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Fertilisers

Exam code: 5070
Written by: Ashika|Reviewed by: Caroline Carroll|Updated 2 July 2026

Fertilisers

Fertilisers

N, P, K Fertilisers

  • Fertilisers contain nitrogen, phosphorus and potassium

    • Nitrogen makes chlorophyll and protein and promotes healthy leaves 

    • Phosphorus promotes healthy roots

    • Potassium promotes growth and healthy fruit and flowers

  • Fertiliser compounds contain the following water-soluble ions:

    • Ammonium ions, NH4+ and nitrate ions, NO3-, are sources of soluble nitrogen

    • Phosphate ions, PO43- are a source of soluble phosphorus

    • Most common potassium compounds dissolve in water to produce potassium ions, K+

  • Common fertiliser compounds include:

    • Ammonium nitrate, NH4NO3

    • Ammonium phosphate, (NH4)3PO4

    • Potassium sulfate, K2SO4

  • Ammonium salts and nitrates are commonly used as fertilisers

  • Different fertilisers contain different amounts of fertiliser compounds so each contains different proportions of nitrogen, phosphorus and potassium