Validation of a New Method for Quantification of Ammonia Volatilization from Agricultural Field Plots

A modified low-cost method of measuring ammonia (NH3) volatilization is described for use with static chambers. This technique utilizes glass tubes coated with oxalic acid placed inside the chambers to adsorb NH3 being evolved from soil. The advantage of this procedure is that it can be used to quantify NH3 emissions from field plots used for evaluating multiple management practices in an agricultural field. A correction factor is required to accurately estimate NH3 levels inside the static chambers. In addition, if the static chambers are made of an NH3 absorbing material, another correction is needed to obtain an accurate estimate of NH3 air concentration. Values measured with this technique can be used to estimate NH3 efflux rates and to determine the efficacy of agricultural practices that could potentially suppress volatilization losses evaluated from research plots. Herein, the modified static chamber method is described and validated by comparison with NH3 gas detector tubes.