Worms are part of the soil's biological components. Image credit wageingenur.nl

Worms are part of the soil’s biological components. Image credit wageingenur.nl

ZIMSEC O Level Combined Science Notes: Biological components of the soil

  • In addition to physical components the soil also has biological components as well
  • These include living plants, animals and dead organic matter
  • Some of these active and useful organisms found in the soil are microscopic
  • These are known as micro-organisms
  • They include bacteria and fungi
  • These micro-organisms break down dead animals and plants
  • During this decay/decomposition process nutrients are released into the soil
  • These nutrients include mineral salts such as phosphates and nitrates as well as are mineral elements required in plant growth and development
  • If there is high organic content in the soil the soil is called fertile
  • It will support healthy plant growth
  • The biological component of the soil play important roles in the life of the soil and the whole ecosystem
  • The fertility of the soil is improved by the action of micro-organisms on dead organic matter in the soil
  • The organic matter is broken down slowly to become part of the soil in the form of humus
  • The organic matter itself and the action of the micro-organisms improve the aeration of the soil
  • Worms and insects make burrows in the soil which allows air to penetrate more easily
  • The soil particles are also held together by the organic content which improves the texture of the soil
  • The particles are held together much more loosely with air spaces
  • This makes the soil lighter and easier to cultivate
  • Loamy soils are said to have a god crumb structure which makes them suited to agricultural activities

To access more topics go to the Combined Science Notes page.