Fragmentation is the process of breakdown of detritus into smaller particles by the detritivores such as earthworms. It is an important step in the decomposition process. The earthworm is also known as the farmer's friend because they aid in the breakdown of complex organic substances and also, in soil loosening.
Humification leads to the accumulation of a dark coloured amorphous substance called humus, which is highly resistant to microbial action, and undergoes decomposition at an extremely slow rate.
The humus is further degraded by some microbes, and the release of inorganic nutrients occurs by the process known as mineralisation.
Bacterial and fungal enzymes degrade detritus into simpler inorganic substances. This process is called catabolism.