Ammonia Volatilization from a Swine Waste Amended Bermudagrass Pasture

Abstract

Ammonia (NH3) volatilization may be an important part of the nitrogen (N) budget in swine-waste-amended farming systems. Ammonia volatilization was quantified from three circular bermudagrass (Cynodon dactylon, [L.] pers) plots receiving three split swine (Sus scrofa domestica) effluent applications during the 1998, 1999, and 2000 growing seasons. Plots were maintained over the course of the study and used to characterize relative volatilization patterns following land-application of effluent. Swine effluent was applied based on total phosphorus concentration to approximate 9 kg ha−1 application−1. Based on the total amount of N supplied via swine effluent, plots were supplemented with ammonium nitrate to meet bermudagrass N requirements of 112 kg ha−1 application−1. Immediately following waste treatments NH3 volatilization rates were quantified using a passive field scale technique, which consisted of a rotating mast and five oxalic acid charged tubes located at the center of each plot. Peak volatilization rates ranged from approximately 3 to 8 kg NH3 ha−1 day−1, and total N losses were between 8 to 31% of N applied as swine effluent supplemented with ammonium nitrate. Ammonia volatilization losses associated with land-applied swine effluent were greatest immediately following application and quickly diminished to background volatilization rates.