Soil hydrologic grouping guide which soil and weather properties best estimate corn nitrogen need

Authors

Gregory Mac Bean, McCain Foods
Curtis J. Ransom, United States Department of AgricultureFollow
Newell R. Kitchen, United States Department of Agriculture
Peter C. Scharf, University of Missouri
Kristen S. Veum, United States Department of Agriculture
James J. Camberato, Purdue University
Richard B. Ferguson, University of Nebraska-LincolnFollow
Fabián G. Fernández, University of Minnesota Twin Cities
David W. Franzen, North Dakota State University
Carrie A.M. Laboski, University of Wisconsin-Madison
Emerson D. Nafziger, University of Illinois Urbana-Champaign
John E. Sawyer, Iowa State University
Robert L. Nielsen, Purdue University

ORCID IDs

Curtis J. Ransom https://orcid.org/0000-0002-1268-7247

Newell R. Kitchen https://orcid.org/0000-0003-2268-9016

Kristen S. Veum https://orcid.org/0000-0002-6492-913X

James J. Camberato https://orcid.org/0000-0002-6677-854X

Fabián G. Fernández https://orcid.org/0000-0002-9539-0050

David W. Franzen https://orcid.org/0000-0003-4862-8086

Carrie A. M. Laboski https://orcid.org/0000-0003-2050-767X

Emerson D. Nafziger https://orcid.org/0000-0002-6578-1624

Robert L. Nielsen https://orcid.org/0000-0002-7673-1681

Document Type

Article

Date of this Version

11-1-2021

Citation

Agronomy Journal. 2021;113:5541–5555.

DOI: 10.1002/agj2.20888

Comments

U.S. government work

Abstract

Nitrogen fertilizer recommendations in corn (Zea mays L.) that match the economically optimal nitrogen fertilizer rate (EONR) are imperative for profitability and minimizing environmental degradation. However, the amount of soil N available for the crop depends on soil and weather factors, making it difficult to know the EONR from year-to-year and from field-to-field. Our objective was to explore, within the framework of hydrologic soil groups and drainage classifications (HGDC), which site-specific soil and weather properties best estimated corn N needs (i.e., EONR) for two application timings (at-planting and side-dress). Included in this investigation was a validation step using an independent dataset. Forty-nine N response trials conducted across the U.S. Midwest Corn Belt over three growing seasons (2014–2016) were used for recommendation model development, and 181 independent site-years were used for validation. For HGDC models, soil organic matter (SOM), clay content, and evenness of rainfall distribution before side-dress N application were the properties generally most helpful in predicting EONR. Using the validation data, model recommendations were within 34 kg N ha–1 of EONR for 37 and 42% of the sites with a root mean square error (RMSE) of 70 and 68 kg N ha–1 for at-planting and side-dress applications, respectively. Compared to state-specific recommendations, sites needing ha–1 or no N were better estimated with HGDC models. In contrast, for sites where EONR was >150 kg N ha–1, HGDC models underestimated N needs compared to state specific. These results show HGDC groupings could aid in developing tools for N fertilizer recommendations.