Nitrogen Loss From Sprinkler Applied Beef Feedlot Effluent.

Loss of nitrogen from sprinkler applied beef feedlot effluent can be costly for both the producer and the environment. Sprinkler application of effluent is common throughout the Great Plains, though little work has occurred focusing specifically on N losses from beef feedlot effluent. The objectives of two studies were to quantify NH₃ and N₂O losses from beef feedlot effluent applications under field conditions and determine the effects of soil pH, percent water filled pore space, NH₄⁺ concentration of the effluent, and weather conditions on NH₃ and N₂O. Nitrogen losses during application were determined from the differences between NH₄⁺-N concentration of samples taken under the sprinklers and samples taken from the effluent. NH₃-N and N₂O emission following application were measured using a closed chamber technique with a recirculating configuration and acid traps. In the first study, sprinklers were protected from the wind and NH₄⁺-N losses during application were not seen. Average rate losses from a second study, with no protection against wind and a mean wind speed of 15 m s^-1, accounted for 55% of the effluent NH₄⁺-N from drift beyond collection jars during sprinkler application. Following application, N losses from both volatilization and N₂O emissions from soil were less than 1% of the original effluent NH₄⁺-N concentration. Soil pH and effluent NH₄⁺-N concentration did not significantly affect the percent of N lost. Increasing wind speed and air temperature resulted in greater N losses during application. Weather factors including: soil temperature, air temperature, %WFPS, and relative humidity had varying effects on NH₃ and N₂O emissions following application.