Fertilization Flashcards
Why do you usually not need to add sulfur and copper?
They are present in spray treatments
What is nitrogen a component of?
amino acids
nucleic acids
chlorophyll
phytohormones
Which nitrogen compound is preferentially taken up?
nitrate (over ammonium)
Can a vine take up OM?
No, it must be mineralized
How does nitrogen affect white wine quality?
increased yield with increased vigor
decrease sugars
increased aromatic compound precursors
increased botrytis
What would happen if you fertilize in the fall?
your nitrogen (ammonium and nitrates) would leach out
When are the nitrogen absorption peaks in the grapevine?
after blooming (green pea stage) and veraison
What happens do nitrogen uptake during a dry season?
There is less nitrogen uptake because soil needs water for nitrogen mineralization which leads to lower YAN
Can rootstock choice affect nitrogen uptake?
yes
What happens when there is too much N?
You have delayed maturity; the vine is focused on growth instead
What happens with less N?
You get more phenolics, more color intensity, anthocyanins, tannins
How do cover crops influence N availability to wine?
it decreases N availability because their is competition for the N
What is phosphorus important for?
support of genetic information
involved in energetic metabolism
involved in respiration
part of phospholipids membrane
Why is phosphorus not taken into account in vine fertilization?
soils generally have a high content
the vine absorbs very well
the vine has low P needs
What is potassium important for?
involved in stomata opening/closure in transpiration regulation
involved in cellular pH
What is the relationship between potassium and magnesium?
Antagonism; high K makes Mg difficult to absorb
Why is magnesium important?
a component of chlorophyll
involved in the neutralization of organic acids (TA and MA)
involved in the cell wall
less easy to absorb by the vines
In red variety management, what can you do when YAN is less than 120 mg/L?
Make a compost addition in order to increase the OM and to avoid a high increase of mineral N.
In red variety management, what can you do when YAN is more than 200 mg/L?
Have a cover crop with high N
What should you do if you have a potassium deficiency with a low CEC?
Foliar spray (if urgent)
Addition on soil (<100 kg/ha/year)
If you add too much, with a low CEC, it will leach out
What should you do if you have a potassium deficiency with a high CEC?
Foliar spray (if urgent)
Addition on soil (100-200 kg/ha/year)
What should you do if you have a magnesium deficiency?
stop potassium additions
Foliar spray (if urgent)
Addition on soil (50 to 150 kg/ha/year)
*Mg additions increase the pH
What do nutrient ranges depend on?
plant material, soil, style of wine, etc.
What are the YAN requirements for red and white wine?
White:150 mg/L
Red: 120 mg/L
What are sources of nitrogen?
Organic matter
Mineral N: nitrate, ammonium
Will you see lower or higher YAN during a dry vintage?
lower YAN, N has decreased mineralization
Is berry weight influenced more by N or water status?
water status
How does increased N influence acidity?
it increases acidity
How does increased N influence acidity?
it decreases acidity
Does increased N mainly effect secondary leaf area?
yes
How does increased N increase botrytis risk?
It increases leaf area which affects the microclimate
Does nitrogen affect # of clusters and cluster mass per vine?
No
Is magnesium easy to absorb by the vine?
no
When should you worry about Mg deficiency?
May/June when you don’t want it to affect PS
Where do you mainly see Fe deficiency?
in limestone soils; antagonist relationship between CaO3 and Fe
Concerning Fe and rootstock choice, what should you check before you plant?
IPC. Percent active limestone content
What does boron deficiency induce?
berry shatter; flower abortion
What is a common Mg fertilizer?
Magnesia; also increases pH.
If you have good fertilization, but big bunches with few berries, what deficiency could you have?
boron
What is the k1/ISB/ISMO?
stability of humus
Why should you dig a soil pit and not just do soil analyses?
you can see all the layers, the roots could go deeper
What does ‘V’ represent?
if the whole CEC is filled
Does Petit Verdot like a water deficit?
no
