Comparison of three simple field methods for ammonia volatilization from manure

Land application of swine manure can result in a loss of nitrogen (N) through ammonia (NH3) volatilization. Accurate NH3 loss assessments are essential to support the development of regional and global emission factors and identify best management strategies for reducing losses. The objectives of this study were to simultaneously assess the reliability and applicability of three simple NH3 flux measurement techniques and their effectiveness and usefulness for the measurement of emissions from surface-applied swine manure. Ammonia losses from two chamber systems were compared: (i) static and (ii) wind tunnel chamber, as well as the (iii) micrometeorological theoretical profile shape (TPS) method. A series of field tests were performed at the Agriculture and Agri-Food Canada (AAFC) Research Farm in Harrington, Prince Edward Island (PE) on a sandy loam, stubble field that was surface applied with 100 kg NH4-N ha-1 of liquid swine manure. After application the three NH3 emission techniques were established and measurements were performed over a 5-d period. Ammonia losses from the wind tunnels were comparable with those from the TPS method. The static chambers were found to underestimate NH3 emissions (by ∼95-99%), compared with both the wind tunnel and TPS methods. It is therefore recommended that either the TPS or wind tunnel approaches be used to more accurately quantify NH3 losses for field systems.