Unsustainable agriculture and its impacts
Trace how food-production pressures can harm people and ecosystems through water, soil, chemical use, habitat and yield pathways.
This original StudyForA sequence supports Cambridge IGCSE Environmental Management 0680 Topics 1–4 for exams in 2027, 2028 and 2029. Named local examples are chosen by the learner and centre; verify current conditions and local context with reliable sources. It is not a Cambridge paper, official grade or complete course.
Before you begin
- Use the 2027–2029 syllabus and check your exam year and centre's entry arrangements. Topics 1–4 are taught on this page; Topics 5–7 are still being built.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What can result from mismanaged irrigation?
What you will learn
- Trace how food-production pressures can harm people and ecosystems through water, soil, chemical use, habitat and yield pathways.
- Use evidence from an unfamiliar case to explain a cause-and-effect link and justify a suitable response.
Connect production pressure to environmental change
Overproduction can create food waste; food shortages may occur when cash crops (coffee, cotton, soya beans and palm oil) or biofuel crops replace food crops.
Mismanaged irrigation can cause soil erosion, salinisation or waterlogging. Overuse of pesticides can select for resistance, trigger pest resurgence and harm pollinators. Overuse of fertilisers can leach nutrients into water, enrich it and cause eutrophication.
Follow soil and biodiversity effects
Exhausting soil nutrients reduces organic content or inorganic ions. Removing natural vegetation through deforestation, overcultivation or overgrazing exposes land and reduces habitat.
Monoculture and intensification can increase soil and water pollution and reduce biodiversity. Soil erosion removes topsoil and nutrients. These changes can reduce future crop yield and affect people who depend on farming.
Explain a chain and use precise language
Build a chain from practice to process to outcome: for example, excess fertiliser can leach into a water body, increasing nutrients and causing eutrophication, which can harm aquatic life.
Avoid claiming that every use of a pesticide or fertiliser causes the same result. Explain how rate, timing, weather, soil and nearby ecosystems influence the effect.
Sources for this lesson
Pause and explain
How can monoculture reduce biodiversity?
Worked example
A field receives excess fertiliser before heavy rain. Explain a possible pathway from application to impact on a lake.
Show the worked solution
- Rain can move soluble nutrients from the field into nearby water.
- Extra nutrients enrich the lake and can stimulate excessive plant or algal growth.
- As that material decomposes, oxygen can fall, harming aquatic organisms; the precise effect depends on conditions.
Answer Excess fertiliser can leach or run off into a lake, causing nutrient enrichment and eutrophication. Decomposition can reduce dissolved oxygen and harm organisms.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A farm overuses pesticide and later finds both resistant pests and fewer pollinators. Explain how these observations can be related.
Give me a hint
Separate selection pressure on the pest from effects on non-target organisms.
Compare my reasoning
- Pesticide use can favour pests with resistance, allowing them to survive and reproduce.
- Pollinators may be harmed if they are exposed to chemicals intended for other organisms.
- Monitor pest response and non-target species, then review whether the type, timing and amount of control are appropriate.
Repeated pesticide use may select for resistant pests, while exposure can affect pollinators. The farm should monitor both target and non-target species and reassess its control methods.
Look for these in your work
- Resistance mechanism explained
- Non-target effect stated
- Monitoring linked to decisions
A region converts diverse vegetation to a single cash crop. Explain one possible food-supply effect and two environmental pathways.
Give me a hint
Distinguish local food availability from the crop's economic value.
Compare my reasoning
- Cash-crop production can reduce land available for food crops, contributing to local food shortages even when the crop earns income.
- Vegetation removal reduces habitat and can increase erosion; monoculture can also reduce biodiversity.
- Intensive inputs may add soil or water pollution, so examine land, water and input management.
A valuable cash crop can still replace food production and contribute to shortages. Clearing vegetation may remove habitat and expose soil, while monoculture and inputs can affect biodiversity and water quality. Outcomes depend on land allocation and management.
Look for these in your work
- Food-supply pathway explained
- Two environmental effects traced
- Economic value not treated as food availability
A farming cooperative reports rising crop yield but declining soil nutrients and polluted drainage water. Give a balanced assessment and two questions for a follow-up investigation.
Give me a hint
A short-term yield gain and long-term soil or water trend can coexist.
Compare my reasoning
- A rising yield is a present benefit, but declining nutrients may threaten future production.
- Polluted drainage may reflect fertiliser or pesticide movement; test the water and identify its source.
- Ask which inputs, timing and rates changed, and whether soil, yield and water trends differ across fields or seasons.
The increase in yield does not erase evidence of declining soil and water quality. Investigate nutrient balance, input use, drainage chemistry and change over time before deciding whether the system is sustainable.
Look for these in your work
- Present and future effects balanced
- Pollution pathway treated as a hypothesis
- Follow-up questions are testable
Common mistakes
- Saying all fertiliser use causes eutrophication
- Confusing salinisation with waterlogging
- Listing impacts without a causal chain
- Ignoring food shortages and waste
What can you explain now?
Which impact is linked to pesticide overuse in the syllabus?
Compare with the explanation
Pesticide resistance and effects on pollinators
The correct answer is “Pesticide resistance and effects on pollinators”. The alternatives “Improved soil drainage in every field” and “Removal of all pests with no ecological effect” do not match the syllabus concept. Trace how food-production pressures can harm people and ecosystems through water, soil, chemical use, habitat and yield pathways.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Trace three unsustainable farming practices to impacts on food, soil, water, people or biodiversity.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.