Is EONR the right target for corn nitrogen fertilizer management?

Authors: Kitchen, Newell; Ransom, Curtis; SCHEPERS, JAMES - University Of Nebraska; HATFIELD, JERRY - Retired ARS Employee; MASSEY, RAY - University Of Missouri; Drummond, Scott

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/2021
Publication Date: 11/7/2021
Citation: Kitchen, N.R., Ransom, C.J., Schepers, J.S., Hatfield, J.L., Massey, R., Drummond, S.T. 2021. Is EONR the right target for corn nitrogen fertilizer management? [abstract]. ASA-CSSA-SSSA Annual International Conference, November 7-10, 2021, Salt Lake City, Utah. Available: https://scisoc.confex.com/scisoc/2021am/meetingapp.cgi/Paper/135099

Interpretive Summary:

Technical Abstract: For corn, N fertilizer use is often summarized from field to global scales using average N use efficiency (NUE). But expressing NUE as averages is misleading because grain increase to added N diminishes near optimal yield. Using three datasets [North America (n=28), Nebraska (n=75), Missouri (n=86) of grain yield in response to N fertilizer, we evaluated NUE near economic optimal N rate (EONR). For those last units of N fertilizer applied to reach EONR, NUE as determined by the N removed with the grain is extremely low (< 10%). Our analysis also shows how precipitation amount and distribution during the growing season impacts NUE. Conditions with too much rainfall and/or uneven rainfall produced low NUE near ENOR. Examining NUE in this way creates unique perspective and helps generate ideas for how to improve N fertilizer management tools, educational programs, and public policies and regulations.