3.1 Soil composition

Question 1

composition of soil (what is the soil made up of)

4

Answer 1

• mineral particles,
• organic content (living plants, animals, microorganisms and their dead remains)
• air
• water

Question 2

percentage of each composition

Answer 2

• mineral particles- 45%
• organic content- 5%
• air- 25%
• water- 25%

Question 3

Mineral particles

Answer 3

• Combination of rock fragments and other inorganic substances.
• They are formed due to physical, chemical and biological weathering of the parent rock.

Question 4

Organic content

Answer 4

mixture of living plants, animals, microorganisms and their dead remains

Question 5

Air

Answer 5

• held within the pore spaces (between the mineral particles and organic content)
• Air enters the soil by diffusion

Question 6

Water

Answer 6

• held within the pore spaces (water that is available for plant growth).
• Water enters the soil when there’s precipitation or when the soil is irrigated

Question 7

particle size of soil

largest to smallest

3

Answer 7

1. Sand (largest) 2.0-0.02 mm
2. Silt 0.02-0.002 mm Silky or soapy
3. clay (smallest) <0.002 mm Sticky when wet and Hard when dried