Controlling Soil Pollution
18 Grade 7 Agriculture questions on Controlling Soil Pollution, with worked marking schemes. 18 questions are available on this topic in full.
Question 1
1 markWhich of the following is an effect of soil pollution on crop production?
A. Increased soil fertility over time
B. Reduced crop yields due to poisoning of soil organisms
C. Improved water-holding capacity
D. Faster germination of seeds
(1 mark)
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1 markA learner wants to reduce soil pollution caused by non-biodegradable materials. Which practice should the learner adopt?
A. Recycling plastic containers instead of burying them
B. Mixing plastics into the compost heap
C. Throwing plastics into the river
D. Burning all plastics in an open pit
(1 mark)
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1 markA farmer in Machakos notices that crops near where he dumps used engine oil are turning yellow and dying. As a Grade 7 learner advising him, which practice would BEST help control this soil pollution?
A. Pouring more water on the affected soil daily
B. Collecting used oil in containers for proper disposal or recycling
C. Planting more crops in the same polluted spot
D. Adding extra inorganic fertiliser to the area
(1 mark)
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1 markDuring an agriculture lesson, learners observe that a nearby stream carries soapy water and oils from a garage into the school garden soil. Which practice would BEST reduce this chemical soil pollution?
A. Directing the dirty water into a treatment or settling pit before it reaches the soil
B. Adding lime to the garden every morning
C. Planting more maize along the stream
D. Watering the garden with the soapy water
(1 mark)
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1 markDuring a clean-up activity, Grade 7 learners separate farm waste into different heaps. They place banana peels, vegetable trimmings and grass clippings together. What is the MAIN advantage of separating these from plastics and metals?
A. They can be composted to make organic manure
B. They burn faster than plastics
C. They are heavier than plastics
D. They cost more money than metals
(1 mark)
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1 markProper disposal of used pesticide containers helps to control soil pollution because it prevents:
A. Earthworms from multiplying
B. Rainwater from reaching the crop roots
C. Toxic chemical residues from leaching into the soil
D. The soil from becoming too fertile
(1 mark)
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1 markWhich of the following materials found on a farm is biodegradable and therefore less likely to pollute the soil?
A. Broken glass bottles
B. Maize husks
C. Polythene sheets
D. Metal scraps
(1 mark)
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1 markA Grade 7 class is advised to control soil pollution from farm chemicals. The BEST method is to:
A. Apply double the recommended amount for faster results
B. Store chemicals in open bare soil
C. Spray chemicals during heavy rain
D. Use pesticides and fertilisers strictly according to recommended rates
(1 mark)
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4 marksDistinguish between biodegradable and non-biodegradable waste, giving one example of each found on a farm.
(4 marks)
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1 markA farmer in Machakos notices that crops growing near a path where plastic wrappers and old polythene bags have collected are stunted and yellowing. Which is the MOST appropriate way for the farmer to control this kind of soil pollution?
A. Burning all the plastics in the field
B. Collecting and recycling the plastic materials
C. Ploughing the plastics deeper into the soil
D. Spraying the area with more fertiliser
(1 mark)
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1 markWhich one of the following is a common source of soil pollution on a Kenyan farm?
A. Ploughing along the contour
B. Improper disposal of plastic bags and containers
C. Mulching with dry grass
D. Rotating legumes with cereals
(1 mark)
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6 marksExplain three effects of soil pollution on the farm and the environment.
(6 marks)
Marking scheme
3 x 2 marks: reduced crop yields due to poisoning of soil/soil organisms; death of beneficial soil organisms e.g. earthworms; contamination of underground/surface water; loss of soil fertility; harm to human/animal health through the food chain. Any 3 well explained = 6.
Question 13
3 marksState three ways in which a farmer can control soil pollution caused by non-biodegradable waste on the farm.
(3 marks)
Marking scheme
Award 1 mark each (max 3): recycling/reusing plastic and metal containers; proper disposal in designated pits/collection points; avoiding littering plastics on the land; separating biodegradable from non-biodegradable waste. Any 3 correct = 3 marks.
Question 14
1 markA farmer in Kiambu notices that vegetables planted near a factory drainage channel are wilting and the soil has turned bluish. Which of the following is the MOST likely cause of this soil pollution?
A. Excessive rainfall on the farm
B. Planting the same crop repeatedly
C. Discharge of industrial chemical waste into the soil
D. Overgrazing by dairy cattle
(1 mark)
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5 marksA farmer in Kiambu has been disposing of used plastic containers, polythene bags and chemical wastes in his vegetable garden, and the crops are now growing poorly.
(a) Identify TWO sources of soil pollution shown in the farmer's practice. (2 marks)
(b) Suggest THREE measures the farmer can take to control soil pollution on his farm. (3 marks)
(5 marks)
Marking scheme
(a) (any TWO, 1 mark each): - Plastic containers / polythene bags (non-biodegradable waste). - Chemical wastes (agro-chemicals/pesticide residues). (b) (any THREE, 1 mark each): - Proper disposal of plastics and polythene by collecting and recycling them instead of dumping in the garden. - Avoiding overuse of farm chemicals / using recommended rates of fertilisers and pesticides. - Using organic manure/compost in place of excess inorganic chemicals. - Separating and safely disposing of non-biodegradable waste away from the soil. - Practising proper waste management such as composting biodegradable waste.
Question 16
1 markOveruse of inorganic fertilisers on a maize farm can lead to soil pollution mainly because it:
A. Adds too much organic matter to the soil
B. Increases the number of earthworms
C. Increases the concentration of harmful salts in the soil
D. Improves the soil structure permanently
(1 mark)
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5 marksA farmer applies excess inorganic fertiliser and pesticides every season.
(a) Explain two ways this practice pollutes the soil.
(b) Suggest one measure the farmer should take to reduce the pollution.
(5 marks)
Marking scheme
(a) 2 x 2 marks: build-up of toxic salts/chemical residues that poison soil organisms; contamination of soil and leaching into ground/water lowering soil life and fertility. (b) 1 mark: apply chemicals at recommended rates/use organic manure/soil testing before application. Total 5.
Question 18
4 marksAs a Grade 7 learner, describe two activities you can carry out at school to create awareness about controlling soil pollution in your community.
(4 marks)
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