1. Fertilizers are substances used to:
a) Increase soil acidity
b) Supply nutrients to plants
c) Kill insects
d) Reduce water content
Answer: b) Supply nutrients to plants
Explanation: Fertilizers enrich soil with essential nutrients for plant growth.
2. Which element is known as the “King of Fertilizers”?
a) Phosphorus
b) Potassium
c) Nitrogen
d) Calcium
Answer: c) Nitrogen
Explanation: Nitrogen is required in largest quantity and enhances leaf growth.
3. Urea is a:
a) Nitrogenous fertilizer
b) Phosphatic fertilizer
c) Potassic fertilizer
d) Mixed fertilizer
Answer: a) Nitrogenous fertilizer
Explanation: Urea contains about 46% nitrogen.
4. The chemical formula of urea is:
a) NH₄NO₃
b) CO(NH₂)₂
c) NH₄Cl
d) (NH₄)₂SO₄
Answer: b) CO(NH₂)₂
Explanation: Urea is carbamide with formula CO(NH₂)₂.
5. Which fertilizer has the highest nitrogen content?
a) Urea
b) Ammonium nitrate
c) Calcium ammonium nitrate
d) Ammonium sulphate
Answer: a) Urea
Explanation: Urea contains 46% nitrogen, highest among solid fertilizers.
6. Superphosphate of lime is a:
a) Nitrogen fertilizer
b) Phosphate fertilizer
c) Potassium fertilizer
d) Micronutrient
Answer: b) Phosphate fertilizer
Explanation: Superphosphate contains calcium dihydrogen phosphate.
7. Potash fertilizers mainly supply:
a) N
b) P
c) K
d) Ca
Answer: c) K
Explanation: Potash fertilizers provide potassium for fruit and flower development.
8. Which of the following is a potassic fertilizer?
a) KCl
b) K₂SO₄
c) KNO₃
d) All of these
Answer: d) All of these
Explanation: All these compounds are sources of potassium.
9. Ammonium sulphate contains nitrogen in the form of:
a) Nitrate
b) Ammonium
c) Urea
d) Both a and b
Answer: b) Ammonium
Explanation: (NH₄)₂SO₄ → nitrogen is present as ammonium ions.
10. Which element is essential for chlorophyll formation?
a) Iron
b) Magnesium
c) Potassium
d) Calcium
Answer: b) Magnesium
Explanation: Magnesium is the central atom in chlorophyll molecule.
11. Which fertilizer is also known as “farmer’s friend”?
a) Ammonium sulphate
b) Urea
c) Superphosphate
d) Green manure
Answer: b) Urea
Explanation: Due to high nitrogen content, urea is widely used.
12. The main nutrient supplied by bone meal is:
a) Nitrogen
b) Phosphorus
c) Potassium
d) Magnesium
Answer: b) Phosphorus
Explanation: Bone meal is a natural source of phosphate.
13. Essential nutrients for plant growth are classified as:
a) Macronutrients and micronutrients
b) Major and minor elements
c) Primary and secondary nutrients
d) All of the above
Answer: d) All of the above
Explanation: Classification is based on quantity and importance.
14. Which of the following is a primary macronutrient?
a) Fe
b) Cu
c) N
d) Zn
Answer: c) N
Explanation: N, P, K are primary macronutrients.
15. Which nutrient deficiency causes stunted growth and yellow leaves?
a) Nitrogen
b) Phosphorus
c) Potassium
d) Magnesium
Answer: a) Nitrogen
Explanation: Nitrogen is vital for protein synthesis → deficiency causes chlorosis.
16. Which nutrient promotes root growth and seed formation?
a) Nitrogen
b) Phosphorus
c) Potassium
d) Calcium
Answer: b) Phosphorus
Explanation: P helps in root development and flowering.
17. Which nutrient improves resistance to disease in plants?
a) Nitrogen
b) Potassium
c) Phosphorus
d) Sulphur
Answer: b) Potassium
Explanation: K strengthens plant tissues and improves disease resistance.
18. Which fertilizer is a source of both nitrogen and phosphorus?
a) Urea
b) Diammonium phosphate (DAP)
c) Superphosphate
d) Ammonium sulphate
Answer: b) Diammonium phosphate (DAP)
Explanation: DAP contains ~18% N and 46% P₂O₅.
19. Which micronutrient is essential for nitrogen fixation in legumes?
a) Iron
b) Molybdenum
c) Zinc
d) Copper
Answer: b) Molybdenum
Explanation: Mo is required by nitrogenase enzyme for nitrogen fixation.
20. Deficiency of potassium in plants causes:
a) Weak stems and poor fruit quality
b) Poor root growth
c) Chlorosis in leaves
d) Reduced flowering
Answer: a) Weak stems and poor fruit quality
Explanation: Potassium improves stem strength and fruit quality.
21. The fertilizer “ammonium phosphate” contains:
a) Only nitrogen
b) Only phosphorus
c) Both nitrogen and phosphorus
d) Both phosphorus and potassium
Answer: c) Both nitrogen and phosphorus
Explanation: Ammonium phosphate provides N and P.
22. Which fertilizer is hygroscopic and must be stored carefully?
a) Ammonium sulphate
b) Urea
c) Superphosphate
d) Potassium chloride
Answer: b) Urea
Explanation: Urea absorbs moisture from air and cakes easily.
23. Which of the following is an organic fertilizer?
a) Urea
b) Compost
c) Ammonium nitrate
d) DAP
Answer: b) Compost
Explanation: Organic fertilizers come from plant/animal waste (compost, manure).
24. Green manure is obtained from:
a) Animal dung
b) Decomposed green plants
c) Ammonium salts
d) Bone meal
Answer: b) Decomposed green plants
Explanation: Leguminous plants like sunn hemp are ploughed into soil as green manure.
25. Which one of the following is not a fertilizer but a soil conditioner?
a) Gypsum
b) Urea
c) Superphosphate
d) Potassium nitrate
Answer: a) Gypsum
Explanation: Gypsum improves soil texture and supplies calcium, but is not a primary fertilizer.
26. Which of the following is a nitrogenous fertilizer?
a) Urea
b) Superphosphate
c) Potassium sulphate
d) Gypsum
Answer: a) Urea
Explanation: Urea contains 46% nitrogen, no P or K.
27. Ammonium nitrate contains nitrogen in which forms?
a) Nitrate only
b) Ammonium only
c) Both ammonium and nitrate
d) Urea
Answer: c) Both ammonium and nitrate
Explanation: NH₄NO₃ provides nitrogen in two readily available forms.
28. Calcium ammonium nitrate (CAN) contains about:
a) 10% N
b) 15% N
c) 25% N
d) 33% N
Answer: c) 25% N
Explanation: CAN typically has ~25% nitrogen.
29. Ammonium sulphate is produced by reaction of:
a) NH₃ + HCl
b) NH₃ + H₂SO₄
c) NH₃ + CO₂
d) NH₃ + HNO₃
Answer: b) NH₃ + H₂SO₄
Explanation: 2NH₃ + H₂SO₄ → (NH₄)₂SO₄.
30. Which nitrogen fertilizer is explosive in nature?
a) Urea
b) Ammonium nitrate
c) Calcium nitrate
d) Sodium nitrate
Answer: b) Ammonium nitrate
Explanation: Ammonium nitrate is used in explosives and fertilizers.
31. The Haber process is used in fertilizer industry for the production of:
a) Urea
b) Ammonia
c) Superphosphate
d) Nitric acid
Answer: b) Ammonia
Explanation: Haber process → N₂ + 3H₂ → 2NH₃ (at high pressure & catalyst).
32. The raw materials for urea production are:
a) NH₃ and H₂SO₄
b) NH₃ and HNO₃
c) NH₃ and CO₂
d) NH₃ and CaCO₃
Answer: c) NH₃ and CO₂
Explanation: Urea is manufactured from ammonia and carbon dioxide.
33. Which fertilizer is obtained by treating phosphate rock with H₂SO₄?
a) Superphosphate
b) DAP
c) Triple superphosphate
d) Ammonium phosphate
Answer: a) Superphosphate
Explanation: Ca₃(PO₄)₂ + H₂SO₄ → Ca(H₂PO₄)₂ + CaSO₄.
34. Triple superphosphate (TSP) contains about:
a) 16% P₂O₅
b) 20% P₂O₅
c) 45% P₂O₅
d) 60% P₂O₅
Answer: c) 45% P₂O₅
Explanation: TSP has a high phosphate content compared to normal superphosphate.
35. Rock phosphate is mainly:
a) Ca₃(PO₄)₂
b) CaSO₄
c) CaCO₃
d) Mg₃(PO₄)₂
Answer: a) Ca₃(PO₄)₂
Explanation: Rock phosphate is tricalcium phosphate, treated with acids to make fertilizers.
36. Diammonium phosphate (DAP) is manufactured by:
a) NH₃ + CO₂
b) NH₃ + H₃PO₄
c) NH₃ + H₂SO₄
d) NH₃ + HNO₃
Answer: b) NH₃ + H₃PO₄
Explanation: DAP contains ~18% N and ~46% P₂O₅.
37. Which phosphatic fertilizer is water-soluble?
a) Rock phosphate
b) Superphosphate
c) DAP
d) Both b and c
Answer: d) Both b and c
Explanation: Superphosphate and DAP are water-soluble and easily absorbed.
38. Potassium chloride (MOP) contains about:
a) 30% K₂O
b) 40% K₂O
c) 50% K₂O
d) 60% K₂O
Answer: d) 60% K₂O
Explanation: Muriate of Potash (KCl) has ~60% K₂O equivalent.
39. Potassium sulphate (SOP) contains about:
a) 25% K₂O
b) 40% K₂O
c) 50% K₂O
d) 60% K₂O
Answer: c) 50% K₂O
Explanation: SOP provides ~50% K₂O and is chloride-free (preferred for sensitive crops).
40. Which of the following is a chloride-free potassic fertilizer?
a) KCl
b) K₂SO₄
c) KNO₃
d) Both b and c
Answer: d) Both b and c
Explanation: SOP (K₂SO₄) and KNO₃ do not contain chloride.
41. Which fertilizer is known as “prilled urea”?
a) Urea in small spherical form
b) Granulated urea
c) Liquid urea
d) Coated urea
Answer: a) Urea in small spherical form
Explanation: Prilled urea = tiny spherical solid particles.
42. Neem-coated urea is used to:
a) Increase N content
b) Reduce leaching losses
c) Increase solubility
d) Supply sulfur
Answer: b) Reduce leaching losses
Explanation: Neem coating slows down nitrogen release and reduces wastage.
43. Which fertilizer is used in acidic soils to neutralize acidity?
a) Ammonium sulphate
b) Superphosphate
c) Basic slag (Ca-silicate)
d) Urea
Answer: c) Basic slag (Ca-silicate)
Explanation: Basic slag adds lime and reduces soil acidity.
44. Which is the cheapest source of nitrogen fertilizer?
a) Urea
b) Ammonium sulphate
c) Ammonium nitrate
d) Calcium ammonium nitrate
Answer: a) Urea
Explanation: Urea has highest N% and lowest cost per kg N.
45. Which fertilizer is best suited for paddy fields?
a) Urea
b) Ammonium sulphate
c) Calcium ammonium nitrate
d) Potassium chloride
Answer: b) Ammonium sulphate
Explanation: In flooded soils, ammonium form is more stable than nitrate.
46. Which fertilizer is highly hygroscopic and used as liquid fertilizer?
a) Ammonium nitrate
b) Urea
c) Calcium nitrate
d) Ammonium sulphate
Answer: c) Calcium nitrate
Explanation: Calcium nitrate is soluble and often used in liquid form.
47. The main raw material for phosphatic fertilizers is:
a) Rock phosphate
b) Gypsum
c) Limestone
d) Dolomite
Answer: a) Rock phosphate
Explanation: Rock phosphate (Ca₃(PO₄)₂) is the basis for superphosphate and DAP.
48. Which fertilizer is produced by Ostwald process (via nitric acid)?
a) Ammonium sulphate
b) Ammonium nitrate
c) Urea
d) DAP
Answer: b) Ammonium nitrate
Explanation: NH₃ → HNO₃ (Ostwald) → NH₄NO₃.
49. Which fertilizer releases nitrogen slowly and continuously?
a) Neem-coated urea
b) Ammonium nitrate
c) Urea
d) CAN
Answer: a) Neem-coated urea
Explanation: Slow-release reduces losses and increases efficiency.
50. Which fertilizer is especially suitable for tobacco crops (sensitive to chloride)?
a) KCl
b) K₂SO₄ (SOP)
c) MOP
d) None
Answer: b) K₂SO₄ (SOP)
Explanation: Chloride damages tobacco → use sulfate of potash.
51. A complex fertilizer contains:
a) Only one primary nutrient
b) Two or more primary nutrients
c) Only secondary nutrients
d) Only organic matter
Answer: b) Two or more primary nutrients
Explanation: Complex fertilizers supply N, P, and/or K together (e.g., NPK, DAP).
52. Which of the following is a complex fertilizer?
a) Urea
b) Diammonium phosphate (DAP)
c) Ammonium nitrate
d) Superphosphate
Answer: b) Diammonium phosphate (DAP)
Explanation: DAP provides both nitrogen and phosphorus.
53. NPK fertilizer contains:
a) Only nitrogen
b) Only phosphorus
c) Nitrogen, phosphorus, and potassium
d) Nitrogen and calcium
Answer: c) Nitrogen, phosphorus, and potassium
Explanation: NPK fertilizers supply all three primary nutrients.
54. Which fertilizer is considered a straight fertilizer?
a) Urea
b) NPK mixture
c) DAP
d) Nitro-phosphate
Answer: a) Urea
Explanation: Straight fertilizers supply only one nutrient (e.g., urea for N).
55. Which of the following is an example of a mixed fertilizer?
a) Urea
b) NPK mixture prepared mechanically
c) DAP
d) Superphosphate
Answer: b) NPK mixture prepared mechanically
Explanation: Mixed fertilizers are prepared by blending straight fertilizers.
56. A fertilizer containing secondary nutrient is:
a) Urea
b) Ammonium sulphate
c) Gypsum
d) Superphosphate
Answer: c) Gypsum
Explanation: Gypsum supplies calcium (Ca) and sulphur (S), which are secondary nutrients.
57. Sulphur deficiency in plants leads to:
a) Delayed flowering
b) Yellowing of young leaves
c) Poor fruit setting
d) All of the above
Answer: d) All of the above
Explanation: Sulphur is essential for protein and oil formation.
58. Which fertilizer supplies magnesium?
a) Dolomite
b) Gypsum
c) Urea
d) DAP
Answer: a) Dolomite
Explanation: Dolomite (CaMg(CO₃)₂) provides calcium and magnesium.
59. Zinc deficiency in plants causes:
a) Chlorosis
b) Poor grain filling
c) Little leaf disease in rice
d) All of the above
Answer: d) All of the above
Explanation: Zn is essential for enzyme activity and growth hormones.
60. Boron deficiency in plants causes:
a) Poor root development
b) Poor fruit and seed setting
c) Death of shoot tips
d) All of the above
Answer: d) All of the above
Explanation: Boron is important for cell wall formation and reproduction.
61. Which micronutrient fertilizer contains zinc?
a) Zinc sulphate
b) Magnesium sulphate
c) Borax
d) Gypsum
Answer: a) Zinc sulphate
Explanation: ZnSO₄ is commonly used to correct zinc deficiency.
62. Which micronutrient fertilizer is used to correct iron deficiency?
a) FeSO₄
b) Borax
c) Gypsum
d) ZnSO₄
Answer: a) FeSO₄
Explanation: Ferrous sulphate supplies iron.
63. Biofertilizers are:
a) Chemical fertilizers
b) Organic manures
c) Microorganisms that enhance nutrient availability
d) Micronutrients
Answer: c) Microorganisms that enhance nutrient availability
Explanation: Biofertilizers include bacteria, fungi, and algae.
64. Which bacteria fix nitrogen in leguminous plants?
a) Azotobacter
b) Rhizobium
c) Clostridium
d) Nitrosomonas
Answer: b) Rhizobium
Explanation: Rhizobium forms nodules on legume roots and fixes nitrogen symbiotically.
65. Which free-living bacteria fixes nitrogen in soil?
a) Nitrosomonas
b) Nitrobacter
c) Azotobacter
d) Thiobacillus
Answer: c) Azotobacter
Explanation: Azotobacter is a free-living nitrogen fixer in soil.
66. Blue-green algae (cyanobacteria) act as biofertilizers by:
a) Adding nitrogen
b) Adding phosphorus
c) Adding potassium
d) Adding calcium
Answer: a) Adding nitrogen
Explanation: Cyanobacteria (like Anabaena, Nostoc) fix atmospheric nitrogen.
67. Which biofertilizer is commonly used in paddy fields?
a) Azotobacter
b) Blue-green algae
c) Mycorrhiza
d) Azospirillum
Answer: b) Blue-green algae
Explanation: BGA fix nitrogen and are widely used in rice fields.
68. Mycorrhizal fungi help plants by:
a) Fixing nitrogen
b) Increasing phosphorus absorption
c) Increasing potassium absorption
d) Providing sulphur
Answer: b) Increasing phosphorus absorption
Explanation: Mycorrhizae enhance uptake of P and water.
69. Phosphate solubilizing bacteria (PSB) improve availability of:
a) Nitrogen
b) Phosphorus
c) Potassium
d) Sulphur
Answer: b) Phosphorus
Explanation: PSB make insoluble phosphates available to plants.
70. Which of the following is a potassium-mobilizing biofertilizer?
a) Bacillus mucilaginosus
b) Azotobacter
c) Rhizobium
d) Nostoc
Answer: a) Bacillus mucilaginosus
Explanation: These bacteria release K from soil minerals.
71. Which fertilizer supplies both nitrogen and sulfur?
a) Ammonium sulphate
b) Urea
c) Superphosphate
d) Ammonium nitrate
Answer: a) Ammonium sulphate
Explanation: (NH₄)₂SO₄ contains ~21% N and ~24% S.
72. Which micronutrient deficiency causes “whip-tail disease” in cauliflower?
a) Iron
b) Zinc
c) Boron
d) Molybdenum
Answer: d) Molybdenum
Explanation: Mo deficiency causes whip-tail in cauliflower.
73. Which micronutrient is provided by Borax fertilizer?
a) Copper
b) Zinc
c) Boron
d) Molybdenum
Answer: c) Boron
Explanation: Borax (Na₂B₄O₇·10H₂O) supplies boron.
74. Copper deficiency in plants is corrected by:
a) CuSO₄
b) ZnSO₄
c) Borax
d) FeSO₄
Answer: a) CuSO₄
Explanation: Copper sulphate supplies copper as a micronutrient.
75. Which biofertilizer produces growth-promoting substances like auxins and vitamins?
a) Azospirillum
b) Rhizobium
c) Nostoc
d) Mycorrhiza
Answer: a) Azospirillum
Explanation: Azospirillum promotes nitrogen fixation and plant growth hormones.
76. Excessive use of nitrogen fertilizers causes:
a) Soil fertility increase indefinitely
b) Nitrate pollution of groundwater
c) Elimination of soil microorganisms
d) None of the above
Answer: b) Nitrate pollution of groundwater
Explanation: Excess nitrates leach into groundwater → harmful to humans (blue baby syndrome).
77. Overuse of fertilizers leads to:
a) Soil acidification
b) Soil salinity
c) Eutrophication of water bodies
d) All of the above
Answer: d) All of the above
Explanation: Fertilizer misuse degrades soil and water quality.
78. Eutrophication is caused mainly by excess:
a) Nitrogen and phosphorus fertilizers
b) Potassium fertilizers
c) Calcium fertilizers
d) Sulphur fertilizers
Answer: a) Nitrogen and phosphorus fertilizers
Explanation: Nutrient enrichment causes algal blooms in water.
79. Which disease is linked with nitrate-contaminated water?
a) Malaria
b) Blue baby syndrome (methemoglobinemia)
c) Typhoid
d) Goitre
Answer: b) Blue baby syndrome (methemoglobinemia)
Explanation: Nitrates reduce oxygen-carrying capacity of blood in infants.
80. Which gas is released from soils rich in nitrogen fertilizers?
a) CO₂
b) CH₄
c) N₂O
d) O₃
Answer: c) N₂O
Explanation: Nitrous oxide is a greenhouse gas emitted from nitrogen fertilizer use.
81. Which fertilizer contributes most to soil salinity?
a) Urea
b) Ammonium sulphate
c) Sodium nitrate
d) Potassium nitrate
Answer: c) Sodium nitrate
Explanation: Sodium salts accumulate, causing salinity.
82. Which of the following improves fertilizer use efficiency?
a) Neem-coated urea
b) Drip irrigation with soluble fertilizers
c) Slow-release fertilizers
d) All of the above
Answer: d) All of the above
Explanation: All methods reduce nutrient loss and increase efficiency.
83. The term “fertilizer use efficiency” means:
a) % of applied nutrient taken up by crop
b) Amount of fertilizer lost in soil
c) Total fertilizer used
d) Yield per hectare
Answer: a) % of applied nutrient taken up by crop
Explanation: Efficiency = nutrient absorbed ÷ nutrient applied × 100.
84. Controlled-release fertilizers are designed to:
a) Release nutrients quickly
b) Release nutrients slowly over time
c) Not release nutrients
d) Eliminate all losses
Answer: b) Release nutrients slowly over time
Explanation: Controlled-release reduces leaching and volatilization losses.
85. Foliar application of fertilizers means:
a) Spraying fertilizer solution on leaves
b) Mixing fertilizer in irrigation water
c) Broadcasting in soil
d) Placing fertilizer deep in soil
Answer: a) Spraying fertilizer solution on leaves
Explanation: Foliar feeding provides quick nutrient supply to plants.
86. Fertigation means:
a) Mixing fertilizers with compost
b) Application of fertilizers through irrigation water
c) Applying fertilizers before sowing
d) Foliar spraying
Answer: b) Application of fertilizers through irrigation water
Explanation: Fertigation is used in drip irrigation systems.
87. Which is the most energy-intensive fertilizer to produce?
a) Urea
b) Ammonium sulphate
c) DAP
d) Potash
Answer: a) Urea
Explanation: Urea requires large amounts of energy (natural gas) for NH₃ production.
88. Which nutrient’s overuse causes lodging in cereals?
a) Nitrogen
b) Phosphorus
c) Potassium
d) Sulphur
Answer: a) Nitrogen
Explanation: Excess nitrogen causes tall, weak stems prone to lodging.
89. Integrated nutrient management (INM) involves:
a) Use of only chemical fertilizers
b) Use of only organic manure
c) Combination of chemical fertilizers, organic manures, and biofertilizers
d) Only irrigation
Answer: c) Combination of chemical fertilizers, organic manures, and biofertilizers
Explanation: INM balances productivity and sustainability.
90. Which fertilizer is preferred for acidic soils?
a) Ammonium sulphate
b) Basic slag
c) Urea
d) Superphosphate
Answer: b) Basic slag
Explanation: Basic slag neutralizes acidity while supplying Ca and P.
91. Which fertilizer is preferred for alkaline soils?
a) Gypsum
b) Sodium nitrate
c) Potassium chloride
d) Lime
Answer: a) Gypsum
Explanation: Gypsum corrects sodicity (alkalinity) by replacing Na⁺ with Ca²⁺.
92. Which of the following helps in reducing ammonia volatilization losses from urea?
a) Deep placement in soil
b) Neem-coating
c) Irrigating after application
d) All of the above
Answer: d) All of the above
Explanation: Proper management practices minimize losses.
93. Nano-fertilizers are:
a) Large fertilizer granules
b) Fertilizers with particle size <100 nm
c) Only organic fertilizers
d) Biofertilizers
Answer: b) Fertilizers with particle size <100 nm
Explanation: Nano-fertilizers increase efficiency and reduce losses.
94. Which nutrient is most responsible for greenhouse gas emissions from fertilizers?
a) N (Nitrogen)
b) P (Phosphorus)
c) K (Potassium)
d) Ca (Calcium)
Answer: a) N (Nitrogen)
Explanation: Nitrogen fertilizers release nitrous oxide (N₂O), a potent greenhouse gas.
95. Which fertilizer is best for oilseed crops (rich in proteins)?
a) Potash fertilizers
b) Sulphur-containing fertilizers
c) Phosphate fertilizers
d) Urea
Answer: b) Sulphur-containing fertilizers
Explanation: Sulphur is essential for oil and protein synthesis.
96. Which fertilizer can be used as an explosive as well as fertilizer?
a) Ammonium sulphate
b) Ammonium nitrate
c) Urea
d) Calcium nitrate
Answer: b) Ammonium nitrate
Explanation: Ammonium nitrate has dual use (fertilizer + explosive).
97. Which is considered the most balanced chemical fertilizer?
a) Urea
b) DAP
c) NPK mixture
d) Ammonium sulphate
Answer: c) NPK mixture
Explanation: NPK supplies all three primary nutrients.
98. Which fertilizer is also called “Murphy’s fertilizer” for tobacco and potato crops?
a) Potassium sulphate (SOP)
b) Ammonium sulphate
c) Urea
d) Superphosphate
Answer: a) Potassium sulphate (SOP)
Explanation: SOP is chloride-free and suitable for sensitive crops like potato and tobacco.
99. The term “balanced fertilization” refers to:
a) Applying maximum nitrogen
b) Applying nutrients in proportion to crop requirement
c) Applying only organic manure
d) Applying fertilizers every week
Answer: b) Applying nutrients in proportion to crop requirement
Explanation: Balanced fertilization avoids deficiency and excess of nutrients.
100. Which sustainable alternative can reduce chemical fertilizer dependency?
a) Compost and green manure
b) Biofertilizers
c) Integrated nutrient management (INM)
d) All of the above
Answer: d) All of the above
Explanation: Combining organic, bio, and chemical sources ensures sustainability.