California’s jurisdictions have begun reducing organic wastes under a new composting law that takes effect in 2025, changing the landscape of waste management and making compost more accessible to farmers and cities alike. Senate Bill 1383, passed in 2016 to curtail emissions of methane and other “super pollutants,” requires local governments in California to reduce the amount of green waste (food scraps and yard trimmings) sent to the landfill by 75 percent before 2025.
The increase in compost volume, farmers say, will make using it less expensive and could help improve climate resiliency on California farms in the face of more frequent droughts. However, it remains to be seen whether cities and private waste management companies can keep up with the increasing volume of green waste. When green waste like food scraps and yard trimmings are sent to the landfill along with other trash, they rot, producing methane, a greenhouse gas about 80 times more potent than carbon dioxide over a 20-year period. But when such organic waste is sent to composting facilities instead of landfills, that methane can be captured and used as “biogas,” an energy source, rather than being released into the atmosphere.
After the biogas has been used to power trucks or provide electricity, compost companies sell the remaining organic matter to farmers, who apply it to their crops. Returning organic matter back to the soil as compost introduces important nutrients that boost soil health and improve crop yield. Mike Barrett, who works at Casbar Farms in Dixon, California, said his farm uses compost mainly for the microbial benefits. “Once we get that microbial life established, we can minimize the amount of fertilizer we put out,” he said, adding that Casbar farms has been able to decrease its fertilizer applications by about half.