Design, fabrication, and application of a dynamic chamber for measuring gas emissions from soil

Dynamic or flow-through flux chambers are convenient tools for field measurements of gas fluxes from sails to the atmosphere. In this study, a dynamic flux chamber is designed and fabricated on the basis of aerodynamic considerations so that the conditions assumed for the flux model are closely satisfied. The chamber consists of an inlet transition zone, a square main body, and an outlet transition zone. Six equally-spaced air channels are installed in bath inlet and outlet transition zones to conduct and spread the flowing air uniformly across the soil surface, which help to produce a simple, horizontal, and uniform airstream above the covered soil surface. Aerodynamic tests in the laboratory show that the air sweeps over the entire covered soil surface with a relatively constant velocity at a given air flow rate, and no stagnant air zones are present. The chamber is used in a field fumigation experiment to measure methyl bromide emission at the soil surface. The emission results obtained from the chamber are consistent with those obtained from micrometeorological methods used in the same experiment.