The basic components of soil are the inorganic and the organic Components.
(a) The inorganic components
The inorganic components comprise rock particles, air, water and mineral salts.
- Rock particles: The basic structure of soil consists of rock particles in a variety of sizes, produced by weathering.
- Soil air: This comes from air in the soil. Microorganisms that decompose organic material in the soil to produce humus need oxygen from soil air.
- Soil water: Some soil water comes from the rain but soil water also rise up from groundwater to replace water lost by e\
- Mineral salts e. g. Nitrates They are needed
- The organic components
The organic components comprise humus and soil organisms e.g.
earthworms, termites, cricket etc.
Humus: This is the decayed remains of dead organisms. Humus has the following important functions as a component of soil:
- It binds inorganic particles together to form aggregates called soil crumbs, ensuring good drainage and aeration of the soil.
- It retains water and minerals, preventing the minerals from being washed (leached) from the topsoil by rainwater.
- It is a source of nutrients released by decomposition
Soil organisms: They include bacteria, fungi, animals Iike termites, crickets, earthworms etc.
- Some bacteria help to increase soil fertility. Other bacteria and fungi are essential for decay of dead organisms.
- The burrowing/digging activity of earthworms, termites and crickets turns the soil over, mixing in the humus, and helping to aerate and drain the soil. Plant roots will therefore have enough water and air to grow and respire.
Soil quality
In agriculture, soil quality defines whether soils are in good condition for agriculture or to support plant growth.
- Where the soils characteristics match those needed for crop cultivation, then we can say that soil is of good quality.
- Sometimes soil quality is also referred to as ° soil health'.
