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Study in West Marin fights global warming




Removing carbon dioxide from the air and burying it in soil could be a way to stop the effects of global warming, a process under study in West Marin.

A delegation from China's Ministry of Agriculture visited a Nicasio Ranch on Thursday to learn about ways to prepare ranchland soil to absorb carbon from the air, helping reduce the impact of climate change.

"The thing that many people don't realize is that soils have always sequestered carbons," said Torri Estrada, environmental program officer for the Marin Community Foundation, which has given $1.4 million to the project. "It's been human interaction and the changing of the landscape that's muted that effect."

It's estimated the over the past 150 years, between 50 and 80 percent of topsoil worldwide has been lost and that more than a third of the carbon dioxide added to the atmosphere during that time has come from changes in land use.

The Marin Carbon Project is trying to determine whether by changing practices for grazing lands, carbon could be better absorbed from the atmosphere.

Soil carbon absorption, or "sequestration," is the process of moving carbon dioxide from the atmosphere into the soil. Through photosynthesis, plants pull carbon dioxide out of the atmosphere and transfer that carbon below ground via roots and to the soil surface.

Research is being conducted on the Nicasio ranch of John Wick - who is director of the project - to determine if managing the land in a way that encourages plant and

shrub growth could make a difference.

"We could develop these practices into programs that our partners can promote in the agricultural community," said Wick, who gave the Chinese delegation a tour of his land. "A lot what is going on right now is the research."

Researcher Whendee Silver of the University of California at Berkeley, who is leading much of the work, said preliminary results - the team is one year into the five-year project - are promising.

"Plants are pulling carbon out

of the atmosphere and ... they put it below ground into soils, into their root systems," said Silver, who spoke to the delegation at Druid's Hall in Nicasio before the ranch tour. "You can see that our experimental plot is much greener than the control plot. We grew much more grasses by adding compost."

That greener grass likely means more carbon is being stored. The carbon in the soil can be measured by probes that can look at content as well as air coming out of the soil.

The project is a collaboration between UC Berkeley, UC Davis, UC Cooperative Extension, Marin Organic, Marin Agricultural Land Trust, the Marin Resource Conservation District, the U.S. Department of Agriculture and Nicasio Native Grass Ranch. It is also supported by the Marin County agriculture commissioner and the Environmental Defense Fund.

A soil survey to establish existing levels of carbon in Marin's rangeland soils has already been completed as part of the project. This baseline data will allow the accurate assessment of how much carbon is absorbed over time.

Charles Han, who served as interpreter for the group of Chinese visitors, said they wanted to learn more about the process.

"They are very interested in land and grass issues," he said. "We have a lot of land in China."

For more information about the Marin Carbon Project, visit www.marincarbonproject.org