Presentation
“CONTROLLED RELEASE FERTILIZERS”
By
Faizan Ali
(2008-ag-2470)
AGR-405
Agronomy 7th
CONTENTS
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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
INTRODUCTION
Controlled-release is one of the modern application th
at 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
CONTRLLED RELEASE FERTILIZERS
HISTORY

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
WHY TO USE CRFS

70 percent of conventionally applied fertilizer
goes unutilized
WHY TO USE CRF

Loss of nutrients due to volatilization
and leaching
WHY TO USE CRFS
Fertilizer run-off in surface water leads to
oxygen depletion
 Negative environmental impacts
 Fertilizer waste through leaching increases
farm expenditures
 Less fertilizer use efficiency

Objectives
Increased crop production
Increased nutrient application and quality
Increased fertilizer use efficiency
Reduction of plant toxicity and stress
Reduction in pollution of soil, water, atmosp
here
Reduction of fertilizer application costs
OBJECTIVES
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

MANUFACTURING OF CRFS
MODE OF NUTRIENT RELEASE


i.
ii.
A Dry mixture of soluble fertilizer and
thickener in a non-permeable envelope
Nutrient release in two phases
water penetrates through opening to wt the
mixture
Nutrients release the device through pore
either by diffusion or connective flows
1. POLYMER COATINGS REMAIN INTACT
Water
Solid
Urea*
Dissolved
Urea
Water
Dissolved
Urea
Dissolved
Urea
Complete
Release
*Or other nutrient
2. SULFUR COATINGS BREAK DOWN
Sulfur
Coating
H2O
Solid
Urea
Solid
Urea
H2O
H2O
H2O
+S
Solid
Urea
H2O
Dissolved
Urea
SCU CONTAINS INTACT AND BREACHED PARTICLES,
THIN AND THICK COATINGS
RELEASE OF N, BASED ON SOLUBILITY
H2O
Urea
Urease
NH4
Root
RELEASE DEPENDS ON GRANULE SIZE
SMALL GRANULES RELEASE FASTER
RELEASE TIME

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
b. Fertilizers in which a
physical barrier controls the
release
c. Inorganic low-solubility
compounds
A. ORGANIC-N LOW-SOLUBILITY COMPOUNDS

I.
II.
Further divided into:
Biologically decomposing compounds e.g
urea-formaldehyde
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
FACTORS EFFECTING NUTRIENT RELEASE
Fertilizer type (solubility, density)
 Thickener type
 Thickener concentration
 Size of device
 Temperature of soil
 Moisture in the soil

ADVANTAGES OF CRFS
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
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ADVANTAGES
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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.
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MARKETED CONTROLLED
RELEASE FORMULATION
1.Urea-formaldehyde reaction products:

also known as Nitroform, Ureaform, Methex.

produced in 1936 and
commercialized in 1955
2.SULFUR-COATED FERTILIZERS:
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Developed in 1960s and 1970s.
Sulfur was used as coated material because of
its low cost
and value as
secondary nutrient
3. Polymer-coated fertilizer
Manufactured inn 1970 in Japan
Polymers are used for high-value
application
Most common three marketed
products are Nutricote, Osmocote and
Polyon
Cotrolled Release Fertilizer
4. MULTICOATED PRODUCTS:

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
5. POLYMER/SULFUR-COATED FERTILIZER:
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
APPLICATION TO SOIL
LIMITATIONS
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

FUTURE NEEDS

Better assessment of expected benefits to the
environment by using CRFs

Development of soil degradable coatings

Improved quantification of economic
advantages
REFERENCES
1. Jacobs, D.F., Bose, R., Hasse, D.L.
“Incorporating controlled release fertilizer
technology into outplanting”, in National
Proceedings. Ogden, 2003, pp. 37-42.
2. Shavit, U., Shaviv, A., Shalit, G., Zaslazvsky, D.,J.
Controlled Release, 1997.