A Fully-Automated Environmental Chamber to Study the Interplay between Soil Desiccation Cracking, Temperature, and CO2 Concentration

ABSTRACT Carbon oxidation (CO2) is a potential weakening mechanism of soil and earthen structures under drought conditions. Further, drought conditions can trigger the formation of cracks in soils, affecting gas exchange between the soil and the atmosphere and potentially leading to changes in CO2 fluxes. Simulating climatic conditions in a controlled laboratory environment is a critical initial step toward comprehending the carbon oxidation behavior of soil experiencing desiccation cracking under elevated temperatures. Although environmental chambers have been previously used to investigate desiccation cracking, the effects of desiccation cracking under high temperatures on carbon oxidation in soils remain poorly understood. This paper presents the design and testing of an environmental chamber specifically developed to study soil desiccation cracking and CO2 concentration. An Arduino-based control system allows for easy and cost-effective interfacing with various sensors and relays, and a Raspberry Pi computer facilitates data collection. To test the chamber’s functionality, the temperature and humidity controls were calibrated, and the CO2 sensor capabilities were validated against a commercial chamber. Next, a slurry specimen of medium plasticity clay was tested inside the chamber. The results demonstrate that the chamber is a reliable and effective tool for studying the desiccation crack behavior and soil-atmospheric interactions, such as soil organic carbon oxidation. By simulating climatic conditions in a controlled laboratory environment, this study contributes to a better understanding of the effects of desiccation cracking under high temperatures on carbon oxidation in soils, enabling the development of strategies to mitigate its adverse effects.