Slow Release = Controlled Release eg CRN = Controlled Release Nitrogen - PowerPoint PPT Presentation

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Slow Release = Controlled Release eg CRN = Controlled Release Nitrogen

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... is chain length, and as a result, mineralization rate. Products. Formolene 30-0-2 ... Mineralization ... the less soluble it is, and the slower it will be mineralized. ... – PowerPoint PPT presentation

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Title: Slow Release = Controlled Release eg CRN = Controlled Release Nitrogen


1
Slow Release Controlled Releaseeg CRN
Controlled Release Nitrogen
2
Why Use Slow Release Fertilizers?
  • More uniform growth response
  • No growth surge
  • Longer growth response
  • Less chance of burn
  • Less leaching of nitrate
  • Labor saving

3
Uncoated Slow Release Fertilizers
  • Urea formaldehyde (UF)
  • Methylene urea (MU)
  • Isobutylidene diurea (IBDU)
  • Natural organics

4
Ureaform and Methylene Urea
  • Very similar materials chemically
  • Mostly granular, some liquids
  • about 40 N, 70 WIN (28 N for liquids, all
    soluble)
  • Formed by reacting urea and formaldehyde chains
    of alternating C and N
  • Main difference is chain length, and as a result,
    mineralization rate

5
Products
  • Formolene 30-0-2
  • FLUF 18-0-0
  • Nitro 26 CRN 26-0-0
  • Nitroform (Powder Blue, Blue Chip) 38-0-0
  • CoRoN 28-0-0 (25 of total N is urea)

6
Different Chain Lengths
7
Ureaform and Methylene Urea
  • Designed to release N for 8-12 weeks
  • Contains unreacted urea, fast greening
  • Requires soil microbial activity
  • temperature sensitive, soil at 78o F is four
    times as active as soil at 42o F
  • moisture sensitive
  • Seasonal response

8
Mineralization
  • The decomposition of complex, N-containing
    organic molecules and the resulting release of NH4

9
MU, UF Chain Length Determines SolubilityThe
longer the chain, the less soluble it is, and the
slower it will be mineralized. Some may be so
long that they are essentially insoluble, and
wont break down.
10
N Release from UF, MU Determined by Solubility
Test
  • Water soluble vs Water insoluble fractions
  • CWSN, cold water soluble N, is soluble at 25o C,
    is quickly available to the turf. Includes
    unreacted urea and short chain molecules
  • CWIN, cold water insoluble N. What remains
    insoluble at 25o C. Longer chain, N is released
    slower, over a period of several weeks
  • HWIN, N insoluble at 100o C. Longest chain, N
    released over months or years

11
How Much Dissolves at 25o C?
100 grams CRN in
71 grams out
Stir
100 - 71 29 grams (29) CWSN and 71 grams
(71) CWIN
12
How Much Dissolves at 100o C?
71 grams CRN in
22 grams out
Stir
Thus, in 100 g of CRN, there are 22 g HWIN
13
Activity Index, AI
  • Basically the fraction of CWIN that goes into
    solution in hot water. It estimates the
    slow-release value of the fertilizer
  • CWIN - HWIN CWIN
  • Fertilizers with a higher AI have increased N
    solubility, better slow-N release
    characteristics.
  • UF should have an AI of gt 40

X 100
14
Summary
  • CWSN - 29
  • CWIN - 71
  • HWIN - 22
  • Activity Index CWIN - HWIN
    CWIN 71 - 22 71

X 100
X 100 69
15
CRN Sources VaryWhich Will Give Longer Response?
36 HWIN
71 HWIN
Formolene 38-0-0
Nutralene 40-0-0
51 CWIN
18 CWIN
Both from Agrevo
13 urea
11 urea
16
WSN vs WIN
  • WIN must be stated on label
  • Expressed as of the product, not the nitrogen
  • Example FLUF contains 18 N, and 4.5 WIN. This
    means that 18-4.513.5 of the N is WSN. What
    of the N is WIN? 4.5/1825

17
IBDU
  • Urea is reacted with isobutyraldehyde
  • Only a single chemical product is formed, not a
    bunch of different molecules. 31 N, 90 WIN
  • Different sized granules available
  • N release depends on solubility and hydrolysis
    (IBDU molecule reacts with water and breaks
    apart), releasing urea.
  • No free urea in IBDU, may need to add

18
IBDU start here
  • Urea breaks down quickly to NH4
  • IBDU is relatively insoluble, so only small
    amounts are available at any one time
  • Release sensitive to soil moisture, temperature
  • Release also depends on granule size and contact
    with soil. Smaller granules release N faster
    than larger granules

19
Liquid Slow Release Fertilizers
  • Chemistry similar to UF, MU
  • Micro-suspension of MU (FLUF)
  • CoRoN, N-Sure 28N, 7 as urea and 21 as short
    chain MU or small ring structure.
  • Get quick and slow release
  • Foliar application?
  • Is slow release slow enough?

20
Liquid Slow Release Fertilizers
  • Easily handled, applied
  • Can be formulated with P and K
  • Some have short storage life
  • Require specialized delivery system
  • Volume of liquid used in application is not
    enough to move the material down into the root
    system - must irrigate in

21
Coated Slow Release Fertilizers
  • SCU, sulfur coated urea
  • Polymer coated urea

22
Sulfur Coated Urea
  • Solid urea core, coated with sulfur and wax
  • 30-38 N, depending on coating thickness
  • Coating is not always perfect, having cracks,
    thin spots, holes, etc.
  • Release determined by 7 day dissolution test
    25-35 are typical figures

23
Polymer Coated Urea
  • Solid urea or other nutrient core, coated with
    various polymers (plastics)
  • Coatings are tough, resist damage, thin
  • Coating chemistry affects membrane properties,
    release rate
  • Release is due to controlled diffusion, which is
    fairly constant over time
  • Release depends on coat thickness, chemistry,
    temperature, moisture

24
Polymer Coatings Remain Intact
Water
Dissolved Urea
Water
Dissolved Urea
Complete Release
Dissolved Urea
Or other nutrient
25
Sulfur Coatings Break Down
Sulfur Coating
Solid Urea
Solid Urea
H2O
Dissolved Urea
26
SCU Contains Intact and Breached Particles, Thin
and Thick Coatings
27
IBDU Releases N Based on Solubility
H2O
Urea
Urease
NH4
Root
28
Release Depends on Granule Size
29
Small Granules Release Faster, Shorter
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