Rescue N Applications for Corn: Yield Response, Leaf Burn, and Yield Loss

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1 Rescue N Applications for Corn: Yield Response, Leaf Burn, and Yield Loss Kelly Nelson, University of Missouri Agronomy Department, Greenley Center Peter Scharf, University of Missouri Agronomy Department, Columbia Bruce Burdick, University of Missouri Agronomy Department, Hundley-Whaley Farm Gene Stevens, University of Missouri Agronomy Department, Delta Center Objectives & Relevance:! The objective of this proposed study is to evaluate yield response of corn to rescue N applications, including broadcast applications which cause leaf burn.! Situations in which corn producers may consider rescue N applications to a standing corn crop: " Corn was planted but wet spring conditions prevented preplant application of N fertilizer " Loss of N fertilizer is suspected due to wet conditions after application! In these situations, either tractor-mounted or high-clearance-mounted applicators can sidedress N fertilizer between corn rows, avoiding leaf burn.! However, these applicators are not always available, or may be configured for other uses such as spraying herbicides, with the result that broadcast applications may be easier to accomplish.! Broadcasting N fertilizer by airplane is another option for rescue applications of N when soil conditions are too wet to carry traffic.! Broadcast applications of N will cause leaf burn, but little if any research has been done to measure how much yield is lost due to this leaf burn for various application times and nitrogen forms.! The amount of yield recovered may also depend on the stage at which N is applied. Procedures:! Trials will be located on four University of Missouri research stations " Bradford Farm near Columbia " Greenley Farm in Novelty " Hundley-Whaley Farm in Albany " Delta Center in Portageville! Treatments will be nitrogen times, sources, and placement (all 150 lb N/acre) " Timings: - Preplant - Corn 1 foot tall - Corn 2 feet tall - Corn 3 feet tall - Corn 4 feet tall - Unfertilized check " Sources: - Dry (probably ammonium nitrate) - 30% urea-ammonium nitrate solution " Placement:

2 - Broadcast - Between rows

3 Current status and importance of rescue N applications for corn:! Corn yield is very responsive to N, so when N deficiencies of corn are suspected, rescue applications have a high chance of being profitable.! Previous MU research has shown that rescue applications can give large yield responses as late as silking, but the proposed experiments would be helpful to add to our understanding of when and where rescue applications are justified and economical.! Need for rescue applications is tied to wet weather and does not occur every year.! In wet years when rescue N applications may bring yield benefits, equipment availability may limit the number of fields receiving rescue applications.! Rescue N applications applied with broadcasting equipment can effectively supply N, but result in leaf burn on the corn.! Nitrogen burn is associated only with rescue N applications, and little is known about the yield effects of nitrogen burn on corn at various growth stages.! Understanding yield loss associated with nitrogen burn at different stages of corn development would help corn producers to make rational decisions about whether to attempt rescue N applications and what type of application equipment to use. Timetable: March 2003 April 2003 May 2003 June 2003 September 2003 Oct-Dec Same as 2003 Equipment preparation Apply planting N treatments Apply Arescue@ N treatments at appropriate times Apply Arescue@ N treatments at appropriate times Harvest Analyze results Strategy for application/transfer of knowledge: Transfer of knowledge will be mainly via written and verbal educational programs, including press releases, newsletter articles, radio interviews, conferences, and transfer via the university=s network of regional Extension Specialists. Budget: For each experimental location: Salaries and wages: Labor (including fringe benefits)...3,500 Supplies: Seed, fertilizer, fuel, stakes, flags, application equipment, etc. 1,000 Travel: Travel to the plot, presentations, and maintenance Total (20 $250)...$5,000/location Annual total 4 $5,000/location... $20,000 2-year $20,000/year... $40,000

4 Resume of KELLY A. N University of Missouri Greenley Research Center P.O. Box 126, Hwy 156 E. Novelty, MO Fax: nelsonke@missouri.edu A. NELSON EDUCATION DUCATION: Ph.D. Weed Science, Dept. of Crop and Soil Sci., Michigan State University, May 2000 M.S. Weed Science, Dept. of Crop and Soil Sci., Michigan State University, May 1997 B.S. Plant Science, Dept. of Agronomy, University of Missouri-Columbia, May 1995 PROFESSIONAL EXPERIENCE XPERIENCE: University of Missouri, Novelty, MO. June 2000 to present. Assistant ProfessorBResearch Agronomist. Michigan State University, East Lansing, MI. May 1995 to May Graduate Research Assistant. Conducted field, greenhouse and laboratory weed science research and taught Principles of Weed Science (CSS 056) laboratory. Ciba Crop Protection, Lee's Summit, MO. May 1994 to August Research Technician. Planted, maintained, sprayed, and evaluated crop protection research plots. MU Integrated Pest Management, Columbia, MO. May 1992 to August Installed, examined, and collected gypsy moth traps in six Northwest Missouri counties. Nelson Family Farm, Skidmore, MO to Implemented soil conservation practices and managed corn, soybean, wheat, swine, and cattle production. PUBLICATIONS UBLICATIONS: Reviewed Publications Nelson, K. A., K. A. Renner, and R. Hammerschmidt Cultivar and herbicide selection affects soybean development and the incidence of Sclerotinia stem rot. Agron. J. 94: Nelson, K. A. and K. A. Renner Yellow nutsedge (Cyperus esculentus) control and tuber production with glyphosate and ALS-inhibiting herbicides. Weed Technol. 16: Nelson, K. A. and K. A. Renner Yellow nutsedge (Cyperus esculentus) control and tuber yield with glyphosate and glufosinate. Weed Technol. 16: Nelson, K. A., K. A. Renner, and R. Hammerschmidt Effects of protoporphyrinogen oxidase inhibitors on soybean (Glycine max L.) growth response, Sclerotinia sclerotiorum disease development, and phytoalexin production by soybean. Weed Technol. 16: Nelson, K. A. and K. A. Renner Glyphosate-resistant and nonresistant soybean growth and development as affected by glyphosate and postemergence herbicide tank mixtures. Agron. J. 93: Nelson, K. A. and K. A. Renner Cost-effective weed control in wide- and narrow-row glyphosate resistant soybean (Glycine max). J. Prod. Agric. 12:

5 Nelson, K. A., K. A. Renner, and D. Penner Weed control in soybean (Glycine max) with imazamox and imazethapyr. Weed Sci. 46: Nelson, K. A. and K. A. Renner Postemergence weed control with CGA and cloransulam-methyl in soybean (Glycine max). Weed Technol. 12: Nelson, K. A. and K. A. Renner Weed control in wide- and narrow-row soybean (Glycine max) with imazamox, imazethapyr, and CGA plus quizalofop. Weed Technol. 12:

6 Extension Nelson, K. A., K. A. Renner, and R. Hammerschmidt Roundup and Cobra applications in soybeansbimpact on canopy development and incidence of white mold. Michigan State University Fact Sheet. pp. 2. Nelson, K. A. and K. A. Renner Weed control in drilled and 30"-wide row Roundup Ready 7 soybean. Michigan State University Fact Sheet. pp. 2. PROFESSIONAL ACTIVITIES CTIVITIES: Weed Science Society of America North Central Weed Science Society of America American Society of Agronomy Crop Science Society of America