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Plant nutrients

Plants use minerals from the soil to build the complex molecules they need to survive and grow. Poor plant growth may be due to a deficiency in one or more minerals.

Mineral requirements

Fertilisers contain minerals such as:

  • nitrates
  • phosphates
  • potassium compounds

These minerals are needed for healthy plant growth. The table summarises why.

MineralElement suppliedWhy needed
NitratesNitrogen, NNitrogen is needed to make amino acids for proteins, which are needed for cell growth
PhosphatesPhosphorus, PPhosphorus is needed to make DNA and cell membranes
Potassium compoundsPotassium, KPotassium is needed in enzymes involved in respiration and photosynthesis
MineralNitrates
Element suppliedNitrogen, N
Why neededNitrogen is needed to make amino acids for proteins, which are needed for cell growth
MineralPhosphates
Element suppliedPhosphorus, P
Why neededPhosphorus is needed to make DNA and cell membranes
MineralPotassium compounds
Element suppliedPotassium, K
Why neededPotassium is needed in enzymes involved in respiration and photosynthesis

show the relative proportions of nitrates, phosphates and potassium in a fertiliser. They help farmers decide which fertiliser is best for the soil conditions in their fields.

A bag of NPK fertiliser. The relative proportions of nitrates, phosphates and potassium is 20:10:10.