6. Managing Nutrients and Water Flashcards
What does the term ‘soil health’ refer to?
The continued capacity of the soil to act as a living ecosystem that sustains plants, animals and humans.
What factors determine the health of soil?
- Soil structure
- The amount of organic matter and humus
- The number of living organisms present
- The amount of available nutrients
What properties of a soil’s structure influence the general health of the soil?
- Good drainage
- Sufficient water holding capacity
- Sufficient oxygen
- The ability to resist erosion
- To allow the roots of the vine to penetrate to a sufficient depth
When is a vineyard’s soil typically tested? Why?
Grape growers may have soil tests conducted when establishing the vineyard and then annually so that corrective measures, such as improving the structure of the soil or adjusting nutrient levels, can be taken.
Why are organic matter and humus important for soil health?
Decomposing organic matter supplies nutrients, and humus improves the structure of soil and its water-holding capacity
Why are living organisms important for soil health?
- Earthworms and microbes break down organic matter into humus and inorganic nutrients that are accessible to the vine
- Ecosystem services
What are the six methods of managing nutrients in the vineyard?
- Fertilisers; organic or inorganic
- Cultivation; weed management
- Herbicides; weed management
- Animal grazing
- Cover crops
- Mulching
What are organic fertilisers?
Organic fertilisers are derived from fresh or composted plant or animal material (manure or slurry)
What is green manure?
Green manure is produced by cover crops that have been grown, mown and turned into the soil to decompose and provide nutrients
What are the advantages of organic fertilisers?
- Cheap or sometimes free
- Some are high in humus, therefore good for soil structure and water retention
- As their nutrients tend to be in organic form, they provide nutrition for soil organisms, promoting the living matter in the soil.
- Become available to the vine gradually (while organisms in the soil break down organic fertiliser to inorganic).
What are the disadvantages of organic fertilisers?
- More labour required to incoperate into the soil for it to be broken down (converted by soil organisms to inorganic fertiliser).
- Can be bulky and difficult to transport
What are inorganic fertilisers?
Inorganic fertilisers, also called synthetic fertilisers, are manufactured from minerals extracted from the ground or synthetic chemicals. They can provide a single nutrient or several nutrients.
What are the advantages of inorganic fertilisers?
- They can provide a single nutrient or several; so can be tailored to the soil’s needs
- Already in inorganic form, readily available to the vine once applied
- Cheaper to transport and distribute compared to organic fertilisers
What are the disadvantages of inorganic fertilisers?
- They hold no benefit for soil organisms and do not improve soil structure
- More expensive to purchase than organic fertilisers
What is cultivation?
Cultivation is a method of weed control that involves ploughing the soil to cut or disturb the weeds’ root systems.
What are the advantages of cultivation?
- This method does not use any chemicals and so can be used in organic and biodynamic viticulture.
- It enables fertiliser and, where relevant, mown cover crops to be incorporated into the soil at the same time as removing weeds.
What are the disadvantages of cultivation?
- Repeated cultivation can damage the soil’s structure and ecology due to the breakdown of organic matter and disruption of earthworms in their habitat.
- It is costly as it requires both skilled labour and machinery.
- Disturbing the soil buries seeds, thus encouraging the weeds to grow back.
- It can increase vine vigour too much as there is no competition for water or nutrients (not
necessarily a disadvantage in low vigour sites (poor soils and/or lack of water)).
What are the three types of herbicides?
- Pre-emergence herbicides
- Contact herbicides
- Systemic herbicides
How do pre-emergence herbicides work?
Pre-emergence herbicides are sprayed before weeds establish. They persist in the surface layers of the soil but are absorbed by the weeds’ roots and inhibit germination of young seedlings.
How do contact herbicides work?
Contact herbicides are sprayed on established weeds and kill the green parts of the weed that they contact, resulting in the death of the plant.