WAEC Agricultural Science 2019 past questions

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

Ten questions from the 2019 WAEC Agricultural Science paper, with answers and explanations. We hold 42 questions from this paper, and the Skolra app has all of them.

WAEC Agricultural Science 2019 questions and answers

1.In a crop rotation system, it is usually preferred that cassava comes last in the rotation becauseit?
1. A
  It requires the highest level of soil fertility to produce a good yield
2. B
  It can tolerate a relatively low level of soil fertility
  Correct
3. C
  It matures and is ready for harvest within three months of planting
4. D
  It is highly susceptible to pest and disease attack
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Answer: B
Why cassava is placed last: In a crop rotation plan, crops are usually arranged in order of their soil fertility demand, from the most "nutrient-hungry" crop first down to the crop that can still give a reasonable yield even when the soil has become depleted. Cassava is well known for doing well on poor, low-fertility soils where many other crops (like maize or vegetables) would fail. Because of this, farmers deliberately place cassava at the end of the rotation, after the soil nutrients have already been used up by the earlier, more demanding crops.
2.Which of the following implements is used for primary tillage?
1. A
  Plough
  Correct
2. B
  Disc harrow
3. C
  Cultivator
4. D
  Ridger
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Answer: A
Primary tillage is the first and deepest operation carried out on virgin or fallow land. It breaks and loosens the compact soil, uproots weeds and crop stubble, and turns the soil over to bury plant residue so it can decompose. This heavy, deep work is done with the plough (mouldboard plough or disc plough).
3.The least important factor for successful incubation of eggs is?
1. A
  Humidity in the incubator
2. B
  Colour of the egg shell
  Correct
3. C
  Turning of the eggs
4. D
  Temperature of the incubator
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Answer: B
For eggs to hatch successfully in an incubator (or under a broody hen), certain conditions must be controlled: temperature (about 37.5°C for chicken eggs), humidity (to prevent the egg losing too much or too little moisture), and regular turning of the eggs (to stop the embryo sticking to the shell membrane and to ensure even heating). These three are essential — if any one of them is wrong, the eggs will fail to hatch or will hatch poorly.
4.During the production of palm oil, the oil palm fruits are boiled in order to?
1. A
  increase the oil content in the mesocarp
2. B
  destroy the nut shell for easy kernel removal
3. C
  loosen the fruits from the bunch
4. D
  soften the fruits for easy pounding and extraction of the oil
  Correct
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Answer: D
In the traditional (and industrial) extraction of palm oil, the harvested oil palm fruits are first boiled before any pounding or pressing is done. Boiling softens the hard, fibrous mesocarp (pulp) of the fruit and breaks down the oil-bearing cells inside it. Once the fruits are softened this way, they can easily be pounded or pressed in a mortar, trough or mill to squeeze out the palm oil. If the fruits were pounded raw, the pulp would be too tough and the oil yield would be very poor.
5.A fresh garden soil sample weighed 25kg. When oven-dried, its weight reduced to 20kg. Calculate the percentage moisture content of the soil sample.
1. A
  20%
  Correct
2. B
  80%
3. C
  5%
4. D
  25%
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Answer: A
Given: Fresh (undried) soil weight = 25 kg; oven-dried weight = 20 kg.
The weight of moisture (water) lost on drying = 25 kg − 20 kg = 5 kg.
Percentage moisture content is found by comparing the water lost to the original fresh weight of the soil, then multiplying by 100:
% Moisture content = (5 ÷ 25) × 100 = 20%
So 20% is correct.
Where the other figures come from:
25% is obtained if a student wrongly divides the water lost by the dry weight (5 ÷ 20 × 100) instead of the fresh weight — the wrong base figure.
6.A disadvantage of farm mechanization?
1. A
  It increases the hectares of land a farmer can cultivate within a short time
2. B
  It causes unemployment among farm labourers
  Correct
3. C
  It ensures timeliness in carrying out farm operations
4. D
  It reduces the drudgery involved in farm operations
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Answer: B
Farm mechanization is the use of machines (tractors, ploughs, harvesters, planters, etc.) to perform farm operations in place of hand tools or manual labour.
7.The growing of only one crop on a piece of land from year to year is known as?
1. A
  Mixed cropping
2. B
  Crop rotation
3. C
  Shifting cultivation
4. D
  Monoculture
  Correct
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Answer: D
Monoculture is the correct answer. It is defined as the continuous cultivation of a single crop species on the same piece of land, year after year, without changing or rotating it.
The tempting wrong answers describe related but different farming systems:
Mixed cropping involves growing two or more different crops together on the same piece of land at the same time (e.g. maize and cassava interplanted) — this is about growing many crops together, not one crop repeatedly.
8.Which of the following groups of organisms are parasites plants?
1. A
  Grasshopper, aphid and weevil
2. B
  Maize, cassava and yam
3. C
  Striga, dodder and mistletoe
  Correct
4. D
  Rat, grasscutter and squirrel
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Answer: C
Striga, dodder and mistletoe are the group of parasitic plants. A parasitic plant is one that attaches itself to a host plant and draws water and nutrients from it instead of making all its own food.
So only the group containing Striga, dodder and mistletoe fits the description of "organisms that are parasitic plants".
9.An advantage of communal land tenure system is that it?
1. A
  It leads to fragmentation of farmland into small, uneconomic plots
2. B
  It gives every member of the community free access to land for farming
  Correct
3. C
  It makes the use of large farm machinery easier
4. D
  It discourages farmers from making permanent improvements on the land
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Answer: B
Communal land tenure is the system in which land belongs collectively to a village, clan or family rather than to one individual. Because ownership is shared, any recognised member of that community can ask for and use a piece of the land to farm without having to buy it.
That free, cost-free access to land for every member is the real advantage of the system, and it is the correct answer.
10.The growth of both trees and arable crops on the same piece of land is?
1. A
  Mixed farming
2. B
  Mixed cropping
3. C
  Agroforestry
  Correct
4. D
  Alley cropping
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Answer: C
Agroforestry is the correct term. It is the land-use practice in which trees (or shrubs) are deliberately grown together with arable crops on the same piece of land, so that the trees and the crops benefit from each other, for example the trees provide shade, reduce erosion and add leaf litter to the soil while the arable crop occupies the space between them.

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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WAEC Agricultural Science 2019 past questions

WAEC Agricultural Science 2019 questions and answers

Practise all 42 questions we hold from the 2019 paper, on a timed CBT screen

More Agricultural Science past questions

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