natural factors

Question 1

how natural factors affect which grape variety to grow (photosynthesis, anthocyanin, tannin, aroma compound v early bud chard PN merlot grenache, late bud CS SB syrah riesling, early ripe chard PN merlot SB syrah, late ripe CS grenache riesling mid-late)

Answer 1

-temperature (budburst >10c, flowering >17c, fruit set 26-32c) affect budding time and hazard (eg frost) occurance. choose variety late budding in cool climate
-different variety has different sensitivity regarding temp eg, chard and PN are early ripening variety and need less heat
-temperature affect photosynthesis via sugar accumulation. >21c b4 ripe malic acid degradation -> rapid loss of acidity while <15c acidity too high for the must. extreme heat / water stress stop stomata and photosynthesis.
-temp and sun help methoxypyrazine reducing herbaceous flavor. tannin accumulate much preveraison and high temp help polymerisation and lower bitterness
-anthocyanin synthesis for blk grape color development best at 15-25c
-sun increases aroma compound and precursor eg terpene fruity
-aspect: cool climate south facing slope riper fruit. warm climate away from sun allowing early ripe grape grow
-altitude: high diurnal range allow grape retain acidity during night in ripe period in warm region mendoza. low diurnal in cool region allow ripe at night mosel
-water body + sun reflection + air move: cooler day/summer, warmer night/winter. allowing early ripe variety chard PN (sn carneros paolo bay cool breeze). inland warm aft allow late ripe variety CS to grow. finger lake no frost, warm gulf stream/bordeaux CS, cold california current/oregon PN
-soil: well drained eg sandy/stony warm up early allow early bud variety in cool climate. lighter color sancerre champagn chalk (or dark etna aborb heat day reradiate at night) reflect sun warm up canopy allow late ripe variety.
-mist/fog: warm air over water to cool land night/morning => sun slow photosynthsis sugar accumulate and acid degrade allow early ripen variety PN and if dry afternoon -> noble rot

Question 1

how natural factors determine vineyard site selection

Answer 1

-if site is located in cool area, locating in south facing slope in north hemisphere enables it to receive sunshine, raising temperature and facilitate better ripening
-if site is located in continental area, locating close to large water bodies enables it to have moderating effect, ie avoiding extreme temperature and better growth of vine

Question 2

Vineyards facing west, which get afternoon sun, can experience what issues?

Answer 2

1. Vineyard may become too hot, particularly if it’s in a warm climate;
2. Grapes face increased risk of sunburn.
3. In certain climates, west-facing vineyards tend to endure damper, cooler weather conditions.

Question 3

What are two advantages of sloping vineyards?

Answer 3

1. Cold, dense air moves downhill displacing warmer air to higher levels, which produce warm thermal layers on the slope (like the Côte d’Or).
2. Soils on slopes tend to be poorer, more coarsely textured and better drained.

Question 4

What are the disadvantages of sloping vineyards?

Answer 4

1. Increased risk of erosion;
2. Higher costs as it requires hand harvesting.

Question 5

What are four advantages of vineyards being planted close to a body of water?

Answer 5

The body of water:
1. Reflects the sun’s rays;
2. Provides source for irrigation;
3. Reduces risk of ground frost;
4. Can provide morning mists to encourage development of noble rot.

Question 6

how different properties of soil affect vine growth

Answer 6

1. texture: smaller particle size (clay) is good at holding water and nutrients. However, waterlooged can lower vigor and even kill the vine. bigger size (sandy) means the soil is well drained and the vineyard may need irrigation. It can avoid excessive ater if there is too much rainfall eg Haut Medoc. In other case, the vineyard may need to add compost and humus to provide nutrients and hold the water.
2. structure: clay (high proportion) hold strong and no room for vine root to get through. gravel/sandy (with clay or humus to hold) enable vine roots to penetrate to deep further to get water.
3. color: lighter color soil reflect sunlight to vine canopy increasing temperature helping ripening, particularly good for those vines that have too much shade. Darker color soil aborb sunlight during the day and release at night, moderating diurnal range.

Question 7

describe the characteristics of maritime (cool/moderate eg bordeaux), mediterranean (around mediternean, coast california, chile, SA, SE Aus) and continental climate in moderate and warm regions respectively and what are the potential hazards or difficulties in growing vines there

Answer 7

there is a small difference annual temperatur between summer and winter in maritime (cool/moderate) and mediterranean climate while rainfall mainly in winter (warm dry summer) for the latter and distribute evenly for the former. continental climate denotes extreme difference in summer (short) and winter temperature with small amount of rainfall. The average GST range of temperature for warm climate is 16.5-18.5c while that of moderate climate is 18.5-21c. Area under continental climate is usually located inland protected from water bodies (eg sea or lake) that have moderating effect to the high diurnal range of temperature. continental climate has a long winter and fast temperature droping spring which may exhibit the hazard of frost. maritime climate may have excessive rainfall that may destroy vine during flower and druit setting period. rainfall before harvest may also lead to spltting of vine. The humidity from too much water and poor ventilation of too much leaves and shade (due to vigor) usually lead to fugal disease. The hot dry summer for mediterranea climate means higher evapotranspiration and water stress may happen that stop normal photosynthesis and grow of vine.

Question 8

Out of the viticulture approach conventional, organic and precision, which one you would adopt if it is located in Italy, Greece and California