UPSC Prelims 2020 · GS Paper I
Question 80: Geography
What is the use of biochar in farming ?
- 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 given above is/are correct ?
AnswerUPSC’s answer is (d).
Biochar is charcoal made by heating biomass with little oxygen. Its porous structure holds water and nutrients, so it can be mixed into growing media, including those used in vertical farming, where it also supports soil microbes such as nitrogen-fixing organisms. All three statements are accepted.
- 1. Biochar can be part of the growing medium in vertical farming.
- 2. It promotes nitrogen-fixing microorganisms.
- 3. Its porous structure helps retain water.
How you could have got this
- If you were sure statement 2 is correct, (c) goes: it leaves 2 out.
What you needed to know: It promotes nitrogen-fixing microorganisms.
- Then, if you were sure statement 3 is correct, (a) and (b) go: each of them leaves 3 out.
What you needed to know: Its porous structure helps retain water.
Only (d) is left. You didn’t need statement 1.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Wrong: statement 3 is also correct.
- (b) Wrong: statements 1 and 3 are also correct.
- (c) Wrong: statement 2 is also correct.
- (d) Right: all three are correct.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2020, General Studies Paper I, Series A. The paper on upsc.gov.in.