A New Dynamic Chamber Technique for Measuring Ammonia Emissions from Land-Spread Manure and Fertilizers

Abstract

A new micrometeorological method for measuring ammonia emission and/or deposition has been developed. The method is based on the stirred dynamic chamber technique in combination with passive diffusion samplers. Measurements are made close to the treated surface where (i) the driving force, represented by the NH₃ concentration difference between the soil and the air, and (ii) the atmospheric resistance are being estimated. The method was shown to be cost-effective and easy to maintain. The equipment gave results of good replicability when tested in field measurements. The relative standard deviation for duplicate determinations of concentration in the chamber was approximately 4%, and the corresponding figure for the average equilibrium concentration obtained in different chambers placed in the same field was approximately 18%. This uncertainty was probably due to the fact that the surface areas on which the chambers were placed were not representative of the whole areas.