Chapter 11 Flashcards
The number of vines per acre in the Mosel region is about:
A. 300
B. 1000
C. 3000
3000
What is the effect of a dry summer climate on the vigor of unirrigated vines?
Dry summers reduce vigor because they do not replenish soil water. As a consequence the vines deplete their water supply and stop growing
A key factor that separates premium wine grape vineyards from mediocre vineyards is A. stony soil B. rootstock C. vineyard slope D. canopy dimensions E. phylloxera
Canopy dimensions
Quantitatively distinguish between thin and thick canopies. _____
When photographed, about 40% of the canopy surface of a thin canopy appears as light patches. The value is much lower with thick canopies. Also, the leaf layer number of thin canopies is 1.5 or lower
Thick canopies adversely affect: A. grape composition B. next year's crop C. grape berry health D. all of the above E. none of the above
all of the above
What is photosynthesis?
Photosynthesis is the use of solar energy to synthesize sugar from carbon dioxide and water
T/F: An increase in light intensity is accompanied by a proportional increase in the rate of photosynthesis.
false. If at low light levels a one unit increase in light intensity yields, for example, a one unit increase in photosynthetic rate, then at higher light levels a one unit increase in light intensity will yield less than a one unit increase in photosynthetic rate
The curve describing the relationship between light intensity and photosynthesis rate plateaus when the light is:
A. as intense as full sunlight on a clear summer day
B. 50% as intense as full sunlight on a clear summer day
C. 10% as intense as full sunlight on a clear summer day
50% as intense as full sunlight on a clear summer day
T/F: The intensity of light per unit area of leaf is greatest if the leaf is perpendicular to the light rays
true
Leaves in deep shade:
A. use sugars synthesized by illuminated leaves
B. photosynthesize enough to meet their own sugar needs but do not export sugars to the rest of the vine
C. hardly photosynthesize at all, but at least remain innocuous
use sugars synthesized by illuminated leaves
T/F: Shade decreases the concentration of monoterpenes in Gewurztraminer
true
T/F: Because the essence of grape growing is converting sunlight into wine, it follows that grape growers should maximize their vines’ interception of sunlight
false, if growers maximize light interception, the vine canopies will be thick and shady and grape yields and quality will be lower than if vines intercept somewhat less light
How does a vineyard determine leaf layer number?
A vineyardist can determine leaf layer number–the measure of canopy “thickness”–by randomly selecting a number of sites at fruit cluster height along the vine row, pushing a rod through the canopy curtain at each site, and recording the number of leaves it contacts. The average number of leaf contacts is the leaf layer number
If canopy height remains constant, then increasing between row-spacing:
A. increases light interception by the vineyard
B. decreases light interception by the vineyard
C. does not change light interception by the vineyard
decreases light interception by the vineyard
T/F: The canopy surface area should not exceed twice the soil surface area
true
T/F: The curtains of the Bordeaux and Burgundy vineyards are shorter and closer together than those of most New World vineyards
true
T/F: Leaf layer numbers differ significantly among premium wine grape vineyards
false, Leaf layer numbers are about the same in premium winegrape vineyards
Grape shoots emerge from: A.leaves B.nodes C.roots D.flower clusters
nodes
T/F: Leaves export sugars to developing grapes
true
When are grape plants most resistant to low temperatures?
When they are dormant
Define “canes”
Shoots that grew in summer are termed canes after they lose their leaves in winter.
Are spurs longer or shorter than canes?
shorter, they have 1-4 or 5 nodes while canes have 8 or more nodes
Explain why the shoots on a severely pruned vine tend to grow very long
The limited number of shoots do not compete for stored sugars, light ,water and mineral resources, so shoot growth is not restricted by shortages of these resources
Explain why pruning decreases crop size.
Severe pruning reduces the number of nodes from which will emerge the shoots bearing the next season’s crop
What is overcropping?
A vine’s production of more crop than it can satisfactorily mature.
About how many leaves does a shoot need to mature its grape clusters?
10-20, if they are well exposed to sunlight
What is the purpose of flower cluster removal?
To prevent overcropping and its accompanying loss of grape quality
T/F: Upright shoots grow more slowly than pendant ones
false
T/F: It is good to keep basal buds in the shade
false. Shade reduces the number of clusters on the shoots that emerge the following year from the nodes
If canopies are thin, leaf layer numbers low, but shoot growth is excessive, the pruner should leave more nodes next year than he left last year. Explain.
Leaving more nodes will increase the number of crop-bearing shoots that following year, and the increased competition for resources among the more numerous shoots will decrease their growth
T/F: Dividing a thick, single-curtain canopy doubles the number of curtains and decreases canopy thickness.
true
T/F: If shoot spacing along cordons remains constant, then dividing a canopy curtain into two fruiting tiers doubles the number of shoots per curtain.
true
T/F: Increasing grape yield lowers grape quality
false, In some cases quality increases as yields increase
What is the big vine theory?
The theory that increased node numbers per vine, but with little change in nodes per meter of row, devigorates the vine.
T/F: Legume cover crops will help devigorate grapevines.
false, Legumes add nitrogen fertilizer to the soil which will invigorate the vines
T/F: Irrigation decreases wine grape quality
false, Under the right circumstances irrigation improves winegrape quality
Rootstocks are used to control_____
vine size
T/F: Strong winds stimulate photosynthesis and speed the accumulation of sugar by the grapes
false, leaf pores close in strong windes and carbon dioxide, which is essential for photosynthesis, cannot enter the leaf
Describe the calculation of degree-days for a day.
Subtract 50 deg F from the average temperature for that day
T/F: Region I is cooler than Region V
true
T/F: California has more Region I acres than Region V acres
false, more region V areas
T/F: Gewurztraminer is less suited to hot regions than is French Colombard
true
T/F: During radiation frosts, the valley floors are warmer than the adjoining hillsides
false, colder air settles in low lying areas
T/F: Wind may warm a vineyard if a layer of warm air exists above the vineyard
true
T/F: If ice encrusts a shoot, the shoot will freeze
false, Not necessarily. If water keeps flowing over the ice, the ice will remain at 32 deg F and the grape shoot will be uninjured
T/F: “Organic growers” eschew pesticides
false, Many organic growers use pesticides
What is a botanical pesticide? A. sulfur B. strychnine C. malathion D. nematodes E. phylloxera
strychnine
Growers control phylloxera by means of ___
rootstocks
Leaf-roll virus is spread by___
grafting
T/F: Several grape clones may share the same name
true
Removing leaves from around grape clusters: A. decreases grape rots B. lowers grape potassium C. Lowers grape pH D. all of the above E. none of the above
all of the above
In regards to winemaking, what is the hazard of treating grapes with sulfur?
If the sulfur remains on the grape, it will be reduced during fermentation to stinky hydrogen sulfide
T/F: Canopy management affects the vine’s microclimate
true
