presentation “controlled release fertilizers”byfaizan ali(2008-ag-2470)agr-405agronomy 7 th
TRANSCRIPT
Introduction History and Objectives Mode of nutrient release Classification of CRFs Advantages of CRFs Controlled release formulations Future needs
WHAT IS A CONTROL RELEASE FERTILIZER?
A synthetic fertilizer, usually encased in capsules, that releases its nutrients over a specific period of time much the same as a controlled-release drug releases its medicine
Controlled-release is one of the modern application that has enhanced how fertilizers are used both
commercially and by consumers. Fertilizer use efficiency can be increased by
modification of fertilizer products Chemical or Physical modificatios e.g coated
encapsulation CRFs will bring revolution in Agricultural
industry in near future
Controlled-Release-Fertilizer
CFRs began to be used in the 1930s
Reguler production started in 1936
CFRs became commercial in mid 1950s
Today used in USA and Japan
70 percent of conventionally applied fertilizer goes unutilized
Loss of nutrients due to volatilization and leaching
Fertilizer run-off in surface water leads to oxygen depletion
Negative environmental impacts Fertilizer waste through leaching
increases farm expenditures Less fertilizer use efficiency
Reduction of topical growth (flush growth) and clippings
Improved agronomic yields Improved rooting Improved cell wall strength Improved soil microorganism
health/populations Retention of desirable color
A Dry mixture of soluble fertilizer and thickener in a non-permeable envelope
Nutrient release in two phases i. water penetrates through opening to wt
the mixtureii. Nutrients release the device through
pore either by diffusion or connective flows
Water
Dissolved Urea
SolidUrea*
DissolvedUrea
Water
Dissolved Urea
CompleteRelease
*Or other nutrient
SolidUrea
H2O
H2O
SolidUrea
SolidUrea
SulfurCoating
H2O
DissolvedUrea
H2O
H2O+ S
Urea
NH4
H2O
Urease
Root
The three common timing formulas are used
1. Immediate release
2. Intermediate release
3. Long term release
SYSTEMATIC CLASSIFICATION
A. ORGANIC-N LOW-SOLUBILITY COMPOUNDS
Further divided into:I. Biologically decomposing
compounds e.g urea-formaldehydeII. Chemically decomposing compounds e.g isobutyledene-diurea
B. FERTILIZERS IN WHICH A PHYSICAL BARRIER CONTROLS THE RELEASE
Granules coated by non-permeable material
Material used can be hydrophobic or hydrophilic
C. INORGANIC LOW-SOLUBILITY COMPOUNDS
Here inorganic material is used for coating e.g:
Metal ammonium phosphates (Mg NH4PO4)
Acidulated phosphates rock
Fertilizer type (solubility, density) Thickener type Thickener concentration Size of device Temperature of soil Moisture in the soil
Fertilizer burn is not a problem with CRFs Less frequent application is required Easier and precise mechanical application Reduced capital and labor outlay Reduced nutrient loss by leaching and
run-off Reduced leaf burn
Flexibility of release periods from 40 to 360 days at 25º C
Reduced seed or seedling damage from high local concentrations of salts
Improved storage and handling properties of fertilizer materials
Product differentiation resulting in improved market potential.
MARKET PRICES FOR SLOW-RELEASE FERTILIZERS
Market prices of CRFs are high because of:
High prices of the ingredients used for encapsulated/coated products
Low production capacities significantly higher marketing and sales
expenses
MARKET PRICES FOR SLOW-RELEASE FERTILIZERS
In the United States encapsulated granular urea is sold at a price of US$ 600.00 to 1 000.00/ton
In Japan polyolefine-coated urea is sold at a price of 150 000 yen (= US$ 1 500.00 per t)
In Western Europe, the average user prices are US$ 700 to 1200 per t.
1.Urea-formaldehyde reaction products: also known as Nitroform, Ureaform, Methex. produced in 1936 and commercialized in 1955
Developed in 1960s and 1970s. Sulfur was used as coated material
because of its low cost and value as secondary nutrient
Manufactured inn 1970 in JapanPolymers are used for high-value applicationMost common three marketed products are Nutricote, Osmocote and Polyon
3. Polymer-coated fertilizer
Cotrolled Release Fertilizer
Fertilizer granules are heated and treated fatty acid and metal hydroxide
The two react to form a coating of the metal salt of a fatty acid, such as calcium stearate
Substrate coated components are nitrite, urea and triple super phosphate
These are hybrid products that utilize a primary coating of Sulfur and secondary polymer-coated fertilizer
These fertilizers were developed to deliver the nutrients at low cost
Very high costs of CRFs Lack of proper legislation in most parts
of the world to restrict the use of soluble fertilizers
Only about 0.15% of the total fertilizers consumption is such products
CRF may be inadequate sources of nutrients in situations with low ambient and soil temperatures
FUTURE NEEDS
Issues related to better NUE and a more environment friendly utilization of CRFs deserve greater attention and deeper insights, as listed below:
Improved utilization of advanced technologies to prepare CRFs.
Better understanding of the mechanisms controlling release rate and pattern
Better assessment of expected benefits to the environment by using CRFs
Development of soil degradable coatings
Improved quantification of economic advantages
1. Jacobs, D.F., Bose, R., Hasse, D.L. “Incorporating controlled release fertilizertechnology into outplanting”, in National Proceedings. Ogden, 2003, pp. 37-42.
2. Shavit, U., Shaviv, A., Shalit, G., Zaslazvsky, D.,J. Controlled Release, 1997.