What is physical decomposition?

Physical decomposition is the process in which large pieces of organic matter are broken down into smaller fragments without any change in their chemical composition. It is the initial step of decomposition and mainly involves mechanical or external factors.

This type of decomposition occurs due to environmental forces such as temperature variations, moisture, wind, and the action of organisms like insects, earthworms, and scavengers. These agents break down dead plants and animals into smaller pieces, increasing the surface area available for microorganisms to act upon.

For example, when dry leaves are crushed into smaller particles by wind or eaten and broken down by insects, it is considered physical decomposition. Although the material remains chemically the same at this stage, it becomes easier for bacteria and fungi to carry out further chemical decomposition.