Submitted to: Soil Use and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 10, 2000
Publication Date: September 20, 2001
Citation: Torbert, H.A., Prior, S.A., Rogers, H.H. Effect of elevated CO2 and temperature on soil C and N cycling. Rees, R.M., Ball, B.C., Campbell, C.D., Watson, C.A., editors. Sustainable Management of Soil Organic Matter. 2001. CAB International. p. 309-315. Interpretive Summary: Recently, scientists have become concerned regarding the concentration of CO2 in the atmosphere which could potentially cause changes to the global environment such as global warming. The objective of this study was to examine how these potential environmental changes (elevated CO2 and warmer temperatures) may impact the soil. Results from this study indicate that nutrient cycling may be increased in agricultural fields with an increase in soil temperature, which could increase nutrient availability to growing plants and therefore reduce the impacts predicted from global warming. Further, increased biomass production with elevated CO2 will likely result in more soil C storage which could further reduce the impact of global change by reducing the concentration CO2 in the atmosphere.
Technical Abstract: Increasing atmospheric CO2 concentration has led to concerns about global environmental changes including potential increases in global temperature. Elevated CO2 can affect plant growth resulting in changes in residue quantity and quality returned to soil, but the impact of such change in conjunction with changes in soil temperature on soil C and N dynamics and long-term soil C storage are not clearly understood. A laboratory incubation study on potential microbial respiration and N mineralization was conducted using Blanton loamy sand (loamy siliceous, thermic, Grossarenic Paleudults) soil samples collected from field plots after five years of growing crops under ambient and elevated CO2 levels. The study was a split-plot design with two crops (soybean [Glycine max (L.) Merr.] and grain sorghum [Sorghum bicolor (L.) Moench.]) as main plots and two CO2 levels (375 and 705 micro liters/liter CO2) as subplots. Differences between three soil temperatures (20, 25, and 30 degrees C) during laboratory incubation were also considered. After five years, a trend for increases in both soil organic C and soil total N was observed with elevated CO2 for both crops. Changes in potential soil microbial respiration and N mineralization during the 60 d incubation were also observed.