Nitrogen Application and Management

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Nitrogen Application and Management

• By Nathan Schnur, Daniel Eibey,
• Alex Mortenson, Lance Van Wyk

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Question at Hand

• When is the best time to apply nitrogen???

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Overview

• Discuss three majors forms of nitrogen used in
  applications on typical farms
• What factors influence nitrogen loss from the
  soil
• Discuss the best time to apply
• Give a recommendation on when, what form, and how
  to apply nitrogen.

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Three Major Forms of Nitrogen

• Anhydrous Ammonia
• Urea-Ammonium Nitrate (UAN)
• Manure
• Before any N is applied soil tests should always
  be conducted

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Anhydrous Ammonia

• Anhydrous Ammonia
• Liquid under high pressure in a tank
• In the form of NH3
• 82 N by volume
• Binds tightly to soil particles
• Very effective form of fertilizer
• Must be knifed into the ground
• Dangerous
• Economically better
• More nitrogen per pound at lower cost than
  alternatives

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Anhydrous Ammonia Cont

• Benefits
• Reduced rate of nitrification
• Reduced rate of denitrification
• Leads to less runoff and leaching potential
• Can be applied fall, spring, side-dress
• Drawbacks
• Dangerous
• Potential for nitrogen loss is still present

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Urea-Ammonium Nitrate (UAN)

• Urea with Ammonium Nitrate
• Comes in liquid form
• 28 or 32 N by volume
• Not as economically efficient as anhydrous
• Relatively Safe
• Can be knifed in or surface applied
• Benefits
• Split applications
• Pre-plant and side-dress options
• Lower input costs (fuel, equipment rental)
• Drawbacks
• Increase potential for nitrogen losses if not
  used properly

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Manure

• Viable option of nitrogen for farmers with
  animals
• Can vary greatly in content of nitrogen
• Benefits
• Readily available for animal farmers
• Drawbacks
• Must be injected into the ground to reduce
  potential for nitrogen loss
• Must be worked in with plow if it is surface
  applied

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Factors Influencing Nitrogen Loss

• Time Influences the Following
• Soil Temperature
• Soil Microbial Activity
• Soil Moisture

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Factors Cont

• Soil Temperature
• As soil temperatures rise so does the rate of
  nitrogen loss
• Nitrification and Denitrification increase with
  temperature
• This increases potential for run-off and leaching
• Soil Microbial Activity
• As soil temperatures rise so does microbial
  activity
• This increase in microbial activity impacts the
  rate of nitrification and denitrification
• Soil Moisture
• Nitrification process prefers unsaturated soil
• Denitrification process prefers saturated soil
• General rule of thumb If soil temperature
  are 60F for three weeks or more it is safe to
  assume 50 of nitrogen applied is in nitrate form

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Timing of Application

• Three Major Times of Application
• Fall Application
• Spring Application
• Spring/Early Summer Side-dress Application

Timing can greatly affect leaching potential
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Fall Application

• Common Practice
• Anhydrous Ammonia
• Soil Temperature must be lt50F
• Must use N-Serve
• Advantages
• Reduces Time Constraints
• Disadvantages
• Nearly 100 of anhydrous is converted to nitrate
  by May 1st
• Increased potential for nitrogen losses

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Spring Application

• Anhydrous Ammonia and UAN are most common forms
  applied in spring
• Advantages
• Decreased risk for nitrogen loss if applied
  properly and with the addition of N-Serve
• Disadvantages
• Time constraints
• Field conditions
• Potential for nitrogen losses

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Spring/Early Summer Side-Dress

• Application begins after emergence
• Anhydrous, UAN, or Manure
• Usually around V4
• Can be done as late as V11
• Can also be used for supplemental nitrogen
  applications
• Advantages
• Maximum nitrogen use
• Minimal losses
• Reduced cost
• Better for the environment
• Less time constraints

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Side-Dressing Cont

• Disadvantages
• Need of specialized equipment if done beyond V7
• Field conditions
• If field is wet, furrows will not close behind
  applicator
• This leads to potential of nitrogen loss

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Summary

• There are many factors and methods of application
  which create problems with nitrogen application
• There is probably no single easy answer to the
  problems of nitrogen application. But
  specialized management techniques will help.
• Soil Testing
• Site Specific Management
• Side-Dressing
• Applications when its beneficial to the plant,
  not just the farmer

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Recommendations

• Criteria for Recommendation
• Minimal Nitrogen Loss
• Maximize Nitrogen Use
• Cost Effective
• Only one application method met these criteria
  and it was Spring/Summer Side-Dress
• Cost effectiveness may not be present in the
  short term but in the long term side-dressing
  should pay for itself with reduced nitrogen use
  and maximized yields.

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• Questions???

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References

• Lentz, E., Mullen, R. Thomison, P. 2006.
  Potential for Nitrogen Loss After All the Rain.
  C.O.R.N Newsletter 2006-14
• Lory, J.A., Scharf, P.C. and Wiebold, W.J. 2002.
  Corn Yield Response to Nitrogen Fertilizer Timing
  and Deficiency Level. Agronomy Journal. 94
• Vitosh, M.L. 1990. Nitrogen Fertilizers, N-P-K
  Fertilizers. Ext. Bulletin E-896, Michigan State
  University
• Binder, D.L., Sander, D.H., and Walters, D.T.
  2000. Maize Response to Time of Nitrogen
  Application as Affected by Level of Nitrogen
  Deficiency. Agronomy Journal 921228-1236
• Iowa State University. 1997. Nitrogen Fertilizer
  Recommendations for Corn in Iowa. Ext Pub 1714
• University of Nebraska Lincoln. How to Apply Soil
  Nitrogen
• Sawyer, J.E. 2001. Nitrogen Application
  Questions. ICM Pub 486(23)
• Devlin D.L., Witney D.A., and Lamond R.E. 1996.
  Water Quality, Best Management Practices for
  Nitrogen. Kansas State University Ext Pub.
  MF-2202
• Mengel, D.B. Types and Uses of Nitrogen
  Fertilizers for Crop Production. Purdue
  University Ext Pub. AY -204. http//www.ces.purdu
  e.edu/extmedia/
• Hardwick J. 2007. Fall Nitrogen Guidelines.
  http//www.agrigold.com
• http//www.extension.iastate.edu

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References Cont

• Photos Courtesy of
• http//serc.carleton.edu/details/images/4506.html
• http//agronomyday.cropsci.uiuc.edu/2003/liquid_ma
  nure/index.html
• http//www.omafra.gov.on.ca/english/engineer/facts
  /06-059f1.jpg
• http//www.ca.uky.edu/agc/pubs/ip/ip71/0420liquid
  20manure.jpg
• http//cropwatch.unl.edu/photos/cwphoto/nh3.JPG
• http//www.agronext.iastate.edu/immag/pubs.html
• http//www.awtank.com/anhydrous_ammonia_tanks.htm
• http//instruct1.cit.cornell.edu/Courses/css412/mo
  d5/ext_m5_pg7.htm
• University of Nebraska Lincoln. How to Apply Soil
  Nitrogen. http//soilfertility.unl.edu/
• University of Nebraska Lincoln. Nitrogen Basics.
  http//soilfertility.unl.edu/