Chapter 6 - Managing Nutrients and Water

Question 1

What are the factors when considering soil health?

Answer 1

1. Structure of the soil - is there good drainage, sufficient water holding capacity, sufficient oxygen, the ability to resist erosion, ability for the roots to penetrate to sufficient depth?
2. The amount of organic matter and humus in the soil
3. The number of living organisms in the soil
4. The total amount of available nutrients

Question 2

How do you control the level of nutrients in the soil and their accessibility to the vine?

Answer 2

Direct application of nutrients (organic and/or inorganic)
Promotion of biological activity and soil structure
Management of weeds that compete with the vines

Question 3

Green manure

Answer 3

Cover crops that are grown, mown, and turned into the soil to decompose and provide nutrients

Question 4

Pros/Cons of organic fertilizer

Answer 4

Pro:
Cheap/free
High in humus - good for soil structure & water retention
Provide nutrition for soil organisms

Con:
Labor required to incorporate into the soil (so the organisms can get to it)
Nutrients are not readily available (pro and can)
Bulky
Expensive to transport and spread

Question 5

Pros/Cons of inorganic fertilizer

Answer 5

Pros:
Can be tailored to the exact mineral needs of the vineyard
Readily available
Chepaer to transport/distribute

Cons:
Do not benefit soil organisms
Do not improve soil structure (no humus)
More expensive

Question 6

Cultivation defn

Answer 6

Method of weed control that involves ploughing the soil to cut or disturb the weeds’ root system

Question 7

Pros/Cons of cultivation

Answer 7

Pros
Becomes organic fertilizer for the soil
No chemicals involved - good for organic & biodynamic farming

Cons
Repeated cultivation can damage the soil’s structure and ecology due to the breakdown of organic matter and disruption of earthworms in their habitat
Costly - labor and machinery needed
Disturbing the soil buries the seeds, causing the weeds to grow back
Decreases competition, therefore increases vine vigor (pro and con)

Question 8

Weed control methods:

Answer 8

Cultivation
Spraying herbicides
Animal grazing
Cover Crops
Mulching

Question 9

3 types of herbicides:

Answer 9

1. Pre-emergence herbicides. They are absorbed by the weeds’ roots and inhibit germination
2. Contact herbicides - kill the green parts of hte weed it contacts therefore killing the weed
3. Systemic herbicides - taken in by the leaves, travels up and down the weed in teh sap and kills the whole plant

Question 10

Pros/Cons of herbicides

Answer 10

Pros
Cheap in terms of labor and machinery
Highly effective
Less damaging to soil structure than cultivation

Cons
Risk of poisoning operator, consumer, environment
Does not encourage vineyard ecosystem
Weeds can become resistant and more will be needed
No competition so increases vine vigor (pro and con)
Not allowed in organic or biodynamic viticulture

Question 11

Pros/Cons of Animal grazing

Answer 11

Pros
Allowed in organic/biodynamic farming
Natural manure
Source of meat

Cons
Animals are costly and require a lot of care
Animals can eat the leaves and grapes so they must be trained high up
Animals are susceptibel to other vineyard pesticides

Question 12

What are cover crops and what are they used for?

Answer 12

Plants specifically planted or allowed to grow that have beneficial effects on the vineyard

1. Suppress weeds
2. Improve soil structure
3. Compete with teh vine for nutrient and water availability
4. Manage soil erosion
5. Enhance biodiversity
6. Provide surface to drive on

Question 13

Cover crops are like yeast, you can use whats naturally growing so it’s cheap and increases biodiversity but specific cover crops matching the needs of the vineyard can also be planted

Question 14

Pros/Cons of cover crops

Answer 14

Pros:
No chemicals used - organic and biodynamic farming okay
Allows growers to influence the vigor of the vine by controlling the competition for water & nutrients
Good surface for machinery esp in regions with high rainfall
Can become green manure - natural fertilizer

Cons:
Risk of too much competition in poor soil/dry environments
Difficult to mow the under-row area, particularly near the vine trunks - added time and labor
Not suitable for steep slopes - slippery when wet

Question 15

What is mulching?

Answer 15

The spreading of matter onto the veinyard soil to suppress weed growth. Usually biodegradable material like straw and bark chips

Question 16

Why would a grower want to remove weeds?

Answer 16

1. They compete with the vines for water and nutrients
2. Bare, moist soils are best at absorbing heat during the day and releasing at night (reduces frost risk)
3. Certain weeds can hamper the passage of machinery and personnel

Question 17

Pros/Cons of mulching

Answer 17

Pros

1. Also acts as inorganic fertilizer and humus
2. No chemicals used - organic and biodynamic okay
3. Can reduce water evaporation from the soil

Cons

1. Bulky - expensive to transport
2. Thick layer required
3. Decreases competition and can cause too much vigor
4. Increases frost risk (soil doesnt absorb heat as well)

Question 18

What are efficiency measures vineyards take when it comes to water usage?

Answer 18

Use of water-efficient irrigation systems and techniques with close monitoring of water uptake by the vines
Use of drought tolerant varietals and rootstocks when possible
Reducing evaporation (ie by applying mulch)
Reducing competitiong (ie removing weed)
Increasing humus level to improve water retention
Promoting roots to grow deep into the soil (ie thru cultivation)

Question 19

Types of irrigation

Answer 19

Drip irrigation (most popular)
Flood irrigation
Channel irrigation
Overhead sprinklers

Question 20

Pros/Cons of Drip irrigation

Answer 20

Pros
Promote root growth by sprinkling water away from the vine
Economic use of water - targeted
Can target only the areas that need water - improves yield and quality
Can also be used to supply fertilizer
Can be used on slopes

Cons
Easily clogged by salts and fertilizer - maintenance and clean water required
Cannot prevent spring frost
Installation cost is high

Question 21

Flood irrigation pros/cons

Answer 21

Pros
Cheap
Little maintenance

Cons
Inefficient use of water
Can only be used on flat/gently sloping land

Question 22

Channel irrigation pros/cons

Answer 22

Pro
Little maintenance
Cheap

Con
Large water source required (ie Andes)
Inefficient use of water (but better than flood irrigation)

Question 23

Overhead sprinklers pros/cons

Answer 23

Pros
Can be used for frost protection as well
Efficient but not as efficient as drip irrigation

Cons
Cost is high bc of the pressure required to pump the water to sprinkle above the vines

Question 24

What is Regulated deficit irrigation (RDI)

Answer 24

System of timing and regulating the amount of irrigation so that the vien is put under mild water stress for a specified time (generally between fruit set and veraison)

Question 25

How do you increase drainage in your vineyard?

Answer 25

1. Install artifical drainage systems before vineyard is planted
2. Leaving natural vegetation or planting cover crops to compete with the vines
3. Improving soil structure to improve drainage (ie by subsoiling to remove any plough plans)