JAMB Agricultural Science 2020 past questions

Checked by the Skolra question team · Last updated 15 October 2026

Ten questions from the 2020 JAMB Agricultural Science paper, with answers and explanations. We hold 79 questions from this paper, and the Skolra app has all of them.

JAMB Agricultural Science 2020 questions and answers

1. 1.

   Which of the following is not normally a pasture crop?

   1. A
      Cassava
      Correct
   2. B
      Stylosanthes
   3. C
      Centrosema
   4. D
      Guinea grass
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   Answer: A

   Guinea grass, centrosema and stylosanthes are all cultivated as pasture (grass and legume) species for grazing. Cassava is a root/tuber crop grown for its starchy tuber and is not normally used as pasture.

2. 2.

   What is the main use of a gunter's chain?

   1. A
      Measuring distances/lengths on a farmland during surveying
      Correct
   2. B
      Weighing farm produce before sale
   3. C
      Measuring rainfall on the farm
   4. D
      Testing the pH of soil
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   Answer: A

   A Gunter's chain is a 66-foot chain of linked metal rods used in chain surveying to measure distances and lay out boundaries on farmland — it has nothing to do with weight, soil pH or rainfall.

3. 3.

   Plant breeders aim at obtaining the following except

   1. A
      Early-maturing varieties
   2. B
      High-yielding varieties
   3. C
      Disease-resistant varieties
   4. D
      Low-quality produce
      Correct
   Show answerHide answer

   Answer: D

   Plant breeding aims to raise yield, resistance to disease and speed of maturity — never to lower quality. Low-quality produce is the opposite of every breeding objective, so it is the one that does not belong.

4. 4.

   A soil with the PH range of 6.1 to 6.9 can be described as

   1. A
      Strongly acidic
   2. B
      Neutral
   3. C
      Slightly acidic
      Correct
   4. D
      Alkaline
   Show answerHide answer

   Answer: C

   Since 7.0 is neutral on the pH scale, a range of 6.1 to 6.9 sits just below neutral, which is described as slightly acidic soil — good for most crops.

5. 5.

   Which of the following is not a source of farm power?

   1. A
      Draught animals
   2. B
      Fertilizer
      Correct
   3. C
      Tractors
   4. D
      Human labour
   Show answerHide answer

   Answer: B

   Man, draught animals and tractors are all recognised sources of farm power. Fertilizer is a soil input that feeds the crop — it does not power any farm operation.

6. 6.

   Improvement of yam through breeding is difficult because

   1. A
      It matures too quickly
   2. B
      It is immune to all pests
   3. C
      It produces too many leaves
   4. D
      It flowers irregularly and sets very few true seeds
      Correct
   Show answerHide answer

   Answer: D

   Yam breeding is difficult mainly because many varieties flower poorly and irregularly and set very few viable true seeds, making controlled crossing slow and unreliable compared with cereals that flower and seed freely every season.

7. 7.

   Under normal circumstances, the concept of consumer sovereignty in agriculture implies that

   1. A
      The consumer's demand ultimately determines what is produced
      Correct
   2. B
      Middlemen determine what is produced
   3. C
      The government fixes what must be produced
   4. D
      The producer alone decides what is produced
   Show answerHide answer

   Answer: A

   Consumer sovereignty means that, through their buying decisions, consumers ultimately determine what is produced — producers respond to demand rather than dictating it, and neither government nor middlemen hold that power under normal market conditions.

8. 8.

   The mating of a white fulani bull and an N'dama cow could be termed?

   1. A
      Cross-breeding
      Correct
   2. B
      Line breeding
   3. C
      Inbreeding
   4. D
      Hybridization
   Show answerHide answer

   Answer: A

   White Fulani and N'dama are both breeds of the same species, cattle. Mating two different breeds of the same species is cross-breeding. Hybridization is reserved for crosses between different species; inbreeding and line breeding involve mating closely related animals of the same breed.

9. 9.

   A soil with pH2 can be described as

   1. A
      Very strongly acidic
      Correct
   2. B
      Neutral
   3. C
      Slightly acidic
   4. D
      Alkaline
   Show answerHide answer

   Answer: A

   On the pH scale, 7 is neutral and lower values are increasingly acidic. A soil pH of 2 is far below neutral, describing a soil that is very strongly (extremely) acidic.

10. 10.

    The length of oestrus cycle (in days) in goat is

    1. A
       7 days
    2. B
       14 days
    3. C
       21 days
       Correct
    4. D
       30 days
    Show answerHide answer

    Answer: C

    The goat's oestrus cycle averages about 21 days (typically 18–24 days), meaning a doe that is not served will come back into heat roughly every three weeks.

The questions come from past JAMB, WAEC and NECO papers. We use software to help write the answer options and explanations, and every answer is checked twice before it goes on the site. How we check

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Practise all 79 questions we hold from the 2020 paper, on a timed CBT screen

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