1. FERTILIZERS

2. Fertilizer Defined Fertilizer – material applied to soil or plants to supply essential elements Four categories: MineralInorganic Organic Synthetic Organic

3. Fertilizer Forms Four main groups: 1) Pressurized liquids 2) Fluids 3) Dry fertilizers 4) Slow-release fertilizers

4. Pressurized Liquids Anhydrous Ammonia Ammonia is gas at normal temperature and pressure, but... - changes to liquid when cooled to -28ºF - stored in high-pressure or refrigerated tanks - transferred to smaller tanks for field apply - liquid is injected into soil

5. Fluid Fertilizers - Nonpressure solutions - Suspensions Popular due to flexible application: - sprayed - injected - mixed in irrigation water

6. Dry Fertilizers Dissolve in soil water to release nutrients Three types: 1) Pulverized fertilizers 2) Granules 3) Prills

7. Slow-Release Fertilizers Dry form; dissolve slowly over weeks/months - Widely used in horticulture - Release nutrients as crops use them - Little loss to leaching - Environmentally friendly

8. Fertilizer Materials Compounds called Nutrient Carriers Primary Macros: - Nitrogen Carriers - Phosphorus Carriers - Potassium Carriers

9. Nitrogen Carriers Haber Process - Uses nitrogen (N 2 ) from air - Natural gas (H 2 ) is Hydrogen source - Heat + Pressure + iron catalyst - Anhydrous Ammonia (82 percent N) results - Reacts with water in soil to release ammonium ions

10. Nitrogen Carriers Anhydrous may be used directly, or changed to other N forms: - Aqua ammonia (20 percent N) - Ammonium nitrate (33 percent N) - Ammonium sulfate (21 percent N) - Sodium nitrate (16 percent N) - Urea (46 percent N) - Urea-ammonium nitrate (UAN, 28/32 percent N) - Urea-formaldehyde, IBDU, and SCU

11. Phosphorus Carriers Mined rock phosphate; Mineral is Apatite Usually treated with acid to break down into simpler compounds (see fig. 14-8) - Rock phosphate - Superphosphate - Triple superphosphate - Phosphoric acid - Ammonium phosphates - Bone meal and manure (organic sources)

12. Potassium Carriers Potash Mines – mixtures of potassium, sodium, and magnesium salts - Processed to purify the potassium (fig. 14-10) - Potassium chloride - Potassium sulfate - Potassium nitrate - Sulfate of potash-magnesia