Explain why farmers add fertilisers to soil and describe two nutrients commonly found in fertilisers.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Farmers add fertilisers to soil to replace essential nutrients that have been removed by crops, ensuring the soil still supplies the elements plants need for growth. This promotes healthy, faster plant development and can increase crop yield.
Two nutrients commonly found in fertilisers are:
1. Nitrogen (N) – required for leaf and shoot growth and protein synthesis.
2. Phosphorus (P) or potassium (K) – important for root development, energy transfer (P) or water regulation and fruit quality (K).
Two nutrients commonly found in fertilisers are:
1. Nitrogen (N) – required for leaf and shoot growth and protein synthesis.
2. Phosphorus (P) or potassium (K) – important for root development, energy transfer (P) or water regulation and fruit quality (K).
Examiner tips
- Use the word ‘replace’ or ‘supply’ to show why fertilisers are added. Mention that they promote growth or yield. Name nitrogen and a second element (phosphorus or potassium) and give a short function for each.
Common mistakes
- Writing ‘fertilisers are added for taste’ – irrelevant. Omitting the function of the second nutrient. Using the wrong element name (e.g. ‘sulphur’ instead of ‘phosphorus’ or ‘potassium’).
Mark scheme (4 marks)
- Fertilisers replace/supply essential elements (nutrients/minerals) that have been removed from the soil by crops
- Fertilisers are needed to promote healthy/faster plant growth (or increase crop yield)
- Nitrogen (N) is a nutrient found in fertilisers, needed for leaf/shoot growth or protein synthesis
- Phosphorus (P) or potassium (K) is a nutrient found in fertilisers, with a correct use stated
Key terms in this question
Related
- All Cambridge International IGCSE Chemistry (0620) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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