Biologic Factors In Soil Formation

Bio means life. Living organisms have an extensive impact on soil. It is estimated that about 50% of soil is comprised of dirt, while almost 50% is made up of water and air. Only a small fraction is actually made up of living and dead life forms. However the role these life forms have cannot be over estimated.

Roots from plant life dig deep into the soil, creating passages for water and air. Animals such as ants, earthworms, rodents, and snakes dig and till the soil extensively. Plants and animals provide nutrients to the soil in the form of waste products, and dead bodies. A variety of micro-organisms perform important jobs in the soil that help to decompose living materials, and that give richness to the soil.