Nitrogen Application and Management

1. Nitrogen Application and Management By: Nathan Schnur, Daniel Eibey, Alex Mortenson, Lance Van Wyk

2. Question at Hand… When is the best time to apply nitrogen???

3. 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.

4. Three Major Forms of Nitrogen • Anhydrous Ammonia • Urea-Ammonium Nitrate (UAN) • Manure • Before any N is applied soil tests should always be conducted

5. 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

6. 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

7. 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

8. 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

9. Factors Influencing Nitrogen Loss • Time Influences the Following • Soil Temperature • Soil Microbial Activity • Soil Moisture

10. 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 ≥60°F for three weeks or more it is safe to assume 50% of nitrogen applied is in nitrate form

11. Timing of Application • Three Major Times of Application • Fall Application • Spring Application • Spring/Early Summer Side-dress Application Timing can greatly affect leaching potential

12. Fall Application • Common Practice • Anhydrous Ammonia • Soil Temperature must be <50°F • 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

13. 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

14. 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

15. 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

16. 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 it’s beneficial to the plant, not just the farmer

17. 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.

18. Questions???

19. 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 92:1228-1236 • 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.purdue.edu/extmedia/ • Hardwick J. 2007. Fall Nitrogen Guidelines. http://www.agrigold.com • http://www.extension.iastate.edu

20. References Cont’ • Photos Courtesy of: • http://serc.carleton.edu/details/images/4506.html • http://agronomyday.cropsci.uiuc.edu/2003/liquid_manure/index.html • http://www.omafra.gov.on.ca/english/engineer/facts/06-059f1.jpg • http://www.ca.uky.edu/agc/pubs/ip/ip71/04%20liquid%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/mod5/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/