Managing Global Resources for a Secure Future

2017 Annual Meeting | Oct. 22-25 | Tampa, FL

35-2 Why the Different Responses between Single and Split Nitrogen Applications?.

See more from this Division: SSSA Division: Soil Fertility and Plant Nutrition
See more from this Session: Ph.D. Oral Competition I

Monday, October 23, 2017: 8:20 AM
Marriott Tampa Waterside, Grand Ballroom D

Jason Clark, University of Minnesota, St. Paul, MN, Fabian G. Fernandez, 1991 Upper Buford Circle, University of Minnesota, St Paul, MN, James Camberato, Agronomy, Purdue University, West Lafayette, IN, Paul R. Carter, DuPont Pioneer, Johnston, IA, Richard B. Ferguson, Department of Agronomy and Horticulture, University of Nebraska - Lincoln, Lincoln, NE, David W. Franzen, North Dakota State University, Fargo, ND, Newell R Kitchen, 243 Agricultural Engineering Bldg, USDA-ARS, Columbia, MO, Carrie A.M. Laboski, Soil Science, University of Wisconsin-Madison, Madison, WI, Emerson D. Nafziger, W301 Turner Hall, 1102 S. Goodwin, University of Illinois-Urbana-Champaign, Urbana, IL, John E. Sawyer, Department of Agronomy, Iowa State University, Ames, IA and John Shanahan, Fortigen (Tetrad Corp.), Lincoln, NE
Abstract:
Split- opposed to single-nitrogen (N) applications may improve corn (Zea mays L.) production, N use efficiency, and lessen environmental impacts due to fertilization. However, these hypotheses have not been fully tested.

Single and split N applications were applied in eight US Midwestern states over a 3-year period (49 sites-years total) varying in soil characteristics and weather. A single (0 to 315 kg-N ha-1 in 45 kg increments) and two split N applications [45 kg-N near planting + V9-sidedress (45SD), and 90 kg-N near planting + V9-sidedress (90SD) at a total of 180 and 270 kg-N ha-1] were evaluated. The series of single N applications were used to evaluate their effect on soil N at the VT development stage. Only the 180 and 270 rates were used to compare the effect of single and split N applications on soil nitrate-N content at tasseling (VTSN), N uptake of corn at physiological maturity (PMN), and grain yield.

Before sidedress application, soil nitrate (0-60 cm depth) at the V5 development stage increased linearly as N rate applied near planting increased in 48 of the 49 sites. After sidedress application, 17 of the 49 sites had no differences between the single and two split N applications for soil N, N uptake, and grain yield. Greater VTSN by 45SD or 90SD relative to single only led to greater PMN in two- of the five-sites and greater grain yield in four- of the nine-sites where 45SD or 90SD was greater than single. This demonstrates that greater soil N at tasseling did not always lead to greater N uptake and grain yield. In only 5% of the response variable comparisons between 45SD and 90SD, were differences found, indicating that applying more N near planting for split applications did little to alter their effect on soil N, N uptake and yield. This presentation will demonstrate under what soil and weather conditions differences between single and split N applications were found and when each can improve soil N, N uptake, and yield.

See more from this Division: SSSA Division: Soil Fertility and Plant Nutrition
See more from this Session: Ph.D. Oral Competition I