Life in soil Flashcards
What does soil contain?
Soil contains minerals particles of different sizes. In a sandy soil particles are larger than in a clay soil.
Loam is a soil that contains:
- A mixture of clay and sand
- A large amount of partly decomposed animal and plant waste called humus.
Simple experiments can be performed on different soil samples to compare the contents:
- Humus content can be found by burning off the humus using a bunsen burner.
- Air content can be found by seeing how much water is needed to fill the air spaces.
- Water content can be found by slowly heating the soil to evaporate the water.
- If a soil has larger particles, then the air content and permeability is usually higher.
- If a soil has larger amounts of humus it will often hold more water and air.
Organisms and Soils
Many organisms live in soil and depend on a supply of oxygen for respiration and water for chemical reactions. These organisms form many food webs.
Humus in the soil is important to living organisms because it will:
- Decompose to release minerals.
- Increase the air content of the soil.
Earthworms are also important to soil structure and fertility because they:
- Bury organic material for decomposition by bacteria and fungi.
- Aerate and drain the soil.
- Mix up soil layers.
- Neutralise acid soil.
Why is aeration important?
The aeration and draining produced by Earthworms will allow organisms to respire aerobically.
Why is neutralising acid and mixing up soil important?
- Neutralisation acid soils is important because some plants will not grow is he pH is too low
- Mixing up soil layers is important so that dead material is decomposed
Who first understood the functions of Earth Worms?
Charles Darwin
