# A farmer uses an NPK fertiliser to increase crop yields. The NPK fertiliser contains ammonium nitrate, potassium chloride and ammonium phosphate. Explain how each of the three elements — nitrogen, phosphorus and potassium — improves the growth of crops.

> AQA GCSE Chemistry (8462) — 4.10.4 The Haber process and the use of NPK fertilisers (Chem only) · Explain · 4 marks

> NPK fertilisers contain compounds of nitrogen, phosphorus and potassium. These fertilisers improve agricultural productivity.

## Mark scheme (4 marks)

1. Nitrogen promotes/is needed for leaf/shoot growth OR nitrogen is needed to make proteins/chlorophyll in plants
2. Phosphorus promotes/is needed for root growth OR phosphorus is needed for respiration/photosynthesis (cell processes)
3. Potassium helps enzymes work / promotes flower and fruit growth / is needed for photosynthesis and respiration
4. Without sufficient NPK nutrients, plants show deficiency symptoms / reduced growth / lower crop yield

## Key terms

- [nitrogen](https://www.gradenine.co.uk/glossary/nitrogen)
- [phosphorus](https://www.gradenine.co.uk/glossary/phosphorus)
- [potassium](https://www.gradenine.co.uk/glossary/potassium)

## Related

- [Revision notes for AQA GCSE Chemistry (8462)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/a-farmer-uses-an-npk-fertiliser-fbef5d51) · Published by Druglandscape Ltd.