“Decomposition is the process by which the organic substances breakdown into complex substances by the action of microorganisms.”


What is Decomposition?

The term decomposition means “to break down”. It usually refers to the rupture or breakdown of the complex organic matter into a simpler inorganic matter. It is one of the essential and important processes of the ecosystem. Thus, we can say that decomposition is a metabolic process, which takes up the complex compounds as raw materials, processes them and converts them into simple compounds.

Bacteria, fungi and a few other microorganisms initiate the process of decomposition and are known as decomposers. They feed on dead organisms to survive.

The dead and decaying plants and animals serve as the raw materials which, on breakdown, produces carbon dioxide, nutrients, and water, etc. The raw materials like dead plants, animals and their remains are known as detritus. These detritus are then processed by the microbes which are collectively called as saprophytes.

Also refer: Putrefaction

Let us know more in detail about its process and the major factors affecting the process of decomposition.

Factors Affecting Decomposition

Following are the important factors affecting the rate of decomposition:

Litter Quality

The rate of decomposition depends on the structural and chemical properties of litter. For eg., the litter of bryophytes are decomposed at a slower rate due to the presence of lignin like complex chemicals.


Temperature regulates the growth and activity of microorganisms. The temperature is different at different elevations. The species diversity and the microorganism count is affected by environmental changes.


The oxygen present in the pores of the soil helps in the growth of microorganisms. In the water-logged soils, the aerobic microorganisms are absent. Here only anaerobic microorganisms can grow and initiate decomposition.

Soil pH

The presence of cations and anions governs the pH of the soil, which in turn affects microbial growth.

Inorganic Chemicals

After decomposition, the elements like potassium, sodium, calcium, magnesium are released into the soil. Some of these are used by the microorganisms for their growth. Thus, it affects the rate of decomposition.


The water present in the soil is responsible for various physiological processes of microorganisms present in the soil. The growth of microorganisms is thus governed by the presence of moisture in the soil.

Process of Decomposition

Process of Decomposition

Process of Decomposition

Death and decomposition are an essential part of all life cycles on earth.  In order to permit a successful continuation of life and growth of new plants and animals, older specimens must die and decompose.  This process provides essential nutrients for plants and also for the growth and development of new organisms.

A complete process of decomposition takes place in five different steps or phases:


It is the initial stage of decomposition. Fragmentation means the breakdown of detritus into smaller pieces by the detritivores.


The fragmented particles may contain a lot of water-soluble nutrients which are inorganic in nature. These nutrients get dissolved in the water and seep into the soil and get precipitated in the process of leaching.


Once the complex material is broken down into smaller particles and the inorganic nutrients are removed, it is time to convert the detritus into simpler inorganic compounds. This process is carried out by various fungal and bacterial enzymes by the process of catabolism.


It is the process of formation of a dark coloured layer of amorphous substance on the soil called humus. It cannot be decomposed easily as it is highly resistant to action by microbes. The layer of humus is very rich in nutrients as it provides high fertility to the soil.


It is the final step in the process. Mineralization is the process of the degradation of the hummus to release inorganic nutrients.

Also Read: Rigor Mortis

For more information on Decomposition and the process of decomposition, keep visiting BYJU’S Biology


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