Viticulture Flashcards
Define PHOTOSYNTHESIS
The process by which green plants use sunlight to produce sugars from CO2 and H2O
The leaves are the main site of photosynthesis in the vine
Sugars produced in photosynthesis are used for vine growth and metabolism
Describe TRANSPIRATION
Evaporation of water from tissue inside the leaf-
Pulls water up through roots and transport nutrients
Water vapour diffuses our of stomata on the underside of the vine leaves
Loss of water in leaf causes water to be pulled upward through soil, through roots and above-ground parts of the vine
Why does the vine need sunlight?
For photosynthesis- process by which green plants use sunlight to produce sugars from co2 and h2o
Why does the vine need HEAT?
Certain amount needed for photosynthesis and transpiration.
Heat is a good mechanism to tell vine when to start growing (leaves etc) (10deg vine starts to wake up)
Methoxypyrazines broken down by heat and light
what is the effect of heat and sunlight on tannin
Tannin creation happens from heat and sunlight when grapes are green.
During veraison causes them to polymerise - go from short chain tannins to long chain tannins = become softer
Why is water a requirement for the vine
Needed for photosynthesis
Transporting things around plant
To build up the grapes
Water needed for structure- otherwise the vine will wilt
Where does the majority of the root action happen?
In the first 1-2 metres
What would be the reason for a vine having a large root system, and how might that have benefited the vine?
A large root system means the roots have gone looking for nutrients/food.
Best fruit is produced when the vine/roots are under light stress
What is the reason for winter pruning ? (Late in season)
Protects from early budding. If you damage the vine later in season (Feb/early March) it has to heal and therefore buds a little later
What can happen to buds when there’s a clear night and clear sunny morning?
Can get scorched
How can sprinklers protect buds?
Create ice, exothermic reaction produces heat. Protects the bud (like an armour)
What are the ideal/“perfect” temps for flowering and pollination?
Flowering = 17deg Pollination = 26deg
What does the pollen tube require as it forms?
Warmth, doesn’t like damp
What do adverse temps at flowering and pollination mean for the vine ?
Mixture/uneven flowering and grape set
What are the extremely important weeks for ripening?
Last 6-8 weeks
What effect does too much nitrogen/soil condition too favourable have on fruit set?
Delays fruit set.
Stressing the vine at the start of the season can help
What happens, with regard to sugars and acids, during veraison?
Sugar starts to go into grape
Vine lives of Malic acid at this stage- uses for energy
(The plant changes its food source)
I.e. sugar levels go up = Malic acid goes down
What effect do warm and dry conditions have on the vine during grape formation?
Higher rate of transpiration = more sugar pulled up into the grape
Warmer climate = higher sugar/ higher level of alcohol = Malic acid lower
Describe continental climate classification
Away from large bodies of water
Dry
More extreme differences between summer and winter temsps
Short, sharp summers
Temps rapidly changing in spring and autumn
E.g. - Burgundy and Alsace
Describe maritime classification
Volatile environment
Relatively humid
Not particularly warm
Start of spring and harvest temps not optimal
Rainfall spread evenly through the year
Low annual differences between summer and winter temps.
Describe Mediterranean classification
Like maritime, but warmer
Low annual differences between summer and winter temps
By body of water
Warm/dry summers
Extended autumn
Sea adds warmth
Annual rainfall tends to fall in the winter months
E.g. Napa valley and Coonawarra
What does GDD stand for and what does it mean?
Growing degree days
E.g. how many days in month are we above 10deg?
What are MJT and GST?
Mean temps in warmest month
Growing season temperature
What is the degree change for every 100m up in altitude?
0.6deg
What are the 5 main nutrients required by the vine, and what for
NITROGEN- for green growth. Legumes can be planted to pull nitrogen into the soil
POTASSIUM - helps water to be taken up - helps with root system
PHOSPHOROUS - required for photosynthesis
CALCIUM - needed in small amount, too much = chlorosis = yellowing of leaves
MAGNESIUM - chlorophyll = needed for green parts
What are the 5 main requirements of the vine
SUNLIGHT WARMTH CARBON DIOXIDE WATER NUTRIENTS
How can a grower influence how the vines requirements are met? (4)
CANOPY MANAGEMENT
SOIL MANAGEMENT
WATER MANAGEMENT
HAZARD MANAGEMENT
What are the key aims of canopy management? (6)
Maximise effectiveness of light interception
Reduce shade within canopy
Ensure microclimate is as uniform as poss- even ripening
Promote balance between vegetative and reproductive functions of vine
Arrange vine canopy for mechanism
Air circulation through canopy to reduce incidence of disease
What is the risk of clay and limestone soil (e.g. Chablis)
Not a lot of nitrogen- if you don’t add to the must, yeasts can struggle, give off sulphur compounds
What is the name given to grape varieties that require relatively low temps at budburst and give 4 examples
Early budding
Chardonnay, Pinot Noir, Grenache, Merlot
What is the name given to grape varieties that require higher temps at budburst and give 3 examples
Late budding
Cabernet sauvignon
Sauvignon Blanc
Syrah
When is Dormancy?
Nov-March
May-Sept
When is Budburst?
March-April
September-October
When is Shoot & Leaf Growth?
March-July
September-January
When is Flowering &Fruit Set?
May-June
November-December
Optimum temp for vine using photosynthesis to create sugar for energy
18-33°C
Anthocyanin synthesis is optimum at what temps?
15-25°C
Give 2 examples of interventions that could be carried out as a result of data collected in PRECISION VITICULTURE
Changing rootstock halfway through rows as crop gets more fertile
Increasing levels of leaf-stripping in areas showing high vigour
PRECISION VITICULTURE
How is data collected ?
On sensors either “remote” (on aircraft) or “proximal” on a tractor or harvester in the field
From which species are most vines?
VITIS VINIFERA
What tends to be the main function of North American Vine species?
ROOTSTOCKS
What are the 4 most important North American vine species?
VITIS LABRUSCA
VITIS RIPARIA
VITIS BERLANDIERI
VITIS RUPESTRIS
What are the 4 sections of a vine?
"MAIN SHOOTS ONE-YEAR-OLD WOOD PERMANENT WOOD ROOTS "
What parts collectively form The canopy”?”
MAIN SHOOTS (and it's main sections -) STEMS BUDS LEAVES LATERAL SHOOTS TENDRILS INFLORESCENCES/GRAPE BUNCHES
What does the Stem transport to and from the different structures, and what does it store?
WATER + SOLUTES
CARBOHYDRATES
What are Nodes?
Swellings along the stem where the other structures are attached
What are Internodes?
The lengths of stem between the nodes
What happens in Spring during the Vine’s growth cycle?
Main shoots on the vine grow from buds retained from previous year
What happens in (late) Summer during the Vine’s growth cycle?
Leaves fall from the vine and green shoots lignify (turn brown and woody) to become Canes
What happens in Winter during the Vine’s growth cycle?
The vine is pruned to leave the necessary structures for the next growing season
Steps taken to increase efficiency of water use - in the vineyard
- water-efficient irrigation systems combined with better monitoring of water uptake by the vines - dripper systems, regulated deficit irrigation
- drought-tolerant varieties i.e. Grenache
- drought tolerant rootstocks (140R)
- reducing evaporation - mulching
- reducing competition - removing weeds
- increase humus levels = water retention - add organic matter such as compost
- promoting growth of vine roots deep into soil (through cultivation)
Advantages and disadvantages of drip irrigation
A: -economic use of water
- control and tailor water supply to areas of vineyard = potentially higher yields and quality
- can supply fertiliser - “fertigation”
- can be used on slopes
D: -high installation costs
- clean water - otherwise blocked drippers
- can be blocked by algae, bacteria, high levels of mineral and salts = maintenance work
- can’t be used in frost protection (aspersion) as below green parts of vine
What are the effects of promoting sunlight exposure within the vine canopy? (6)
- Increased sugar levels in grapes through greater overall photosynthesis in the vine
- increased tannin levels and greater polymerisation of those tannins, leading to less bitterness
- enhanced anthocyanin (colour) development in black grapes
- decreased malic acid
- increased levels of some favourable aroma precursors and compounds (e.g. terpenes - fruity/floral aromas eg grape in muscat)
- decreased methoxypyrazines - herbaceous, e.g. cab Sauv
When is grape development?
June-Oct NH
Dec-April SH
When is harvest?
Sept-Oct NH
March-Apr SH
When is leaf fall and dormancy?
Nov-Dec NH
May-Jun SH
What are the stages that make up grape development?(4)
Early grape growth
Veraison
Ripening
Extra-Ripening
What is involved in summer pruning?
- Disbudding
- Shoot removal
- Shoot positioning
- Pinching
- Shoot trimming
- Leaf removal
- Crop thinning/green harvesting
List 5 main canopy management techniques
- Vine Training
- Winter pruning
- Vine trellising
- Plant vigour management (nitrogen fertilisation, irrigation, cover cropping etc)
- Summer pruning
What is the purpose of disbudding?
Removal of buds to manage vine balance and yields, and to remove buds that are poorly positioned (facing down or too close together)
Name the (7) stages of the vine growth cycle
DORMANCY - Jan-Mar BUDBURST - Feb-April SHOOT AND LEAF GROWTH - Feb-July FLOWERING AND FRUIT SET - May-June GRAPE DEVELOPMENT - June-Oct HARVEST - Sep-Oct LEAF FALL & DORMANCY - Nov-Dec
Describe the changes the grape is going through at Flowering and fruit set
Flowering describes the opening of individual flowers within the inflorescence.
What is Coulure?
Condition of grape bunch where fruit set has failed for a high proportion of flowers.
Caused by an imbalance of carbohydrate levels - resulting from low rates of photosynthesis - could be a result of cold, cloudy conditions or hot, arid conditions with high water stress.
Can also be from vigorous shoot growth diverting carbs from inflorescence.
Fertile soils, heavy fertiliser applications and vigorous rootstocks can cause strong shoot growth and lead to coulure
What is Coulure?
Condition of grape bunch where fruit set has failed for a high proportion of flowers.
Caused by an imbalance of carbohydrate levels - resulting from low levels of photosynthesis - cold, cloudy conditions, or hot arid conditions (high water stress)
Can also occur from vigorous shoot growth diverting carbohydrates from inflorescence
Fertile soils, vigorous rootstocks = strong growth and therefore coulure.
REDUCES YIELD DRAMATICALLY
What is millerandage?
High proportion of seedless grapes
Still ripen normally, though smaller than grapes with seeds
Reduced yield - reduced amount of wine that can be produced. Some grapes remain small, green and unripe - negatively affect wine quality.
Can result from cold, windy weather at fruit set.
Susceptible varieties = chardonnay, merlot
Define the approach of conventional grape growing
Conventional viticulture is the result of a change to viticulture that happened in the 2nd half of the 20th century. It became intensive fruit farming. The aims included raising production levels, and reducing the amount of labour needed.
This was achieved by mechanisation, chemical inputs, irrigation and clonal selection.
Agrochemicals - pests and diseases
Mineral fertilisers
Viticulture became a monoculture
Advantages - Ability to mechanise
Reduction of competition from other plants
Specific needs of grape variety - irrigation, nutrition level, treatments against hazards, pests and diseases.
Increase yields, minimise costs
Disadvantages - Plants in monoculture more prone to disease - fungal diseases spread more quickly as all plants affected simultaneously
- Depleted nutrients due to no natural ecosystem
- Residual chemical from treatments can find their way into ground water or air - creating environmental damage
Define the approach of organic grape growing
Seeks to improve soil of vineyard and range of microbes in it - increased health and disease-resistance of the vine
Rejects the use of synthetic fertilisers, fungicides, herbicides and pesticides
- Application of compost - breaks down in soil. Slow release of nutrients, improves soil structure, increases biomass in soil
- Cover crops - prevent erosion of the soil, improvement of life of soil
- Natural fertilisers - animal dung, natural calcium carbonate. Restore natural balance of vineyard
- Reduction of monoculture - cover crops, planting hedges, “islands” of biodiversity
Sulphur and copper sulfate to combat mildews, monitoring weather patterns to see when the spraying is necessary
Natural predators
Ecosystem mechanisms
Advantages - Improvement of vine health, disease-resistance of vine
- Improvement of soil health
- Elimination of spraying synthetic chemicals
- saving on cost of synthetic chemicals
Disadvantages -
- possible reduction in yield (small)
- significant reductions in yield in difficult years
- increased reliance on copper sprays, which in turn leads to build-up in soil
- cost and time of certification sought
Define the approach of Biodynamic grape growing
Based on work of Rudolf Steiner and Maria Thun
Organic practices but also incorporates philosophy and cosmology - regarding farm as an organism and seeking to achieve balance between physical and “higher” non-physical realms
Grape growing practices coincide with cycles of the planets, moons and stars
Costs a little more than organic - additional labour to tend vineyard
Homeopathic remedies “preparations” to fertilise soil, treat diseases and ward off pests.
One example - 501 (horn silica) filling a cow’s horn with ground quartz and burying for 6 months. Then dug up, dynamised, sprayed onto soil. Thought to encourage plant growth
Define the approach of Sustainable grape growing
3 themes - Social, economic, environmental sustainability
Aims to promote natural ecosystems Maintain biodiversity Manage waste Minimise applications of chemicals and energy use Reduce impact on wider environment
Encouraged to develop in-depth knowledge of lifecycles of the vine and vineyard pests - monitor weather forecasts to predict/prevent outbreaks
Integrated Pest Management - key part of SA - setting thresholds of when action needs to be taken, identifying and monitoring pests, preventative measures, evaluating and implementing control options.
Intervene when level of damage will exceed cost of interventions
Advantages - more thoughtful approach - economic, social, environmental impact of viticulture
- Deployment of scientific understanding of threats to successful grape growing to minimise interventions needed
- reduction in spraying of synthetic and traditional treatments
- cost saving has incentivised grape growers to work more sustainably
Disadvantages - Not protected term therefore can be used to promote without clear standards
-nationwide standards for sustainability can be set too low
2 rootstocks that are tolerant of root-knot nematodes
Ramsey
Dog Ridge
(both V. champini)
Which rootstocks are highly tolerant of drought? (and why)
V. Berlandieri, V. Rupestris
110R and 140R
Able to root deeply and quickly
Rootstocks based on V. Riparia (eg Riparia Gloire) are what?
Tolerant of water-logged soil so can be useful in regions with high rainfall and water-retaining soils
Which rootstock is favourable for soils of high salinity?
Based on V. Berlandieri - tolerant of soils with higher levels of dissolved salt -
1103P
Rootstocks with high tolerance to acidic soils?
99R and 110R - hybrids of V. rupestris and V. Berlandieri
What do rootstocks based on V. Berlandiere - such as 41B tend to be tolerant of?
Soils with high lime content (i.e. high PH)
Give examples of low vigour rootstocks, and what are the benefits?
Benefits - Can advance ripening, useful in cool climates
V.riparia - 420A and 3309C
Give examples of high vigour roostocks, and what are the benefits?
140R
V. Rupestris
Benefits - useful if grape grower wants to boost vine growth and yields in vineyard areas with infertile soils and dry conditions
Give an example of when you might want to use a high vigour rootstock?
to produce grapes for sparkling wine, where high yields of grapes with delicate aromas and high acidity is more desirable than low yields of grapes with more concentrated aromas, colour and/or tannin
