FERTILIZATION AND COVER CROPS

Question 1

What is miccorrhizae?

Answer 1

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.

Question 2

Name the 4 macro nutrients for the vine

Answer 2

Nitrogen (N)
Potassium (K+)
Magnesium (Mg2+)
Phosphorus (P)

Question 3

What is the function of Nitrogen (N) in the vine? (6)

Answer 3

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

Question 4

What is the function of Potassium? (K+) (5)

Answer 4

Most active cation in plant metabolism
Respiration and photosynthesis
Carbohydrate metabolism
Breakdown and translocation
Fruit formation

Question 5

Why is magnesium (Mg2+) important? (2)

Answer 5

Activation of respiration enzymes
Photosynthesis

Question 6

Why is phosphorus (F) important for the vine?

Answer 6

Energy storage and transfer
Cell growth
Root and seed formation/growth
Plant membranes

Question 7

With what other nutrients is K competing?

Answer 7

Ca, Mg, Na. Dominance of K will inhibit the uptake of other nutrients

Question 8

Which nutrients are uptaken the most around ph 6? (5)

Answer 8

Iron
Manganese
Boron
Copper and zinc

Question 9

What is essential for nutrient uptake?

Answer 9

Water

Question 10

Which micro nutrients are required for the vine? (5)

Answer 10

Fe - Iron
Mn - Manganese
Zn - Zink
B - Boron
Cu - Copper

Question 11

What are the risks of too much N for the vine?

Answer 11

Poor fruitset
Low anthocyanin & phenolics (high risk of sunburn)
Slow ripening
Disease pressure (due to big and dense canopy)

Question 12

What are the risks with too high N for the final wine?

Answer 12

Lower tartaric Acid
Higher pH
Higher K
Lower tannin and anthocyanin
Reduced flavour compounds and more herbaceousness

Question 13

What are the two forms of N?

Answer 13

Nitrate (NO3-)
Ammonium (NH4+)

Question 14

What is the main transporter of N in the xylem?

Answer 14

Glutamine

Question 15

Where is an excess of N stored in the vine?

Answer 15

In the leaves, it competes with the carbohydrate reserves

Question 16

What are the main uptake moments of N in the cycle of the vine?

Answer 16

During bloom and veraison

Question 17

What can cause higher levels of abscisic acid in the vine?

Answer 17

High canopy density - shading
Lack of water
Pests and diseases

Question 18

Define pH

Answer 18

A measure of concentration of free H+ ions in a solution

Question 19

What can be caused by a high pH? (5)

Answer 19

High vigor
High N
Leafshading
Keeping old ineffective leaves on the vine

Question 20

Name 3 types of fertilisers

Answer 20

Chemical
Organic (organic origin, compost/mulch etc)
Biodynamic (manure/preparations etc)

Question 21

When are nutrient foliar sprays used?

Answer 21

As quick fix
Between flowering and veraison

Question 22

What is the effect of Increasing N status?

Answer 22

Higher yield
Higher aromatic compound precursors (white)
Higher risk of botrytis
Lower sugar content

Question 23

How much mg/l YAN is recommended?

Answer 23

150 mg/l

Question 24

What is ideal soil pH?

Answer 24

6-7

Question 25

What are the two main things to consider when deciding on fertilisation?

Answer 25

Soil analysis
Plant behaviour (vigor)

Question 26

What can you do if the YAN is too low? What is too low?

Answer 26

<120 mg/l
Compost addition in order to increase the OM

Question 27

When is YAN too high? And what can you do about it?

Answer 27

> 200 mg/l
Cover crops with high competition

Question 28

With what nutrients is the CEC relevant?

Answer 28

K and Mg

Question 29

Why causes too high N a delayed maturation and higher AC levels in the berries?

Answer 29

More leaf area –> more pruning weight –> vine is focussed on growing instead of grape ripening

Question 30

What is the difference between high N levels for white or red wines?

Answer 30

White: higher yield and vigor, lower sugar, higher aromatics
Red: lower color, anthocyanin and tannin

Question 31

What does an increase of N with the levels of glutathione?

Answer 31

It increases

Question 32

What does glutathione?

Answer 32

It is a sort of protector of wine, good for ageing.
It avoids oxidation by ‘hunting’ for quinones

Question 33

What does glutathione?

Answer 33

It is a sort of protector of wine, good for ageing.
It avoids oxidation.

Question 34

What are positive consequences of cover crops? (5)

Answer 34

Decrease erosion
Decrease runoff
Decrease leaching
Increase water infiltration
Increase soil aggregate stability

Question 35

What do cover crops do?

Answer 35

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

Question 36

What releases accumulated nutrients quicker, mulching or mowing?

Answer 36

Mulching (2-9 weeks)

Question 37

What are the negative impacts of cover crops?

Answer 37

Competition for water
Competition for nutrients
Reduction of vineyard temperature –> attract frost
Extra cultivation needed –> risk compacting the soil

Question 38

What is the aim for % Soil Organic Matter?

Answer 38

2-4%

Question 39

Why are earthworms important in the soil?

Answer 39

Because they will create poes that arre big enough for water to infiltrate

Question 40

The higher the C/N ratio, the…

Answer 40

Longer it will takes for the material to decompose

Question 41

Describe how temperature and soil moisture influence mineralisation of organic material

Answer 41

Temp: in winter the temperature is too low for much mineralisation
Moisture: dry soils slow mineralisation down

Question 42

How come that cover crops increase frost risk?

Answer 42

Reduced solar interception, lower topsoil temperatures
Raising the level of cold air to nearer the vine canopy
depleting moisture content from topsoil.