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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Water Management and Systems Research » Research » Publications at this Location » Publication #426716
Research Project: Improving Crop Performance and Precision Irrigation Management in Semi-Arid Regions through Data-Driven Research, AI, and Integrated Models

Location: Water Management and Systems Research

Title: Excess nitrogen may decrease maize grain yields when water is limited

Author
item Donovan, Tyler
item Comas, Louise
item SCHNEEKLOTH, JOEL - Colorado State University
item DEISS, LEONARDO - Colorado State University
item SCHIPANSKI, MEAGAN - Colorado State University

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/18/2026
Publication Date: 5/27/2026
Citation: Donovan, T.C., Comas, L.H., Schneekloth, J., Deiss, L., Schipanski, M.E. 2026. Excess nitrogen may decrease maize grain yields when water is limited. Agricultural Water Management. 332. Article e110456. https://doi.org/10.1016/j.agwat.2026.110456.
DOI: https://doi.org/10.1016/j.agwat.2026.110456

Interpretive Summary: Crop nitrogen requirements when water is limited are unclear. A field study with two levels of water and six levels of N was conducted on maize in the US Great Plains Region for three years. Maize grain yield and aboveground vegetation increased with N availability when water was fully available, but excess N hurt shoot growth and yield when water was limited. Additionally, excess N hurt maize root growth when water was limited. Maximum grain yield was achieved with 30% less N under limited water. Maize N uptake increased with N and water availability, but depressed total aboveground biomass and grain yield. Adjusting N inputs based on soil N availability and crop N demand is necessary to maximize yields and resource use efficiency in water limited systems and will become increasingly important as water limitations become more common.

Technical Abstract: The effects of nitrogen (N) availability on plant growth when water availability becomes limited are unclear in the literature. Using maize as a model system, a field study with two levels of water (100% and 70% plant evapotranspiration) and six levels of N availability (50 – 327 kg N ha-1 as the sum of fertilizer N, irrigation water N, and soil residual inorganic N) was conducted in the US Great Plains Region from 2021 to 2023. The results show that maize grain yield and total aboveground biomass increased with N availability when water was fully available, but excess N was detrimental when water was limited. Additionally, excess N depressed maize root biomass relative to moderate N availability when water was limited. Maximum grain yield was achieved with an average of 30% less N under limited water relative to full water. Maximum grain yields with limited water were 36%, 59%, and 29% less than full water for the 2021, 2022, and 2023 growing seasons, respectively. The 2023 season received more precipitation and had lower fertilizer N inputs due to residual N accumulation from previous years, yet a yield reduction at the higher N availabilities was still observed in the water limited treatment. Maize N uptake increased with N and water availability during both vegetative and reproductive growth. High N uptake, however, was not only uncoupled with and, thus, not co-limiting with water, but depressed total aboveground biomass and grain yield. Adjusting N inputs based on soil N availability and crop N demand is necessary to maximize yields and resource use efficiency in water limited systems and will become increasingly important as water limitations become more common.