|CLARK, J - University Of Minnesota|
|FERNANDEZ, F - University Of Minnesota|
|CAMBERATO, J - Purdue University|
|SAWYER, J - Iowa State University|
|FERGUSON, R - University Of Nebraska|
|CARTER, P - Dupont Pioneer Hi-Bred|
|SHANAHAN, J - Dupont Pioneer Hi-Bred|
|NAFZIGER, E - University Of Illinois|
|FRANZEN, D - North Dakota State University|
|LABOSKI, C.A.M. - University Of Wisconsin|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/31/2015
Publication Date: 11/15/2015
Citation: Clark, J.C., Fernandez, F.G., Camberato, J.J., Sawyer, J.E., Kitchen, N.R., Ferguson, R.B., Carter, P.R., Shanahan, J., Nafziger, E.D., Franzen, D.W., Laboski, C. 2015. What plant and soil testing from 16 sites in eight midwestern states tells us about split nitrogen applications [abstract]. ASA-CSSA-SSSA International Annual Meeting, November 15-18, 2015, Minneapolis, Minnesota. Paper No. 92889.
Technical Abstract: It is hypothesized that split-nitrogen (N) relative to single near-planting applications improve corn (Zea mays L.) production, N recovery efficiency, and lessen environmental impacts of fertilization. However, these hypotheses have not been fully tested. A 16-site study across eight US Midwestern states was conducted to compare near-planting and split N applications. Sixteen treatments were applied: eight rates from 0 to 314 kg N/ha as a single or split N [45 kg N at planting + V9-sidedress (45SD)], and 90 kg N at planting + V9-sidedress (90SD) to achieve a total of 179 and 269 kg N/ha. Before sidedress application, soil NO3 N (0-60 cm depth) at the V5 development stage was 22, 31, 49 and 64 mg/kg for the 45SD, 90SD, single 179 kg N/ha and single 269 kg N/ha applications, respectively. At tasseling plant biomass and N content were similar for single and 90SD, but the single application was approximately 8% higher than 45SD at both rates. At tasseling soil (0-60 cm depth) NO3 N for the 179 kg N/ha rate had 10, 25, and 18 mg NO3 N/kg for the single, 45SD, and 90SD applications, respectively. No differences in plant N content, biomass, and grain yield was found at maturity between N application timings. Post-harvest (0-90 cm depth) soil NO3 N for the 179 kg N/ha rate was 4, 6, and 8 mg/kg for the single, 90SD, and 45SD applications, respectively. At the 269 kg N/ha rate soil NO3 N was similar for the 45SD and 90SD (18 and 20 mg/kg) with the single application being lower (11 mg/kg). Inconsistent results were observed for in-season measurements and between individual locations. Overall, relative to single N applications, split N applications resulted in similar end of season plant N content and yield and similar or higher post-harvest soil NO3 N.