FERTILIZATION AND COVER CROPS Flashcards
What is miccorrhizae?
A symbiotic association between a fungus and a plant.The term mycorrhiza refers to the role of the fungus in the plant’s rhizosphere, its root system. Mycorrhizae play important roles in plant nutrition, soil biology, and soil chemistry.
Name the 4 macro nutrients for the vine
Nitrogen (N)
Potassium (K+)
Magnesium (Mg2+)
Phosphorus (P)
What is the function of Nitrogen (N) in the vine? (6)
Component of:
Amino acids and proteins
nucleic acid (genetic information basis)
Chlorophyll (convert light energy
Phytohormons (communication within the plant)
Necessary for vine growth and development
What is the function of Potassium? (K+) (5)
Most active cation in plant metabolism
Respiration and photosynthesis
Carbohydrate metabolism
Breakdown and translocation
Fruit formation
Why is magnesium (Mg2+) important? (2)
Activation of respiration enzymes
Photosynthesis
Why is phosphorus (F) important for the vine?
Energy storage and transfer
Cell growth
Root and seed formation/growth
Plant membranes
With what other nutrients is K competing?
Ca, Mg, Na. Dominance of K will inhibit the uptake of other nutrients
Which nutrients are uptaken the most around ph 6? (5)
Iron
Manganese
Boron
Copper and zinc
What is essential for nutrient uptake?
Water
Which micro nutrients are required for the vine? (5)
Fe - Iron
Mn - Manganese
Zn - Zink
B - Boron
Cu - Copper
What are the risks of too much N for the vine?
Poor fruitset
Low anthocyanin & phenolics (high risk of sunburn)
Slow ripening
Disease pressure (due to big and dense canopy)
What are the risks with too high N for the final wine?
Lower tartaric Acid
Higher pH
Higher K
Lower tannin and anthocyanin
Reduced flavour compounds and more herbaceousness
What are the two forms of N?
Nitrate (NO3-)
Ammonium (NH4+)
What is the main transporter of N in the xylem?
Glutamine
Where is an excess of N stored in the vine?
In the leaves, it competes with the carbohydrate reserves
What are the main uptake moments of N in the cycle of the vine?
During bloom and veraison
What can cause higher levels of abscisic acid in the vine?
High canopy density - shading
Lack of water
Pests and diseases
Define pH
A measure of concentration of free H+ ions in a solution
What can be caused by a high pH? (5)
High vigor
High N
Leafshading
Keeping old ineffective leaves on the vine
Name 3 types of fertilisers
Chemical
Organic (organic origin, compost/mulch etc)
Biodynamic (manure/preparations etc)
When are nutrient foliar sprays used?
As quick fix
Between flowering and veraison
What is the effect of Increasing N status?
Higher yield
Higher aromatic compound precursors (white)
Higher risk of botrytis
Lower sugar content
How much mg/l YAN is recommended?
150 mg/l
What is ideal soil pH?
6-7
What are the two main things to consider when deciding on fertilisation?
Soil analysis
Plant behaviour (vigor)
What can you do if the YAN is too low? What is too low?
<120 mg/l
Compost addition in order to increase the OM
When is YAN too high? And what can you do about it?
> 200 mg/l
Cover crops with high competition
With what nutrients is the CEC relevant?
K and Mg
Why causes too high N a delayed maturation and higher AC levels in the berries?
More leaf area –> more pruning weight –> vine is focussed on growing instead of grape ripening
What is the difference between high N levels for white or red wines?
White: higher yield and vigor, lower sugar, higher aromatics
Red: lower color, anthocyanin and tannin
What does an increase of N with the levels of glutathione?
It increases
What does glutathione?
It is a sort of protector of wine, good for ageing.
It avoids oxidation by ‘hunting’ for quinones
What does glutathione?
It is a sort of protector of wine, good for ageing.
It avoids oxidation.
What are positive consequences of cover crops? (5)
Decrease erosion
Decrease runoff
Decrease leaching
Increase water infiltration
Increase soil aggregate stability
What do cover crops do?
Fixate N
Release N after mulching/mowing and mineralisation
Provide food of micro organisms
Out grow undesirable weeds
Can improve access to the vineyard
- Could host predatory insects
What releases accumulated nutrients quicker, mulching or mowing?
Mulching (2-9 weeks)
What are the negative impacts of cover crops?
Competition for water
Competition for nutrients
Reduction of vineyard temperature –> attract frost
Extra cultivation needed –> risk compacting the soil
What is the aim for % Soil Organic Matter?
2-4%
Why are earthworms important in the soil?
Because they will create poes that arre big enough for water to infiltrate
The higher the C/N ratio, the…
Longer it will takes for the material to decompose
Describe how temperature and soil moisture influence mineralisation of organic material
Temp: in winter the temperature is too low for much mineralisation
Moisture: dry soils slow mineralisation down
How come that cover crops increase frost risk?
Reduced solar interception, lower topsoil temperatures
Raising the level of cold air to nearer the vine canopy
depleting moisture content from topsoil.
