Unit 3: Agriculture and the Environment TQ:

2-Mark Question

1. Define subsistence farming.

Model Answer:

Subsistence farming is farming where crops and/or livestock are mainly produced to provide food for the farmer and their family, rather than for sale.

Why this works:

• Identifies production mainly for the farmer/family (1 mark)

• Contrasts it with production for sale/profit (2nd mark)

4-Mark Question

2. Explain two environmental impacts of intensive agriculture.

Model Answer:

Water pollution: Fertilizers and pesticides can be washed from fields into rivers and lakes by surface runoff, causing eutrophication or harming aquatic organisms.

Soil degradation: Intensive cultivation can remove nutrients from the soil and leave it exposed to erosion, reducing soil fertility and agricultural productivity.

Why this works:

• Two distinct environmental impacts → 2 marks

• Each impact is explained using cause and effect → 2 more marks

• Uses appropriate Unit 3 terminology such as runoff, fertilizers, eutrophication, soil erosion and fertility.

6-Mark Question

3. Discuss the advantages and disadvantages of using irrigation in agriculture.

Model Answer:

Irrigation provides crops with water when rainfall is insufficient or unreliable. This allows farmers to grow crops in dry areas and can increase crop yields because plants receive enough water for photosynthesis and growth. Irrigation can also allow farmers to grow crops throughout the year, increasing food production and income.

However, excessive irrigation can cause waterlogging, which fills soil spaces with water and reduces the oxygen available to plant roots. It can also cause salinisation because water evaporates and leaves dissolved salts behind in the soil, reducing soil fertility. Irrigation systems may also place pressure on rivers and groundwater if too much water is extracted.

Overall, irrigation can significantly increase food production, particularly in areas with unreliable rainfall, but it must be carefully managed to prevent soil degradation and depletion of water resources.

Why This Works:

• Advantages + disadvantages balanced

• Each point explains HOW or WHY

• Uses specific processes: waterlogging, salinization and water extraction

• Conclusion evaluates when irrigation is beneficial rather than simply saying it is good or bad.

8-Mark Question

4. Describe how soil can be conserved and evaluate the importance of sustainable soil management.

Model Answer:

Soil can be conserved using several techniques. Contour ploughing involves ploughing across the slope rather than up and down it, reducing the speed of surface runoff and therefore reducing soil erosion. Terracing creates a series of level steps on steep slopes, which slows runoff and allows more water to infiltrate the soil. Farmers can also plant cover crops or leave crop residues on the surface, protecting the soil from rainfall and wind erosion. Crop rotation can maintain soil fertility because different crops have different nutrient requirements, while legumes can add nitrogen to the soil.

Sustainable soil management is important because fertile soil is essential for producing food and maintaining agricultural productivity. Preventing erosion also reduces the loss of valuable topsoil and decreases sediment entering rivers. However, some conservation methods require additional labour, machinery or investment, meaning poorer farmers may find them difficult to implement.

Overall, sustainable soil management is essential for long-term food production because soil forms very slowly and can take many years to recover once degraded. However, conservation methods need to be affordable and suitable for local farming conditions if they are to be effective.

Why This Works:

• Gives several specific conservation methods

• Explains how each method works

• Links soil conservation to food production and sustainability

• Includes a realistic limitation: cost/labor

• Ends with an evaluative judgement

10-Mark Question

5. Assess the effectiveness of different methods of increasing agricultural productivity while reducing environmental damage.

Model Answer:

Agricultural productivity can be increased through the use of improved seeds, fertilisers, irrigation, pesticides, mechanization and improved livestock breeds. High-yielding varieties can produce more food from the same area of land, while fertilisers replace nutrients such as nitrogen, phosphorus and potassium that have been removed by crops. Irrigation can provide reliable water supplies, allowing crops to grow where rainfall is insufficient.

However, these methods can create environmental problems. Excessive fertilizer use can cause nutrient runoff and eutrophication in water bodies, while pesticides can kill non-target organisms and contaminate soil and water. Over-irrigation can cause waterlogging and salinization. Mechanization can increase soil compaction and requires fuel, contributing to greenhouse gas emissions.

More sustainable approaches can reduce these impacts. Integrated pest management uses biological controls and only uses chemical pesticides when necessary. Crop rotation can maintain soil fertility and reduce pest and disease build-up, while conservation techniques such as contour ploughing and terracing reduce soil erosion. Drip irrigation can deliver water directly to crop roots, reducing water wastage.

The effectiveness of each method depends on local conditions. For example, drip irrigation may be highly effective in a water-scarce region, while crop rotation may be more suitable for farmers who cannot afford expensive irrigation systems.

Overall, the most effective approach is not simply to maximize agricultural production, but to increase productivity while protecting soil, water and biodiversity. Combining appropriate modern technology with sustainable farming methods is likely to provide the best long-term balance between food production and environmental protection.

Why This Works:

• Covers multiple methods of increasing productivity

• Explains the environmental consequences

• Gives sustainable alternatives

• Considers different economic and physical conditions

• Makes a clear final judgement

• Shows the progression: method → benefit → environmental problem → solution → evaluation

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