UPSC CSE Prelims
Question 21
What is the use of biochar in farming?
- Biochar can be used as a part of the growing medium in vertical farming.
- When biochar is a part of the growing medium, it promotes the growth of nitrogen-fixing microorganisms.
- When biochar is a part of the growing medium, it enables the growing medium to retain water for a longer time.
Which of the statements given above is/are correct?
View correct answer and explanation
Correct answer: D
Correct Option: D (1, 2 and 3)
Explanation: Biochar is porous, carbon-rich char added to soil or soilless media; its surfaces can support microbes and improve moisture retention, including in vertical-farming growing media.
Statement / Pair / Item-wise Analysis:
1. Correct - Biochar can be mixed into substrates used in vertical farming.
2. Correct - Suitable biochar can furnish niches favouring beneficial microbes, including some nitrogen-fixers.
3. Correct - Its pore structure and surface properties can improve water-holding capacity.
Option-wise Analysis:
A. Incorrect-omits correct item 3 (Its pore structure and surface properties can improve water-holding capacity).
B. Incorrect-omits correct item 1 (Biochar can be mixed into substrates used in vertical farming); omits correct item 3 (Its pore structure and surface properties can improve water-holding capacity).
C. Incorrect-omits correct item 2 (Suitable biochar can furnish niches favouring beneficial microbes, including some nitrogen-fixers).
D. Correct-includes all and only valid statements/items 1, 2, 3.
Review note: Effects on microbes and water vary with feedstock, pyrolysis temperature and application rate.