JAMB Agricultural Science 2021 past questions

Checked by the Skolra question team · Last updated 23 October 2026

Ten questions from the 2021 JAMB Agricultural Science paper, with answers and explanations. We hold 75 questions from this paper, and the Skolra app has all of them.

JAMB Agricultural Science 2021 questions and answers

1. 1.

   Which of the following is not an example of edaphic factors?

   1. A
      Soil structure
   2. B
      Rainfall
      Correct
   3. C
      Soil texture
   4. D
      Soil pH
   Show answerHide answer

   Answer: B

   Edaphic factors are those environmental factors that relate directly to the soil and how it affects plant and animal life — things like soil texture, soil structure, soil pH, soil moisture, soil organisms, and soil nutrient content.

   So the correct answer is rainfall, since the other three (soil texture, soil pH, soil structure) are genuine soil-related, edaphic factors.

2. 2.

   Ginger is propagated by

   1. A
      seeds
   2. B
      rhizomes
      Correct
   3. C
      budding
   4. D
      stem cuttings
   Show answerHide answer

   Answer: B

   Ginger (Zingiber officinale) does not reproduce true-to-type from seed in commercial practice, and it is not propagated by stem cuttings or budding either, because the useful part of the plant is the underground stem, not the above-ground shoot.

3. 3.

   Subsistence agriculture is characterized by

   1. A
      Cultivation on a small scale mainly to feed the farmer's family, using simple tools and family labour
      Correct
   2. B
      Large-scale cultivation of crops purely for export to earn foreign exchange
   3. C
      Heavy use of machinery and hired labour to maximize output for sale
   4. D
      Specialization in a single cash crop grown solely for the market
   Show answerHide answer

   Answer: A

   Subsistence agriculture is farming carried out mainly to feed the farmer and his family, not to sell for profit. It is practised on a small piece of land, using simple, crude tools such as the hoe and cutlass, and depends on family labour rather than hired workers or machines. Output is usually just enough for the household, with little or no surplus for the market.

4. 4.

   Fertile soil is one which

   1. A
      has been ploughed and left fallow for a full planting season before use
   2. B
      is completely free of soil organisms such as earthworms and bacteria
   3. C
      contains a high proportion of clay to hold moisture close to plant roots
   4. D
      contains all the essential plant nutrients in the right quantities and proportions for optimum crop growth
      Correct
   Show answerHide answer

   Answer: D

   Fertile soil is defined by its ability to supply crops with all the essential plant nutrients (nitrogen, phosphorus, potassium, and the other macro- and micro-nutrients) in adequate quantities and in the correct balance for healthy, optimum plant growth. This is the option that states the soil contains all the essential plant nutrients in the right quantities and proportions for optimum crop growth.

5. 5.

   The practice of bee farming is called

   1. A
      Pisciculture
   2. B
      Apiculture
      Correct
   3. C
      Apiary
   4. D
      Sericulture
   Show answerHide answer

   Answer: B

   Apiculture is the correct term for the practice of bee farming (rearing bees mainly for honey, beeswax and pollination services).

   Sericulture is a tempting mix-up because it also ends in "-culture", but it actually refers to silk farming, the rearing of silkworms for silk production, not bees.

   Pisciculture is fish farming, a completely different branch of animal agriculture.

6. 6.

   Root-knot disease of tomato is caused by

   1. A
      bacteria
   2. B
      nematodes
      Correct
   3. C
      fungi
   4. D
      viruses
   Show answerHide answer

   Answer: B

   Root-knot disease of tomato is caused by nematodes — specifically root-knot nematodes of the genus Meloidogyne. These are microscopic roundworms that invade the roots of tomato and many other crops, causing the roots to develop characteristic swellings or "knots" (galls). These galls disrupt the plant's uptake of water and nutrients, leading to stunted growth, wilting, and yellowing of leaves.

7. 7.

   The main aim of mechanized agriculture is

   1. A
      To reduce the area of land under cultivation
   2. B
      To increase efficiency and reduce drudgery in farm operations
      Correct
   3. C
      To increase the cost of farm production
   4. D
      To increase the number of farm labourers needed
   Show answerHide answer

   Answer: B

   Mechanized agriculture means using machines (tractors, ploughs, harvesters, planters) to carry out farm operations instead of relying only on manual labour or simple tools like the hoe and cutlass.

8. 8.

   Which of the following agricultural extensions aims at reaching a large number of farmers at the same time?

   1. A
      Mass media method
      Correct
   2. B
      Result demonstration method
   3. C
      Farm and home visit
   4. D
      Method demonstration
   Show answerHide answer

   Answer: A

   Agricultural extension methods are grouped into individual, group, and mass contact methods, based on how many farmers each one reaches at once.

9. 9.

   Rain water is made available to crops through

   1. A
      Surface run-off
   2. B
      Leaching of the soil
   3. C
      Infiltration into the soil
      Correct
   4. D
      Transpiration by the plant
   Show answerHide answer

   Answer: C

   Infiltration into the soil is correct. When rain falls, it soaks (infiltrates) into the soil profile and settles around the root zone as soil moisture, which the crop's roots then absorb. This is the direct process by which rainwater becomes available for crop use.

10. 10.

    Which of the following is not a problem of forest management?

    1. A
       Overgrazing by livestock in forest reserves
    2. B
       Indiscriminate/illegal felling of trees
    3. C
       Bush burning and fire outbreaks
    4. D
       Afforestation
       Correct
    Show answerHide answer

    Answer: D

    Forest management deals with protecting and sustaining forest resources, and it faces several real problems in Nigeria.

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

Spotted a wrong answer? Tell us from the app or on the contact page and we check it.

Practise all 75 questions we hold from the 2021 paper, on a timed CBT screen

Every question has the answer and an explanation, in the Skolra app.

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