Automated Monitoring of Soil Respiration: an Improved Automatic Chamber System

Abstract

We designed, constructed and tested an automated chamber system for continuously monitoring soil respiration. Our objective was to design a system that would permit monitoring of CO2 efflux rates over long time periods without altering microclimate inside the chamber. The measuring principle is based on the measurement of the increase in CO2 concentration within an automated chamber in a fixed amount of time using a non linear regression method. The chamber operates by closing over the soil in response to a control signal and remains closed for a fixed amount of time. In this way, the chamber allows normal drying and wetting of the soil between measurements. We report results that show the reliability of soil CO2 efflux measurements in comparison with Li-Cor 6400. The system holds great potential for long term continuous measurements campaigns in natural environments.