1
Which one of the following processes during decomposition is correctly described ?
- Catabolism – Last step in the decomposition under fully anaerobic condition
- Leaching – Water soluble inorganic nutrients rise to the top layers of soil
- Fragmentation – Carried out by organisms such as earthworm
- Humification – Leads to the accumulation of a dark coloured substance humus which undergoes microbial action at a very fast rate
Answer
(3) Fragmentation – Carried out by organisms such as earthworm
Solution
As per NCERT, detritivores (e.g. earthworm) break down detritus into smaller particles; this process is called fragmentation. ⇒ (3) is correct.
(1) Catabolism is the degradation of detritus into simpler inorganic substances by bacterial and fungal enzymes; decomposition is largely an oxygen-requiring process, and catabolism is not its last step.
(2) By leaching, water-soluble inorganic nutrients go down into the soil horizon and get precipitated as unavailable salts.
(4) Humus is highly resistant to microbial action and undergoes decomposition at an extremely slow rate.
Answer: (3)
NEET 2013