Introduction
Soil is generally a mixture of inorganic (i.e. mineral) and organic material or matter.
The inorganic material can consist of the following:
- Sand
- Silt
- Clay
These are sometimes referred to as the 'fine earth' elements.
Gravel or stones may also be a component part of the inorganic material in a soil.
The organic material may be living or dead, although typically most organic material will be dead or decaying plant matter.
Micro-organisms (such as bacteria and fungi) will invariably be present within the soil, whilst macrofauna (such as earthworms and mites) might be present depending upon the soil type.
Other important components of the soil are:
Soil water, which fills the pore spaces between the soil particles and aggregates and those spaces not taken up by plant roots, soil air, earthworms etc. The water content of a soil will vary according to the physical make up of the inorganic and organic components, as well as weather conditions.
Soil air provides the other component of a soil and fills the pore spaces not taken up by the soil water, plant roots, earthworms etc.
Diagrammatic representation of the soil components:
