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A crimson clover cover crop being used in the conservation tillage system at the carbon dioxide enrichment study site in Auburn, Alabama. Click the image for more information about it.

Farming Practices Influence the Effects of Rising Carbon Dioxide

By Laura McGinnis
August 29, 2006

If atmospheric carbon dioxide (CO₂) concentrations double within the next century, as some scientists predict, how should agriculture respond?

Agricultural Research Service (ARS) scientists in Auburn, Ala., are in the eighth year of a study to help answer this important question. At the ARS Soil Dynamics Research Unit, scientists are examining how different farm management practices can help store carbon in the soil, thus keeping it out of the air. Their research explores how increasing concentrations of atmospheric CO₂ affect crops.

Plant pathologist G. Brett Runion is conducting the research with plant physiologist Stephen A. Prior and research leader H. Allen Torbert.

The scientists are using cylindrical, open-top field chambers to expose growing crops to varying levels of atmospheric CO₂. Measurement of soil and plant responses to rising CO₂ enables the scientists to understand how to manage agricultural systems to increase the amount of carbon stored in plant residues and soil.

Increased carbon storage has multiple benefits, such as reduced soil erosion and compaction, increased water-holding capacity for plants and a slower rise in atmospheric CO₂ concentrations.

Runion is also using a system called ACES—for “automated carbon efflux system”—to track carbon as it flows from soil to atmosphere. Currently the group is using ACES to compare the effects of CO₂ on conventional and conservation tillage systems for a sorghum-soybean crop rotation.

Read more about the research in the August 2006 issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture’s chief scientific research agency.