Measurement of NH3 Emission At Dairy Lagoon Water Application Sites.

Nutrient management plans (NMPs) for field-scale application of dairy lagoon water to crops require information about volatilization losses of NH₃. Equilibrium models are commonly used to estimate NH₃ emissions from lagoon water. However, such models do not always accurately reproduce observed NH₃ emissions, which may be partly due to an incomplete mechanistic understanding of NH₃ production. In this study, NH₃ emissions from three different liquid sources [(pure solutions of (NH₄)₂SO₄ (AS), dairy anaerobic lagoon liquid (DALL), and recycled water constituents (RWC)] were measured using a small flow-through chamber and acid-trap technique.  Emissions from DALL and RWC were compared with similar results from pure (NH₄)₂SO₄ solutions, and relationships between NH₃ flux and pH, temperature, and total ammoniacal nitrogen (TAN) under controlled conditions were investigated. The NH₃ flux was found to vary linearly with the TAN concentration. Information gathered by this study will facilitate the application of Eddy covariance flux measurements to quantify NH₃ losses from dairy lagoon water and agricultural fields under NMP conditions.