Can something be old as dirt and the next big thing? According to Helge Hellberg, of Marin Organic, it can.

“I believe the sustainable food movement will be focused more and more on soil,” Hellberg told a group of farmers, food producers, educators and advocates at a panel on carbon sequestration at this year’s Eco-Farm conference. “Farmers,” he added, “are crucial because they’re the ear to the soil.”

Well-managed, fertile soil has always been the foundation of sustainable agriculture. Recently, it is also being seen as a pivotal component in the mitigation of climate change. The Marin Carbon Project, a collaboration between Marin Organic, scientists at UC Berkeley, and ranchers in Marin, among others, aims to identify land practices that capture and store carbon in the soil.

Why store carbon in the soil?  Changes in land use and land management (such as industrial agriculture practices, which have stripped a great deal of the arable land in this country of its nutrients) have accounted for around one third of the greenhouse gases that are currently in the atmosphere. Returning to practices that create fertile, nutrient-rich soil not only benefits the food system, it also pulls a percentage of that carbon into a solid form. (See more on the carbon cycle here).

According to Becca Ryals, of UC Berkeley, the Marin Carbon Project is focusing on two promising techniques: the addition of organic amendments (compost) and keyline subsoiling (a form of low-disturbance tillage that loosens soil 12-18 inches down, allowing water to drain deep into the soil, as seen in the above photo). One of the project’s two test sites is the Carbon Farm, a 539-acre pasture in Nicasio. The farm is owned by John Wick & Peggy Rathmann, who set out to preserve and manage their land ecologically. The native grasses on their farm, like in most rangeland ecosystems, are important because many of them have long, perennial roots that store a considerable amount of carbon underground.

The Carbon Project is measuring and comparing carbon in the soil over time in plots where composting, and subsoiling are practiced. “We hope to produce scientifically sound data that we can then bring to rangeland managers so that they may also want to do sequestration projects,” said Ryals.

Many in the room were optimistic about the power of this fairly simple science. Wick read the following quote by Australian author Allan Yeomans, whose father invented the keyline system and Yeomans Plow: “If the organic matter in the top foot of all the world’s field and pasture soils were increased by 1.6%, the greenhouse effect would be back to near normal.”

Jeffrey Creque, Ph.D., an environmental agriculture consultant who has worked with Wick and Rathmann in developing the Carbon Farm, also rang in. “For anyone who’s been farming organically for any length of time, [carbon sequestration in soil] is not a surprising development, but it’s also a pretty exciting time for farmers and ranchers,” he said.

Creque pointed to the USDA’s recent addition of an Office of Ecosystem Services and Markets. The new office will offer financial incentives for land owners to provide clean water and air, wildlife habitat, and carbon storage by recognizing that these crucial aspects of sustainable farming are indeed “services.”

Carbon sequestration will be the first ecosystem service examined by the new office.

Helge Hellberg says Marin Organic is also developing models for how to apply carbon sequestration to California’s Assembly Bill 32, which was passed in 2006 but has yet to be implemented. AB 32 aims to reduce greenhouse gas emissions to 1990 levels by 2020 — an initial reduction of approximately 30 percent, followed by an 80 percent reduction below 1990 levels by 2050.

Marin Organic is also working on a carbon auditing system for businesses in the area as well as a carbon labeling program – which would identify products as carbon neutral or carbon negative.

Beyond providing a possible financial boost for farms and ranches already using sustainable practices, Hellberg believes the nation’s focus on carbon will have an even greater impact.  “Pesticides essentially kill carbon,” he says. “A carbon credit system could offer conventional farmers incentive to transition to organic.”

Photos: USDA, Yeoman’s Concepts, and the Conservation Research Institute

Note: This is the first in a series of articles produced for CUESA highlighting the themes raised at the 2009 Eco-Farm Conference.  This post originally appeared in CUESA’s weekly e-letter.