Intercomparison of Chamber Methods for Soil Respiration Measurement in a Phytotron System

Soil CO2 emission is one of the primary components in carbon balance of terrestrial ecosystems. In soil CO2 flux measurements, chamber method is currently the most common technique. Prior to compare or synthesize the data collected from different chamber methods, potential biases must be quantified for each measurement system. We have conducted an intercomparison experiment among four closed dynamic chamber systems and an automatic open-closed chamber system in a temperature-controlled phytotron. Due to the disturbed CO 2 concentrations inside the phytotron during the measurements with closed dynamic chambers and the changes in soil water content, the interpretation of the data was difficult to quantify the biases of individual methods. However, the experiment provided not only valuable information on the performance characteristics of the five instruments to varying soil temperature and CO2 concentration but also useful insights for better designs and strategy for future intercomparison in a controlled environment.