Question

Recommended C: N ratio of the initial material for composting is

• A. 60:1
• B. 30:1
• C. 75:1
• D. 100:1

Hint:

Optimal initial composting C:N ratio is $30:1$; finished compost typically stabilizes at a C:N ratio of $10:1\text{--}12:1$.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Aerobic microbial decomposition of organic residues depends on the nutrient stoichiometry of carbon and nitrogen substrates.

Step 2: Detailed Explanation:
The optimal initial Carbon-to-Nitrogen (C:N) ratio for rapid and efficient aerobic composting is approximately 25:1 to 30:1 (ideally 30:1).
- If C:N $> 30:1$, nitrogen becomes limiting, slowing down microbial activity and decomposition rate.
- If C:N $< 20:1$, excess nitrogen is volatilized and lost as ammonia gas ($\text{NH}_3$).

Step 3: Final Answer:
Therefore, the recommended initial C:N ratio for composting is 30:1.