Fertilisers (Cambridge (CIE) IGCSE Chemistry)

Fertilisers

NPK fertilisers

• NKP fertilisers contain nitrogen, potassium and phosphorus for improved plant growth

  • Nitrogen makes chlorophyll and protein and promotes healthy leaves 

  • Potassium promotes growth and healthy fruit and flowers

  • Phosphorus promotes healthy roots

• Fertiliser compounds contain the following water-soluble ions:

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

  • Phosphate ions, PO₄^3- are a source of soluble phosphorus

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

• Ammonium salts and nitrate salts are commonly used as fertilisers, including:

  • Ammonium nitrate, NH₄NO₃

  • Ammonium phosphate, (NH₄)₃PO₄

  • Potassium nitrate, KNO₃ 

• Different fertilisers contain different amounts of fertiliser compounds

  • So, each fertiliser contains different proportions of nitrogen, potassium and phosphorous