Measurement of soil respiration using closed chamber method: An IRGA technique

A closed chamber method (CC‐method) using an infra‐red gas analyzer (IRGA) for measuring soil respiration was examined. Two major factors which potentially cause errors: (i) volume of air sampled from the chamber; and (ii) measuring period of time, were examined in laboratory experiments. Field measurements were also conducted with both the CC‐method and the open‐flow IRGA method (OF‐method) throughout a year. The results of laboratory experiments showed that (i) sampling volume of air should be less than 0.2% of the volume of the chamber; and (ii) the air within the chamber should be sampled several times within 20 min. Field measurements showed that soil respiration rates measured by the CC‐method were not significantly different from those by the OF‐method. The results of this study indicate that the CC‐method is as effective for the measurement of the soil respiration rates as the OF‐method.