LAGOON NITROGEN BALANCES

Authors: Harper, Lowry; Sharpe, Ronald

Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/4/2004
Publication Date: 10/31/2004
Citation: Harper, L.A. 2004. Lagoon nitrogen balances. American Society of Agronomy Abstracts. Abstract No. 5534. CD-ROM.

Interpretive Summary: High animal production concentration provides increased efficiency and improved economics; however, it also presents a challenge to manage wastes to minimize trace-gas emissions and other losses which could have potential short-and long-term effects on the surrounding environment. The purpose of these studies was to determine accurate emissions of nitrogen gases from swine production systems. Scientists at the J.Phil Campbell, Sr., Natural Resources Research Center, USDA-ARS, Watkinsville, GA, located instrumentation over swine lagoons, in animal housing, and in sprayfields of a production system in eastern North Carolina. Ammonia emissions were evaluated from the lagoons, animal housing, and waste-recycling crops. Other types of nitrogen gases, called biological gases, were measured including nitrous oxide and nitrogen gas. The scientists were able to account for 95% of all incoming nitrogen. Total ammonia emissions from the lagoons, houses, and field application of effluent accounted for 16% and benign nitrogen gas accounted for 43% of incoming nitrogen. The remaining nitrogen left the operation as protein with a small amount stored on site. The use of anaerobic lagoons for animal waste management was found to emit significantly less ammonia to the atmosphere than previously estimated. Evaluation of ammonia emissions and nitrogen cycling will allow producers and regulators to better understand nitrogen utilization and develop more efficient management systems.

Technical Abstract: High animal concentration provides increased production efficiency and improved production economics; however, it also presents a challenge to manage wastes to minimize trace-gas emissions and other losses which could have potential short-and long-term effects on the surrounding environment. The purpose of these studies was to determine accurate emissions of nitrogen gases from swine production systems. Instrumentation were located over the lagoons, in the animal housing, and in the sprayfields. Ammonia emissions from lagoons varied diurnally and seasonally and were related to lagoon ammonium concentration, acidity, temperature, and wind turbulence. Denitrification of significant quantities of ammonium to nitrogen gas was measured in all lagoons. There were little emissions of nitrous oxide from the lagoon but small soil emissions were measured from application of effluent to nearby crops. By measuring all forms of input and output nitrogen in a swine finishing operation, we were able to account for 95% of the incoming feed nitrogen. Total ammonia emissions from the lagoons, houses, and field application of effluent accounted for 16% of incoming nitrogen. Chemical conversion (chemodenitrification) of ammonium to dinitrogen gas accounted for 43% of incoming nitrogen. The use of anaerobic lagoons for animal waste management was found to emit significantly less ammonia to the atmosphere than previously estimated.