UPSC Prelims 2020 · GS Paper I
Question 91: Geography
What are the advantages of fertigation in agriculture ?
- 1.Controlling the alkalinity of irrigation water is possible.
- 2.Efficient application of Rock Phosphate and all other phosphatic fertilizers is possible.
- 3.Increased availability of nutrients to plants is possible.
- 4.Reduction in the leaching of chemical nutrients is possible.
Select the correct answer using the code given below :
AnswerUPSC’s answer is (c).
Fertigation applies fertiliser through the irrigation water, usually by drip. Acid injection can neutralise the alkalinity of irrigation water, nutrients are placed in the root zone so plants take up more, and less is lost by leaching. But rock phosphate and many other phosphatic fertilisers dissolve poorly and can clog or precipitate in the lines, so efficient application of all of them is not possible.
- 1. Acid injection controls the alkalinity of irrigation water.
- 2. Rock phosphate and other poorly soluble phosphatic fertilisers cannot be applied efficiently.
- 3. Nutrients placed in the root zone are more available to plants.
- 4. Split, targeted doses reduce leaching.
How you could have got this
- If you were sure statement 2 is not correct, (a), (b) and (d) go: each of them includes 2.
What you needed to know: Rock phosphate and other poorly soluble phosphatic fertilisers cannot be applied efficiently.
The red flag in statement 2 is “all”. In UPSC’s papers, statements with “all” were true 41% of the time (76 statements). A hint, not a rule.
Only (c) is left. You didn’t need statements 1, 3 or 4.
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: includes statement 2, since rock phosphate and similar fertilisers do not suit fertigation.
- (b) Wrong: includes statement 2 and leaves out statement 3.
- (c) Right: statements 1, 3 and 4.
- (d) Wrong: includes statement 2 and leaves out statement 1.
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.