Maize grain yield and crop water productivity functions in the arid northwest U.S.

Authors: Tarkalson, David; King, Bradley - Brad; Bjorneberg, David - Dave

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/25/2022
Publication Date: 2/3/2022
Publication URL: https://handle.nal.usda.gov/10113/7663882
Citation: Tarkalson, D.D., King, B.A., Bjorneberg, D.L. 2022. Maize grain yield and crop water productivity functions in the arid northwest U.S. Agricultural Water Management. 265. Article 107513. https://doi.org/10.1016/j.agwat.2022.107513.
DOI: https://doi.org/10.1016/j.agwat.2022.107513

Interpretive Summary: Increased water demands and drought have resulted in the need to provide data to guide deficit water management decisions in irrigated corn grain production. The objective of this study was to develop relationships between corn grain production factors and corn water use and water input under low and high nitrogen input systems on a soil type common to corn production in the arid Northwest U.S. The treatments consisted of two N inputs (0 and 246 kg nitrogen per hectare per year) and four water input treatments ranging from 100 to 25 percent of full irrigation. The full irrigation treatment crop evapotranspiration was 20 percent less than evapotranspiration model calculated crop use, indicating that crop coefficient values should be adjusted for corn in the arid Northwest United States. Crop water production functions were developed using quadratic relationships between corn grain yield and crop evapotranspiration and water input. These relationships are valuable to understanding corn response over a range of water availability and in developing tools to assess future production under water shortages.

Technical Abstract: Increased water demands and drought have resulted in the need to provide data to guide deficit water management decisions in irrigated corn grain production. The objective of this study was to develop relationships between corn grain production factors and corn water use (evapotranspiration) and water input under low and high nitrogen input systems on a soil type (silt loam) common to corn production in the arid Northwest U.S. The treatments consisted of two N inputs (0 and 246 kg nitrogen per hectare per year) and four water input treatments ranging from 100 to 25 percent of full irrigation. The full irrigation treatment crop evapotranspiration was 20 percent less than evapotranspiration model calculated crop use, indicating that crop coefficient values should be adjusted for corn in the arid Northwest United States. There were no grain yield response differences between N input treatments in 2017 but during 2018 and 2019 (treatments on same plots), crop evapotranspiration versus grain yield and water input versus grain yield relationships were different for the N input treatments. Crop water production functions were developed using quadratic relationships between corn grain yield and crop evapotranspiration and water input. The range of grain yield across all years and treatments were 15.03 to 7.23 metric tons per hectare. The range of crop water productivity across all years and treatments were 1.6 to 2.6 kilograms per cubic meter of water use. The crop evapotranspiration at maximum crop water productivities across all years and treatments had a range of 60 to 71 percent of model calculated crop evapotranspiration. These relationships are valuable to understanding corn response over a range of water availability and in developing tools to assess future production under water shortages.