ARCHIVE: Fertiliser Manual (RB209)

Analysis of some fertiliser and liming materials

The materials listed below are used individually and some are used as components of compound or multi-nutrient, fertilisers.

Typical percentage nutrient content (can vary slightly in some materials)

Nitrogen fertilisers

Ammonium nitrate 33.5-34.5% N
Liquid nitrogen solutions 18-30% N (w/w)
Calcium ammonium nitrate (CAN) 26-28% N
Ammonium sulphate 21% N, 60% SO3
Urea 46% N

Calcium nitrate

15.5% N, 19% CaO

Phosphate fertilisers  
Triple superphosphate (TSP) 45-46% P2O5
Di-ammonium phosphate (DAP) 18% N, 46% P2O5
Mono-ammonium phosphate (MAP) 12% N, 52% P2O5
Rock phosphate (eg. Gafsa) 27-33% P2O5
Potash, magnesium and sodium fertilisers  
Muriate of potash (MOP) 60% K2O
Sulphate of potash (SOP) 50% K2O, 45% SO3
Potassium nitrate 13% N, 45% K2O
Kainit 11% K2O, 5% MgO, 26% Na2O, 10% SO3
Sylvinite minimum 16% K2O, typically 29% Na2O
Kieserite (magnesium sulphate) 25% MgO, 50% SO3
Calcined magnesite typically 80% MgO
Epsom salts (magnesium sulphate) 16% MgO, 33% SO3
Agricultural salt 50% Na2O
Sulphur fertilisers  
Ammonium sulphate 21% N, 60% SO3
Epsom salts (magnesium sulphate) 16% MgO, 33% SO3
Elemental sulphur typically 200-225% SO3 (80 – 90% S)
Gypsum (calcium sulphate) 40% SO3
Ashed poultry manure typically 20% P2O5, 10% K2O
Steelmaking slag typically 1.7-2.5% P2O5 + NV 55-58
Liming materials Neutralising Value (NV)
Ground chalk or limestone 50-55
Magnesian limestone 50-55, over 15% MgO
Hydrated lime c.70
Burnt lime c.80
Sugar beet lime 22-32 + typically 7-10 kg P2O5, 5-7 kg MgO, 3-5 kg SO3/tonne

The chemical and physical forms of nutrient sources, as well as growing conditions, can influence the effectiveness of fertilisers. A FACTS Qualified Adviser can give advice on appropriate forms for different soil and crop conditions.

The reactivity, or fineness of grinding, of liming materials determines their speed of action. However, the amount of lime needed is determined mainly by its neutralising value.


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