Plant SciencePlant Nutrition
Topic: Sources of Plant nutrients and Forms. (2032)
Brian Sobecki
Evaluating Organic and Inorganic Fertilizers.
• Organics– Materials related to, produced with or based on
the use of fertilizer or plant or animal origin without chemical fertilizers or pesticides.
– Some of these include• Natural organics
– Straw (cereals, beans)
– Green manures (clover, vetch, peas)
– High Calcium Lime
– Forest Products ( bark and sawdust, humus)
Organics
• Major Animal Materials– Bloodmeal
– Hoof and Horn
– Manure
• Synthetic Organics– Urea
– Sulfur coated Urea
– Urea-formaldehyde
– Biuret
Organics
• Processed organics:– Sewage sludge
– Processed crop residues
Benefits of Organics– Soil tillage improved.
– Water Retention improved.
– Temperature increased. ( beneficial biological action)
– Some of the newer processed organics are granulated for easier application.
– Increased worm population ( increases aeration)
Inorganics
• Inorganics– Materials produced by or composed of matter
other than plant or animal.
• Benefits of inorganics:– Meets consumer desires– Generally lower in cost per unit of plant food.– Generally less material to handle because of
higher analysis.
Inorganics: Benefits cont.
– Consistent and higher Analysis
– Ease of handling
Nitrogen Sources
• Two categories based on availability in the soil:– Quickly available:
• Inorganic salts that are readily soluble in water.
• Produced from raw materials such as Natural Gas and Minerals
• Examples: Ammonium Sulfate, Ammonium Nitrate, and Urea
Nitrogen Sources
– Slowly Available:• Do not go readily into solution in water.
• Will release slowly in time.
• Example: Urea Formaldehyde
Phosphorus Sources
• The most widely used source of phosphorus is rock Phosphate.– Mined, ground and then treated with different
acids to create two different phosphate groups.• Superphosphate: Which is treated with sulfuric acid.
• Triple SuperPhosphate: Which is treated with phosphoric acid.
Phosphorus Sources
• Other sources:• Ammonium phosphate: Organic Phosphorus sources
and slag.
• Slag - byproduct from the making of steel.
Potassium Sources
• Potassium Chloride or Muriate of Potash:– Processed from mined potassium salts.
• Sulfate of Potash:– Potassium chloride treated with sulfuric acid.
• Potassium Nitrate: – Potassium Chloride treated with Nitric Acid
Fertilizers
• Forms of Nutrients:– Liquid– Solid
• Fertilizer Labels– Information included on fertilizer labels:
• Net weight
• Brand and Grade
Fertilizers
• Guaranteed analysis giving the minimum percentage of each nutrient.
– Usually Nitrogen, Phosphorus, and Potassium are given in this way:
» N: P: K
» N = actual % of nitrogen in fertilizer
» P = Percent of (P2O5)
» K = Percent (K2O)
Fertilizers
• To get the actual amounts of Nitrogen, Phosphorus and Potassium in the fertilizer follow these rules:
– To get the actual amount of Nitrogen Multiply the percent of N in the fertilizer by the total amount of fertilizer.
– To get the total amount of Phosphors take the percent of P2O5 multiply by the total amount of fertilizer then multiply that by .44 to get the total amount of Phosphorus.
– To get the total amount of Potassium take the percent of K2O time the total amount of fertilizer then multiply by .83 to get the total amount of potassium.
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