Monday, November 5, 2007 - 11:00 AM
100-4

Nitrogen Recommendations for Corn: A Southeastern Perspective.

Carl Crozier1, Jeff White2, Ronnie Heiniger1, Randy Weisz3, Jared Williams4, Ravi Sripada5, and Nan Hong6. (1) North Carolina State University, Vernon James Research & Extension Ctr., Plymouth, NC 27962, (2) Soil Science, North Carolina State University, Box 7619, Raleigh, NC 27619, (3) Crop Science, North Carolina State University, Box 7620, Raleigh, NC 27620, (4) Brigham Young University, Brigham Young University-Idaho, 243 Benson, Rexburg, ID 83460-1110, (5) Building 3702 Curtin Road, USDA-ARS Pasture Systems & Watershed Mgmt Research Unit, Building 3702, Curtin Road, University Park, PA 16802-3702, (6) Monsanto, Monsanto Company, 800 N Lindbergh, St. Louis, MO 63141

Basic nitrogen management principles and new precision technologies are combined in an emerging strategy for corn N recommendations.  We have developed separate crop response calibration databases that utilize soil tests or aerial photography for site-specific fertilizer recommendations.  Economic optimum N rates for corn are correlated with results of the soil nitrogen test developed by the University of Illinois, although soil drainage class modifies the relationship.  Data suggest that wetter sites may be subject to either reduced mineralization or enhanced denitrification, since higher optimum N rates are associated with any given soil N test level.  Existing commercial aerial photography services can also generate color infrared images that are correlated with optimum late nitrogen sidedress rates.  Calibration data are available for corn at the V-T stage, implying that other decision aids must be used for the majority of the N applied to the crop (at planting or at an earlier sidedress stage).  Coupling these two technologies may allow us to make improved rate prescriptions, with early-season N rates based on the soil test and late-season rates based on the aerial image.  Groundwater samples from a 15-ha experimental area document reductions in leaching losses associated with incorporation of the remote-sensing calibration for corn and for wheat, so we expect additional potential water quality benefits from coupling soil- and plant-based technology.

Back to Symposium--Advances in N Calibration for Corn
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Back to The ASA-CSSA-SSSA International Annual Meetings (November 4-8, 2007)