Question

Given below is a table of factors affecting microbial decomposition. ($'+'$ means 'favouring' and $'-'$ means inhibiting or lowering). Select the correct option.

• A. a
• B. b
• C. c
• D. d

Answer 1

Answer: (B)

b

Answer 2

Rate of decomposition of detritus depends upon chemical quality of detritus, temperature, soil moisture and soil pH. A soil temperature of $25^\circ C$ and more hastens decomposition, taking from a few weeks to a few months for complete mineralisation and humification. Moisture is essential for decomposition. Excessive moisture impedes decomposition probably due to anaerobiosis. Chitin and lignin are very slow to get decomposed. Cellulose decomposition takes time. Therefore, detritus with small amount of lignin/chitin/cellulose which is rich in . nitrogen and water soluble substances (like sugars) decomposes rapidly. Aerobic conditions are essential for activity of decomposer organisms because decomposition is oxygen requiring process. Anaerobiosis reduces decomposition and causes piling up of detritus.