The Growing Environment Flashcards
Temperature
Temps under 10C ensure dormancy; temps of -20C can damage and -25 kill
Above 10C stimulates budburst, and successful and uniform if sig temp rise at this point. Warm soil temps can also promote. Cold temps that bring frost can be harmful for new buds and growth which can reduce yields.
Optimum temp for photosynthesis is 18 - 33C so temp not usually a limiting factor.
Warm temps promote successful unform flowering (above 17C) and fruit set (optimum 26 - 32C). Cold damp causes issues and can reduce yields and perhaps quality.
Warm temps (>25C) promote bud fruitfulness in the next year and so impacts yield in next year.
Impacts ripening: sugar accumulation is faster in warmer temps (optimum photosynthesis and increased grape transpiration promotes movement of sugar into grape).
Malic acid degenration increases in warm temps. Temps above 21C in final months of ripening can lead to rapid loss of acidity and below 15C can be too acidic.
Formation of aroma compounds and precursors is complex but generally riper flavors for warmer temps. Cool may hinder breakdown of methoxypyrazines.
Anthocyanins synthesis optimal at 15 - 25 and perhaps tannin synthesis
Extreme heat (espec when also dry) can cause photo to slow or stop; slowing growth, ripening. Water stress can cause phot to stop due to stomata shutting to prevent water loss. This inhibits CO2 uptake which is necessary.
Sunlight
Needed for photo which is critical for vine growth, early grape growth, ripening. Full sunshine not critical and becomes an issue only if falls below 1/3 full sunshine. Fog can slow, avg cloudy day won’t
Enhances development of anthocyanins in black grapes; reduces methoxypyrazines
Greater accumulation of tannin pre veraison and promotes tannin polymerization post veraison which reduces bitterness.
Increases some favorable aroma compounds (such as terpenes the fruity floral found in muscat).
Sunshine warms grapes which increases the rate at which malic acid is used for respiration
Prolonged sunshine and heat can lead to sunburn which is negative for quality and yield.
Sunshine in late spring / early summer is associated with successful fruit set and exposure of compound buds to sunshine promotes fruitfulness in following year
Natural factors effecting temp and sunlight
Regions at lower latitudes (nearer the equator - Mendoza, RSA, NSW) get more solar radiation than higher latitudes (No France, DE). The intensity of the solar radiation is also greater.
Radiation is adsorbed (held by water droplets, dust, ozone) and scattered as it travels through the atmosphere, which decreases its intensity. Curvature of the earth means neare the poles, radiation must travel through a larger section of atmosphere. It also hits the earth at a low angle so radiation is spread over larger area (more diffuse)
At the equater it travels through a smaller section of atmosphere and hits the earth at a near perpendicular angle so radiation is more intense (less diffuse). So all else equal temps are warmer and sunlight more intense at lower latitudes than higher.
Number of hours of solar radiation at diff times of year is also determined by latitude. Low latitudes receive similar daylight hours (heat and sun) throughout the year. High latitude have longer daylight hours in summer and shorter in winter. These longer hours is helpful in the cooler areas.
Grapes generally grow between 30 and 50 deg’s latitude on each side of the equator with some exceptions. generally too hot near the equator and too cold near poles.
Altitude, Slopes and Aspect, Proximity to water, Winds, Soil Characteristics, Mist Fog Clouds,
Altitude
Temps fall by 0.6C for every 100m in alt increase so high altitude can be favorable for low latitude sites that might otherwise be too hot .
Salta Argentina (low latitude) up to 3,000m; Burgundy and Loire (high latitude) are at low altitudes.
Sunshine is more intense at higher altitude because solar radiation travels through less atmosphere as it reaches the site. Ultraviolet radiation (lower wavelength vs visible sunlight) is also greater. Both are thought to promote anthocyanin and tannin synthesis.
High altitude sites usually have high diurnal range. Ground absorbs energy from sun at day and releases at night. At lower altitudes the air in atmosphere (particularly water vapor) absorbs some of the energy so it is retained at night. At higher altitudes, air is thinner and holds less moisture so heat escapes rapdily for cooler night temps. In warm climates high diurnal ranges can help retain acidity.
Slope and Aspect
Vineyards on slopes will face a direction - called aspect
Vineyards facing the sun during the day (south in northern hemisphere and vice versa) will receive more solar radiation than those facing opposite.
The importance of slope and aspect increases at higher latitudes. Here sun hits earth at low angle and angle is lowest in spring and autumn. Slope increases the angle (nearer to perpendicular) at which sun hits surface. This increases intensity and heat. Can make a big diff on higher latitude vineyards. Extends the growing season. Burgundy Grand Cru
In warm climates may plant on slopes facing away from the sun to limit heat and light. Earlier ripening varieties or less alcohol more acid. Stellenbosch, whites are on south facing.
East facing benefit from morning sun which can heat atmosphere when temps are at lowest. Can extend hours of vine growth and ripening. Grape canopy which may be covered in dew can also dry out earlier reducing spread of fungal disease.
West facing get afternoon sun and may be too hot, espec in warm climates, may get sun burnt. But in places where coasts are to the west (CA, AUS) may get cooling breezes.
Slopes provide additional benefits: shallower, poorer soils and better drainage. Shelter from winds and rain, protection from frost (air movement down slopes prevents frost forming). But soil erosion and inability to use machinery are cons.
Proximity to Water
Large bodies of water can have sig impact
Water heats up and cools down more slowly than dry land. During the day, the water and air above a body of water remains relatively cool and lowers the temperature in the local area. Air above dray land heats up more quicly than above water and then rises. Cool air from above the water is drawn to the land to replace the warm air, resulting in cool humid afternoon breezes.
The opposite happens at night. Water retains the warmth gained during the day whereas the land, without solar radiation quicly loses heat. the warmth of the body of water keeps the local area warmer. Same effect over the year with large bodies of water giving cooler summers and milder winters.
In Finger Lakes, in NY, proximity to deep lakes reduces severity of winter freeze. MOvement of air helps protect against spring frost. In Carneros the proximity of the San Pablo bay provides a cool moderating influence so chard and pinot can thrive. Later ripening varieties are further inland.
Coastal currents can also influence. Bordeaux gets warm air from the Gulf Stream which flows fromthe Gulf of Mexico allowing Cab Sauv to ripen. Willamette at a similar latitude gets the cold California current and hence is better for Pinot.
Can benefit from solar radiation reflected from water surface. Depends on the angle at which the radiation hits the water, which is greatest at high latitudes. Advantageous in cool climates.
El Nino Southern Oscillation (ENSO) is a climatic cylce in the Pacific Ocean. Two phases El Nino and La Nina. El Nino when warm water in western Pacific becomes warmer than avg which causes high rain and hurricanes in South America and California. But brings warmer drier conditions to Washington & Oregon and warm temsp and drought to western Australia. Typically every 3 - 7 years with extreme rarer but happening more frequently.
La Nina is when eastern Pacific is cooler than avg. Cooler wetter in Washington & Oregon and warmer drier in South America and wetter in Australia.
Winds
Can have a warming or cooling effect.
Near bodies of water may experience cooling breezes during the day. Valleys facing the coast or other areas of low land (Petaluma Gap) can mean winds are felt very far inland. Valleys can also lead to stronger winds as they are funnelle.
Winds travelling over hot land masses can bring warm air like the Zonda in Mendoza.
Breezes also reduce the presence of humid stagnant air in the canopy that encourages fungal diseases.
Also increase evapotranspiration so vine’s water needs may be higher than in non windy area.
Strong winds can cause damage to vines and trellising, which may result in lower yields and increased labor and equipment costs.
Rows of trees can be planted at the edge of vineyards to act as windbreaks, but they can compete with vines for water and nutrients. Fences too but less aethetic and more maintenance
Characteristics of the soil
Soils can impact temp through: drainage, texture, color
Soil that drains freely (stony or sandy) warm up more quickly in the spring than damp soils. Rising soil temps encourage breakdown of starch in the roots, which stimulates budburst. So desirable for cool climates to have free draining to promote early budburst and hence longer season, though spring frost an issue. Warm soils also encourage root growth for more water and nutrient absorption
Color: Light colored like chalk (Sancerre Champagne) reflect some solar radiation. This extra light in lower part of canopy (which is usually shadier) can increase photosynthesis and grape ripening in cool cloudy climates. In warm climates this may increase heat during warmest part of the day.
Dark colored soils (volcanic Etna) absorb energy and re-radiate it when temps are cooler (i.e. night). Can be useful in cool climates or for late ripening varieties allowing development of color and degradation of acid into the night.
Stony soils are also effective at absorbing heat and releasing at night.
Mist, Fog, Clouds
Mists are formed by tindy drops of water collecting in the air just above an area of ground or water.
Usually formed when warm air is rapidly cooled, causing water vapor in the air to condense. May occur for example at night when warm air over water meets cooler conditions above land.
Dense mist is called fog. both can form at any time though morning is common (Sonoma, Napa, Leyda Valley, Sauternes)
Clouds form higher in the sky.
Depending on density, photosynthesis could be limited. Less solar radiation can lower temps, particularly if they delay when the morning sun begins to warm the land. Where they are regular they can slow down sugar accumulation and acid degradation, which can be beneficial in warm areas or for early ripenin varieties.
They can also increase humidity and therefore fungal diseases. Or noble rot in areas with warm dry afternoons.
Water
Minimun of 500mm/yr in cool and 750mm/yr in warm. For Turgidity (no wilting), photosynthesis, and temp regulation. And acts as a solvent for nutrients in the soil so plant can uptake them.
Water vapor diffuses out of stomata. This loss causes water to be pulled up from the soil - called transpiration
If vine has sufficient water, stomata open all day (CO2 in / O2 out). Water stress will cause stomata to partially close (reduce or stop photosynthesis - no CO2) and stunt growth slow/stop ripening.
Lack of rainfall has been a big problem in California, Argentina, South Africa, Australia. Irrigation needed.
Plentiful water in spring supports growth of many leaves and large canopy. But too avail in late spring early summer prolongs vegetative growth which is a competitive source of sugars for grapes. So mild water stress before veraison can be beneficial. Excess vegetative also can lead to shading (reduced anthocynanins, tannin polymerization, aroma compounds, too much methoxypyrazines, rot, mildew)
Too much water late in season can dillute grapes or split them (infection, mildew). Defecit during ripening can lead to shrivelled grapes.
Damp soils are often cold, espec early in season which can delay bud burst which can shorten growitn season. Warm promotes and stimulates root growth and ability to take up water and nutrients.
Natural Factors that affect water availability
Rainfall: Caused by water vapor condensing and precipitating. Warm temps cause moisture from land to evaporate and rise. As it rises it cools and condenses into clouds and eventually rain. Snow and hail are other forms of precipitation that can be sources of water when they melt. Topography can impact; mountain ranges can force winds of warm moist air upwards over high altitudes which cools condenses and precipitates. So one side can be wet and the other in a rain shadow (Alsace with Vosges and Washington State with Cascades)
Characteristics of Soil & Land: Can have sig impact on avail of water to the roots. Dependent on drainage, water holding properties (a function of texture and organic matter content) and depth. Hawkes Bay gets 1,000mm but it’s so free draining irrigation necessary. Jerez 650mm with none in growing but the albariza clay soil retains and forms a crust so irrigation not needed. Water-logged soils are a problem, reducing oxygen avail to roots and eventually killing. Topography: slopes have more run off for less penetration of water, causes erosion, and leaching of nutrients.
Evapotranspiration Rate: Amount of transpiration from the vine combined with the evaporation of water from the soil surface. The rate at which water is no longer available because it has been taken up by the vine or lost to evaporation. Depends on temperature, humidity, and wind (hot and dry like Mendoza faster). A high rate means more water is needed so hot dry need more than cool wet
Nutrients
Vine acqires all nutrients from the soil. In general require low levels of nutrients.
Nitrogen: essential for vine growth and can have major impact on vigor and grape quality. A component of proteins and chlorophyll (required for photosynthesis). Too much causes excess vegetative growth (with sugars going to that vs berry ripening) and potentially shading and poor ventilation. Too little results in reduced vigor and yellowing of leaves. Grapes with low nitrogen can be problematic. Overall restricted nitrogen produces higher quality grapes.
Potassium is essential for vine growth and helps regulate the flow of water in the vine. Very high levels can cause problems in the uptake of magnesium which may result in reduced yields and poor ripening. High levels can lead to high levels in the grapes which can lead to high pH in the wine. Low levels lead to low sugar accumulation in the grapes, reduced yields, and poor growth in general.
Phosphorous: Important for photosynthesis. Vines need only a small amount and usually there is enough naturally present in the soil. A deficiency leads to poorly developed root systems (and hence diminished ability to take up water and nutrients), reduced growth and lower yields.
Calcium: Important role in the structure of plant cells in photosynthesis. Deficiency is rare but can have a negative impact on fruit set.
Magnesium: found in chlorophyll and has a key role in photosynthesis. Deficiency can result in reduced yield and poor ripening.
Several others play a role: sulfur, manganese, boron, copper, iron, zinc
Natural factors influencing nutrient availability
Vine nutrients dissolve in soil water and then are taken up by the roots. Soil then impacts water and nutrient availability.
Soil pH has an influence on nutrient availability with different nutrients more or less avail. Iron is poorly available in soils with higher pH (i.e. soils with a lot of calcium carbonate like limestone) and this causes chlorosis. Leaves turn yellow and photosynthesis stops. Vines have a hard time taking up phosphorous in acidic soils.
Organic nutrient compounds (i.e. manure and compost) are not available in a form the vine can take up and need to be converted into inorganic compounds. Organic contain carbon / inorganic do not
Organisms that live in the soil (bacteria, fungi, worms) feed on the organic material and convert it into available forms in a process called mineralisation. Hence soil life and ecosystems are important.
Diff textures have diff abilities to hold nutrients. High proportion of clay are good while sand is bad. Humus can increase holding ability. Clay is small and has high surface area to volume ration for better adsorption
Soils on slopes are thinner and less fertile than valley floors
Climate Classifications
Climate: The annual pattern of temperature, sunlight, rainfall, humidity, and wind averaged out over several years (30 is typical).
Growing Degree Days (GDD): Heat summation model created by Amarine and Winkler (1944) originally intended for California. Subract 10C from avg mean temp in a month in the growing season, multiply by no of days in a month. Make that same calc for all growing season mo’s (April to Oct in North) and add to get GDD. 5 Bands: Winkler Zone 1 is cool whereas V is hot.
Huglin Index (1978): Similar to GDD but takes into account mean and max temperatures and increased day length at higher latitudes. Widely used in Europe
Mean Temp of the Warmest Month (MJT): Smart and Dry 1980. Mean temp of either July or January as warmest months as well as measures of continentality, humidity, hours of sunshine.
Growing Season Temperature (GST). Mean temp of whole growing season; in bands, correlates to GDD
Generic Headings based on Koppens climate classification (1900) considering temp and rainfall patterns.
Maritime: low annual diff’s b/n summer and winter. Rainfall evenly spread through year. Bordeaux
Mediterranean: low annual diff b/n summer and winter. Rainfall in winter months for dry summers. Napa and Coonawarra
Continental: More extreme diff’s b/n summer and winter temps. Short summers and cold winters with temps rapidly changing in spring and autumn. Burgundy and Alsace.
Often used with temp ranges of avg growing season temp
Cool 16.5C or below; Moderate 16.5 - 18.5; Warm 18.5 - 21; Hot over 21
Weather
Annual variation that happens relative to climatic average
Some regions experience greater variation. Bordeaux can have varying amounts and timing of rainfall. 2013 was cold and wet with uneven flowering, reducing yields and rainy humid harvest forcing producers to pick early with low quantity and quality. 2016 had good spring weather and harvest weather for higher yield and quality. Central Valley in CA is far more consistent and predictable.
These differences and their impact are called vintage variation. In some wine styles it is expected and welcomed in others like sparkling or high volume wines it is unwelcome.
Weather can impact yields
