MCQ on BioChar

 

UPSC Prelims Question (2020)

Question: What is the use of biochar in farming?

Statements:

1. Biochar can be used as a part of the growing medium in vertical farming.

2. When biochar is a part of the growing medium, it promotes the growth of nitrogen-fixing microorganisms.

3. When biochar is a part of the growing medium, it enables the growing medium to retain water for longer time.

Which of the statements are correct?
Answer choices:
(a) 1 and 2 only
(b) 2 only
(c) 1 and 3 only
(d) 1, 2 and 3

Correct Answer: (d) – All statements are correct. 

Explanation:

• Statement 1 — True. Biochar, being a porous, carbon-rich amendment, can be part of vertical farming mediums to enhance soil structure and support plant growth. 

• Statement 2 — True. Biochar promotes microbial activity, including that of nitrogen-fixing organisms, aiding nutrient cycles in the soil. 

• Statement 3 — True. Its porous nature increases water retention and nutrient-holding capabilities of the growing medium

According to above there are 10 questions for practice.

Q1. Which of the following statements regarding biochar is/are correct?

1. Biochar improves the water-holding capacity of soil.

2. Biochar enhances the growth of beneficial soil microbes.

3. Biochar increases the leaching of nutrients in soil.

Options:
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

✅ Answer: (a)
Explanation:

• Statement 1: True – Biochar’s porous structure retains moisture.

• Statement 2: True – It creates microhabitats for microbes.

• Statement 3: False – Biochar reduces leaching by holding nutrients.

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Q2. Biochar can play a significant role in carbon sequestration because:

(a) It oxidizes quickly in soil and releases CO₂ into the atmosphere.
(b) It breaks down completely within a year in most soils.
(c) It stabilizes carbon in the soil for hundreds of years.
(d) It absorbs water and prevents evaporation.

✅ Answer: (c)
Explanation:
Biochar locks carbon in soil for 100–1000 years, acting as a long-term carbon sink.

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Q3. Consider the following statements regarding biochar:

1. It can reduce the need for nitrogen-based fertilizers.

2. It increases the emission of nitrous oxide from the soil.

3. It is produced through the combustion of biomass in the presence of oxygen.

Which of the statements is/are correct?

(a) 1 only
(b) 1 and 2 only
(c) 2 and 3 only
(d) 1 and 3 only

✅ Answer: (a)
Explanation:

• Statement 1: True – Biochar improves nutrient efficiency, reducing fertilizer need.

• Statement 2: False – It reduces nitrous oxide emissions.

• Statement 3: False – Biochar is produced via pyrolysis, i.e., absence of oxygen.

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Q4. Biochar is most beneficial in which of the following soil conditions?

(a) Saline soils
(b) Highly fertile soils
(c) Nutrient-depleted and semi-arid soils
(d) Acidic soils with high organic content

✅ Answer: (c)
Explanation:
Biochar is especially useful in poor, dry soils by improving fertility and water retention.

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Q5. Which of the following are potential co-products of biochar production?

1. Syngas

2. Bio-oil

3. Ammonia

4. Hydrogen

(a) 1 and 2 only
(b) 1, 2 and 4 only
(c) 1, 2 and 3 only
(d) 2 and 4 only

✅ Answer: (b)
Explanation:

• Syngas and bio-oil are common byproducts.

• Hydrogen is present in syngas.

• Ammonia is not a direct byproduct of pyrolysis.

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Q6. Adding biochar to concrete mixtures can:

1. Increase compressive strength

2. Increase thermal resistance

3. Act as a long-term carbon sink

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

✅ Answer: (d)
Explanation:
Research shows biochar enhances strength, thermal resistance, and captures CO₂ in building materials.

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Q7. In the context of environmental sustainability, biochar contributes to:

1. Reducing methane emissions from landfills

2. Replacing chemical pesticides

3. Treating wastewater

(a) 1 and 2 only
(b) 1 and 3 only
(c) 2 and 3 only
(d) 1, 2 and 3

✅ Answer: (b)
Explanation:

• Statement 1: True – Waste that would emit methane can be converted to biochar.

• Statement 2: False – Biochar does not replace pesticides.

• Statement 3: True – It’s used as a filtration material in wastewater treatment.

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Q8. Why is biochar currently underrepresented in carbon credit markets?

1. Lack of standardised carbon accounting methods

2. Absence of MRV frameworks

3. High carbon emission during its production

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

✅ Answer: (a)
Explanation:
Biochar production is low-emission, but its adoption is hindered by lack of standards and verification systems.

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Q9. Consider the following benefits of biochar:

1. Reduces soil erosion

2. Increases crop yield

3. Improves drought resilience

Which of the above are correct?

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

✅ Answer: (d)
Explanation:
Biochar binds soil, boosts yield, and retains moisture, making all three statements true.

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Q10. Which of the following strategies can help promote large-scale biochar adoption in India?

1. Inclusion in crop residue management schemes

2. Integration with State Action Plans on Climate Change (SAPCC)

3. Exemption from environmental clearances

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

✅ Answer: (a)
Explanation:

• Strategies 1 and 2 are practical and recommended.

• Statement 3 is inaccurate — environmental safeguards should not be bypassed.