3. The Growing Environment Flashcards
How do you calculate GDDs for Celsius and Fahrenheit (4)?
- Subtract 10 for C, 50 for F (temp. below which vines can’t grow) from avg. mean temp of a month in the growing season.
- Multiply this by no. of days in that month.
- Make same calculation for each month in the growing season (April-October / October-April).
- Add totals together to get GDD.
Why is it beneficial to encourage soil life/ecosystems in the vineyard?
Organisms such as earthworms/bacteria/fungi are essential for converting organic nutrient compounds found in manure/compost into inorganic ones, which is the form they must be in to be taken up and used by the vine.
Why does the importance of aspect and slope steepness increase at high latitudes (5)?
- solar radiation hits the Earth at a lower angle at high latitudes.
- the angle of the sun is lower in the spring/autumn than in the summer.
- the slope increases the angle (closer to perpendicular) at which the sun hits the Earth’s surface = more intense heat+light
- warmth can be a limiting factor at higher latitudes, so slope+aspect make a big difference as to what grapes can grow and how ripe they can get.
- more warmth during the spring/autumn extend the growing season for vines grown on slopes that face the sun.
What is transpiration in plants?
Caused by?
What is an evapotranspiration rate?
How does the ET rate affect the vine’s need for water?
Transpiration is the drawing up of water by the vine from the soil, through the roots and the above-ground parts of the plant. This is caused by loss of water from leaf stomata.
The amount of transpiration from the vine, combined with the evaporation of water from soil surface (high ET rate means that more water is required to meet vine’s requirements)
What can an excess of Potassium lead to (2)?
A deficit (2)?
Excess K: hinders uptake of Magnesium, leading to lower yields and poor ripening. High K in grapes = buffering effect for acidity, raises pH and affects wine quality.
Defecit of K: low sugar accumulation in grapes, reduced yield + poor vine growth.
What factors define a Mediterranean climate (2)?
Give 2 examples:
- Low annual differences between summer and winter temperatures
- Annual rainfall happens in winter months, with dry summers
- Ex. Napa Valley + Coonawarra
What are 5 different climate classifications?
Breifly describe how they work:
- Growing Degree Days; calculation of days per growing season that have suitable temperatures (50F +) for grape-growing.
- The Huglin Index; similar to GDD, but also takes into account mean and max. temperatures and increased day length at higher latitudes.
- Mean Temperature of the Warmest Month; aka MJT (Mean January/July Temperature), measures the mean temperature of the (thoretically) hottest month in the growing season (July for N. Hem. / Jan. for S. Hem.)
- Growing Season Temperature; uses mean temperatures of entire growing season, then divided into bands.
- Koppen’s Classification; consideration of temp. + rainfall patterns (Maritime / Mediterranean / Continental)
How does a region’s topography affect its soils (4)?
- Slopes = greater surface run-off in vineyards, less penetration of water into soil and less water available for vine roots.
- This is advantageous in regions w/high rainfall.
- Run-off causes erosion of soil+leaching of nutrients.
- Soil on slopes = usually thin due to erosion, limiting area over which vines can obtain water+nutrients.
How are winemakers / grapegrowers adjusting their practices in response to Climate Change (7)?
- Vine growth cycle starts sooner / moves more quickly. Therefore, grapegrowers need to make decisions regarding when to harvest. Harvesting sooner helps to retain acidity but might prohibit ripeness of tannins/aroma compounds and color accumulation. Harvesting later will lessen these problems, but will result in wines with less acidity and more alcohol.
- Acidification may be necessary.
- Irrigation may be necessary.
- Grapegrowers might need to switch out current varieties for those that are more suitable for a drier/warmer environment or late-ripening varietals.
- New wine regions are emerging or gaining prominence, (e.g. England, Canada) which might increase investment.
- Increased presence of sustainable practices (renewable energy, protection of environment.)
- Adjustment of vineyard orientations (more north-facing in N. Hem, south-facing in S. Hem.)
What is continentality?
Which types of regions have high/low continentality?
A measure of the difference between the annual mean temperatures of the hottest and coldest months
usually inland regions = more continental
coastal regions = less continental
How does proximity to bodies of water affect solar radiation reflection (3)?
Vineyards can benefit from solar radiation reflecting off the water’s surface and onto the vines.
Amount of radiation depends on angle at which sun hits water; amount of reflection is greatest at high altitudes.
This is advantageous in cool climates that have limited sunshine, e.g. Mosel Valley.
What is believed to be the relationship btw/ night-time temperatures and aroma compounds (2)?
What is an exception to the general theory?
It is thought that warmer night temps = greater breakdown of methoxypyrazines, which is important in cool climates.
Cooler temps are associated w/retention of other compunds, e.g. rotundone.
Cold night temps (<15C / 59F) seem to be beneficial in some regions, e.g. Wachau, Austria, where many top sites have both cold days and nights.
What can an excess of Nitrogen lead to (3)?
A deficit (3)?
Which is better?
Excess nitrogen = excessive veg. growth (sugars diverted to shoots/leaves), less ripening, shading by canopy leading to fungal disease.
Defecit of nitrogen = reduced vigor + yellowing of leaves. Grapes that are low in N can impair yeasts during fermentation (N is a yeast nutrient), leading to stuck fermentation, reductive odors, caused by stressed yeasts.
Overall, restricted supply of N is better.
What’s a maritime climate (2)?
Give 2 examples:
- Low annual differences between summer and winter temperatures
- Rainfall spread out throughout year
- e.g. Bordeaux / Mornington Peninsula, Australia
What is ENSO (2)?
- El Nino-Southern Oscillation
- A climatic cycle in the Pacific Ocean that significantly affects weather patterns of the surrounding areas.
How can El Niño negatively affect viticulture in North/South America, as well as Australia (3)?
High levels of rainfall + risk of hurricanes in S. America + California.
Rainfall can disrupt pollination+fruit set, lead to excessive water availability which = more vegetative growth, less ripening.
Australia = warmer temps + drought = vine stress + damage.
How do slopes/aspects affect grapes (3)?
- Slopes facing the equator will receive more solar radiation than those facing away (S-facing for Northern Hem., N-facing for Southern Hem.)
- Slopes facing east benefit from morning sunshine that can heat up atmosphere when air+soil temps are lowest (extends ripening hours, dries out canopy earlier to reduce fungal disease).
- Slopes facing west may be too hot in afternoon (can be alleviated in areas with coastal breezes e.g. W. Australia).
How does proximity to large bodies of water moderate temperatures of grape-growing areas (5)?
- Large bodies of water heat up and cool down slower than dry land
- During the day, water and air above a body of water remain cool and lowers temperature of local area
- Air above dry land heats up more quickly and this warm air rises
- Cool air from above water is drawn to land to replace the warm air as it rises, resulting in cool, humid afternoon breezes
- Opposite happens at night: water retains warmth absorbed during the day, land loses heat quickly = cooler summers + milder winters.
Given the cooler average temperatures in locations at higher latitudes, what helps the vine to produce enough sugar for ripening grapes (2)?
- Locations at higher latitudes (i.e. further away from the equator) 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.
Summarize the importance of temperature and its influence on FLOWERING and FRUIT SET (3):
- Warm temps (>17C / 64F) promote uniform flowering.
- Ideal temps for fruit set = 26-32C (79-90F).
- Cold, damp conditions = problems for flowering/fruit set = reductions in yield + potential quality.
Give an example of a vineyard area in a cool-moderate region that benefits from its specific exposure, and then one from a warm-hot region as well:
- Grand Cru sites in the Cote d’Or, Burgundy; the site is in a cool climate, but the south-east facing slopes receive enough sun exposure to fully ripen the grapes.
- Cima Corgo in the Douro Valley; hot climate, so vines benefit from northern exposure, meaning that they receive less sunlight, retain acidity and avoid sunburn.
How can warmer conditions from climate change be beneficial for some regions (3)?
Increased quality+production potential in regions once thought to be too cool to ripen grapes (Canada / England).
Drier conditions = greater transpiration and promotes mild water stress, which can help ripening in regions that already experience plentiful rainfall.
Drier conditions = less risk of fungal disease
Describe how the soil in a vineyard can be composed of different layers (2):
- Soil can be made of different layers formed at different periods of time, each w/its own texture, structure and characteristics.
- Sediment in topsoil might be different from bedrock underneath, e.g. sediment may have been transported by water, winds, glaciers, gravity (valley floors receiving sediment from slopes).
How can having substantially larger or smaller yields in a given vintage affect a winery economically?
LESS yield: problematic for cash flow + customer relations (businesses and consumers may find replacement product, switch permanently).
MORE yield: winery may not have capacity for increased volume of fruit, finding routes to market/customers for all wine (at a profit) may prove difficult.
How does altitude affect grapes?
How can altitude be beneficial (3)?
What are 2 examples of high altitude regions?
- Temperature falls ~0.6 degrees C every 100m increase
- Vineyards at low LATITUDE sites would be too warm without high ALTITUDE (e.g. Salta Province, ranging from 1280 - 3000m ASL)
- Sunshine and UV radiation are greater at higher altitudes because the rays travel through LESS ATMOSPHERE before reaching the vines.
- High altitude sites have high diurnal range, which helps grapes to retain freshness while also ripening sufficiently.
- Salta, Argentina and Mt. Etna, Sicily.
Identify the ideal temperature(s) for the following:
Budburst
Flowering
Fruit Set
Photosynthesis
Budburst: >10C (50F)
Flowering: 17C (63F)
Fruit Set: 26 - 32C (79-90F)
Photosynthesis: 18-33C (64 - 92F)
What is humus?
Organic matter in the soil formed by partial decomposition of plant material by organisms such as microbes and earthworms.
Grapes for wine production can successfully grow btw/which 2 lines of latitude?
30-50o latitude either side of the equator.
Summarize the importance of temperature and its influence on BUDBURST (4):
- Temps >10C (50F) stimulate budburst.
- Budburst is more successful/uniform when there is a distinct rise in temp (as in Continental climates).
- Warm soil temps also promote budburst.
- Cold temps can bring frost = harmful to new buds/growth = substantially reduced yields.
How do characteristics of the soil affect the grapes (2)?
Give specific examples to illustrate:
- Gravelly soils with larger particles (e.g. Bordeaux) will drain freely, warm up more quickly and retain more heat than clay-heavy soils with finer particles (e.g. Alberese soils in Chianti)
- Light coloured soils reflect some energy from solar radiation - Dark coloured soil (and stony soils) absorb more energy and re-radiate it when temperatures are cooler
When is plentiful water desired / not desired during the growing season (5)?
- plentiful water in spring = growth of lots of leaves to photosynthesize + support growth of vine and ripening of grapes.
- if too much water in late spring/early summer, encourages vegetative growth which competes for sugars, delaying/hindering ripening.
- mild water stress btw/budburst and véraison is beneficial for grapes.
- excess water close to harvest can dilute sugar, cause skins to split, encourage grey rot.
- however too much water stress near harvest can lead to grape shriveling.
What are some ways that climate change is affecting weather events (2)?
Increased frequency + severity of erratic weather events, e.g. storms, hurricanes, floods, frosts, heatwaves.
All lead to substantially reduced yields/quality.
