When looking for ways to counteract climate change, one solution lies under our feet. According to world-renowned soils scientist Professor Rattan Lal of Ohio State University, a mere 2% increase in the carbon content of the planet’s soil could offset 100% of all greenhouse gas emissions going into the atmosphere! In other words, put CO2 back into the ground by encouraging nature and plants to do their job. One ton of carbon stored in the soil is equivalent to more than 3 tons of CO2 removed from the atmosphere.
Recent research by the Marin Carbon Project, which focused on ranching practices, showed that compost made from ordinary yard clippings, household food scraps, and dairy manure could rejuvenate worn out soil, allowing it to rapidly absorb CO2 from the atmosphere. They calculated that 1/2 inch of compost applied over just 5% of the State’s grazing lands could capture a year’s worth of greenhouse gas emissions from California’s farm and forestry industries. The organic matter from a one-time application of compost jump-started a positive feedback loop in the soil that lasted for over six years, and may last for several decades.
This research was so compelling that the State of California recently approved a protocol to allow ranchers to sell carbon credits under California’s cap-and-trade system. The American Carbon Registry, an organization that certifies how carbon credits are measured, in October 2014, approved one for applying compost to rangeland. For the first time, the State of California recognizes that carbon sequestration in the soil is an effective strategy for mitigating climate change!
The implications are just beginning to be understood. The Sierra Club, in February, approved a new Agriculture and Food policy that supports healthy soil, and in May the Loma Prieta Chapter formed a Soils Committee to promote carbon sequestration in soil. The city of San Francisco has recently calculated that they can offset 100% of all their GHG emissions by making compost from the yard waste they collect, and spreading it on city land.
The message is becoming clear -- whether it’s ranches, farms, forests, or your own backyard: put compost on top of soil to stimulate plant growth and attract the soil organisms that pull CO2 out of the atmosphere and store it in the ground. For even better results, cover the compost with a layer of mulch. An old adage, “Feed the soil, not the plant” is just as important today as it was centuries ago. In the words of Thomas Jefferson, “Civilization itself rests upon the soil.”
Bill Buchholz is a member of the Loma Prieta Chapter Soils Committee, Forest Protection Committee, and the national Forest Certification Committee.