Agriculture & crops

Answer: (c) 1, 3 and 4 only

Fertigation, applying water-soluble fertiliser through the drip irrigation water, makes nutrients more available near the roots and cuts losses by leaching, and acid injection can lower the alkalinity of irrigation water. It cannot be used for rock phosphate or other phosphatic fertilisers that do not dissolve.

• ✓ 1. Acidifying fertilisers such as phosphoric acid injected with the water lower the pH of alkaline irrigation water; this is a recognised benefit, and UPSC's key treats it as correct.
• ✗ 2. Phosphate fertilisers tend to precipitate in irrigation water; the Tamil Nadu Agricultural University guide says super phosphate must be avoided, and only soluble forms such as phosphoric acid or mono-ammonium phosphate suit fertigation. Rock phosphate does not dissolve.
• ✓ 3. The Centre's Per Drop More Crop scheme promotes fertigation to improve nutrient application efficiency, because fertiliser is delivered with irrigation water straight to the root zone, so more of it reaches the plant.
• ✓ 4. Small, frequent doses given near the roots are absorbed quickly, so less fertiliser is lost by leaching.

Remember · Fertigation = fertiliser through drip water: soluble fertilisers only, more nutrient use efficiency, less leaching; no rock phosphate.

Question and answer: UPSC's official GS Paper I (2020, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (a) Tobacco, cocoa and rubber

The 'New World' is the Americas; the 'Old World' is Asia, Africa and Europe. Tobacco, cacao (cocoa) and Para rubber are all American plants that Europeans carried across the Atlantic after 1492. Every other option contains at least one Old World crop.

• ✓ (a) Tobacco was used by Native Americans before Europeans adopted it; cacao is native to the Amazon and Orinoco basins; the rubber tree (Hevea brasiliensis) is native to the Amazon basin and was later planted in Asia.
• ✗ (b) Cotton was domesticated independently in South Asia as well — traces are found at Harappan sites — so it is not solely a New World gift.
• ✗ (c) Coffee comes from Ethiopia and sugarcane from South and Southeast Asia, both Old World crops.
• ✗ (d) Wheat was domesticated in West Asia, and coffee in Africa; only rubber here is American.

Remember · Columbian Exchange, Americas → Old World: tobacco, cocoa, rubber, maize, potato, tomato, chilli, groundnut, pineapple, papaya. Old World → Americas: wheat, sugarcane, coffee.

📘 Read it in NCERT: Class 11 Themes in World History, Ch 6 (practise this chapter) · Class 10 India and the Contemporary World – II, Ch 3 (practise this chapter) · Class 12 Themes in Indian History, Part I, Ch 1 (practise this chapter) · Class 11 Themes in World History, Ch 1 (practise this chapter)

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (d) textile fibre

Himalayan nettle (Girardinia diversifolia) is prized for the strong bast fibre in its stems, which is spun and woven into cloth, so it is a sustainable source of textile fibre.

• ✓ (d) The bast fibre of its bark is used for clothing, ropes, mats and sacks, and the Ministry of Textiles has supported research on products from Himalayan nettle among natural fibres.
• ✗ (a) Anti-malarial drugs come from plants like cinchona (quinine) and Artemisia (artemisinin), not from Himalayan nettle.
• ✗ (b) Biodiesel comes from oil-bearing seeds such as jatropha and pongamia; nettle is valued for its fibre, not for oil.

Remember · Himalayan nettle (Girardinia diversifolia, 'bichhu buti') yields bast fibre for textiles; Uttarakhand and the Ministry of Textiles have promoted it.

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (c) 3–2–4–1

Lowest to highest forest cover as a share of the State's area is Maharashtra (about 16.5%), Madhya Pradesh (about 25.1%), Odisha (about 33.2%) and Chhattisgarh (about 41.1%). This gives the order 3–2–4–1.

• ✓ 3. Maharashtra has the smallest share: 50,777.56 sq km of forest cover, 16.50% of its area (ISFR 2019).
• ✓ 2. Madhya Pradesh has the largest forest cover in absolute area (77,482.49 sq km) but only 25.14% of its area, because the State is so large.
• ✓ 4. Odisha has 51,618.51 sq km of forest cover, which is 33.15% of its area.
• ✓ 1. Chhattisgarh has the highest share of the four: 55,610.57 sq km, or 41.14% of its area.

Remember · Forest cover share of state area: Maharashtra 16.5% < Madhya Pradesh 25.1% < Odisha 33.2% < Chhattisgarh 41.1%. Madhya Pradesh is first in area but not in percentage.

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (d) 1, 2, 3 and 4

Why not the tempting option · UPSC's key counts ozone among the gases released due to crop-residue burning. Ozone is a secondary pollutant that forms in the air from the nitrogen oxides and volatile organic compounds in the smoke, but the question says 'due to the burning', which covers that. The doubt does not change the answer: carbon monoxide, methane and sulphur dioxide are certainly emitted, and (d) is the only option that contains all three. In the exam, settle the sure statements first and let the option grid decide the rest.

UPSC counts all four. Burning crop residue puts carbon monoxide, methane and sulphur dioxide straight into the air, and the smoke's nitrogen oxides and volatile organic compounds go on to form ground-level ozone. Since 1, 2 and 4 are certain, only option (d) can be right.

• ✓ 1. Burning rice straw releases carbon monoxide; about 7% of the carbon in the straw leaves as CO.
• ✓ 2. Methane is also released; about 0.66% of the carbon in burnt rice straw is emitted as CH4.
• ✓ 3. Ozone is not emitted as such; it forms in the air from the nitrogen oxides and volatile organic compounds in stubble smoke, so it is released into the atmosphere 'due to' the burning. In any case CO, CH4 and SO2 are certain, and (d) is the only option that contains all three.
• ✓ 4. Stubble burning emits sulphur dioxide along with carbon monoxide, nitrogen oxides, methane and fine particles.

Remember · Crop-residue burning gives CO, CO2, CH4, N2O, NOx, SO2 and particulates; the smoke's VOCs and NOx then form ground-level ozone.

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink · Report an error

Answer: (a) pesticides in agriculture

Carbofuran, methyl parathion, phorate and triazophos are toxic insecticides used on crops. They feature in the Government of India's lists of pesticides that are banned or restricted because of their harm to health and to birds, fish and bees.

• ✓ (a) All four names appear in the Ministry of Agriculture's list of banned and restricted pesticides. Methyl parathion was banned by an August 2018 order, and phorate and triazophos were barred from manufacture and import from 1 January 2019, with use to end by 31 December 2020.
• ✗ (b) Food preservatives are additives regulated under food-safety rules; none of these four is a preservative.
• ✗ (c) Fruit ripening is done with ethylene-releasing agents or, illegally, calcium carbide. These chemicals are insecticides, not ripening agents.
• ✗ (d) Moisturisers in cosmetics are humectants and emollients; these four are toxic to humans and have no cosmetic use.
• • Since then The Government's list of pesticides banned for manufacture, import and use, updated to 1 October 2022, includes methyl parathion, phorate and triazophos; carbofuran appears as a banned 50% SP formulation.

Remember · Carbofuran, methyl parathion, phorate and triazophos are hazardous agricultural insecticides, banned or being phased out in India.

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (d) 1, 2 and 3

All three statements are correct, because farming is a major source of reactive nitrogen. Fertilised soils release nitrous oxide, and manure and urine from cattle and poultry give off ammonia.

• ✓ 1. When reactive nitrogen such as fertiliser reaches the soil, microbes convert part of it into nitrous oxide, an oxide of nitrogen and a greenhouse gas.
• ✓ 2. Much of the protein that cattle eat is lost in manure and urine, and this nitrogen escapes as ammonia and other nitrogenous gases.
• ✓ 3. Poultry waste is rich in nitrogen, and under aerobic conditions it can evaporate as ammonia, which is a reactive nitrogen compound.

Remember · Agriculture is a big source of reactive nitrogen: soils give nitrous oxide, while cattle and poultry manure gives ammonia.

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (a) 1 and 3 only

Rice covers by far the largest kharif area, and cotton covers more land than sugarcane, so statements 1 and 3 are correct. Jowar covers far less area than oilseeds, and sugarcane area has moved up and down rather than falling steadily, so statements 2 and 4 are wrong.

• ✓ 1. In the Government's five-year normal (average of 2016-17 to 2020-21), kharif rice covers 39.54 million hectares, far above any other kharif crop, such as maize (7.54) or bajra (7.40).
• ✗ 2. Kharif jowar covers only 1.91 million hectares, while kharif soyabean alone covers 11.21 million hectares, so jowar is well below oilseeds.
• ✓ 3. Cotton covers about 12.38 million hectares against about 4.71 million hectares for sugarcane.
• ✗ 4. Sugarcane area (million hectares) went 5.07 (2014-15), 4.93, 4.44, 4.74 and 5.06 (2018-19). It fell, then rose again, so it did not steadily decrease.

Remember · Among kharif crops rice has the largest area; cotton area is well above sugarcane's; jowar covers much less than oilseeds; sugarcane area fluctuates rather than falls steadily.

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (c) 2, 4 and 5

Why not the tempting option · UPSC's key is (c). Statement 3 is plainly wrong — Conservation Agriculture governs how soil and crops are managed, not which crops may be grown — and every option other than (c) includes it, so the answer is settled whatever one makes of statement 1. 'Avoiding monoculture' is close to FAO's diversification principle, but FAO states that principle as rotations and associations of at least three crop species (statement 5), and no option pairs 1 with 2, 4 and 5 without 3. In the exam, eliminate by the clearly wrong statement first.

Conservation Agriculture (CA) rests on three practices: minimum soil disturbance (minimum or no tillage), a permanent organic cover on the soil (crop residues or mulch), and diversification of crops through rotations and associations. Statements 2, 4 and 5 are these three practices; nothing in CA asks farmers to stop growing plantation crops, and every option except (c) includes that wrong statement 3.

• ✗ 1. Not counted by UPSC's key. FAO states its diversification principle positively — rotations and associations of at least three crop species — which is statement 5; 'avoiding monoculture' is not listed as a separate practice, and no option combines 1 with 2, 4 and 5 without the wrong statement 3.
• ✓ 2. Minimum mechanical soil disturbance, meaning low-disturbance no-till or direct seeding, is the first CA principle.
• ✗ 3. CA is a way of managing the soil and crops, not a restriction on crop type. None of its principles asks a farmer to avoid plantation crops.
• ✓ 4. Keeping the soil covered with crop residue or other organic material (permanent soil organic cover) is the second CA principle.
• ✓ 5. Species diversification through crop rotation or association is the third CA principle; FAO asks for at least three different crop species in the rotation.

Remember · Conservation Agriculture = minimum soil disturbance + permanent soil cover + crop rotation or diversification; CA restricts how soil is managed, not which crops are grown.

Question and answer: UPSC's official GS Paper I (2018, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink · Report an error

Answer: (b) 2 only

Only statement 2 is correct. India's GM mustard hybrid (DMH-11) carries the barnase, barstar and bar genes, which give a pollination-control system for producing hybrid seed. It was developed at the University of Delhi, not by IARI and Punjab Agricultural University, and its genes do not give pest resistance.

• ✗ 1. The transgenes are barnase (makes the plant male-sterile), barstar (restores fertility) and bar (tolerance to the herbicide Basta, and a marker for selecting transformed lines). None is a pest-resistance gene like Bt.
• ✓ 2. The barnase-barstar system controls pollination, so two chosen diverse parent lines can be cross-pollinated to make a high-yielding hybrid.
• ✗ 3. It was developed by the Centre for Genetic Manipulation of Crop Plants (CGMCP), University of Delhi South Campus, and cleared by the GEAC in 2022, not by IARI and Punjab Agricultural University.

Remember · GM mustard DMH-11 (Delhi University's CGMCP) uses the barnase-barstar-bar genes for hybrid seed production through pollination control, not for pest resistance.

Question and answer: UPSC's official GS Paper I (2018, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (d) 1, 2, 3 and 4

All four spread plant diseases. Most plant pathogens travel as spores or bacteria, and these are carried by wind, blown dust, splashing rain and even by birds.

• ✓ 1. Spores stick to birds' feathers and beaks and are dropped on other plants. Chestnut blight spores, for example, are spread by many bird species, and powdery mildew fruiting bodies are carried on feathers.
• ✓ 2. Dust is lifted soil, and soil is a recognised carrier of fungal spores. Blowing dust moves them from diseased fields to healthy ones.
• ✓ 3. Rain splash and running water carry spores and bacteria from an infected leaf to healthy plant surfaces.
• ✓ 4. Wind brings the first spores from neighbouring fields or far away, and then spreads the secondary infection from plant to plant.

Remember · Plant pathogens are dispersed by wind, water (rain), dust or soil, insects and birds. Every listed agent can spread plant diseases.

Question and answer: UPSC's official GS Paper I (2018, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink · Report an error

Answer: (b) 2 and 3 only

Statement 1 is wrong: NPOP was launched by the Department of Commerce in the Ministry of Commerce and Industry, not by the Ministry of Rural Development. Statements 2 and 3 are correct.

• ✗ 1. NPOP began in 2001 under the Department of Commerce (Ministry of Commerce and Industry), mainly to certify organic products for export. It does not run under the Ministry of Rural Development.
• ✓ 2. APEDA, which also works under the Commerce Ministry, acts as the Secretariat for implementing NPOP.
• ✓ 3. Sikkim converted its entire agricultural area to certified organic by 2015 and was formally declared a 100 per cent organic state in 2016, the first in India.

Remember · NPOP: launched 2001 by the Commerce Ministry; APEDA is its Secretariat. Sikkim was declared India's first fully organic State in 2016.

Question and answer: UPSC's official GS Paper I (2018, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (d) 1, 2 and 3

All three uses are correct. Reading a crop's full DNA reveals markers for traits such as drought tolerance and disease resistance, cuts the years needed to breed a new variety, and shows how crops and their disease-causing organisms interact.

• ✓ 1. When 90 chickpea genomes were sequenced, the work gave millions of genetic markers that can be used to breed varieties with better drought tolerance and disease resistance.
• ✓ 2. Breeding a new chickpea variety normally takes 4–8 years; the scientists behind the chickpea genome said the sequence could cut this to half.
• ✓ 3. Sequencing crop and pathogen genomes lets researchers study plant–pathogen interactions and plant resistance at gene level.

Remember · Genome sequencing in crops: finds trait markers (drought, disease resistance), speeds up breeding (chickpea: 4–8 years cut to about half) and reveals host–pathogen interactions.

Question and answer: UPSC's official GS Paper I (2017, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (c) 1 and 3 only

Leaving the soil undisturbed (reduced or zero tillage) and leaving crop residue on the field both conserve water, because the residue cover cuts evaporation and lets more rain soak in. Gypsum is a soil amendment for sodic soils, not a water-saving practice.

• ✓ 1. No-till or reduced tillage, together with residue mulch, is the basis of conservation farming because it conserves water and prevents erosion.
• ✗ 2. Gypsum supplies soluble calcium to replace exchangeable sodium in sodic soils. It is used to reclaim such soils and is not a way of saving irrigation water.
• ✓ 3. Crop residue left on the soil surface reduces evapotranspiration (water loss to the air), raises infiltration rates and suppresses weeds.

Remember · Water-saving conservation farming: minimum or no tillage plus a residue mulch. Gypsum is for reclaiming sodic soils, not for saving water.

Question and answer: UPSC's official GS Paper I (2017, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (b) Neem coating slows down the rate of dissolution of urea in the soil

A thin coat of neem oil makes urea release its nitrogen into the soil slowly, so more of it is taken up by the crop and less is lost; this raises nitrogen use efficiency and cuts the quantity of urea needed. Neem coating also makes subsidised urea hard to divert to industrial uses. The Centre made neem coating compulsory for all domestic urea from 1 September 2015 and for imported urea from 1 December 2015.

• ✓ (b) Neem coating slows the release of nitrogen from urea to the soil, which the Department of Fertilizers credits for higher nitrogen use efficiency and lower urea consumption.
• ✗ (a) Neem compounds act by slowing the conversion and release of nitrogen already supplied by urea; they are not promoted for boosting biological nitrogen fixation by soil microbes.
• ✗ (c) Slower release can reduce nitrogen losses, but no coating stops nitrous oxide emission from fields altogether; 'not at all released' overstates the effect.
• ✗ (d) Neem-coated urea is a fertiliser only; it contains no weedicide.

Remember · Neem-coated urea (100% mandatory from 2015): slow nitrogen release, higher nitrogen use efficiency, lower urea use, and no diversion of subsidised urea to industry.

Question and answer: UPSC's official GS Paper I (2016, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (b) 2 only

FAO's GIAHS programme exists to recognise and protect living traditional farming systems, together with their landscapes, agro-biodiversity and local knowledge, through 'dynamic conservation'. It does not aim to modernise these systems for higher output, and it has nothing to do with granting Geographical Indication tags.

• ✗ 1. Replacing traditional practice with modern technology to maximise yields runs against the programme's purpose, which is to conserve heritage farming systems while keeping them viable.
• ✓ 2. FAO states the overall goal as identifying and safeguarding these heritage systems with their landscapes, agricultural biodiversity and knowledge systems.
• ✗ 3. Geographical Indications are granted under national law (in India, the Geographical Indications of Goods Act, 1999), not by FAO; a GIAHS listing confers no GI status.

Remember · GIAHS (FAO, launched 2002): dynamic conservation of traditional agricultural systems, their landscapes, agro-biodiversity and knowledge; it is recognition, not modernisation or GI tagging.

Question and answer: UPSC's official GS Paper I (2016, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (c) 1 and 3 only

Drip irrigation reduces weeds and soil erosion, but it does not reduce soil salinity; salt tends to build up at the edge of the wetted zone. Water goes only to the plant's root zone, so the rest of the field stays dry and there is little surface flow to wash soil away.

• ✓ 1. Water is placed at the plants, not spread over the whole field, so the soil between rows stays dry and fewer weeds grow. FAO lists reduced weed control among the advantages of drip irrigation, and ICAR notes that it reduces weed pressure.
• ✗ 2. Drip does not cut soil salinity: FAO notes that the dissolved salts accumulate at the periphery of the wetted soil mass, and salt accumulation at the wetting front is listed as a demerit of drip irrigation. (Drip does let farmers use saline water, and it spares leaves from salt burn, which is a different point.)
• ✓ 3. Water is delivered slowly through emitters with no flooding or heavy surface flow, so soil structure is disturbed least. A field study in a peer-reviewed journal measured suspended soil loss of 5.26 t per ha under furrow irrigation, 2.53 t per ha under subsurface drip at 120% of crop evapotranspiration, and none under deficit subsurface drip.

Remember · Drip irrigation: saves water, fertiliser and labour, keeps weeds down and spares soil structure; drawbacks are clogged emitters and salt build-up at the wetting front.

Question and answer: UPSC's official GS Paper I (2016, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink · Report an error