R2102 2.2 Desribe the characteristics and uses if different types of organic matter added to the soil

Question 1

Benefits of adding organic matter- Sandy / Clay soils

Answer 1

1. Sandy soils - improves water and nutrient retention
2. Clay soils - opens up dense structure to be more free-draining and adding nutrient retention

Question 2

Types of Bulky organic matter to maintain organic matter and humus levels in the soil (7)

Answer 2

1. Farmyard manure
2. Garden compost
3. Composted municipal waste
4. Spent mushroom compost
5. Leaf mould
6. Chipped bark
7. Green manures

Question 3

Farmyard Manure (6)

Answer 3

1. Consists of straw or other bedding mixed with animal faeces and urine
2. Provide nitrogen and other nurtrients
3. Needs to be well rotted. If not well rotted in can scorch plants with excessive nutrients
4. Should be worked into soil when conditions are favourable
5. Should not be worked into wet or compacted soils
6. Provides organic matter, humus and improves soil structure

Question 4

Garden Compost (6)

Answer 4

1. Plant material and kitchen vegetable waste incorporated into the soil when it has been fully composted. Should be dark, crumbly and sweet smelling
2. Good soil conditioner - helps prevent soil capping
3. Supplies nutrients in a slow release form
4. Can be basis of no-dig systems
5. May contain pests and pathogens if not composted at high enough temperatures
6. Free and on-site

Question 5

Spent Mushroom compost (7)

Answer 5

1. By product of mushroom industry
2. Now made from straw capped with chalk
3. High PH - alternative to liming
4. Can be used a mulch or incorporated into soil
5. Must not be used with plants that like acid conditions
6. Too much use can lead to nutrient deficiencies
7. Usually fairly local

Question 6

Composted garden waste (5)

Municipal waste

Answer 6

1. Essentially same as garden compost but done in bulk
2. High temperatures kill inactive weeds and pathogens
3. Usually too high in nutrients to be used alone. Very high ph
4. Can be mixed with composted barks, coir etc to give a good container compost
5. Common issues are contamination with plastics and glass

Question 7

Leaf mould (6)

Answer 7

1. Made from rotted leaves of decidous trees
2. Can be used as mulch or as a compost ingredient
3. Composted in mesh cages or polythene bags
4. Low in nutrients
5. Unless from trees growing in very acidic condition they are rich in calcium
6. Good base as a neutral or lime free potting compost

Question 8

Chipped Bark (6)

Answer 8

1. Mainly used a mulch
2. Nitrogen deficient so it does not decompose readily which means it lasts a long time on the soil
3. It can rob plants of nitrogen
4. It is light so can be blown around or float on water
5. Can be expensive
6. Birds can throw it around looking for food making some areas look untidy

Question 9

Composted straw (6)

Answer 9

1. For mulching
2. Sold as mineralised straw or ‘strulch’
3. Suppress weeds
4. Should not remove nitrogen from soil
5. Can look messy on borders
6. Sustainable

Question 10

Cocoa shell (4)

Answer 10

1. Excellent weed supressing mulch
2. Can be hard to get hold as also used a animal feed
3. Can be harmful for dogs
4. Sustainability issues

Question 11

Pine needles (3)

Answer 11

1. Covered with a protective layer that slows decompostion
2. Low in calcium and the resins are converted to acids
3. Valued for calcifuge plants propagation

Question 12

Green manure (3)

Answer 12

1. Normally broadcast sown in autumn
2. Green manure is then dug in or cut, left to wilt then dug into the soil
3. e.g. Vicia faba (winter field bean)

Question 12

Green manure (3)

Answer 12

1. Normally broadcast sown in autumn
2. Green manure is then dug in or cut, left to wilt then dug into the soil
3. e.g. Vicia faba (winter field bean)

Question 13

Benefits of green manure (8)

Answer 13

1. Covers bare ground
2. Compete out weeds
3. Reduce soil erosion
4. Capture soluble nutrients that would otherwise have been leeched
5. Add organic matter
6. Increase micro-organism activity in the soil
7. Develop and maintain soil fertility and structure
8. Shelter for benefical insects in winter

Question 14

Drawbacks of green manures (4)

Answer 14

1. Occupy ground that might be cropped
2. They offer a slow-release of nutrients
3. They may harbour pests and disease that will affect a later crop
4. They are hard work - have to be sown and dug in

Question 15

Crop debris to maintain soil structure

Answer 15

Plant crop debris or crop residues to avoid any erosion of bare soil and help maintain water levels for the new crop.

Question 16

Purpose of mulching (8)

Answer 16

1. Decorative finish (e.g. chipped bark on borders)
2. Weed supression
3. Moisture retention - therefore less watering needed
4. Protect the soil surface and prevent erosion
5. Maintaining / increasing soil organic matter
6. Stimulating benefical soil organisms
7. Modifying soil temperatures (insulates)
8. Protecting edible crops from soil contact / splash (e.g. straw under strawberries)

Question 17

Organic mulch: Use / pros / cons

Answer 17

Use : Used on surface of the soil to supress weeds and retain soil moisture levels. It will break down gradually so will need to be replaced

Pro: The decaying mulch will help the soil structure as the organic matter is incorporated into the soil

Con: Soil organisms may take nitrogen from the soil below to help break down the mulch

Question 18

Inorganic mulch: use / pro / con

Answer 18

** Use:** A man-made substance which is used to supress weeds and retain soil moisture

Pro: They do not break down in the soil and usually last a long time

** Con:** Add no benefit to the soil. Have an energy cost in their manufacture

Question 19

Inorganic mulch (4)

Answer 19

1. Polythene sheet - effective weed suppressant and can help warm soil. But does not allow water through to roots
2. Woven geotextile membrane (e.g. Mypex) - supresses weeds and will allow water to penetrate. Often used underneath gravel.
3. Gravel - allows water to penetrate. Can be decorative. Improves drainage, often used around alpines. It does not supress weeds, unless applied VERY deeply. Often used over geotextile membrane - without this the gravel will get mixed into the soil. Finite resource.
4. Glass - similar to gravel in its properties as a mulch. generally cruished and recycled safety glass. More sustainable than gravel.

Question 20

Disadvantages of mulching

Answer 20

1. Too much can bury and suffocate plants - water and oxygen cant get to roots
2. Can contribute to rotting bark if piled up around trees
3. Mulch can create excess heat in the summer