Before selling carbon credits,...( of carbon change however differences...)

"The accuracy and scale of soil texture data highly influence the accuracy of Century model estimations of soil carbon," said Bricklemyer. "The model accurately estimated soil carbon content and the influence soil clay content had on the amount of carbon in the soil."

Although texture was important in determining SOC storage estimates, the effect of no-tillage management on the rate of carbon storage was not influenced by texture in this study. Some scientists have found that high clay content, or heavy soils, store carbon more rapidly under no-tillage management than soils with little clay content, others have found that clay content has no affect on carbon storage rates under no-tillage practice.

Bricklemyer says that because the effects of clay content on the rate of soil carbon under no-tillage change are not well understood by the research community, clay content information was not directly used by the Century model for carbon change calculations.

"This study also points out the importance of establishing benchmark monitoring sites, under actual farm conditions, where soil texture, soil carbon and other soil properties can be accurately measured and re-measured over time," said Bricklemyer. "Such a system, which currently doesn't exist in the U.S., would help us improve and validate estimates of carbon sequestration over time."

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Contact: Sara Uttech
suttech@soils.org
608-268-4948
American Society of Agronomy
18-May-2007