Soil Fertility Iowa State University

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Nitrogen

»» Corn Nitrogen Rate Calculator ««

Extension Publications

Presentations

Soil nitrogen dynamics. J.E. Sawyer. 2020. Soil fertility and nutrient management short course. Iowa State University Extension and Outreach, Ames.
Nitrogen diagnostic tools in corn production. J.E. Sawyer. 2020. Soil fertility and nutrient management short course. Iowa State University Extension and Outreach, Ames.
Nitrogen management for corn production. J.E. Sawyer. 2020. Soil fertility and nutrient management short course. Iowa State University Extension and Outreach, Ames.
Nitrogen dynamics with a rye cover crop. J. Sawyer, J. Pantoja, S. Patel, J. Lundvall, and D. Barker. 2017. Crop Advantage Series, Iowa State University Extension and Outreach, Ames.
Corn nitrogen rate calculator and the impact of nitrogen application on corn production. J.E. Sawyer, D.W. Barker, and J.P. Lundvall. 2017. Crop Advantage Series, Iowa State University Extension and Outreach, Ames.
Nitrogen management - products. J.E. Sawyer. 2017. Soil fertility and nutrient management short course. Iowa State University Extension and Outreach, Ames.

View presentations 2016 and earlier -- click here to expand

Impact of nitrogen application timing on corn production. J.E. Sawyer, D.W. Barker, and J.P. Lundvall. 2016. North Central Extension-Industry Soil Fertility Conference, Des Moines, IA
Nitrogen for corn production. J. Sawyer. 2013. TFI Nutrient Stewardship Summit, Des Moines, IA.

Newsletter Articles

Fall Anhydrous Applications: Do’s and Don’ts (9/2023)
New public-private partnership seeks Iowa farmers to advance nitrogen fertilizer recommendations (9/2022)
Using the Late Spring Soil Nitrate Test in 2022 (6/2022)
Considerations for spring preplant nitrogen application for corn with high fertilizer prices (4/2022)
Give careful consideration to likely high soil and cornstalk nitrate levels this fall (10/2021)
Yellow soybean too early this season? (8/2021)
Nitrogen deficient soybean with excess soil moisture (7/2021)
Fall 2020 nitrogen considerations (9/2020)
Wind damaged corn - nutrient content? (8/2020)
Biological breakdown of wind destroyed corn (8/2020)
Spring corn nitrogen fertilization considerations (3/2020)
Corn Residue Breakdown as Affected by Tillage and N Application (11/2019)
Fall fertilizer nitrogen application (10/2019)
Nitrogen fertilization options with delayed or rescue applications (6/2019)
UAN and herbicide applications on emerged corn (6/2019)
Springtime precipitation - a tool for estimating nitrogen application need for corn (6/2019)
Late-spring soil nitrate test (LSNT) use in 2019 (5/2019)
Effects of unharvested, shattered, or hailed-out soybean fields on nutrient supply for corn? (3/2019)
Equipment considerations for anhydrous ammonia application (3/2019)
Anhydrous ammonia application - spring 2019 (3/2019)
Understanding anhydrous ammonia application in soil (3/2019)
Potential nitrogen loss in spring 2017 (5/2017)
A new late-spring soil nitrate test publication now available (5/2017)

View newsletter articles 2016 and earlier -- click here to expand

Late-vegetative corn stage soil sampling for nitrate-N (6/2016)
Precipitation and nitrogen this spring (6/2016)
The corn nitrogen rate calculator website redo (5/2016)
Anhydrous ammonia applications and corn planting (4/2016)
Nitrogen Loss? (12/2015)
Fertilizer nitrogen application this fall (10/2015)
Nitrogen issues so far this spring (6/2015)
UAN and herbicides on emerged corn (5/2015)
Starter fertilization sometimes boosts corn yield (03/2015)
Estimating nitrogen losses in wet corn fields (6/2014)
Compressed spring workload in 2014? What are nitrogen application options? (4/2014)
Wet conditions and change in soil profile Nitrate (5/2013)
Soil profile nitrate in corn fields following the 2012 drought(2/2013)
Soil fertility management issues following drought-damaged crops - nitrogen (8/2012)
Emerged corn, herbicides and nitrogen (5/2012)
Anhydrous ammonia application and dry soils(10/2011)
Estimating nitrogen losses (6/2011)
Measuring corn nitrogen status (6/2011)
Applying additional nitrogen (and sulfur) after wet conditions (6/2011)
Fact or fiction: ammonia application should not exceed 10 lb N per unit soil CEC (2/2011)
Corn stalk nitrate interpretation (9/2010)
Yellow corn, wet soils, and N loss - Part 4 (2/2009)
Yellow corn, wet soils, and nitrogen loss - Part 3 (7/2008)
Yellow corn, wet soils, and N loss - Part 2 (6/2008)
Yellow corn, wet soils and N loss - Part 1 (6/2008)
Measuring the nitrogen status (6/2008)
Estimating nitrogen losses (6/2008)
Nitrogen loss - how does it happen? (6/2008)
Importance of nitrogen in soils (5//2008)
It's a late spring: should you apply nitrogen or plant corn? (5/2008)
Don’t double dip soybean (11/2007)
Nitrogen loss: How does it happen? (5/2007)
Estimating nitrogen losses (5/2007)
Corn response to supplemental nitrogen (5/2007)
Increasing the frequency of corn in crop sequences (2/2007)
Corn stalk nitrate interpretation (9/2006)
The Illinois soil nitrogen test: should it be used in Iowa? (10/2005)
Remember 50°F (9/2005)
Myths and facts about residue breakdown (4/2004)
Equipment maintenance: fertilizer applicators (2/2002)
Post-plant nitrogen applications on corn (5/2001)
Equipment considerations: dry granular fertilizer (4/2001)

Conference Proceedings and Reports

Helmers, M.J. 2021. 4Rs of nitrogen management and cover crops for reducing nitrate-N losses. p. 71-77. In 32nd Integrated Crop Management Conf. Proceedings. 1-2 Dec. Iowa State Univ. Extension and Outreach.
Sawyer, J.S., J. Lundvall, C. Martins, and A.P. Mallarino. 2021. Integrating rye seed production and red clover into corn systems and nitrogen management. Final Report to the Leopold Center of Sustainable Agriculture. 30 June 2021. Department of Agronomy, Iowa State Univ.
Helmers, M.J. 2019. Stacking of in-field and edge-of-field practices for nitrate-N reduction. p 159-163.In 31st Integrated Crop Management Conf. Proceedings. 4-5 Dec. Iowa State Univ. Extension and Outreach.
Sawyer, J.E. 2019. Nitrogen use in corn - what long-term data tells us. p. 115-122. In The Integrated Crop Management Conf. Proceedings. Dec. 4-5, 2019. Iowa State Univ. Extension and Outreach.
Dougherty, B., C. Pedersen, D. Andersen, M. Helmers, and A.P. Mallarino. 2018. The impact of manure management and cover crops on drainage water quality and yields. p. 101-107. In 30th Integrated Crop Management Conf. Proceedings. Nov. 28-29, 2018. Iowa State Univ. Extension.
Sawyer, J.E. 2018. Corn nitrogen fertilization: production and environmental aspects. p. 75-81. In The Integrated Crop Management Conf. Proceedings. Nov. 28-29, 2018. Iowa State Univ. Extension and Outreach.
Sawyer, J. 2018. Nitrogen use: It’s not your grandfather’s corn. p. 23. In Proc. 2018 Crop Advantage Series. AEP 0200. Iowa State Univ. Extension and Outreach, Ames.
Mallarino, A.P. 2017. Watch potassium management - It also affects corn response to nitrogen and soybean diseases. p. 153-159. In The Integrated Crop Management Conf. Proceedings. Nov. 30-Nov. 29-30, 2017. Iowa State Univ. Extension.
Hirniak, J.N., and A.P. Mallarino. 2017. Nitrogen and potassium interactions in corn. p. 103-108. In 47th North-Central Extension-Industry Soil Fertility Conf. Proceedings. 15-16 Nov. 2017. Vol. 33. Des Moines, IA. International Plant Nutrition Institute, Brookings, SD.
Fawcett, J., A. Weaver, J. Rogers, C. Schneider, T. Mitchell, C. Beedle, L. Rossiter, and J. Michel. 2017. On-farm corn and soybean fertilizer demonstration trials. Iowa State Univ. Research Farm Annual Reports. ISRF17, RFR-A1733. Iowa State Univ., Ames, IA.
Fawcett, J., A. Weaver, L. Rossiter, C. Beedle, M. Schnabel, Z. Koopman, C. Schneider, and T. Mitchell. 2017. On-farm corn and soybean planter demonstration trials. Iowa State Univ. Research Farm Annual Reports. ISRF17, RFR-A1745. Iowa State Univ., Ames, IA.
Sawyer, J.E., S. Patel, J. Pantoja, D.W. Barker, and J.P. Lundvall. 2017. Nitrogen dynamics with a rye cover crop. p. 161-167. In Proc. 29th Annual Integrated Crop Manag. Conf., Ames, IA. 29-30 Nov. 2017. Iowa State Univ., Ames.
Mallarino, A.P., J. Hirniak, R. Oltmans, and M. Schnabel. 2017. Continuous corn response to nitrogen and potassium in northern Iowa. Farm Progress Reports: Vol. 2016: Iss. 1, Article 85.

View conference proceedings and reports 2016 and earlier -- click here to expand

Sawyer, J.E., D.W. Barker, and J.P. Lundvall. 2016. Impact of nitrogen application timing on corn production. p. 55-60. In 46th North-Central Extension-Industry Soil Fertility Conf. Proceedings. Nov. 2-3 2016. Vol. 32. Des Moines, IA. International Plant Nutrition Institute, Brookings, SD.
Sawyer, J., S. Patel, and J. Lundvall. 2016. Enhancing corn yield in a rye cover cropping system. Final project report to the Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation and Water Quality, State Soil Conservation Committee Research and Demonstration grant
Sawyer, J.E. 2015. Nitrogen input decisions with tight crop production margins. p. 143-148. In Proc. 27th Annual Integrated Crop Manag. Conf., Ames, IA. 2-3 Dec. 2015. Iowa State Univ., Ames.
Mallarino, A.P., R. Oltmans, and M. Rees. 2016. Continuous corn response to nitrogen, potassium, and sulfur in southeast Iowa. Southeast Research and Demonstration Farm Annual Reports. ISRF15-34, RFR-A1588. Iowa State Univ., Ames, IA.
Mallarino, A.P., K. Pecinovsky, R. Repke, and L. Thompson. 2016. Corn, soybean, oat, and alfalfa yields as affected by the crop rotation and nitrogen fertilization for corn in northeast Iowa. Northeast Research and Demonstration Farm Annual Reports. ISRF15-13, RFR-A15103. Iowa State Univ., Ames, IA.
Mallarino, A.P., M. Schnabel, M. Smidt, R. Repke, and L. Thompson. 2016. Crop yields of long-term rotations and nitrogen fertilization of corn in northern Iowa. Northern Research and Demonstration Farm Annual Reports. ISRF15-22, RFR-A1598. Iowa State Univ., Ames, IA.
Patel, S., J.E. Sawyer, J.P. Lundvall, and J. Hall. 2015. Root and shoot biomass and nutrient composition in a winter rye cover crop. p. 113-118. In Proc. Forty-Fifth North Central Extension-Industry Soil Fertility Conf., Des Moines, IA. 4-5 Nov. 2015. Vol. 31. International Plant Nutrition Inst., Brookings, SD.
Wortmann, C.S, J. Sawyer, and S. Tonn. 2015. On-farm study researches novozymes fermentation spent residuals. Univ. of Nebraska Extension and Iowa State Extension and Outreach, Lincoln, NE.
Barker, D., J. Sawyer, and M. Castellano. 2015. Evaluation of fertilizer additives for enhanced nitrogen efficiency in corn. Final project report (2013 and 2014). Iowa State Univ., Ames, IA.
Laboski, C.A.M., J.J. Camberato, and J.E. Sawyer. 2014. Evaluation of Adapt-N in the corn belt. p. 7-14. In Proc. Forty-Fourth North Central Extension-Industry Soil Fertility Conf., Des Moines, IA. 19-20 Nov. 20143. Vol. 30. International Plant Nutrition Inst., Brookings, SD.
Sawyer, J.E. 2014. Corn nitrogen rate management: facts, concepts, and Mother Nature. p. 121-127. In Proc. 26th Annual Integrated Crop Manag. Conf., Ames, IA. 3-4 Dec. 2014. Iowa State Univ., Ames, IA.
Sawyer, J.E., J.L. Pantoja, and D.W. Barker. 2014. Corn nitrogen rate response and crop yield in a rye cover crop system. p. 59-63. In Proc. Forty-Fourth North Central Extension-Industry Soil Fertility Conf., Des Moines, IA. 19-20 Nov. 2014. Vol. 30. International Plant Nutrition Inst., Brookings, SD.
Sawyer, J., J. Pantoja, and D. Barker. 2014. Corn and soybean production with a winter rye cover crop. Research and Demonstration farms 2013 annual reports. Iowa State Univ., Ames, IA
Sawyer, J.E. 2013. Options for in-season adjustment of nitrogen rate for corn. p. 145-151. In Proc. 25th Annual Integrated Crop Manag. Conf., Ames, IA. 4-5 Dec. 2013. Iowa State Univ., Ames, IA.
Sawyer, J.E. 2013. Comparison of the MRTN and Adapt-N derived N rates for corn. p. 60-67. In Proc. Forty-Third North Central Extension-Industry Soil Fertility Conf., Des Moines, IA. 20-21 Nov. 2013. Vol. 29. International Plant Nutrition Inst., Brookings, SD.
Sawyer, J., J. Pantoja, and D. Barker. 2013. Corn and soybean production with a winter rye cover crop. Research and Demonstration farms 2012 annual reports. Iowa State Univ., Ames, IA
Castellano, M.J., M.J. Helmers, J.E. Sawyer, D.W. Barker, and L. Christianson. 2012. Nitrogen, carbon, and phosphorus balances in Iowa cropping systems: sustaining the soil resource. p. 145-156. In Proc. 24th Annual Integrated Crop Manag. Conf., Ames, IA. 28-29 Nov. 2012. Iowa State Univ., Ames, IA.
Sawyer, J.E., and A.P. Mallarino. 2012. Nutrient considerations with corn silage and stover harvest. p. 131-136. In The Integrated Crop Management Conf. Proceedings. Nov. 28-29, 2012. Iowa State Univ. Extension.
Sawyer, J.E., and D.W. Barker. 2012. Quantifying corn N deficiency with active canopy sensors. p. 65-64. In Proc. 2012 Wisconsin Crop Management Conf., Madison WI. 10-12 Jan., 2012. Vol. 51. Univ. Wisconsin-Extension and College of Ag. and Life Sciences, Univ. of Wisconsin-Madison, WI.
Sawyer, J., J. Pantoja, and D. Barker. 2012. Nitrogen fertilization of corn grown with a cover crop. Research and Demonstration farms 2011 annual reports. Iowa State Univ., Ames, IA
Pantoja, J.L., J.E. Sawyer, D.W. Barker, and M. Al-Kaisi. 2011. Corn residue harvesting effects on yield response to N fertilization. p. 83-89. In North-Central Extension-Industry Soil Fertility Conf. Proceedings. Vol. 27. Des Moines, IA
Sawyer, J.E., J.L. Pantoja, D.W. Barker. 2011. Effect of a rye cover crop and crop residue removal on corn nitrogen fertilization. p. 115-121. In Proc. 23rd Annual Integrated Crop Manag. Conf., Ames, IA. 1 Nov-2 Dec. 2011. Iowa State Univ., Ames, IA.
Pantoja, J.L, J.E. Sawyer, and D.W. Barker. 2010. Nitrogen fertilization requirement and corn-soybean productivity in a rye cover cropping system. p. 88-96. In Proc. Fortieth North Central Extension-Industry Soil Fertility Conf., Des Moines, IA. 17-18 Nov. 2010. Vol. 26. International Plant Nutrition Inst., Brookings, SD.
Sawyer, J.E., and D.W. Barker. 2010. Quantifying nitrogen deficiency and application rate with active canopy sensors. p. 97-108. In Proc. Fortieth North Central Extension-Industry Soil Fertility Conf., Des Moines, IA 17-18 Nov. 2010. Vo. 26. International Plant Nutrition Inst., Brookings, SD.
Sawyer, J., D. Barker, and M. Hanna. 2010. Crop response to shallow placement of anhydrous ammonia in corn. Final project report. Iowa State Univ., Ames, IA.
Sawyer, J., J. Pantoja, and D. Barker. 2010. Nitrogen fertilization of corn grown with a cover crop. Research and Demonstration farms 2009 annual reports., Iowa State Univ., Ames, IA.
Sawyer, J.E. 2008. Fertilizing crops in the new price age - nitrogen. p. 253-260. In Proc. 20th Annual Integrated Crop Manag. Conf., Ames, IA. 10-11 Dec. 2008. Iowa State Univ., Ames, IA
Sawyer, J.E., and G.W. Randall. 2008. Nitrogen rates, p. 59-71. In G. Laing (ed.) Final Report: Gulf Hypoxia and Local Water Quality Concerns Workshop. Upper Mississippi Sub-basin Hypoxia Nutrient Committee, Ames, IA. 26-28 Sep. 2005. ASABE, St. Joseph, MI.
Randall, G.W., and J.E. Sawyer. 2008. Nitrogen application timing, forms and additives. p. 73-85. In G. Laing (ed.) Final Report: Gulf Hypoxia and Local Water Quality Concerns Workshop. Upper Mississippi Sub-basin Hypoxia Nutrient Committee, Ames, IA. 26-28 Sep. 2005. ASABE, St. Joseph, MI.
Sawyer, J., and D. Barker 2008. Illinois soil nitrogen test evaluation, 2006-2007 final project report. Final report to the Iowa State University, College of Agriculture Corn and Soybean Initiative.
Pedersen, P., J. Sawyer, D. Barker, D. Ruiz Diaz, and J. Stuart. 2008. Educating growers about living mulch systems for grain crop production. Final project report to the Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation, IFLM program.
Sawyer, J.E., J.P. Lundvall, and J.A. Hawkins. 2007. In-season nitrogen management for corn production. p. 38-45. In Proc. Thirty-Seventh North Central Extension-Industry Soil Fertility Conf., Des Moines, IA. 14-15 Nov. 2007. Vol. 23. International Plant Nutrient Inst., Brookings, SD.
Sawyer, J., J. Lundvall, and J. Hawkins. 2007. Demonstration of in-season nitrogen management strategies for corn production. Final project report to the Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation, IFLM program.
Sawyer, J., J. Lundvall, and J. Hawkins. 2007. Demonstration of in-season nitrogen management strategies for corn production. Crop year 2006 project report to the Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation, IFLM program.
Sawyer, J.E. 2006. Managing nitrogen for high corn yields. p. 191-199. In Proc. 18th Annual Integrated Crop Manag. Conf., Ames, IA. 29-30 Nov. 2006. Iowa State Univ., Ames, IA.
Laboski, C.A.M., J.E. Sawyer, D.T. Walters, L.G. Bundy, R.G. Hoeft, G.W. Randall, and T.W. Andraski. 2006. Evaluation of the Illinois soil nitrogen test in the North Central region. p. 86-93. In Proc. Thirty-Sixth North Central Extension-Industry Soil Fertility Conf., Des Moines, IA. 7-8 Nov. 2006. Vol. 22. Potash & Phosphate Inst., Brookings, SD.
Mallarino, A.P., and E. Ortiz-Torres. 2006. A long-term look at crop rotation effects on corn yield and response to nitrogen fertilization. p. 209-217. In Proc. 18th Annual Integrated Crop Manag. Conf., Ames, IA. 29-30 Nov. 2006. Iowa State Univ., Ames, IA.
Sawyer, J., J. Lundvall, J. Hawkins, and D. Barker. 2006. In-season sensing for nitrogen stress in corn. Developed for the in-season nitrogen management project, Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation, IFLM program.
Sawyer, J., J. Lundvall, and J. Hawkins. 2006. Demonstration of in-season nitrogen management strategies for corn production. Crop year 2005 project report to the Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation, IFLM program.
Mallarino, A.P., David Rueber, and E. Ortiz-Torres. 2006. Grain yield of corn, soybean, and oats as affected by crop rotation and nitrogen fertilization for corn. In annual progress reports-2005. Northern research and demonstration farm. ISRF05-22. Iowa State Univ., Ames, IA.
Sawyer, J.E., and E.D. Nafziger. 2005. Regional approach to making nitrogen rate decisions for corn. p. 16-24. In Proc. Thirty-Fifth North Central Extension-Industry Soil Fertility Conf., Des Moines, IA. 16-17 Nov. 2005. Vol. 21. Potash & Phosphate Inst., Brookings, SD.
Sawyer, J.E., and M. Al-Kaisi. 2005. Soil nitrogen and carbon management project. Final project report to the Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation, IFLM program.
Sawyer, J., J. Lundvall, and J. Hawkins. 2005. Demonstration of in-season nitrogen management strategies for corn production. Crop year 2004 project report to the Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation, IFLM program.
Barker, D.W., and J.E. Sawyer. 2005. Nitrogen application to soybean at early reproductive development. Agron. J. 97:615-619.
Sawyer, J.E. 2005. Does it pay to fertilize corn with nitrogen? In Proc. Agriculture and Environment Conf. 8-9 March. Iowa State Univ., Ames , IA
•Mallarino, A.P., E. Ortiz-Torres, and K. Pecinovsky. 2005. Effects of crop rotation and nitrogen fertilization on crop production. p. 40-41. In Annual progress reports-2004. Northeast research and demonstration farm. ISRF04-13. Iowa State Univ., Ames, IA.
Sawyer, J.E. 2004. With high fertilizer prices is it business as usual or should fertilization practices change? p. 163 - 176. In Proc. 16th Annual Integrated Crop Manag. Conf., Ames , IA. 1-2 Dec. 2004. Iowa State Univ., Ames , IA.
Nafziger, E.D., J.E. Sawyer, and R.G. Hoeft. 2004. Formulating N recommendations in the corn belt using recent data. p. 5-11. In Proc. Thirty-Fourth North Central Extension-Industry Soil Fertility Conf., Des Moines , IA. 17-18 Nov. 2004. Vol. 20. Potash & Phosphate Inst., Brookings , SD.
Sawyer, J.E., D.W. Barker, and J.P. Lundvall. 2004. Using chlorophyll meter readings to determine N application rates for corn. p. 136-143. In Proc. Thirty-Fourth North Central Extension-Industry Soil Fertility Conf., Des Moines, IA. 17-18 Nov. 2004. Vol. 20. Potash & Phosphate Inst., Brookings , SD.
Sawyer, J.E., and M. Al-Kaisi. 2004. Soil nitrogen and carbon management project. In Proc. Agriculture and the Environment Conf. 1-2 March. Iowa State Univ., Ames, IA
Baker, J.L. 2004. Limitations of improved nitrogen management to reduce leaching and increase use efficiency. In Proc. Optimizing Nitrogen Management in Food and Energy Production and Environmental Protection, 2nd International Nitrogen Conf. on Science and Policy. The Scientific World 1(S2), 10-16.
Baker, J.L. 2004. In-field nutrient availability and balances, and potential implications on management systems to reduce losses. In Proc. Agriculture and the Environment Conf. 1-2 March. Iowa State Univ., Ames, IA
Kanwar, R., C. Pederson, J. Baker, A.P. Mallarino, J. Sawyer, and K. Pecinovsky. 2003. Fertilizer and swine manure management systems: Impacts on crop production and nitrate-nitrogen leaching with subsurface drainage. Annual progress reports-2002. Northeast Research and Demonstration farm. ISRF02-13. Iowa State Univ., Ames, IA.
Sawyer, J.E., D.W. Barker, J.P. Lundvall, and M. Al-Kaisi. 2003. Evaluation of the amino-sugar based soil test in Iowa corn production. p. 125-136. In Proc. Thirty-Third North Central Extension-Industry Soil Fertility Conf., Des Moines, IA. 19-20 Nov. 2003. Potash & Phosphate Inst., Brookings, SD.
Sawyer, J.E., D.W. Barker, and M. Al-Kaisi. 2003. Iowa experience with the Illinois N test. p. 46-54. In Proc. Wisconsin Fertilizer, Aglime and Pest Manag. Conf., Madison, WI. 21-23 Jan. 2003. Univ. of Wisc., Madison, WI.
Sawyer, J.E. and D. Barker. 2001. In-season nitrogen fertilization of soybean. p. 158-161. In Proc. Thirty First North Central Extension-Industry Soil Fertility Conf., Des Moines, IA. 14-15 Nov. 2001. Potash and Phosphate Inst., Brookings, SD.
Sawyer, J.E. 2001. Nitrogen fertilizer and swine manure application to soybean. p. 33-44. In. Proc. 13th Annual Integrated Crop Manag. Conf., Ames, IA. 5-6 Dec. 2001. Iowa State Univ., Ames, IA.
Sawyer, J.E. 2000. Nutrient management - what's Doable. p. 15-24. In Proc. Agriculture and the Environment Conf.: a wake up call for Iowans. 7-8 March. Iowa State Univ., Ames, IA.
Sawyer, J.E. and D. Barker. 1999. Foliar fertilization of corn with mono-potassium phosphate and urea. Final research report. Iowa State Univ., Ames, IA

Featured Publication

Ue of the End-of-Season Corn Stalk Nitrate Test
John Sawyer, Antonio Mallarino
Details how to use the end-of-season plant test to provide information on nitrogen supply to corn for the season that just ended and how to sample and interpret test results in order to make more informed nitrogen application decisions.

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