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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVING PRODUCTION STRATEGIES IN CHANNEL CATFISH FARMING

Location: Warmwater Aquaculture Research Unit

Title: Initial Influence of Fertilizer Nitrogen Types on Water Quality

Authors
item Mischke, C -
item Zimba, Paul

Submitted to: Aquaculture Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 20, 2009
Publication Date: June 1, 2010
Citation: Mischke, C.C., Zimba, P.V. 2010. Initial Influence of Fertilizer Nitrogen Types on Water Quality. Aquaculture Research. 41:968-972.

Interpretive Summary: We compared water quality variables and plankton populations when using different types of nitrogen fertilizers. Few differences were found, so any form of nitrogen used for pond fertilization should perform in a similar way without causing substantial water quality problems. Ammonium nitrate and urea contain a higher percentage of nitrogen, requiring less volume than other nitrogen fertilizers. If both urea and ammonium nitrate are available, we recommend using the one with the least cost per pound of nitrogen. If both types of fertilizer have an equal cost per pound of nitrogen, we recommend using urea because there was an increase of desirable zooplankton concentrations in the urea treatment compared to the other nitrogen sources.

Technical Abstract: Using different sources of nitrogen as fertilizer in nursery ponds may affect water quality and plankton responses. We evaluated water quality variables and plankton population responses when using different nitrogen sources for catfish nursery pond fertilization. We compared calcium nitrate (12% N), sodium nitrite (20% N), ammonium chloride (26% N), ammonium nitrate (34% N), and urea (45% N) in 190-L microcosms at equimolar nitrogen application rates. Sodium nitrite-fertilized microcosms had higher nitrite and nitrate levels during the first week; no other differences in water quality among fertilizer types were detected (P>0.05). No differences in green algae, diatoms, or cyanobacteria were detected among treatments; desirable zooplankton for catfish culture were increased in urea-fertilized microcosms. Based on these results, any form of nitrogen used for pond fertilization should perform similarly without causing substantial water quality deterioration. Ammonium nitrate and urea contain a higher percentage of nitrogen, requiring less volume to achieve dosing levels. If both urea and ammonium nitrate are available, we recommend using the one with the least cost per unit of nitrogen. If both types of fertilizer have an equal cost per unit of nitrogen, we recommend using urea because of the potential advantage of increasing desirable zooplankton concentrations.

Last Modified: 9/2/2014
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