342.T1

Model Agricultural Core Curriculum: SupplementUniversity of California, Davis

Sources of Primary Plant Nutrients

Types of Nitrogen Fertilizers

• There are two main classifications of nitrogen fertilizers.

– Quickly available inorganic salts such as ammonium sulfate (NH4SO2) urea.

– Slowly available complex molecules such as sulfur-coated urea, manure, sewer sludge.

342.T2

Model Agricultural Core Curriculum: SupplementUniversity of California, Davis

Sources of Primary Plant Nutrients

Nitrogen Salts

• Inorganic salts which dissolve easily in water.• They are produced industrially using natural gas,

atmospheric nitrogen, and minerals.

Examples: Ammonium sulfate NH4SO2 Ammonium nitrate (NH4NO3) Potassium nitrate(KNO3)

342.T3

Model Agricultural Core Curriculum: SupplementUniversity of California, Davis

Sources of Primary Plant Nutrients

Complex Nitrogen Containing Compounds

• These fertilizers do not dissolve easily in water.• Their nutrients are released slowly. This provides

a more even supply of nutrients to plants.

Examples: Urea, leguminous cover crops, and manures.

342.T4

Model Agricultural Core Curriculum: SupplementUniversity of California, Davis

Sources of Primary Plant Nutrients

Phosphorus Sources

• Rock phosphate: a mined rock which is treated with acids to form chemical fertilizers.

• Slag: by-product of steel production.

• Ammonium phosphate (NH4PO3): an inorganic salt made using rock phosphate.

342.T5

Model Agricultural Core Curriculum: SupplementUniversity of California, Davis

Sources of Primary Plant Nutrients

Potassium Sources

• Potassium chloride or muriate of potash: these are produced from processed potassium salts.

• Sulfate of potash: potassium chloride combined with sulfuric acid.

• Potassium nitrate: potassium chloride treated with nitric acid.