soil nutrients and fertilizers - sri nopriani, sp.mp . jargon
Post on 19-May-2018
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Lenny Sri Nopriani, SP.MP
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
Types of Fertilizers
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
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
Low nutrient content
Comes from sources other than animals or plants
Advantages of Inorganic
Can make the desired ratio of nutrients
easy to get
Disadvantages of Inorganic
No organic material
possible chemical building up in growing media
Dissolve in water and are applied as a liquid solution
fertilizing through irrigation water
Includes granular and slow release applied to the growing media
Granular vs. Slow Release
easy to find
more expensive because it is coated
more uniform release of nutrients over time period
Fertilizer analysis expresses weight as a percent of nitrogen, phosphorus and potassium
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
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?
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 safetyexplosive & used in drug production
Toxic to microorganismswill kill the bugs in your soil for a few weeks
Other Inorganic N Sources
Ammonium nitrate, sulfate, and phosphate are commonly used because they form soluble white crystalline solids that are easy to handle
Main source is rock phosphate
Mined from ancient marine sediments that contain apatite70% 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
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
Usually applied as gypsum (CaSO4)
Source is sedimentary rocks
Minimal processingsoluble and good source of Ca and S with only grinding
Other applications include superphosphate (H2SO4) and elemental sulfur
Benefits and Drawbacks
Concentrations of nutrients are specific and predictable
Can apply exactly whats needed
Overdoing it may result in conditions toxic to plants and/or soil microbes (from nutrient ions or secondary ingredients)
Incomplete source of nutrients
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.
Placing a band of fertilizer near the soil surface and to the sides after seedlings emerge from the soil.
Mixing fertilizer uniformly into the top one to two inches of growing media around the plant.
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.
Spreading fertilizer to cover the entire production area
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.
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.
Simple and inexpensive
depends on water pressure in the hose and in the smaller tube to proportion
Example: H ozon
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:
Does it have the needed nutrients?
Will it release them at the right time?
Is it affordable?
Is it convenient enough to use?
Are its side effects acceptable?