EXAMINING THE IMPACT OF POULTRY LITTER APPLICATION ON WATER QUALITY: RESULTS FROM A FIELD EXPERIMENT

Organoarsenic compounds and trace elements are added to poultry feed for disease control and improved productivity. However, as these compounds accumulate to only a minor extent in tissue, they are excreted into poultry litter and potentially become environmental problems when the litter is applied as fertilizer. This study examines the pathway of arsenic and other species released from poultry litter with the overall goal of documenting the processes controlling their fate and transport/ transformation within agricultural watersheds.

Twenty monitoring wells and four zero-tension lysimeters have been installed at a field site in the Delmarva Peninsula, a region of intense poultry production. Prior to this study, the site had not been litter-applied for more than five years. The site is also instrumented with soil moisture sensors and a novel redox monitoring system to monitor litter leachate through the vadose zone and to examine if the litter leachate affects redox conditions. The wells and lysimeters were sampled before and after a poultry litter application (2 tons per acre), which took place in October 2009. Results show that water-soluble species from poultry litter are mobile, but so far, impact has been limited to soil water. Further sampling will continue to examine if these species are observed in ground or surface waters at the site.