CENTRAL VALLEY COMMUNITY COMPOSTING
Summary for COAR Fall Gathering 2025
Our objective is to engage in community-centered research and education to advance small-scale composting in the San Joaquin Valley.
BACKGROUND: Compost is a scalable action that mitigates climate change and fosters healthy agroecosystems by preventing
landfill methane emissions, reducing demands for synthetic fertilizers, and improving soil health. Small-scale, decentralized composting as a critical strategy to address multiple challenges: local food insecurity, soil degradation, and limited access to affordable soil amendments.
With previous funding from UC Climate Action Seed Grants we have partnered with community-based organizations to form Central Valley Community Compost (CVCC).
TEAM MEMBERS AND COMMUNITY PARTNERS:
UC Merced: Rebecca Ryals & Michael Rodriguez
Through previous work we have established relationships with partner community-based organizations through financial support, regular site visits, monthly meetings, Memoranda of Understanding (MOU), and supporting community outreach events.
SUPPORTING EQUITABLE AGROECOLOGICAL TRANSITIONS: When we intentionally center small farmers and BIPOC communities disproportionately impacted by environmental racism, composting can be a tool for equity and climate justice. This work aims to have UC actively and responsibly support marginalized communities and land stewards who have worked to improve environmental quality.
Compost enriches soil health leading to more productive community gardens and farms, contributing to local food security and sovereignty. Moreover, small-scale composting can reduce localized air-pollutant emissions.
POLICY CONNECTIONS: California’s Senate Bill 1383 (2016) legislates the need to divert organic waste from landfills and composting is the primary strategy to meet these goals. Just recently, Senate Bill 279 (2025) increases the capacity for community and on-farm composting. Community Composting aligns many other state agency initiatives such as the Climate Change Scoping Plan, Natural and Working Lands Implementation Plan, and Healthy Soils Initiative.
CENTRAL VALLEY COMMUNITY COMPOSTING
PREVIOUS RESEARCH ACCOMPLISHMENTS WITH UC CLIMATE ACTION GRANT:
Mapping of technical potential of community composting to divert organic waste in the Central Valley.
Community partners have implemented small-scale composting systems and composted over 30,000 lbs of organic waste at four community garden sites.
Community partners collected compost monitoring data to track compost feedstocks and resource needs.
Hundreds of compost samples have been analyzed for various compost properties and nutrient availability.
Intensive field measurements of 5 compost piles to study greenhouse gas and air pollutant emissions over time.
Preliminary soil sampling at community garden sites.
PREVIOUS EDUCATION ACCOMPLISHMENTS WITH UC CLIMATE ACTION GRANT: There are many educational opportunities linked with community-scale composting for students of all ages and practitioners of all levels.
Held over 15 hands-on workshops for community members to learn about the benefits of composting and a variety of composting strategies.
Developed formal curriculum for a weeklong Bobcat Summer STEM Academy at UC Merced for middle school students.
Shared educational posts and resources on social media.
NEXT STEPS WITH COAR:
Support our current community partners in upscaling composting operations.
Expand our network and implement additional community compost sites in the Central Valley.
Create “Train the Trainer” resources so community partners can host their own composting workshops.
Co-create new research questions on optimizing the composting process (i.e. biochar co-composting)
Community composting partners “story mapping”.
Further research impacts on soil health and crop quality.