Compost is a valuable commodity in the agricultural community. When applied to soil, it enhances water-holding capacity, provides stable, slow-release nutrients, enhances soil carbon sequestration and increases forage production without harming native plant communities. Within the carbon farming framework, compost application can be part of a smart, comprehensive plan to manage carbon at a whole farm level. In a rangeland setting, it is best to identify sites most appropriate for compost application with a professional land manager and conduct application alongside a holistic or managed grazing regime.

From a climate perspective, compost is a triple win. It increases sequestration (the drawdown of atmospheric carbon into the soil), mitigates emissions from other sources (landfilling, burning or allowing organic materials to rot in ponds or pits, which releases the powerful, short-lived greenhouse gases methane, nitrous oxide and black carbon) and enhances the land’s resilience to extreme weather (flooding and drought). Composting can offer an alternative strategy for manure management in Marin and across the state of California

Compost may be made onsite but there are also some excellent local compost operations in Marin County. One option is West Marin Compost. This agricultural compost facility was developed to serve as a regional processing site for County green waste and animal manure from neighboring farms and ranches as well as the host dairy.


Many people incorrectly call all sorts of raw organic waste (like mulch or manure) compost. Compost can be made from anything that was once alive, but it is not the “raw” material itself. Unlike mulch or dried manure, compost is the final product of a managed thermophilic process through which microorganisms break down organic materials into forms suitable for beneficial application to the soil. A well-managed composting process has plenty of oxygen, goes through a high-heat phase that accelerates the natural biodegradation of organic materials and produces a stable form of organic matter that is made up of carbon and nitrogen, contains other important nutrients, and is free of weed seeds and harmful pathogens. For environmental and agronomic reasons, it is important to note that the type of nitrogen found in compost (organic N) is not the same as the nitrogen in synthetic fertilizers (inorganic N).


For the original MCP experiments conducted in Marin and the Sierra Foothills Extension Research and Extension Center, the compost used was an organic OMRI-certified green waste product produced in Marysville by Feather River Organics. The first three demonstration projects in Marin used a manure and green waste–based product from West Marin Compost.

If you are an agricultural producer or landowner seeking assistance in development of a Carbon Farm Plan (CFP), contact your local RCD or NRCS office.

Get started with your CFP.