Microclimate in open-top chambers: Implications for predicting climate change effects on rice production

A new open-cop chamber (OTC) system, designed to maintain increased CO2 concentration and temperature, was verified to generate abiotic microenvironment closely approximating that in the natural environment of flooded rice under field conditions in the tropics. Although field tests demonstrated that the system could set and control temperature and CO2 to +/-10% precision for >90% of the time, changes in chamber microenvironment conditions that could influence crop growth and development did occur The primary changes in microclimate between chamber and open field were in light transmission (9%) and higher night temperature within the chambers. These differences contributed to 12% reduction in vegetative and reproductive yields inside the chamber compared with that under field conditions. Data from the microclimate assessment suggest that the plant response should be corrected accordingly to approximate the climate change response of rice. This is essential to improve the efficiency of model predictions based on experiments conducted through the OTC approach.