RHS Level 2 R2102 O.M and Compost

Question 1

What is soil organic matter?

Answer 1

It originates from dead plants and parts of plants including dead leaves and roots from growing plants, dead micro-organisms, dead animals and animal wastes, living organisms.
It is constantly changing. Broken down by soil flora and fauna, particularly micro-organisms.

Question 2

Describe mineralisation.

Answer 2

The breakdown of organic matter to release nutrients.

Fresh OM changes from identifiable material to humified OM which is not recognisable and well rotted

Question 3

Describe humification

Answer 3

The formation of humus.

Humus holds nutrients on it’s surface.

Question 4

State some beneficial soil organisms and say why.

Answer 4

Worms - increase aeration and movement of OM through soil.
Bacteria - help mineralisation, nitrogen fixing, detoxification of chemicals.
Fungi - mycorrhiza, breakdown of OM, e.g. leafmould
Nematodes - predators of pests

Question 5

State some Non beneficial soil organisms and say why.

Answer 5

Bacteria, fungi, nematodes can all attack plants. Bacteria may immobilise nitrogen.

Question 6

What are the benefits of Organic Matter?

Answer 6

1) Improved soil structure. Clay soils broken up allowing more air. Sandy soils are held together.
2) Nutrient and water holding capacity is improved.
3) Workability is improved, a clay soil is less sticky or hard.
4) The colour of soil will be darkened, absorbing more warmth.
5) A source of nutrients.

Question 7

Describe the characteristics, uses and benefits and limitations of Farmyard Manure.

Answer 7

Needs to be well composted.
Soil improver or mulch.
Supplies a moderate range of nutrients.
Variable in content.
Can contain weed seeds and chemicals.
May need further composting.

Question 8

Describe the characteristics, uses and benefits and limitations of Garden Compost.

Answer 8

Soil improver or mulch.
Moderate range of nutrients.
Excellent content of micro-organisms.
Known content if home made.
Relatively small quantities.

Question 9

Describe the characteristics, uses and benefits and limitations of Mushroom compost.

Answer 9

Composted manure left from growing mushrooms.
Soil improver or mulch.
Moderate range of nutrients.
High pH.
Can contain chemicals.
Already well broken down.

Question 10

Describe the characteristics, uses and benefits and limitations of Composted green waste.

Answer 10

Usually council collected green waste.
Soil improver or mulch.
Moderate range of nutrients.
Often high pH.
Can immobilise nitrogen in the first year of application.
Excellent content of micro-organisms.

Question 11

Describe the characteristics, uses and benefits and limitations of Leaf Mould.

Answer 11

Rotted down leaves which have been collected up and kept in bags for a year.
Excellent soil improver or mulch.
Low range of nutrients.
Relatively P&D free.

Question 12

Describe the characteristics, uses and benefits and limitations of Chipped bark.

Answer 12

Mulch.
Low levels of nutrients.
Can cause nitrogen immobilisation if incorporated.
Very ornamental
Waste product

Question 13

Describe the characteristics, uses and benefits and limitations of Composted straw.

Answer 13

Mulch.
Low levels of nutrients.
Nitrogen immobilisation is possible unless fully composted.
Can harbor slugs.

Question 14

Describe the characteristics, uses and benefits and limitations of Green manure.

Answer 14

Crops grown as soil cover, improver.
Soil improver or mulch.
Returns nutrients retained from the soil.
May add nitrogen.
All material grown in situ.
Can suppress seed germination.

Question 15

Describe the characteristics, uses and benefits and limitations of crop debris.

Answer 15

Soil improver or mulch.
Returns nutrients retained from the soil.
All material grown in situ.
Can suppress seed germination.
Can immobilise nitrogen.