This is the presentation given by Dr. Jason Kruse at the Golf Industry Show in Las Vegas, NV on February 29, 2012

1. Jason Kruse, Ph.D.
University of Florida
jkk@ufl.edu

2. Situation
• Prices for many products have risen steadily
– Revenue increases have not kept pace
• Reduced budgets have resulted in staffing cuts
• Increasing demands placed on existing
facilities
– Events
– People
• Increasing expectations regarding aesthetics
and play

3. Situation
• Expectations
– Reduce/eliminate pesticides
– Reduce/eliminate fertilizers
– Organic???
• Goals
– First and foremost – Safe,
playable surface!
– Make sure the turfgrass is not a
point of discussion

4. Overview
• Role of nutrients in plant growth
• Fertilizer carriers - Nitrogen
• Cultural management practices
• Fertilizer price trends, predictions, purchasing
recommendations

5. Role of Nutrients in Plants

6. Plant Nutrition
• An actively growing turfgrass plant is 75 - 85% water.
– The remaining 15 - 25% of the plant’s weight is dry matter.
• Sixteen (16) elements are essential because a plant
cannot successfully complete its life cycle without
them.
• A major portion of the plant dry matter content
consists of three (3) elements:
– Carbon
– Hydrogen
– Oxygen
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7. Plant Nutrition
• Plants obtain carbon and oxygen from the
atmosphere.
– Carbon dioxide (CO2), a gas, enters the leaves
through the stomata.
– Water (H2O) taken in by the roots supplies
hydrogen and oxygen.
7

8. Essential Elements
• Macronutrients • Micronutrients
– Nitrogen (N) – Iron (Fe)
– Phosphorus (P) – Manganese (Mn)
– Potassium (K) – Boron (B)
– Copper (Cu)
• Secondary – Zinc (Zn)
– Calcium (Ca) – Molybdenum (Mo)
– Magnesium (Mg) – Chlorine (Cl)
– Sulfur (S)
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9. Macronutrients – Nitrogen (N)
• Present in the greatest quantities: 2 – 5% in
dry leaf tissue.
• Sufficiency Ranges:
– Creeping Bentgrass = 4.5 – 6.0%
– Kentucky Bluegrass= 2.6 – 3.5%
– Ryegrass = 4.5 – 5.5%
– St. Augustinegrass = 2.0 – 3.0%
– Zoysiagrass = 2.0 – 3.0%
– Bermudagrass = 2.5 – 3.5%
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10. Macronutrients – Nitrogen (N)
• Major impact on a number of factors:
– Effects on plant growth and metabolism,
influencing grass response to a number of
environmental stress conditions;
– Potential environmental implications;
– Must be routinely applied for a healthy, stress-
tolerant turf;
– Accounts for the highest cost of a turfgrass
fertilization program.
10

11. 11

12. Macronutrients – Nitrogen (N)
• N Compounds in Plants - taken up as NO3-
(nitrate) and NH4+(ammonium).
– Amino acids – building blocks for proteins.
– Proteins
– Chlorophyll – photosynthesis
– Hormones - auxins, cytokinins, and ethylene.
– Nucleic Acids - DNA, RNA
12

13. Nitrogen Deficiency
• The most common nutritional deficiency
• Growth slows dramatically
• Oldest leaves first become chlorotic (lose their
dark green color, become yellowish), while
newest leaves stay green.
– Nitrogen is transferred from the oldest,
expendable leaves to the newest, most valuable
leaves
13

14. 14

15. 15

16. Macronutrients – Phosphorus (P)
• Present in the soil solution in very low
concentrations and uptake is primarily as
H2PO4- (pH<7.0), HPO42- (pH>7.0), or certain
soluble organic phosphates.
• Phosphorus content of turfgrass shoot tissues
may range from 0.10 to 1.00% by dry weight.
– Sufficiency range is 0.15 – 0.5%.
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17. Macronutrients – Phosphorus (P)
• Uses in the plant:
– Component of the energy molecules ATP and ADP.
• These compounds serve to store and transfer available
energy within the plant.
– Structural constituent
• Phospholipids
• Phosphoproteins
• Nucleic acids
• Sugar phosphates
• Nucleotides
• Coenzymes
17

18. Macronutrients – Phosphorus (P)
• Visual Symptoms of deficiency
– Initially show up as reduced shoot growth and a
dark green color.
• As P deficiency continues, lower leaves may turn
reddish at the leaf tips and then progress down the
blade.
• Stunted growth - caused by limited P for energy
transformations.
• Element of impairment
Photo credit: Rosa Say
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19. Macronutrients – Phosphorus (P)
• Applications should be based on soil/tissue
test results

20. Macronutrients – Potassium (K)
• Taken up and stored as the ionic (K+) form.
• Shoot tissue concentration of 1.0 to 3.0% by
weight.
• Used in the plant:
– Enzymes activator
– Most important solute in the vacuole
• Osmoregulation = water regulation in plants
– Used in carbohydrate, amino acid, and protein
synthesis
20

21. Macronutrients – Potassium (K)
• Visual symptoms of deficiency
– Interveinal yellowing of older leaves (lower),
followed by dieback of leaf tip, scorching or firing
of the margins, and total yellowing of the leaf
blade including the veins.
– May appear weak or spindly.
– Under high evaporative demand, wilting and leaf
firing may be accelerated as well as wear injury in
high traffic areas.
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22. Macronutrients – Potassium (K)
• Deficiencies result in:
– Increased respiration and transpiration
– Reduced environmental stress tolerance
– Increased disease incidence
– General reductions in growth
22

23. Bottom Line
We must maximize our benefit of
management practices to ensure a safe,
enjoyable facility for our customers

24. Nitrogen Fate
• What are some of the potential fates for N
applied to a turf surface?
– Taken up by grass
– Microorganisms
– Denitrification
– Volatilization
– Leaching

25. Sources of Nitrogen
• Fertilizer
• Returned Clippings
• Organic Matter
• Lightning (precipitation)

26. Consider the Whole System!
• What can you change in your current system
to further reduce N need?
– Mowing
– Irrigation
– Fertilization
– Equipment repair/replacement
– Inventory management
– Employees

27. Mowing/Maintenance
• Increase mowing height
– Increase root depth and photosynthetic capacity
• Reduce highly maintained areas
– Reducing fairway width/length to emphasize
landing areas
– Reduce/Eliminate flower beds/ornamentals
– Fairways vs roughs

28. Seasonal Growth
28

29. Irrigation
• Conduct irrigation audit
• Ensure application rate/amount does
not exceed infiltration
• Match irrigation to weekly ET rates,
accounting for rainfall received
– On-site weather station
– http://fawn.ifas.ufl.edu
• Irrigation + rainfall should not wet
profile below rootzone, only refill it!

30. Soil Compaction
• Compacted soils
– Reduced pore space = reduced root growth =
reduced N uptake
– Decreased infiltration increases risk of runoff
• Monitor compaction, vary method/depth of
aerfication

31. Consider Your Fertilizer Material

32. Quickly Available N
• Very soluble
• Rapid response
• Short response
• Cheap
• Minimal temperature
dependency
• High leaching potential
• Tendency to burn

33. Quickly Available N
• Ammonium nitrate 33-0-0
• Ammonium sulfate 21-0-0
• Ammonium phosphates
– mono-ammonium phosphate 11-48-0
– di-ammonium phosphate 20-50-0
• Potassium nitrate 13-0-44
• Urea (organic?) 46-0-0

34. Slow Release Nitrogen Sources
• Slow initial response
• Longer response than quick release
• Some, but not all, are dependent on
temperature for N release
• Low burn potential
• Moderately expensive to expensive
• Less N leaching

35. 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

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

37. 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

38. 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)

39. Different Chain Lengths
Methylene Urea
N-C-N
N-C-C-C
N-C-C-C-C
N-C-C-C-C-C-C-C
Urea Formaldehyde
N-C-N
N-C-C-C-C-C-C-C
N-C-C-C-C-C-C-C-C-C
N-C-C-C-C-C-C-C-C-C-C-C-C
N-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C

40. 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

41. Nitroform
• Urea formaldehyde
• Insoluble organic
• 38% N; 65-71% WIN
• Biological N release
– Rate influenced by soil
temperature

42. Nutralene
• Methylene urea
• 40% N; 38% WIN
• Biological N release
• More rapidly available
than UF
• Not as adversely
influenced by cool
temperatures

43. 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

44. IBDU
• 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, less on
dependant on temperature
• Release also depends on granule size and
contact with soil. Smaller granules release
N faster than larger granules

45. IBDU
• 31% N -90% WIN
• N released by hydrolysis
• Relatively unaffected by
– Temperature
– pH
• Particle size important
• Excellent cool season
response

46. Liquid Slow Release Fertilizers
• Chemistry similar to UF, MU
• Micro-suspension of MU (FLUF)
• CoRoN, N-Sure; 28%N, 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?

47. 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

48. CoRon
• 28% N solution
• Polymethylene ureas
and amine modified
polymethylene ureas
• N release dependent
upon microbial action

49. N-Sure
• 30% N
• Ring structured
Triazones may contain
methylene diurea
• N release by microbial
action
• Response very similar
to CoRon

50. Coated Slow Release Fertilizers
• SCU, sulfur coated urea
• Polymer coated urea
• Poly Coated Sulfur Coated Urea

51. Sulfur Coated Urea
• Molten sulfur (S) sprayed on urea in rotating drum,
coated in wax sealant
• Experimentally produced in 1950’s, commercially in
1972
• N release determined by:
– Coating thickness
– Microbial degradation
– Temperature
– Moisture
– Coating failure (cracks, abrasion)

52. Sulfur Coated Urea
• 32-38% N
• Release depends upon
– Thickness of sulfur coating
– Biological activity
– Soil environment
• Temperature
• pH
• Cool temperature
response erratic
• Coating fragile, uneven

54. 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

55. Polyon
• 40% N
• Polyurethane coated urea
• N release influenced by
– Coating thickness
– Diffusion rate
– Soil temperature
• Good for both warm and
cool season
• Coating is abrasion
resistant

56. Poly-S
• Coated with sulfur and a
polymer
– Cheaper than regular
polymer coated fertilizers
• Release dependent on
– Temperature
– Soil moisture

57. Fertilizer Programs
• Minimum of 30-50% slowly available N is
appropriate
– Choose CRN source based on environmental
conditions, budget, level of traffic
• 4-10 lbs N/M annually, depending on level of
use/traffic
– Do not apply more than 1 lb soluble N/M at one time
– Carefully consider use of coated products in high traffic
areas due to potential damage to coating
• Late fall application of IBDU has been shown to
improve spring color

58. Consider site-specific
management

59. PERCENT N RELEASED OVER TIME FOR SELECTED
CRN MATERIALS
100
80
60
40
20
0
7 14 28 42 56 84 112 140 180
NITROFORM NUTRALENE MILORGANITE
POLYON SCU AN

60. Weeks of “Greening”
Nitrogen Source Application Rate Weeks Greening
Urea 1 4
Ammonium Sulfate 1 4
POLYON Regular 1.25 12
Nutralene 1.5 12
Nitroform 2 16
IBDU 1.5 12

61. Relative Product Price
Nitrogen Source Analysis $/ton $/lb N
Urea 46-0-0 700 0.76
Ammonium Sulfate 21 - 0 - 0 300 0.71
POLYON Regular 43 - 0 - 0 1,500 1.74
Nutralene 40 - 0 - 0 1,300 1.63
Nitroform 38 - 0 - 0 1,500 1.97
IBDU 31 - 0 - 0 1,500 2.42

62. Smart Purchases

63. Why is Nitrogen Fertilizer so High
Priced?
• High prices have coincided with spikes in price
of gas
• Fertilizer shipping costs are important
– U.S. imports more than 8 million metric tons of
Nitrogen fertilizer annually
• Natural gas is used to manufacture N-
fertilizers

64. Why is Nitrogen Fertilizer so High
Priced?
Nitrogen (atm) Anhydrous
+ Natural gas Ammonia
Heat
N2 + CH4 + H2O 2NH3 + CO
Pressure

65. Why is Nitrogen Fertilizer so High
Priced?
Anhydrous
Ammonia
+ +
Sulfuric Nitric + CO2
Acid acid
Ammonium Sulfate Ammonium Nitrate Urea

66. Price Volatility
• Price for fertilizers spiked in 2008/2009
– Spike in natural gas prices
U.S. Natural Gas Wellhead Price
12
10
8
6 Data 1: U.S. Natural Gas Wellhead Price
(Dollars per Thousand Cubic Feet)
N9190US3 U.S. Natural Gas Wellhead…
4
2
0
Mar-…
Aug-…
Mar-…
Aug-…
Mar-…
Aug-…
Nov-…
Nov-…
Nov-…
Feb-…
Sep-…
Feb-…
Sep-…
Feb-…
May-…
Sep-…
May-…
May-…
Dec-…
Dec-…
Dec-…
Oct-1982
Oct-1995
Oct-2008
Jan-1973
Apr-1976
Jan-1986
Jan-1999
Jul-1979
Jul-1992
Jul-2005
Apr-1989
Apr-2002
Jun-1978
Jun-1991
Jun-2004

67. Price Volatility
• While prices have stabilized, futures prices
trend upwards through 2016
• Price of natural gas is only a small piece of the
picture…

68. Fertilizer Consumption
Millions of metric tons consumed annually
45,000
40,000
35,000
30,000
25,000
US
20,000 China
15,000
10,000
5,000
0
2002 2003 2004 2005 2006 2007 2008 2009 2010

69. Effect of Demand on Price

70. Volatile Prices

71. Volatile Prices
• Fertilizers
– As much as 85% of variable expenses
– Prices increased dramatically
• Nitrogen and Phosphorus
– 300-400% increase from 2002-2008
– Within year price changes over past 3-4 seasons:
• +/- $100/ton for anhydrous ammonia seasonally
• +/- $500/ton for phosphorus seasonally
Source: Kenkel, P. and T. Kim. 2009. Optimal cash purchase strategies to reduce fertilizer price risk. Southern
Agricultural Economics Association Annual Meeting, Atlanta, Georgia, January 31 – February 3, 2009.

72. Volatile Prices
• With so much within year variability, time of
purchase is critical!
– Price is driven by world market
– Suppliers stockpile fertilizer for peak demand
– Dealers attempt to shift risk through advance
purchase programs
– It is possible to save as much as 16% if purchased
at correct time of the year

73. Volatile Prices
• Best time of year to purchase
– Urea: 1st or 2nd week in July
– Phosphorus: 1st week in November
• Highest prices
– Urea: March/April
– Phosphorus: March

74. Summary
• Proper nutrient management is essential
• Careful management of cultural practices can
have significant impact on effectiveness of N
applications
• Important to understand differences in fertilizer
materials/use
• Slow release fertilizers have potential to save
time/labor and wear on equipment
• Budget savings can be realized through scheduled
purchases of fertilizer materials

75. Questions?
Jason Kruse, Ph.D.
PO Box 110670
Gainesville, FL 32611
352-273-4569
jkk@ufl.edu