Anorganic Fertilizer Lenny Sri Nopriani, SP.MP
Jargon Fertilizer Synthetic Fertilizers can be organic or inorganic Organic: from living material, contains C-C bonds; does not imply organic certification (e.g. biosolids) Inorganic: not from living material (e.g. rock phosphate) and/or manufactured/synthetic (e.g. anhydrous ammonia)
Soil Nutrients and Fertilizers
Macro vs Micro Nutrients Macro nutrients are required by the plant in relatively large amounts Micro nutrients are required only in small amounts minor or trace elements
Macro nutrients Non-mineral elements carbon (C) hydrogen (H) oxygen (O) Primary Nutrients Nitrogen (N) Phosphorus (P) Potassium (K) Secondary Nutrients calcium (Ca) magnesium (Mg) sulfur (S)
Micro nutrients Iron (Fe) Copper (Cu) Zinc (Zn) Boron (B) Molybdenum (Mo) Manganese (Mn) Chlorine (Cl)
Fertilizers
Types of Fertilizers Complete Incomplete Organic Inorganic Soluble Insoluble
Complete vs. Incomplete Complete has all three primary nutrients-nitrogen phosphorous & potassium Examples: 10-10-10, 15-30-15, 20-5-20 Incomplete DOES NOT have all three primary nutrients Examples: 20-0-0, 0-20-0, 12-0-44
Organic Fertilizers Comes from plant or animal matter and contains carbon compounds Examples: urea, sludge and animal tankage
Advantages of Organic Slow release of nutrients Not easily leached from the soil Add organic components to growing media
Disadvantages of Organic Hard to get Not sterile Low nutrient content Expensive
Inorganic Fertilizers Comes from sources other than animals or plants Chemical products
Advantages of Inorganic Can make the desired ratio of nutrients easy to get lower cost
Disadvantages of Inorganic No organic material possible chemical building up in growing media
Soluble Fertilizer Dissolve in water and are applied as a liquid solution Fertigation fertilizing through irrigation water big advantage
Insoluble Fertilizer Includes granular and slow release applied to the growing media
Granular vs. Slow Release Granular relatively inexpensive easy to find Slow Release more expensive because it is coated more uniform release of nutrients over time period
Fertilizer Analysis Fertilizer analysis expresses weight as a percent of nitrogen, phosphorus and potassium 20-10-20
Fertilizer Analysis For Example A 100 Kg bag of fertilizer has an analysis of 15-5-15. How many pounds of nitrogen, phosphorus and potassium are in the bag? Nitrogen: 100Kg X 15%=15Kg Phosphorus: 100Kg X 5%=5Kg Potassium: 100Kg X 15%=15Kg
Fertilizer Ratios A fertilizer with a 10-10-10 analysis would have a 1:1:1 ratio A fertilizer with a 24-8-16 analysis would have a 3:1:2 ratio What would be the ratio for a fertilizer with an analysis of 36-18-27? 4:2:3
Inorganic Nitrogen Fertilizers Created through Haber-Bosch process Combine N2 and H2 under high temperature and pressure to create NH3 gas Anhydrous ammonia will boil & volatilize under normal atmospheric conditions Compression and refrigeration turn it to liquid Applied by injection into to soil to minimize losses into the air
Benefits & Drawbacks Very high concentration of N (82%) Readily absorbed by human tissue requires use of protective gear Public safety explosive & used in drug production Toxic to microorganisms will kill the bugs in your soil for a few weeks
Anhydrous Ammonia
Other Inorganic N Sources Ammonium nitrate, sulfate, and phosphate are commonly used because they form soluble white crystalline solids that are easy to handle
Phosphorus Main source is rock phosphate Mined from ancient marine sediments that contain apatite 70% is from US & Asia Minimal processing Beneficiation (remove clay, carbonate, or silica contents through sieving and flotation) Grind finely May treat with sulfuric acid to dissolve apatite, increase P solubility (creates superphosphate)
Rock Phosphate Mining in India
Forms of Inorganic Phosphorus
Potassium Mined from sedimentary or salt lake deposits of KCl or K2SO4 (e.g. Utah & Dead Sea) Separate K salts from Na salts US imports 80% of its K fertilizers Commonly available as: KNO3(saltpeter)- KCl K2O (potash)- K2SO4
Mining Potash in Utah
Sulfur Usually applied as gypsum (CaSO4) Source is sedimentary rocks Minimal processing soluble and good source of Ca and S with only grinding Other applications include superphosphate (H2SO4) and elemental sulfur
Collecting Sulfur
Benefits and Drawbacks Highly concentrated Concentrations of nutrients are specific and predictable Fast release Can apply exactly what s needed Overdoing it may result in conditions toxic to plants and/or soil microbes (from nutrient ions or secondary ingredients) Incomplete source of nutrients
Application Procedures Banding Sidedressing Topdressing Perforating Broadcasting Foliar spraying Fertigation
Banding Placing a band of fertilizer about two inches to the sides and about two inches below seed depth. DO NOT place below the seeds because fertilizer will burn the roots.
Sidedressing Placing a band of fertilizer near the soil surface and to the sides after seedlings emerge from the soil.
Topdressing Mixing fertilizer uniformly into the top one to two inches of growing media around the plant.
Perforating Placing fertilizer in 12-18 holes drilled 18 to 24 around the canopy drip line of fruit trees. Cover the holes and fertilizer slowly dissolves.
Broadcasting Spreading fertilizer to cover the entire production area
Foliar Spraying Spraying micronutrients in a solution directly on plant leaves. Quickly corrects nutrient deficiencies Fertilizer concentration should not be too high or leaf burning will occur.
Fertigation Incorporating water-soluble fertilizer into the irrigation system of greenhouse and nursery crops. Concentrated solutions usually pass through proportioners or injectors to dilute to the correct ratio. Venturi-type Positive-displacement
Venturi-type Simple and inexpensive less accurate depends on water pressure in the hose and in the smaller tube to proportion Example: H ozon
Positive-displacement More expensive very accurate physically inject and mix specific amounts of concentrated solution and water Examples: commander proportioners, and Smith injectors
Rules for applying fertilizers Method used should be practical, effective and cost efficient Method used affects nutrient availability for plant use Fertilizer must be dissolved and reach plant roots
Choose the Right One... In order to pick a good fertilizer, ask yourself: 1 Does it have the needed nutrients? 2 Will it release them at the right time? 3 Is it affordable? 4 Is it convenient enough to use? 5 Are its side effects acceptable?