of Temperature: above 25 degrees
- promote increased bud fruitfulness and impacts yields next year
Effect of Temperature: Warm Temps
- sugar accumulation is faster as good conditions for photosyn
- increase grape transpiration as promotes movement of sugar into the grape
- malic acid degradation increased
Effect of Temperature: above 21 degrees
- final months of ripening
- leads to rapid loss of acidity (anything below 15 degrees reduces acid loss so acidity levels in must is too high)
Effect of Temperature: 15 degrees to 25 degrees
- anthocyanin synthesis optimum
- if it is too cool, it hinders breakdown of methoxypyrazines
Effect of Temperature: Extreme heat
- causes photosynthesis to slow or stop
- water stress slows or stops photosyn due to shutting of stomata to prevent water loss and limits intake of CO2
Effect of Temperature: Grape Varieties
- late ripening: need greater amount of heat through growing season to ripen sufficiently
- early ripening (e.g. Chardonnay, Pinot noir) need less heat in total and will ripen very early in warm climates
Effects of Sunlight: why the vine needs sunshine
- needs sunlight for photosynthesis
- berry formation
- ripening
- needs at least 1/3 full sunshine but full sunshine is not a complete necessity
Effect of Sunlight: Benefits (7)
- good in late spring/early summer for fruitfulness
- development of anthocyanins
- reduction of methoxypyrazines
- accumulation of tannins pre-veraison
- tannin polymerisation post-veraison
- development of aroma compounds
- lower acidity due to grape respiration
Effects of Sunlight: Negatives (2)
- sunburn
- fog which can slow photosyn (not ideal but not very bad)
Latitude: name 3 lower and 2 higher latitude regions
- lower: NSW, Mendoza, South Africa
- higher: northern France, Germany (closer to the poles)
Latitude: closer to the equator
- more intense solar radiation
radiation travels through a smaller section of the atmosphere, hits the earths surface at a larger angle and therefore is more powerful
Latitude: closer to the poles
- solar radiation has to travel through a larger section of the atmosphere to reach the surface
hits at a lower angle so it spreads at larger area
Latitude
If all factors were considered equal, temps would be WARMER and sunshine more INTENSE at lower lats than at higher lats
Lower lat grapes are HIGH in sugar, LOWER in acidity, RIPER aromas, RIPER tannins and better COLOUR
What does latitude determine?
- determines number of hours of solar radiation
- lower latitude = similar daylight hours (heat and sunlight) throughout all seasons- higher latitude = longer daylight hours in summer and shorter in winter - longer time for photosyn in growing seasons which is helpful in allowing vine to produce sugar for ripening grapes
Latitude: grapes near the equator
- too hot
- water stressed
- sunburnt
Latitude: grapes near the poles
- not warm enough
- lack of sugar in the grapes
Altitude - how much does the temperature fall every 100m decrease in altitude?
- approx 0.6 degrees
EXAMPLE:
Salta: 3000m above sea level and grapes struggle to fully ripen
Burgundy/Loire: high latitude area. Plated at low altitudes so grapes can fully ripen
Where is sunshine more intense - higher or lower altitudes?
- Higher
- solar radiation travels through less atmosphere
- UV radiation greater
- both factors promote anthocyanin and tannin synthesis
Benefits of higher altitude sites
- high diurnal range
- air is thinner so less moisture and heat rapidly escapes
Benefits of lower altitude sites
- air absorbs moisture so heat is retained at night
On what side of the slope are sites planted in the Northern hemisphere?
- south-facing
Receives more solar radiation
On what side of the slope are sites planted on the Southern hemisphere?
- north-facing
Receives more solar radiation
Slopes and Aspect: Higher Latitudes
- solar radiation hits earth at low angle
- lowest in Spring and Autumn
- slope increases the angle which increases the intensity of heat and light exposure
- extra warmth and light during the spring and autumn extend viable growing season (e.g. in Grand Cru Alsace and Burgundy sites which are on SE facing slopes)
Slopes and Aspect: Warm Climates
- want to limit heat and light
- plant on slopes away from the sun
- get less alcohol and more acidity (e.g. in Stellenbosch white varieties are planted on south-facing slopes to help retain refreshing acidity)
Slopes and Aspect: East-facing slopes
benefits from morning sunshine which:
- heats up atmosphere when air and soil temps are at their lowest
- extends vine growth and grape ripening
- dew-covered canopy dries out quicker which prevents fungal disease
Slopes and Aspect: West-facing slopes
Afternoon sun:
- can get too hot
- risk of sunburn increases
- coastal areas can help alleviate this (e.g. Cali, Western Australia)
Additional benefits of vines planted on slopes
- shallower, poorer soil
- better drainage
- shelter from wind and rain
- protection from Frost
Negs:
- soil erosion
- can’t use machinery
Benefit of planting close to body of water is…
- water heats up and cools down more slowly than dry land
- over the year, larger bodies of water give cooler summers and milder winters
Proximity to water: day time benefits
- water and air above a body of water remain relatively cool
- lowers the average temperature
- air above land heats up quicker and rises so cool air from the water is drawn to land to replace it which gives cool, humid afternoon breezes
Proximity to water: night time benefits
- water retains warmth while land loses heat quickly
- warmth from water keeps local area warmer
Examples of sites close to water
Finger Lakes: reduces severity of the winter freeze and protects against spring frosts
Carneros: Proximity to San Pablo Bay means that can grow early ripening varieties such as Pinot Noir and Chardonnay. Inland, can grow late ripening Cab due to warm afternoon breezes
Impact of Ocean Currents: Margaux vs Willamette Valley
- both at 45 degrees latitude
Margaux:
- late ripening Cab
- gulf stream benefits
- average growing season temp is 17.7 degrees
Willamette Valley:
- early ripening Pinot Noir
- cooled by cold California current
- average growing season temp is 15.9 degrees
wine regions shielded from ocean influences are…
warmer and drier (e.g. in western USA)
Reflections from water surfaces…
- can benefit from reflected radiation from water surface
- depends on angle at which solar radiation kits water
- advantageous in cool climates with limited sunshine
El Nino Southern Oscillation (ENSO)
- climate cycle in Pacific Ocean and has a significant impact on weather pattern
- El Nino
- La Nina
El Nino
- warm water in western Pacific ocean moves eastwards along the Equator towards the Caribbean
- Eastern PO becomes warmer than average causing high rainfall and risk of hurricanes to South Am and Cali
NEGATIVES
- disrupt pollination and fruit set
- excessive water so increases vegetative growth
- hinder ripening
POSITIVE
- warmer than average temps for PNW
What are the impacts of El Nino on Australia?
- warmer temps and drought
- causes extreme vine stress and damage
How often does El Nino occur?
- every 3 to 7 years but likely to be more frequent due to climate change
La Nina
- causes Eastern PO to be cooler than average
- causes cooler/wetter conditions in the PNW
- warmer and drier in California and South America
- causes wetter/cooler conditions in Australia
Winds
- can be warming or cooling
- near a body of water helps bring in cool breezes during the day, moderating the diurnal range
- reduces humid/stagnant air in canopy - reduces risk of fungal disease
Winds: valleys facing coast/low lands
- can feel winds in land
- e.g. Petaluma Gap
- can also funnel wind
Wind: hot land masses
- brings in warm air to heat vineyard
- e.g. Zonda in Mendoza