Figure 1. Research locations across eight states included in the 3-year split nitrogen application study (2014-2016).
Study Factors:
160 lbs/acre (near economic optimum rate)
240 lbs/acre (above economic optimum rate)
S - Single application near planting
40+SD - 40 lbs at planting + remainder at V9 side-dress
80+SD - 80 lbs at planting + remainder at V9 side-dress
Figure 2. Percent of sites where soil nitrate at tasseling was affected by N application timing (S, 40+SD, and 80+SD) only at the 160 lbs/acre total N application rate.
Figure 3. Percent of sites where nitrogen uptake at maturity was affected by N application timing (S, 40+SD, and 80+SD) at a total N application rates of 160 and 240 lbs/acre.
Table 1. Corn yield ranges across all site-years of the study associated with N rates and application timings.
Figure 4. Percent of sites where grain yield was affected by N application timing (S, 40+SD, and 80+SD) at a total N application rates of 160 and 240 lbs/acre.
Table 2. Critical soil or weather values where larger values were associated with greater corn yield for split-N applications (40+SD or 80+SD) and smaller values were associated with greater corn yield for single N applications.
† SDI, Shannon diversity index (measured from 30 d before to 30 d after sidedress)
Table 3. Critical soil or weather values where larger values were associated with greater corn yield for single N applications and smaller values were associated with greater corn yield for split-N applications (40+SD or 80+SD).
† CEC, Cation exchange capacity.
‡ Mean temp. was measured from planting to V5 development stage.
Authors: Dr. Jason Clark, South Dakota State University and Dr. Fabian Fernandez, University of Minnesota
The results from this study are part of a regional study as described in Kitchen, N.R., J.F. Shanahan, C.J. Ransom, C.J. Bandura, G.M. Bean, J.J. Camberato, P.R. Carter, J.D. Clark, R.B. Ferguson, F.G. Fernández, D.W. Franzen, C.A.M. Laboski, E.D. Nafziger, Z. Qing, J.E. Sawyer, and M. Shafer. 2017. A public-industry partnership for enhancing corn nitrogen research and datasets: project description, methodology, and outcomes. Agron. J. 109:2371-2388. doi: 10.2134/agronj2017.04.0207
Research was conducted by Dr. Jason Clark, South Dakota State University, Dr. Fabian Fernandez, University of Minnesota, and the others involved in this regional project was a part of the Pioneer Crop Management Research Awards (CMRA) Program. This program provides funds for agronomic and precision farming studies by university and USDA cooperators throughout North America. The awards extend for up to four years and address crop management information needs of Pioneer agronomists, sales professionals, and customers.
September 2018
The foregoing is provided for informational use only. Please contact your Pioneer sales professional for information and suggestions specific to your operation. 2014-2016 data are based on average of all comparisons made in over 49 locations through December 1, 2016. Multi-year and multi-location is a better predictor of future performance. Do not use these or any other data from a limited number of trials as a significant factor in product selection. Product responses are variable and subject to a variety of environmental, disease, and pest pressures. Individual results may vary.