Decomposition is the process that involves the breakdown of complex organic matter or biomass from the body of dead plants and animals with the help of decomposers into inorganic raw materials such as carbon dioxide, water, and other nutrients. The various processes involved in decomposition are as follows:

• Fragmentation: It is the first step in the process of decomposition. It involves the breakdown of detritus into smaller pieces by the action of detritivores such as earthworms.
•  Leaching: It is a process where the water soluble nutrients go down into the soil layers and get locked as unavailable salts.
•  Catabolism: It is a process in which bacteria and fungi degrade detritus through various enzymes into smaller pieces.
•  Humification: The next step is humification which leads to the formation of a darkcoloured colloidal substance called humus, which acts as reservoir of nutrients for plants.
•  Mineralization: The humus is further degraded by the action of microbes, which finally leads to the release of inorganic nutrients into the soil. This process of releasing inorganic nutrients from the humus is known as mineralization.

Decomposition produces a dark coloured, nutrient-rich substance called humus. Humus finally degrades and releases inorganic raw materials such as CO₂, water, and other nutrient in the soil.