IRRIGATION Flashcards
Why is water important for the vine? (3)
Transpiration
Production carbohydrates (around 5%)
Creates pathway for nutrient uptake
When do you reach field capacity (FC)
Field capacity its reached after all the water is drained from the macro pores.
What is meant by the total available water?
All the water in the soil between field capacity and the permanent wilting point
Give the amount of bars for saturation, field capacity, refill point and wilting point
Saturation: 0 bar (free draining water)
FC: -0.1 bar (readily available water)
RP: -1.0 bar (poorly available water)
WP: -15.0 bar (wilting point)
What is the difference between adhesion and cohesion when talking about capillary rise?
Adhesion: attracts water to solid parts
Cohesion: keeps molecules of water together
What is capillary rise?
the amount of water that can be pulled up in relation to the diameter of the ‘pipe’
What is the difference between transpiration and evapotranspiration?
Transpiration (vine) is an active process, evapotranspiration (soil) is not
How does a vine suck up water?
Transpiration causes suction in the ‘tubes’ that actively sucks up water from the roots. The suction by transpiration must be greater.
A NEGATIVE PRESSURE IS A HIGHER SUCTION
What is meant by stomata conductance?
How easily there can be exchange in the stomata
What is crucial when assessing water needs for the vines? (soil)
To take the waterholding capacity into account from all the soil layers
At which moment has waterstress the biggest impact on yield and vegetative development?
Post flowering
Pre veraison
How can waterstress be indicated with the appearance of the shoots? (4)
No new leaf production and shoot tip will fall
Shorter shoots
Smaller diameter shoots
Lateral shoots will dry and fall
How do leaves indicate waterstress? (5)
Leaf formation will slow down
Leaves in direct sunlight feel hot
Leaves will become pale (bleached green color)
Leaves will become scorched
Basal leaves will become chlorotic and fall
Name a few (4) ways how waterstress be indicated by the fruit?
Smaller grape berries
Loose clusters
Veraison might be delayed
Shrivelled berries
In what way has the leaf area of the vine an influence on the water use?
The bigger the leaf area the higher the need for water
Name 4 ways to measure soil moisture
Gravimetric
Volumetric
Matric potential
Remote sensing
What is the maximum amount of waterstress a vine can handle (bar)?
-5 bar
What is the best moment of the day to measure leaf water potential?
Pre-sunrise because at that stage the vine is still in ‘balance’
If tendrils are surpassing the shoot tips, what does that tell you?
Canopy in rapid growth and no water limitation
What is the general range for soil water holding capacity?
100-500mm
What is the risk of flood irrigation?
If the land is not very equal, it will cause some parts of the vineyard to receive more water than other
At which periods can irrigation be necessary? (5)
End of winter
Prior to bloom (to ensure shoot growth)
Post bloom to harvest
Close to harvest (to avoid shrivelling)
Post harvest, when canopy is still active (storage)
Which two rootstocks are the most resistant to drought?
1103 P
140 Ru
Both crossing between berlandieri and rupestris
Which rootstocks are the least resistant to drought?
Riparia Gloire
101-14 (widely used)
3309C
Explain transpiration control
Stomata control
Abscisic acid is produced in the roots and goes to the leaves. Close to permanent wilting point the leaves stores this acid and causes the stomata to close (stop transpiration and losing water)
Why are 100% gravel soils not suitable for viticulture?
Because every vineyard need at some depth a subsoil that can store water.
How much days after irrigation are is the stomata control back to normal?
2-3 days
How much rain needs a vineyard for profitable viticulture?
300-500mm
Do you prefer a small or big irrigation amount before a heatwave?
Big. In order to create reservoir for the vine
What is the best moment to irrigate? (time of day/temp)
When it is cool
Why can iron rich soils be reddish or blue/grey color?
Roots consume oxygen so they reduce the iron. It makes the soil grey/blue
How can waterstress increase astringency in the final wine?
Water stress causes smaller bunches/berries. So less flesh and more skin. Higher amount of tannin in final wine
