• Nitrogen (N)
  • Phosphorus (P)
  • Potassium (K)

Nitrogen (N)
Nitrogen (chemical symbol N) is an element essential for plant growth.
Nitrogen makes up about 78 percent of the air we breath.  In this form, though, it is inert and insoluble, meaning plants can't use it.  Fertilizer makers take nitrogen out of the air and combine it with hydrogen from natural gas to make ammonia.

Ammonia is used in two ways:  it is applied directly to crops as a nitrogen fertilizer, or it is used as a building block to make other nitrogen fertilizer products, including urea, ammonium nitrate, ammonium sulfate or water-based, liquid fertilizers.  All of these different nitrogen products have different properties and levels of nitrogen that can be used in the various climates and cropping patterns found around the world.

Common Nitrogen Products:
Ammonia (82-0-0) -- Used as an applied fertilizer or as a building block for other fertilizer products.  Stored as a liquid under pressure or refrigerated, it becomes a gas when exposed to air and is injected into the soil as a gas.

Urea (46-0-0) -- A solid nitrogen product typically applied in granular form.  Can also be combined with ammonium nitrate and dissolved in water to make liquid nitrogen fertilizer.

Ammonium nitrate (34-0-0) -- Another solid nitrogen product typically applied in granular form.

Ammonium sulfate (21-0-0) -- A solid product that is largely a byproduct of coke ovens, where sulfuric acid is used to remove ammonia evolved from the coal.

Nitrogen solutions -- Typically a combination of urea and ammonium nitrate dissolved in water to form a highly soluble liquid fertilizer, typically containing 32 parts nitrogen. 
Phosphorus (P)
Phosphorus (chemical symbol P) is present in all living cells and is essential to all forms of life.  It is present all around us, in the soil, rocks, plants and animals.  Found throughout the human body, it is concentrated in our teeth and bones.

The source of phosphorus in fertilizer is phosphate rock, which is mined from the earth's crust.  The largest deposits occur in the United States, North Africa and China.  Typically, phosphate rock is mined and then reacted with different kinds of acids to produce different phosphate products.

Common Phosphate Products:
Triple Superphosphate (0-46-0) A highly concentrated form of phosphate produced in both granular and non-granular forms.

Monoammonium phosphate (MAP, 12-52-0) and diammonium phosphate (DAP, 18-46-0) -- These two products are called ammoniated phosphates, because phosphoric acid is treated with ammonia to form these basic phosphate products that also contain nitrogen.  They are widely produced in the granular form for blending with other types of fertilizers, and are also produced in nongranular forms for use in liquid fertilizers. 

Potassium (K)
Potassium (chemical symbol K) is also found throughout nature, and is found in the human body in muscles, skin and the digestive tract.  It essential to plant, animal and human life.

Good health requires sufficient intake of potassium, and plants we eat get it from potash fertilizers.  Plants grown for food require large amounts of potassium.  It is one of the three nutrients, along with nitrogen and phosphorus, needed in large amounts by plants.  Plants use potassium in such functions as photosynthesis, protein formation and water use.

Potassium, or potash, is mined from naturally occurring ore bodies that were forms as sea water evaporated.  The deposits are a mixture of crystals of potassium chloride (KCl) and sodium chloride (NaCl), also known as table salt.  After it is mined, the potassium chloride is separated from the mixture and results in a granular fertilizer. Most of the world's potash deposits are found in Canada, Russia, Belarus, Germany and the United States.