Date post: | 08-May-2015 |
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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
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
Overview
• Role of nutrients in plant growth
• Fertilizer carriers - Nitrogen
• Cultural management practices
• Fertilizer price trends, predictions, purchasing recommendations
Role of Nutrients in Plants
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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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.
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Essential Elements
• Macronutrients
– Nitrogen (N)
– Phosphorus (P)
– Potassium (K)
• Secondary
– Calcium (Ca)
– Magnesium (Mg)
– Sulfur (S)
• Micronutrients
– Iron (Fe)
– Manganese (Mn)
– Boron (B)
– Copper (Cu)
– Zinc (Zn)
– Molybdenum (Mo)
– Chlorine (Cl)
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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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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.
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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
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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
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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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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
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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
18 Photo credit: Rosa Say
Macronutrients – Phosphorus (P)
• Applications should be based on soil/tissue test results
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
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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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Macronutrients – Potassium (K)
• Deficiencies result in:
– Increased respiration and transpiration
– Reduced environmental stress tolerance
– Increased disease incidence
– General reductions in growth
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Bottom Line
We must maximize our benefit of management practices to ensure a safe,
enjoyable facility for our customers
Nitrogen Fate
• What are some of the potential fates for N applied to a turf surface?
– Taken up by grass
– Microorganisms
– Denitrification
– Volatilization
– Leaching
Sources of Nitrogen
• Fertilizer
• Returned Clippings
• Organic Matter
• Lightning (precipitation)
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
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
Seasonal Growth
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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!
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
Consider Your Fertilizer Material
Quickly Available N
• Very soluble
• Rapid response
• Short response
• Cheap
• Minimal temperature dependency
• High leaching potential
• Tendency to burn
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
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
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
Uncoated Slow Release Fertilizers
• Urea formaldehyde (UF)
• Methylene urea (MU)
• Isobutylidene diurea (IBDU)
• Natural organics
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
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)
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
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
Nitroform
• Urea formaldehyde
• Insoluble organic
• 38% N; 65-71% WIN
• Biological N release
– Rate influenced by soil temperature
Nutralene
• Methylene urea
• 40% N; 38% WIN
• Biological N release
• More rapidly available than UF
• Not as adversely influenced by cool temperatures
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
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
IBDU
• 31% N -90% WIN
• N released by hydrolysis
• Relatively unaffected by – Temperature
– pH
• Particle size important
• Excellent cool season response
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?
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
CoRon
• 28% N solution
• Polymethylene ureas and amine modified polymethylene ureas
• N release dependent upon microbial action
N-Sure
• 30% N
• Ring structured Triazones may contain methylene diurea
• N release by microbial action
• Response very similar to CoRon
Coated Slow Release Fertilizers
• SCU, sulfur coated urea
• Polymer coated urea
• Poly Coated Sulfur Coated Urea
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)
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
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
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
Poly-S
• Coated with sulfur and a polymer – Cheaper than regular
polymer coated fertilizers
• Release dependent on
– Temperature
– Soil moisture
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
Consider site-specific management
PERCENT N RELEASED OVER TIME FOR SELECTED
CRN MATERIALS
7 14 28 42 56 84 112 140 1800
20
40
60
80
100
NITROFORM NUTRALENE MILORGANITE
POLYON SCU AN
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
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
Smart Purchases
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
Why is Nitrogen Fertilizer so High Priced?
N2 + CH4 + H2O
Nitrogen (atm) + Natural gas
Heat
Pressure
Anhydrous Ammonia
2NH3 + CO
Why is Nitrogen Fertilizer so High Priced?
+ Nitric acid
Anhydrous Ammonia
+ CO2
Urea Ammonium Nitrate
+ Sulfuric
Acid
Ammonium Sulfate
Price Volatility
• Price for fertilizers spiked in 2008/2009
– Spike in natural gas prices
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4
6
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12
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73
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78
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79
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82
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86
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98
9
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91
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92
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95
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U.S. Natural Gas Wellhead Price
Data 1: U.S. Natural Gas Wellhead Price(Dollars per Thousand Cubic Feet)N9190US3 U.S. Natural Gas Wellhead…
Price Volatility
• While prices have stabilized, futures prices trend upwards through 2016
• Price of natural gas is only a small piece of the picture…
Fertilizer Consumption
Millions of metric tons consumed annually
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
2002 2003 2004 2005 2006 2007 2008 2009 2010
US
China
Effect of Demand on Price
Volatile Prices
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.
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
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
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