Effects of Soil CO2 on Corn and Soil Environment: Simulation of CO2 Leakage from Carbon Capture and Storage (CCS) Site.

Carbon capture and storage (CCS), a technology to capture CO2 from major industrial sources and inject into underground reservoirs for long-term isolation, can be an ultimate mitigation of climate change. However, potential leakage of CO2 from the facilities could lead to serious damage to soil systems. In general, monocots and C4 plants were reported to be more tolerant to high soil CO2 than dicots and C3 plants. Therefore, a greenhouse study was conducted to investigate the effects of CO2 on responses of corn plants, known as tolerant to elevated soil CO2. Treatments included CON (no injection), CO2 (99.99% CO2 injection), ACID (H2SO4+HNO3 addition) and CO2+ACID. The pure CO2 was injected to soil in the specially designed growth box with gas conduit. The ACID and CO2+ACID treatments were employed to examine the effects of soil CO2 leakage on the acidic soil environment such as agricultural fields in South Korea. Soil CO2 and O2 were maintained 30% and 16%, respectively, in the CO2 treatments. The CON and ACID treatments had an ambient CO2 and O2 levels. In the CO2, ACID and CO2+ACID treatments, chlorophyll contents were decreased compared to the CON from the 8th day of incubation. In the ACID treatment, chlorophyll content was recovered to the similar level as that in the CON on the 15th day, while that was remained lower in the CO2 and CO2+ACID treatments until the end of experiment. Prolonged incubation of 30 days reduced shoot and root length in the CO2 and CO2+ACID treatments, but the magnitude of reduction was only by 16% compared to the CON. These indicate that corn plant might have been adapted to the elevated CO2 condition. Overall results indicate that elevated soil CO2 concentration of 30% during 30days was not lethal to the corn plant and imply that the plants have compensation mechanisms to the CO2-induced stress.