Effects of Anhydrous ammonia application timing on corn yield and profitability

Nitrogen (N) application timing is a critical decision for Illinois corn (Zea mays L.) producers balancing operational efficiency, economic return, and environmental stewardship. This study compared agronomic and economic outcomes of fall versus spring anhydrous ammonia applications across 19 central Illinois sites from 2013 to 2020, using a randomized complete block design with N rates from 0–361 kg N ha-1. Yield response to N was analyzed to determine agronomic optimum N rate (AONR), economic optimum N rate (EONR), and maximum return to N (MRTN). Corn yield responded to N at all sites, but the effects of timing were inconsistent. Across sites, mean EONR, yield, and MRTN for fall-applied ammonia were 213 kg N ha-1, 14.4 Mg ha-1, and $953 ha-1, respectively. For spring applications, these were 187 kg N ha-1, 14.4 Mg ha-1, and $1,104 ha-1. Differences in EONR between timings ranged from 44 kg N ha-1 higher in spring to 75 kg N ha-1 higher in fall. Yield differences at EONR ranged from 1.5 Mg ha-1 higher with spring N to 0.6 Mg ha-1 higher with fall N. Overall, EONR with spring N was, on average, 26 kg N ha-1 lower compared to fall. Site-level responses varied widely, with no consistent links to soil or weather parameters, highlighting the complexity of N dynamics across environments. Results indicate spring anhydrous ammonia can improve Nitrogen use efficiency (NUE) and reduce fertilizer needs without sacrificing yield, supporting more economically and environmentally sustainable production. Further research integrating soil N measurements and additional N sources is needed to refine N rate guidelines and strengthen recommendations within Illinois.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Crop Sciences

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Link, Blake

Contributors dc:contributor

• Jones, John D.
• Nafziger, Emerson D
• Brown, Howard M.

• Corn
• Nitrogen
• Anhydrous Ammonia
• Fertilizer
• Profitability
• Mrtn
• Eonr
• Rtn
• Nue
• Fnue

Statement dc:rights

• Copyright 2025 Blake Link

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/129966

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F129966