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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 #405249
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: Nitrogen and water availability effects on soil N dynamics

Author
item DONOVAN, TYLER - Colorado State University
item SCHIPANSKI, MEAGAN - Colorado State University
item SCHNEEKLOTH, JOEL - Colorado State University
item Comas, Louise

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/8/2023
Publication Date: 11/1/2023
Citation: Donovan, T., Schipanski, M., Schneekloth, J., Comas, L.H. 2023. Nitrogen and water availability effects on soil N dynamics. ASA-CSSA-SSSA Annual Meeting Abstracts. Meeting Abstract.

Interpretive Summary: N/A

Technical Abstract: There are relatively few studies on how nitrogen fertilizer and water interactions alter nitrogen mineralization (N min) rates, but these interactions have been shown to have both direct and indirect, positive, and negative effects on mineralization rates. Given that N min can be the largest source of N for agronomic crops during the growing season it is important to understand how nitrogen and water alter mineralization rates. Our study was conducted on a continuous corn cropping system at the USDA-ARS Great Plains Research Center in Akron, Colorado during the 2021 and 2022 growing season. Six N fertilizer rates ranging from 22 to 275 kg per ha were used capturing low to excessive N, and two water treatments of 100% ET and 70% ET were used capturing full water and near dryland conditions for the region. Extractable nitrogen was measured every two weeks from emergence to physiological maturity by taking soil samples from the 0 – 15 cm depth with an 18 mm soil probe. Net N min was also measured every two weeks from germination to physiological maturity by incubating undisturbed soil cores (15 cm depth) with ion exchange resin at the bottom in PVC in-field. Extractable N was higher with increased N fertilizer rates, higher in the water limited treatment, higher in 2022 than 2021, and decreased as the growing season progressed. Nitrogen mineralization rates followed a similar trend where mineralization rates were higher with higher N fertilizer rates, higher in the 2022 growing season, decreased later in the growing season, but N min was higher under the full water availability. Our results show that N fertilizer and water availability can alter soil N dynamics by increasing N min rates, especially earlier in the growing season, such that irrigation and fertilizer applications can potentially create a legacy effect leading to increased N min and extractable N as treatments are repeated each growing season.