Cleaning up with compost

The rolling green pastures west of Petaluma where Hank Corda stood last week in blue jeans and a camouflage ball cap are not an obvious location to mount a worldwide offensive against climate change.

No factories billow smoke on the 850-acre ranch that’s been in Corda’s family for a century, nor do many vehicles traverse the narrow road. One might surmise the only gross polluters here are the black-and-white dairy cows that graze the property.

In fact, rangelands are a major source of carbon loss through the farming techniques used for harvesting and soil management. A major key to solving the problem, researchers contend, is in the soil on a hillside below Corda’s ranch home.

There, workers dumped compost made of manure and green landscape waste to trap carbon dioxide in the ground and also absorb it from the air. The ranch, which is at the head of San Antonio Creek, is one of three test sites for a novel “carbon-farming” program that researchers say could dramatically lower greenhouse-gas emissions and blunt the effects of climate change, but only if it can be replicated on a mass scale.

The Marin Carbon Project has drawn attention from scientists around the world and, closer to home, from agricultural producers in neighboring counties. It has also caught the attention of Sacramento lawmakers, including Assemblyman Marc Levine, D-San Rafael, who was expected to introduce legislation Monday to expand the program in California.

Advocates say if compost was applied to just 5 percent of California’s grazing lands, the soil could capture a year’s worth of greenhouse gas emissions from the state’s farm and forestry industries.

Corda, a self-described libertarian, is not normally one to buy into big, government-funded ideas. But he agreed to let project managers dust about 20 acres of his ranch with compost and to monitor the progress because he supports helping the environment and boosting his bottom line.

If nothing else, the compost should promote lovely growth in the silage crops that were planted on the spot. Corda’s also hoping he’ll be rewarded with carbon offset credits.

He predicted that some of his ranching neighbors, who have questioned his involvement in the program, will one day regret that stance.

“Old habits die hard,” he said.

Interest in composting and other carbon-farming techniques is growing in Sonoma County among ranchers, viticulturists, orchard growers and other agricultural producers, said Kara Heckert, executive director of the Sonoma County Resource Conservation District.

“I don’t see that kind of enthusiasm often. When people start calling me, that’s a little unusual,” she said.

She said in addition to greenhouse-gas reductions, practices such as composting increase water retention in soils, which is a particularly good thing in times of drought.

“As a practice, you might be working with a landowner that doesn’t necessarily believe in climate change,” she said. “But they certainly understand things like increasing water-holding capacity and increasing crop yields, which helps with their bottom line.”

“Carbon farming” is just a fancy term for what normally occurs during agricultural production and the process of pulling carbon dioxide from the atmosphere into the plant and down through the roots. The goal is to promote practices that improve the rate of carbon dioxide conversion.

Composting has shown the greatest potential for carbon “sequestration.” Research conducted in Marin County and in the Sierra foothills revealed that a single dusting of compost on rangeland can boost the soil’s carbon storage for at least 30 years.

But there are significant hurdles to expanding the practice, including the cost of purchasing and transporting compost to farms. About 30 million tons of organic material ends up in California’s landfills, said Torri Estrada, director of policy at the Carbon Cycle Institute.

He envisions a network of regional facilities producing compost or farmers and ranchers doing so themselves on-site. The compost used on Corda’s ranch came from a Nicasio dairy farm in Marin County.

Estrada said the goal over the next five years is to show that local agricultural agencies can plan and implement successful carbon farming programs.

“It’s not research anymore,” Estrada said. “We know what we need to implement.”

Levine’s proposed legislation would expand research into the compost program by drawing $50 million from the state’s cap-and-trade funds. The money would fund 50 pilot projects around the state, including, Levine said, in North Bay counties.

He called the legislation an historic opportunity to alter the climate change conversation from one of how to reduce greenhouse gases, to how to absorb gases already in the atmosphere. All by doing nothing more than putting more compost on the ground.

“Collecting this data will help us understand whether this is worth pursuing at an even greater scale of investment,” Levine said last week.

You can reach Staff Writer Derek Moore at 521-5336 or On Twitter @deadlinederek.

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