Soil, Nutrients, water and The Vine

Question 1

Describe soil health

Answer 1

Describes the continued capacity of the soil to act as a living ecosystem that sustains plants, animals and humans. It is related to: 1. The structure of the soil: beneficial properties include drainage, sufficient water-holding capacity, sufficient oxygen, ability to resist erosion and to allow the roots to penetrate
2. The amount of organic matter and humus in the soil: decomposing organic matter supplies nutrients, and humus improves the structure of soil
3. Living organisms in the soil: earthworms and microbes break down organic matter into humus and inorganic nutrients that are accessible to the vine
4. the total amount of available nutrients that the vine needs to grow successfully

Question 2

Why Nutrient management is important

Answer 2

The right balance of nitrogen, phosphorous and potassium as well as many other nutrients is essential for healthy vine growth and the ripening of grapes.
Soil nutrients are depleted by viniculture and therefore it is important for the grape grower to monitor nutrients levels for deficiencies

Question 3

Techniques for nutrient management

Answer 3

Direct application of nutrients in either organic or inorganic form, some involve the promotion of biological activity and soil structure, and some involve the management of weeds (unwanted plants) that can compete with the vine for nutrients (and water). Many of these techniques have multiple functions and can influence accessibility of water as well of nutrients.
The removal of weeds is usually desirable for additional reasons. Bare, moist soils are best at absorbing heat during the day and the heat they release at night reduces frost risk. By comparison, weeds, as well as cover crops and mulches, can increase frost risk. Some weeds also hamper the passage of machinery and personnel.

Question 4

What are organic fertilisers

Answer 4

Organic fertilisers are derived from fresh or composted plant or animal material, such as manure or slurry. Cover crops can be grown, mown and turned into the soil to decompose and provide nutrients.
Organic fertilisers are often cheap or even free. Some are high in humus and therefore good for soil structure and water retention. The nutrients tend to be in organic form, they provide nutrition for soil organisms, promoting the living matter in the soil.
The organic fertilizers need to be broken down into inorganic nutrients by these organisms, these fertilisers require incorporation into the soil, which requires labor.
This also means nutrients become available gradually, which is better for the vine.

Question 5

North American vine species

Answer 5

V. Lambrusca, Vitis riparia, vitis berlandieri and vitis rupestris.

Question 6

Nitrogen

Answer 6

Nitrogen can have an impact on vine vigour and on grape quality. It is a component of proteins and chlorophyll (required for photosynthesis).

Question 7

Potassium

Answer 7

Helps regulate the flow of water in the vine. High potassium levels can cause problems in the uptake of magnesium, this may lead to reduced yields and poor ripening. High levels of K can lead to a higher concentration in the grape - higher pH.

Question 8

Phosphorus

Answer 8

Important for photosynthesis. Vines need only a small amount. Deficiency leads to poorly developed root system (and hence a diminished ability to take up water and nutrients) reduced wine growth and lower yields.

Question 9

Calcium

Answer 9

Important role in the structure of plant cells and in photosynthesis.

Question 10

Magnesium

Answer 10

Found in chlorophyll and has a key role in photosynthesis.

Question 11

Inorganic fertilisers

Answer 11

Also called synthetic fertilisers, are manufactured from minerals extracted from the ground or synthetic chemicals. The nutrients are already in an inorganic form and therefore can be more readily available to the vines. More tailored, they can provide single or several nutrients

Question 12

Cultivation

Answer 12

Cultivation is a method of weed control that involves ploughing the soil to cut or disturb the weeds’ root system.
Advantages:
- does not use chemicals so it can be used for biodynamic and organic
- it enables fertilisers, mown crops to be incorporated into the soil at the same time it removes weeds
Disadvantages:
- 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, labour and machinery
- disturbing the soil buries seeds, encouraging weeds to grow back
-it can increase vine vigour too much

Question 13

Herbicides

Answer 13

Herbicides are chemicals sprays that kill weeds.
- Pre-emergence herbicides before weeds establish.
- contact herbicides sprayed on established weeds and kill the green part they contact, resulting in the death of the plant.
- systemic herbicides are sprayed on established weeds and are taken in by the leaves. The herbicides travels up and down the weeds in the sap and kills the whole plant.

Question 14

What are cover crops

Answer 14

Cover crops are plants that are specifically planted, or allowed to grow, that have a beneficial effect on the vineyard. Cover crops may be grown to suppress weeds. They may also be planted to improve soil structure, compete with the vine for nutrient and water availability in fertile sites, manage soil erosion, enhance biodiversity and provide a surface to drive on.
Examples are beans and clover, or cereals like ryegrass and oats.
The cover crop must be managed so that it does not compete too much with the vine for water and nutrients at key times in the vine cycle.

Question 15

Advantages and disadvantages of cover crops

Answer 15

Advantages:
- This method does not use any chemicals and increases soil biological activity and biodiversity in the vineyard, so is commonly used in organic and biodynamic viticulture
- The ability to influence the vigour of the vine by introducing competition for water and nutrients
- The provision of a good surface for machinery, particuarly in climates with high annual rainfall.
Disadvantages
- A reduction in the vigour through competition for water and nutrients that can be excessive in poor soils
- The difficulty of mowing the under-row area, particularly near the vine trunks, which has implications on time and labor
- The unsuitability for steeply sloping vineyards, as they are slippery when wet.

Question 16

Define mulching

Answer 16

Mulching is the spreading of matter onto the vineyard soil to suppress the growth of weeds. Mulches are usually made of biodegradable materials, such as straw or bark chips, that ultimately provide nutrients for the vines. Materials with a high nutrient content can be chosen in nutrient-poor vineyards.

Question 17

Irrigation

Answer 17

If the vineyard is located in an area that is likely to receive very little water through the growing season, or has very free-draining soils, irrigation may be necessary and should be a part of vineyard design and establishment. Irrigation systems can be fitted in an established vineyard if the need is persistent, but this can be much more difficult because of potential disruption to the vineyard in order to lay pipes.

Question 18

How to efficiently manage water supply

Answer 18

• Use of certain water-efficient irrigation systems and techniques combined with better monitoring of water take- up by the vines (e.g dripper systems and regulated deficit irrigation)
• Use of drought-tolerant grape varieties (Grenache) and rootstocks ( 140 )
• Reducing evaporation e.g. applying a mulch
• Reducing competition e.g removing weed
• Increasing humus levels in the soil to improve water retention (e.g by adding organic matter)
• Promoting growth of vine roots deep into the soil

Question 19

Water quality

Answer 19

• Water with dissolved solids like mud can block sprinklers and drip irrigation systems ( needs filtering before use)
• High levels of salt (high salinity)(Australia) particularly a problem when drip irrigation is used, as the salt accumulates at the root zone rather than being washed

Question 20

Drip irrigation

Answer 20

Narrow water pipes are laid along each row, typically tied to the lowest trellis wire. Drippers are fitted at appropriate intervals. The drippers are positioned far enough away from the vines to encourage the roots to grow and seek out water.

Question 21

Key benefits of Drip irrigation

Answer 21

• They permit economic use of water
• It is possible to control water supply to individual rows or blocks of vines, allowing more tailored
• They can also be used to supply fertiliser (liquid fertiliser can be added to water supply) this is called fertigation.
• They can be used in sopes

Question 22

Disadvantages of drip irrigation

Answer 22

• Instalation costs are high, although maintenance cost are moderate
• Clean water is required, otherwise the drippers quickly become blocked
• Even with clean water, the drippers can gradually become blocked by algae, bacteria…
  They cannot be used in frost protection

Question 23

Flood irrigation

Answer 23

• Flood irrigation: water is stored behind a sluice and at the scheduled time released to flood the vineyard.

Question 24

Overhead sprinklers,

Answer 24

Pump water and shower it over the vineyard. They are expensive to install and maintain due to the high pressure needed and relatively large amount of water compared to drip irrigation

Question 25

Channel irrigation:

Answer 25

Channel irrigation: Similar, water flows down furrows dug between the vine row, which can help increase efficiency of water use. These systems are common in Argentina because of abundant water from the Andes.

Question 26

When in the vinecycle is positive to have plentiful water supply

Answer 26

In spring encourages the establishment of a large leaf surface area to support the production of high yields of grapes

Question 27

When is desirable mild water stress in the vinecycle

Answer 27

Between fruit set and veraison to stop the growth of shoots and ecourage grape development and ripening

Question 28

What is RDI

Answer 28

Regulated deficit irrigation: Is a system of timing and regulating the amount of irrigation so that the vine is put under mild to moderate water stress for a specified time within the growing season.

Question 29

What are main benefits of using RDI

Answer 29

Vine growth and grape development can be better controlled and that less water can be used. This type of irrigation regime is often favoured for black grapes as it can reduce grape size, which increases the proportion of of skin to juice and hence increases the concentration of anthocyanins and tannin, often seen as a sign of quality.

Question 30

What is a water management technique that leads to high quality wines in Medoc?

Answer 30

The presence of fast-draining gravel soils in maritime climate