Irrigation — Class 8 CBSE Science MCQs with Solutions
Free Class 8 CBSE Science Irrigation MCQs with step-by-step solutions (12 questions). Part of Crop Production and Management. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Irrigation · easy · theory
What is irrigation?
A. The supply of water to crops at regular intervals ✓ Correct
B. The removal of weeds growing along with the crop
C. The loosening of soil before sowing seeds
D. The separation of grain seeds from the chaff
Solution: Irrigation is defined as the supply of water to crops at regular intervals; the other options describe weeding, tilling and threshing.
Q2 — Irrigation · easy · theory
Which of the following is a reason why crops must be supplied with water?
A. Seeds may fail to germinate if the soil is too dry ✓ Correct
B. Water is needed only on the day the crop is harvested
C. Crops grow best when the soil is kept completely dry
D. Water is supplied only to help weeds grow faster
Solution: Crops need water because seeds fail to germinate in dry conditions; water also dissolves and transports nutrients to all parts of the plant and protects the crop from frost and hot air currents.
Q3 — Irrigation · easy · theory
Plants are made up of nearly what percentage of water?
A. 90% ✓ Correct
B. 30%
C. 50%
D. 70%
Solution: Plants are nearly 90% water, which is why a regular supply of water through irrigation is essential.
Q4 — Irrigation · easy · theory
Which of the following is a source of water for irrigation?
A. Wells ✓ Correct
B. Weedicides
C. Silos
D. Ploughs
Solution: Wells, along with tubewells, ponds, lakes, rivers, dams and canals, are sources of irrigation water; weedicides kill weeds, silos store grain and ploughs till soil.
Q5 — Irrigation · medium · theory
Which of the following is a traditional method of irrigation?
A. Dhekli ✓ Correct
B. Sprinkler system
C. Drip system
D. Seed drill
Solution: Dhekli is a traditional lever-based method, while the sprinkler and drip systems are modern methods and the seed drill is a sowing tool.
Q6 — Irrigation · medium · theory
Why do crops usually need to be watered more frequently during summer?
A. Because the rate of evaporation of water is higher ✓ Correct
B. Because plants stop growing in the heat
C. Because the soil loses its nutrients faster
D. Because weeds absorb most of the water
Solution: In summer the higher rate of evaporation makes water disappear faster, so crops must be irrigated more often.
Q7 — Irrigation · medium · theory
The sprinkler system of irrigation is especially useful for
A. uneven land where water is scarce ✓ Correct
B. flat fields that already have plenty of water
C. fruit plants where not a single drop should be wasted
D. drying fresh grains before they are stored
Solution: Sprinklers spray water like rain and are very useful on uneven land where water is scarce, whereas the no-wastage case for fruit plants describes the drip system.
Q8 — Irrigation · medium · theory
The pumps used to lift water for irrigation are commonly run on
A. diesel, biogas, electricity or solar energy ✓ Correct
B. only human and cattle power
C. only wind energy
D. only burning coal
Solution: Irrigation pumps are commonly operated using diesel, biogas, electricity or solar energy.
Q9 — Irrigation · medium · theory
Compared with modern methods, the traditional methods of irrigation are
A. cheaper but less efficient ✓ Correct
B. more expensive but more efficient
C. cheaper and also more water-saving
D. the only methods that can be used on lawns
Solution: Traditional methods rely on cattle or human labour and are cheaper but less efficient than modern water-economising methods.
Q10 — Irrigation · hard · theory
A farmer has a fruit orchard in an area where water is very scarce and wants to waste no water at all. Which irrigation method should he choose?
A. Drip system ✓ Correct
B. Sprinkler system
C. Moat (pulley system)
D. Chain pump
Solution: The drip system delivers water drop by drop directly to the roots with no wastage, making it a boon for fruit plants where water is scarce; the sprinkler, though modern, sprays water over the whole area and the moat and chain pump are less efficient traditional methods.
Q11 — Irrigation · hard · theory
Apart from keeping the plant alive, the water supplied by irrigation helps the crop mainly by
A. dissolving nutrients so they can be transported to all parts of the plant ✓ Correct
B. adding humus to the soil around the roots
C. fixing atmospheric nitrogen inside the root nodules
D. uprooting the weeds growing near the crop
Solution: Water dissolves nutrients and carries them to every part of the plant; humus comes from manure, nitrogen is fixed by Rhizobium bacteria and weeds are removed by weeding, not by irrigation.
Q12 — Irrigation · hard · theory
One farmer waters his field with a rahat (lever system) and another with a sprinkler. Which statement about them is correct?
A. The sprinkler uses water more economically than the rahat ✓ Correct
B. The rahat is a modern method that saves the most water
C. The sprinkler is a traditional method worked by bulls
D. Both methods waste exactly equal amounts of water
Solution: The rahat is a traditional, less efficient method, while the sprinkler is a modern method that uses water economically.