importance’s of living organisms
Add humus to the soil when they die
Help in decomposition of organic matter to release nutrients for plant use.
Help in fixing nitrogen in the soil e.g. Rhizobium in root nodules of legumes.
Burrowing animals help in mixing various layers of the soil profile with organic matter.
Burrowing animals and earthworms help in improving soil aeration.
Burrowing animals and earthworms make tunnels in the soil which help to improve drainage and water infiltration in the soil.
Some bind soil particles together hence improving soil structure and stability. E.g., earth worms.
Some produce antibiotics that can be used to control bacteria e.g Aspergilus and other penicillin producing fungi.
Some carry out inorganic transformations of minerals e.g. in well drained soils, Iron and manganese are oxidized to higher oxidations.
Some cause disease to plants.
Some transmit diseases to plants ( vectors)
Some compete for nutrients with the plants ( immobilization)
Some damage the plants physically
Denitrifying bacteria cause loss of nitrogen from the soil.