nitrogen sources and turf response
DESCRIPTION
Nitrogen Sources and Turf Response. Laurie Trenholm UF-IFAS Turf Specialist. Quick Release Nitrogen. Soluble in water Provide fairly rapid response in turf Volatilize readily if not irrigated in Useful for repair of injured turf- athletic fields - PowerPoint PPT PresentationTRANSCRIPT
Quick Release Nitrogen• Soluble in water• Provide fairly rapid response in turf• Volatilize readily if not irrigated in• Useful for repair of injured turf- athletic fields• Provide for quicker turf establishment if
growing plugs or sprigs in• Response seen for 30-45 days unless applied
at excessive rate
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Ammonium Sulfate
• 21% N (NH4)2SO4
• Highly soluble and leachable• Subject to volatilization• Very acidifying – useful in high pH
soils• High salt index - 3.25 – must be
watered in• Deep green and longer response
than many other soluble N sources
Urea• 46% N• Soluble Synthetic
Organic• Nonionic, highly
leachable• Subject to volatilization• Low acidity - 1.8/kg N• Low salt index - 1.62
Urea• Organic (but quick-release) N source• Converted to ammonium-N form by enzyme
urease in the soil after short time in the soil• This happens within about 24 hours• After this conversion, much less likely to
leach if rainfall does occur
Ammonium Nitrate
• 33 – 34 % N• Very soluble• Subject to volatilization and
leaching• Low acidity
– 1.8kg acid/kg• High salt index -2.99• Can be explosive• Short term response
Slow or Controlled Release Nitrogen• Use various mechanisms to release N
– Coating through which N diffuses– Chemical reaction used to create chemical bonds that ties
the N up
• Release rates vary widely between products and due to temperature and microbial activity
• More expensive than QRN• Less likely to leach than QRN if applied to bare soil,
few differences in healthy turf that provides a ground cover
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Sulfur Coated Urea • 32-38% N• Release depends upon
– thickness of sulfur coating– microbial activity– soil environment
• temperature• pH
• Cool season response-erratic• Coating fragile- some spreaders
may crack• Response usually 60-90 days
Polymer Coated • Variable N• N release varies, influenced by
– coating thickness– soil temperature– not soil moisture– not influenced by soil moisture,
pH, microbial activity• Week 1: Moisture comes in through
polymer coating, dissolves encapsulated N inside
• After week 1: Soil temperature causes N to diffuse through membrane
Polymer-Sulfur Coated Urea
• N release influenced by– coating thickness (vary by
product)– diffusion rate– Less influenced by soil
temperature and moisture• Good for both warm and cool
season application
Urea Formaldehyde• Insoluble organic• 38% N ; 65-71% WIN• Biological N release
– release by microbial activity– soil temperature
• Less effective in cool seasons• Reaction of urea and formaldehyde
gives chains of alternating C and N – Longer chains, slower release
• Nitroform, Blue Chip, Nutralene• Can also be in solution
Methylene Urea• 40% N - 36% WIN• Microbial N release• More rapidly available than
UF• Not as adversely influenced
by cool temperatures• Reaction of urea and
formaldehyde gives chains of alternating C and N
Triazones• 30% N• Ring structured Triazones may
contain methylene diurea• N release by microbial action• Response very similar to UF
solutions
IBDU - Isobutylidene Diurea
• 31% N • 90% slow release• N released by hydrolysis as urea• Release due to
– pH (lower better)– Soil moisture– Granule size
• Good cool season response• Less effective during heavy rain
periods due to rapid release
Release Curves% N release over time
• Urea Formaldehydes– 1 mo: 20-40%– 2 mo: 23-45%– 4 mo: 31-53%– 6 mo: 38-58%
• IBDU– 1 mo: 21%– 2 mo: 32%– 4 mo: 50%– 6 mo: 63%
• Polyon (Polymer Coated Urea)– 1 mo: 49%– 2 mo: 75%– 4 mo: 90%– 6 mo: 94%
• Sulfur Coated Urea– 1 mo: 70%– 2 mo: 84%– 4 mo: 95%– 6 mo: 99%
UF Materials ComparisonNitroform
GUARANTEED ANALYSISTotal Nitrogen (N)........................................ 38%
4.5% Urea Nitrogen6.9% Slowly Available Water Soluble Nitrogen*26.6% Water Insoluble Nitrogen
Derived from: urea-formaldehyde*6.9% slowly available Nitrogen from methylenediurea and dimethylenetriurea.
NutraleneGUARANTEED ANALYSISTotal Nitrogen (N)*.......................................40%6% Urea Nitrogen20% Slowly Available Water Soluble Nitrogen*14% Water Insoluble Nitrogen
Derived from: methylene urea*20% slowly available Nitrogen from methylenediurea and dimethylenetriurea.
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SRN Materials Label Comparison Polyon
GUARANTEED ANALYSISTotal Nitrogen (N)........................................ 30%
1.5% Ammoniacal Nitrogen28.5% Urea Nitrogen*8.0% Soluble Potash0.955% Water Soluble Magnesium0.2175% Water Soluble IronDerived from: Muriate of potash, polymer coated urea, sulfate of ammonia, sulfate of potash-magnesia, iron sucrate*22.8% slow release Nitrogen from polymer coated urea.
XCU (Polymer Sulfur Coated Urea)
GUARANTEED ANALYSISTotal Nitrogen (N)*....................................38-39%Urea Nitrogen
Derived from: polymer coated sulfur coated urea*38-39% slowly available Nitrogen from polymer sulfur coated urea.
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Palm Beach County Nitrogen Demo Plots
Treatments:1.Control2.Urea (soluble) at 0.5 lb N 1,000 ft-2
3.Urea (soluble) at 1.0 lb N 1,000 ft-2
4.Polyon at 1 lb N 1,000 ft-2
5.Polyon at 2 lb N 1,000 ft-2
6.Milorganite at 1 lb N 1,000 ft-2
7.Methylene urea 1 lb N 1,000 ft-2
• Treatments applied Mar 12• Irrigated in with ~ ¼” water• Irrigated 3 x week to apply
0.08-0.3” each time
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