Describe how the use of pesticides and fertilisers helps to increase crop yields to feed the growing human population, and suggest one disadvantage of using each of these methods.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Farmers around the world use a range of chemicals to maximise the amount of food they can produce from their land. Demand for food continues to rise as the global human population increases.
Model answer (4 marks)
Pesticides kill pests and other organisms that damage or eat crops, so more of the crop survives to harvest, increasing yield.
Disadvantage of pesticides: they can harm non‑target organisms, reducing biodiversity and polluting waterways.
Fertilisers supply essential nutrients such as nitrates and minerals to the soil, promoting faster and greater plant growth, which increases crop yield.
Disadvantage of fertilisers: excess fertiliser can leach into waterways, causing eutrophication and algal blooms that kill aquatic organisms.
Disadvantage of pesticides: they can harm non‑target organisms, reducing biodiversity and polluting waterways.
Fertilisers supply essential nutrients such as nitrates and minerals to the soil, promoting faster and greater plant growth, which increases crop yield.
Disadvantage of fertilisers: excess fertiliser can leach into waterways, causing eutrophication and algal blooms that kill aquatic organisms.
Examiner tips
- Use the exact wording from the mark scheme (e.g. ‘kill pests’ and ‘provide essential nutrients’).
- Show the cause–effect chain: pest control → more crop survives, nutrients → faster growth → higher yield.
- Give one specific disadvantage for each method, as the scheme expects.
- Keep the answer concise – 4 points, no extra explanation.
Mark scheme (4 marks)
- Pesticides kill pests / organisms that damage or eat crops, so more of the crop survives to harvest (increasing yield).
- One disadvantage of pesticides: e.g. they can harm non-target organisms / reduce biodiversity / accumulate in food chains / pollute waterways.
- Fertilisers provide essential nutrients (e.g. nitrates/minerals) to the soil, promoting faster / greater plant growth and increasing crop yield.
- One disadvantage of fertilisers: e.g. excess fertiliser can leach into waterways causing eutrophication / algal bloom, leading to death of aquatic organisms.
Key terms in this question
pesticides · fertiliser · crop yield
Related
- Revision notes: Feeding the human race →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
More Feeding the human race questions
- Explain how the use of biological pest control and fertilisers together can redu…
- Biological control is one method used to help feed the growing human population.…
- Explain how the use of fertilisers and genetic engineering together can help far…
- Explain how genetic engineering can be used to improve crop plants to help feed …