California Healthy Soils Program

California's Healthy Soils Program (HSP), run by the California Department of Food and Agriculture (CDFA) since 2017 and funded through California Climate Investments (cap-and-trade auction proceeds), issues competitive grants to farmers, ranchers, tribes and non-profits for practices intended to build soil carbon and cut on-farm emissions.

Build soil carbon and reduce on-farm emissions via compost application, cover cropping, reduced or no tillage, and hedgerow planting.

Applicants estimate expected greenhouse-gas benefits using CDFA's COMET-Planner/COMET-Farm modelling tools as part of each grant application. A January 2024 round made roughly $12 million available, and California's 2024 Proposition 4 climate bond allocated a further $65 million to the program.

HSP has awarded more than $105 million across over 1,500 incentive-grant projects, which CDFA estimates will deliver a combined lifetime reduction of more than 1.1 million tCO2e - equivalent, the agency says, to taking about 24,000 cars off the road for ten years.

A 2023 peer-reviewed review in Frontiers in Sustainable Food Systems found significant uncertainty in soil-carbon quantification methods and only modest realistic mitigation potential from most soil-carbon practices at scale, and noted some incentivised practices (e.g. no-till) can increase nitrous-oxide emissions even as they raise soil carbon. Reviewers also flagged that direct greenhouse-gas monitoring is optional for some HSP project types, meaning the program's headline tonnage is a modelled projection rather than a verified measurement.