What is the dark-coloured amorphous substance formed during decomposition called?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Humus
Decomposition breaks down dead plant and animal matter, called detritus, into simple inorganic substances. It runs through steps: fragmentation, leaching and catabolism, followed by humification and mineralisation in the soil. Humification forms a dark-coloured, amorphous (shapeless) substance called humus. Lignin is a tough chemical in detritus that slows down decomposition.
NCERT Extract:
Decomposition – “… Humification and mineralisation occur during decomposition in the soil. Humification leads to accumulation of a dark coloured amorphous substance called humus that is highly resistant to microbial action and undergoes decomposition at an extremely slow rate. Being colloidal in nature it serves as a reservoir of nutrients. The humus is further degraded by some microbes and release of inorganic nutrients occur by the process known as mineralisation.”