Submitted to: Journal of Environmental Quality
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/9/2004
Publication Date: 6/16/2004
Citation: Sharpe, R.R., Schomberg, H.H., Harper, L.A., Endale, D.M., Jenkins, M. 2004. Ammonia volatilization from surface-applied poultry litter under conservation tillage management practices. Journal of Environmental Quality. 33(4):1183-1189. Interpretive Summary: The production of over 4 billion poultry in the Southeastern U. S. results in more than 4 million tons of feces/litter each year which must be disposed. Land application of the waste is the preferred method of disposal and allows for the recycling of nutrients by crops. During and after land application, nitrogen can be lost to the environment by several pathways including ammonia (NH3) volatilization to the atmosphere. Elevated atmospheric levels may pollute surface waters and contribute to forest decline and species changes in natural ecosystems. The study was conducted at the J. Phil Campbell, Sr. Natural Resource Conservation Center in Watkinsville, GA to determine the emission rates of ammonia after application of poultry litter under field conditions. Litter was surface applied to supply 80 to 125 lb nitrogen per acre. Ammonia losses to the atmosphere ranged from 5 to 23 lb per acre (3 to 24% of applied nitrogen) during the winter and summer, respectively. The largest losses occurred during hot, dry, windy conditions. Losses of 23 lb ammonia per acre could result in nitrogen deficiency in the crop and could potentially be harmful to the environment. Precipitation of 0.7 inches essentially halted ammonia losses to the atmosphere. The results of this study are applicable to the 51 million acres of conservation tillage in the Southeast and should be useful to poultry producers as well as state and federal environmental agencies.
Technical Abstract: Land application of poultry litter can provide essential plant nutrients for crop production but ammonia (NH3) volatilization from the litter can be detrimental to the environment. A multi-season study was conducted to quantify NH3 volatilization rates from surface applied poultry litter under different conservation tillage management. Litter was applied to supply 90 to 140 kg N ha-1. Evaluation of NH3 volatilization was determined using gas concentrations and the flux gradient gas transport technique using the momentum balance transport coefficient. Ammonia fluxes ranged from 3.3 to 24% of the total N applied during the winter and summer, respectively. Ammonia volatilization was rapid immediately after litter application and stopped within 7 to 8 days. Precipitation of 17 mm essentially halted volatilization, probably by transporting litter N into the soil matrix. There was no differences in total NH3 volatilization between no-till and paraplowed treatments.