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, PO43- 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
Exam Tip
You may be asked to select a compound or combination of compounds from a list which would be the most effective as a fertiliser.
Look for the compound or combination of compounds that contain the most elements from nitrogen, phosphorous and potassium.
