Question

Describe the processes and products of decomposition.

Explain the main steps involved in the process of decomposition.

Answer 1

The steps of decomposition are fragmentation, leaching, catabolism, humification, and mineralization.

1. Fragmentation: Detritivores like earthworms break down detritus into smaller fragments or particles.
2. Leaching: In this process, water-soluble inorganic nutrients percolate into the soil horizon and get precipitated as unavailable salts.
3. Catabolism: The bacterial and fungal enzymes degrade detritus into simpler inorganic substances. All of the above steps occur simultaneously.
4. Humification: It leads to the accumulation of a particularly decomposed, dark-coloured, amorphous colloidal organic substance called humus. Humus serves as a reservoir of nutrients. It is resistant to microbial action and undergoes decomposition at an extremely slow rate. Humus changes the soil texture and increases the capacity of water holding in the soil.
5. Mineralization: Some microorganisms degrade humus and release inorganic nutrients by the process of mineralization.
   
                 Decomposition cycle

Answer 2

1. Fragmentation: The first step in the decomposition. It involves the breakdown of detritus into smaller pieces by detritivores such as earthworms, woodlice, and maggots.
2. Leaching: Fragmented particles may include water-soluble, inorganic nutrients. These contaminants dissolve in water, penetrate soil, and precipitate during leaching.
3. Catabolism: Once broken down, complex materials and inorganic nutrients are removed, and the detritus can be converted into simpler organic compounds. It is a process in which bacteria and fungi degrade detritus through various enzymes into smaller pieces.
4. Humification: The next step is humification, which forms a dark-coloured colloidal substance called humus that acts as a reservoir of nutrients for plants.
5. Mineralisation: The humus is further degraded by microbial action, which finally releases 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 nutrients into the soil.