Case Studies

Marin Agricultural Land Trust – Enhancing Carbon Sequestration

Marin County’s topography is one of rolling hills, coastal bluffs and flat interior valleys separated by hills. While the topography, non-prime soils, and lack of reliable water supplies are deterrents to more intensive agriculture like row crops, some areas in Marin are rich in alluvial soils that support diverse vegetable and specialty crops. Due to foggy, moist conditions, Marin’s coastal agriculture is well known for its quality grasslands, making the area well-suited for grazing.

Value of the Land 

Livestock grazing is the single largest land use on the planet, occupying about a quarter of Earth’s landscape. About half of the land in California supports livestock grazing in some way. In Marin County, much of the land is managed for perennial grasses and the livestock they support – primarily cows, sheep, and goats. According to the U.C. Cooperative Extension report, approximately 167,000 acres in Marin – about 50% of the land area – are farms or ranches, supporting 255 agricultural operations. Of these businesses 64 are considered “large farms” (annual gross income of $100,000 or more) and 191 are considered small or mini-farms (annual gross income of less than $100,000).  Agriculture in Marin, composed primarily livestock grazing operations (159), organic produce operations (56) and dairies (30, including 1 sheep and 2 goat) contributes over $49 million annually to the local economy.

The Marin Agricultural Land Trust (MALT) preserves working farms in Marin County. In doing so, these efforts protect much more than the land itself. Benefits of sustainable working farm management include production of local food, protection of habitat and open rangeland, and enhancement of ecosystem services such as clean air, clean water, and carbon sequestration.

Conservation Concerns

In the early 1960s, Marin County’s plan for coastal development envisioned dramatic changes for West Marin, including plans for a city with a population of 125,000 on the shores of Tomales Bay. If implemented, the planned development would have ended a 150-year-old tradition of family farming.  As “For Sale” signs started to line rural roadways, farmers, environmentalists and other Marin citizens joined forces to do something about it; the Marin Agricultural Land Trust (MALT) was formed in 1980.

This farmland trust became the first of its kind in America, and the model has been replicated to save family farms all over the country.  Across America, an acre of farmland is paved over every minute.  But in Marin, MALT has permanently protected nearly half of the farmland in the county.  Now, with the global threat of climate change causing local and regional impacts that can present further challenges to farmland and rangeland management, MALT continues to be a conservation leader, working towards scalable solutions to protect working lands.

What’s Being Done 

In 2008 MALT became one of the founding members and fiscal sponsors of a partnership that would become the Marin Carbon Project. This community of scientists, ranchers, agencies, and policymakers in and around Marin County is working to develop and advance climate-friendly land use practices, known as carbon farming, that could help make food production part of the climate solution. The Marin Carbon Project is working to respond to the rapid pace of global climate change by enhancing carbon sequestration in rangeland, agricultural, and forest soils through applied research, demonstration and implementation.

MALT has been a critical member of this work.  Initial efforts included baseline mapping of carbon levels in different soil types on 35 sites, most of which were on MALT conservation properties. With a goal to understand if and how carbon sequestration rates change, data collection efforts began to point to the hypothesis that carbon could be added to working soils – and measured. It became clear that dairies which had been spreading liquid manure on farmlands had higher levels of carbon in their soils than high intensity grazing lands. As studies continued, scientist collaborators quantified that the addition of ½ inch of compost can “restart” the normal carbon cycle in depleted agricultural soils. Five years of data shows that single act sequesters more carbon, retains more soil moisture, and can yield as much as a 50% increase in productivity measured by biomass. This data has led MALT to work with partners to consider a more carbon-focused approach to management. Working with NRCS, 34 potential carbon positive practices were identified to support “Farm Carbon Planning”.


This is a collaborative process. Once a landowner participant is selected, consultants, MALT staff and NRCS partners go out on the land and identify what management practices might work. Using the Farm Plan template for Marin as well as the landowner’s local knowledge and rangeland manager’s professional expertise, potential opportunities are identified. Data is complied and potential projects overlaid on a property map. Some sites may have riparian lands with potential for creek restoration or grazing land with potential for compost application or former oak savannah lands with potential for silvicultural restoration, or all of the above. The acreage of these areas is mapped and potential carbon gains are quantified. This is not a “cookie-cutter” approach to management. On the first three Farm Plans, 8 to 13 practices out of 34 potential practices were identified for implementation. This focus on carbon management enables landowners to build more resilient and sustainable system, which over time will also yield higher productivity and expanded ecosystem benefits.

The economic incentives are not limited to higher yields. In 2014, the American Carbon Registry, a group that certifies carbon offsets, used results from the Marin Carbon Project to approve a protocol for adding compost to rangeland. Through the new protocol, ranchers who spread compost on their pastures can now sell carbon offset credits through voluntary carbon markets. While the cost of a ton of carbon is currently less than the cost of management interventions, positive change is on the horizon. As efficiencies of scale are achieved through refined measurement metrics and models as well as expanded resources and infrastructure such as digesters to process liquid manure and facilities to create stable compost for soil amendments, the agricultural carbon market will continue to grow. Combined with improved productivity and more sustainable systems, landowners are reaping multiple benefits from a carbon-focused management approach.

Supported by MALT’s community connections, MCP’s Implementation Task Force is engaging agricultural producers as ecosystem stewards to provide on-farm ecological benefits, improve agricultural productivity and economic sustainability, and mitigate global climate change through carbon farming. These efforts focus on developing and implementing “Carbon Farm Plans”. The Marin Carbon Project has already helped write and implement the first Carbon Farm Plans on three MALT conservation ranches. In the next three years, 20 more Carbon Farm Plans will be written in partnership with MALT, NRCS, and willing landowners who apply to participate in the program.

Plans for the Future

The Marin Carbon Project (MCP) aims to enable landowners and land managers of agricultural ecosystems to serve as stewards of soil health and to undertake carbon farming in a manner that can improve on-farm productivity and viability, enhance ecosystem functions, and stop and reverse climate change.  MCP’s long-term goal is to develop a countywide agricultural carbon sequestration program with producer outreach, technical infrastructure, economic supports, and scale to serve as a model for other regions in California, the western US, and the nation.  MCP has begun working towards this goal by launching a soil carbon program in Marin County, starting on three farms, and securing the policy and economic supports necessary to support adoption of carbon-beneficial practices at scale in Marin County. The MCP is also working to build capacity of partner organizations and policymakers to facilitate protocol development and implementation of these practices.  As part of this project they are working to build the capacity of the agricultural sector in Marin County to enable landowners and managers to effectively implement agricultural management practices and participate in markets for carbon sequestration and other ecosystem services.

MALT continues to be a driving force of these efforts. The land trust working with partners to identify ways to change practices to better sequester carbon and is engaged in developing tools for “carbon farm planning” and “land smart management” that will help scale up the lessons being learned on the ground at this land trust. MALT is also working with NRCS and Colorado State University to assess the benefits of EQUIP project interventions and refine carbon modeling to quantify carbon benefits.  These efforts further MALT’s mission to protect land and working farms by ensuring sustainable management practices.  MALT continues to rely on adaptive management planning, and is working to create tools, resources, and structures within easements to make farm carbon planning more scalable and streamlined in the conservation easement process.

Engaging Stakeholders

Stakeholder engagement through carbon farm planning communication is critical to successful project implementation. Carbon Farm Plan participants are willing partners in initial project demonstration and research efforts. Public support of implementation continues to grow as there is increasing understanding of the many benefits of carbon farm planning. For example, compost applications not only directly benefit rangeland managers through increased productivity, but also remove agricultural waste from the waste stream. By working with dairy farms to capture and process liquid manure, land applications of unstable compost can be avoided in favor of green-waste enriched solid compost, keeping costs to apply industrial fertilizers down. This turns a waste liability that can lead to methane production in landfills or nutrient loading through land applications into an asset.  The compost management protocol can lead to long-term carbon sequestration, avoided emissions, reduced pressure on landfills, improved water quality, and productivity gains, and this is just one of 34 potential management solutions.

As stakeholders’ understanding the co-benefits of carbon management practices in the agricultural sector grows, so does support of multiple interventions at different scales. MALT is continuing to partner with the MCP to work with land owners to develop and implement carbon farm planning. The capacity and expertise in building partnerships to work towards sustainable conservation that the land trust brings to the table is critical in expanding the MCP’s efforts. Local interventions also support regional growth of these efforts. For example, the MCP partnership has set up new compost facility at a local dairy to make compost and distribute to different markets in California. Encouraged by MCP advocacy, the State of California is further supporting these efforts by investing funds in project implementation as well as infrastructure deployment. Proposals are underway to purchase digesters to process liquid manure. These digesters will produce energy, and the byproducts can then be mixed with other green waste and composted, saving space and avoiding methane emissions in landfills and producing more compost to support soil amendment practices. MALT is also working with research institutions including universities and NRCS to amass data and build tools to support scalable carbon farm management planning.  While MALT is engaged in a variety of carbon management initiatives, stakeholder understanding and by-in is essential to making these projects successful.  As public support grows so do funding streams. There are multiple opportunities to expand and deploy the 34 carbon farming planning practices.  Ultimately, the growth of these initiatives and implementation of these practices furthers MALT’s mission to protect the land by supporting sustainable and resilient family farming practices.

Key Partners

It takes a whole community to preserve a farm.  In addition to individual supporters, MALT works with a number of public agencies and agricultural organizations to ensure Marin County farmland is protected and farming continues to be a vital part of the landscape, culture and economy. View a full list of partners here. Partners that have been especially critical for the MCP include:

  • USDA Natural Resources Conservation Service
  • California Coastal Conservancy
  • Department of Conservation’s Regional Farmland Conservation Program
  • Rathmann Family Foundation
  • 11th Hour Project

Lessons Learned

  • Carbon sequestration is a management game changer. Increasing carbon stored in the soil can increase moisture storage, which can mean longer growing seasons and increased productivity. Carbon-focused management planning on working lands helps create more sustainable ecological and economic systems for landowners.
  •  Improving land stewardship yields numerous benefits. Thinking more wholly about the land and all actions on the land yield real positive change. With additional information, people are taking actions that are helping people reinvest in their properties and improve long-term stewardship.
  • Small changes in management practices can yield big results. The Marin Carbon Project has shown that a single application of compost can sequester carbon in soils, increase plant production, and if scaled to 5% of California’s rangelands could offset up to 10% of the commercial and residential energy sector.