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ARS Home » Southeast Area » Tifton, Georgia » Southeast Watershed Research » Research » Publications at this Location » Publication #415478
Research Project: Shifting the Balance of Water Resources and Interacting Agroecosystem Services Toward Sustainable Outcomes in Watersheds of the Southern Coastal Plain

Location: Southeast Watershed Research

Title: USDA LTAR Common Experiment measurement: Dissolved ammonia (NH3) concentration

Author
item Pisani, Oliva
item Kovar, John
item Malone, Robert - Rob
item Morrow, Amy
item Cole, Kevin

Submitted to: Protocols.io
Publication Type: Research Notes
Publication Acceptance Date: 10/4/2024
Publication Date: 10/4/2024
Citation: Pisani, O., Kovar, J.L., Malone, R.W., Morrow, A.J., Cole, K.J. 2024. USDA LTAR Common Experiment measurement: Dissolved ammonia (NH3) concentration. Protocols.io. https://doi.org/10.17504/protocols.io.j8nlk8b61l5r/v1.
DOI: https://doi.org/10.17504/protocols.io.j8nlk8b61l5r/v1

Interpretive Summary: This protocol is part of a set of protocols for the LTAR Cropland Common Experiment. This protocol outlines the measurement of dissolved ammonia in water samples. Ammonia can originate from municipal effluent and agricultural runoff, and can contribute to eutrophication and hypoxia of surface waters. The goal of this protocol is to provide repeatable guidelines to achieve consistent data collection, instrument maintenance, data processing, and quality control for obtaining these data at established or new sites.

Technical Abstract: Ammonia can form naturally from organic matter mineralization or can enter the aquatic environment via anthropogenic sources such as municipal effluent discharge and agricultural runoff. The presence of ammonia (NH3) vs. ammonium (NH4+) in water depends on water pH and temperature. The un-ionized NH3 form is toxic to aquatic organisms, and both forms (NH4+ and NH3) can contribute to eutrophication and hypoxia of surface waters. The reported measurement of ammonia in water is typically the total ammonia N (TAN = NH3 + NH4+). The recommended techniques for measuring NH3 in water are the colorimetric salicylate and phenate methods, whereby an indophenol color complex is proportional to the NH3 concentration in the sample.