The Growing Environment Flashcards
Describe the effects of temperature on each phase of the vine cycle.
- Dormancy - Cold temps (below 10C/50F) cause dormancy, extremely cold temps (-20C/-4F) cause winter freeze/damage
- Budburst -In spring 50F or higher stimulates budburst. Warmer soils can help. Cold temps w frost can damage buds and reduce yields.
- Shoot and leaf growth- needs photosynthesis, which requires warmer temps of 64-91F
- Flowering and fruit set - requires warm temps to be uniform (above 63F for flowering, 79-90F for fruit set). Cold, damp=problems
- Above 77F promotes bud fruitfulness for following season/yields in next growing season
- Ripening - @Warm temps cause faster sugar accumulation (photosynthesis, more transpiration), malic acid degradation, rapid loss of acidity if over 70F, must too acidic if under 59F; methoxypyrazines not broken down as much in cooler climates (herbaceous); anthocyanin synthesis (color development) needs 59-77F
What is the level of sunshine needed for grape growth and ripening?
One third of full sunshine. An Average cloudy day will not slow photosynthesis.
Describe the effects of sunshine at different stages of vine cycle.
- Grape growth and ripening - Sunlight needed for photosynthesis
- Color (anthocyanin) development
- Reducing level of methoxypyrazines (herbaceous aroma/flavor)
- Accumulation of tannins pre-veraison, tannin breakdown after veraison - less tannic bitterness
- Development of compounds like terpenes
- Lowers acidity levels by warming grapes and increasing rate at which malic acid is used in respiration
- Late spring/early summer - sunshine associated w successful fruit set and exposure of compound buds to sunshine promotes bud fruitfulness in next year’s growing season
HAZARD: sunburn - sunny or warm climates need careful canopy management to provide shading (Australia, Spain Priorat, Rhone)
What are terpenes?
Aroma compound responsible for many fruity and floral aromas like grapey notes in Muscat
How does latitude impact temperature and sunlight?
- Latitude - lower latitude = more warmth and sunshine bc solar raditiation travels less closer to Equator = higher sugar, lower acidity, riper aromas, riper + higher tannins
What latitudes are suitable for grape growing for wine production?
30-50 degrees latitude on each side of the Equator
At what rate does temperature fall with increasing altitude? What does this mean for grapegrowing?
Approximately 0.6C (1.1F) over every 100 m increase in altitude
High altitude sites can be good in areas of low latitude that would normally be too hot - altitude tempers latitude heat (eg Salta, Argentina, 3k meters above sea level)
What is aspect?
the direction vineyards planted on slopes are facing
How does altitude impact temp and sunlight?
- Altitude - sunshine more intense at high altitudes; high altitude sites have high diurnal range (bc air is thinner, can’t hold onto as much heat at night, nights are cooler)
How do slopes and aspect affect temp and sunlight?
- Slopes and aspect - facing the sun (south facing in N, north facing in S) will receive more solar radiation than those facing opposite direction; slope increases the angle at which solar radiation hits Earth’s surface, increasing intensity of heat and light (important in high latitudes w less sunlight/warmth) - eg Alsace and Burgundy GC vineyards are on s-e facing slopes; opposite can be achieved in warm climates eg Stellenbosch on south facing slopes (in S hemisphere)
East facing slopes preferred bc they receive morning sunshine, any dew dries out faster and prevents mildew or rot, extends hours of vine growth and ripening
West facing may become too hot bc of afternoon sun - coasts (like Cali or W Australia) can mitigate this w cool afternoon sea breezes
What are other benefits and hazards of slopes?
\+ Shallower, poorer soils Better drainage Shelter from winds and rain (Rhone - mistral) Protection from frosts
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Soil erosion
Inability to use machinery
Explain how proximity to water impacts nearby vineyards.
Water heats up and cools down more slowly than dry land.
During the day, bodies of water remain relatively cool, lowering the average temp in area.
At night, water retains warmth gained during day and keep slocal area warmer.
Overall effect extends over the year - larger bodies of water give cooler summers and milder winters.
EX - FLX - winter freeze not as severe ; Carneros - cooling afternoon breeze from San Pablo Bay allows early-ripening grape varieties like Chard and PN to grow there
Ocean currents also have effect. EX - Gulf Stream makes BDX warmer for CS; cool Cali current makes Willamette Valley cooler for PN
Radiation from water’s surface can amplify effect of sunshine in cool climates or in cloudy conditions (like Alsace - prox to rivers)
El Niño - warmth + dry conditions to Washington, Oregon, Australia
La Niña - cooler, wetter conditions in Washington, Oregon, Australia; warmer and drier conditions in SA + California
What are the effects of winds?
- Areas near bodies of water experience cooling breezes during the day, moderating diurnal range
- Valleys facing coast or low land mean that winds can be felt relatively far inland; air is funnelled so stronger winds
- Winds over hot land masses can bring warm air (eg Zonda in Mendoza)
- Winds + breezes reduce occurrence of humid air, discourages fungal diseases
- Increase evapotranspiration rate, so vine needs more water in windier areas
HAZARDS - can damage vines and trellising, which lowers yields and increases costs; plant rows of trees at edge of vineyards as windbreaks; fences are less aesthetic and require maintenance
How to characteristics of the soil impact temperature?
- Drainage - free draining soils warm up more quickly (stonier, absorb sunlight). This encourages early budburst in cool climates; OJO spring frosts); also encourages root growth
- Color and texture- light colored soils (chalk, limestone) reflect energy to lower parts of canopy; dark colored soils (volcanic) absorb more energy and re-radiate most of it when temps are cooler at night; stone soils do this well too
What is mist?
Tiny drops of water collecting in the air just above an area of ground or water - happens when warm air is rapidly cooled, causing water vapor in the air to condense
Dense mist = fog
Morning is most common time
Commonly found in: Sonoma, Napa, Leyda Valley, Sauternes
Can reduce photosynthesis - if cloud mists fog are regular than sugar accumulation and acid degradation can slow down (good in warm areas or for early-ripening varieties)
Can increase humidity and incidence of rot