The Bordessa family has been dairy farming in California for five generations and now have two farms just outside the tiny hamlet of Valley Ford in western Sonoma County. They are organic dairy producers, members of the Organic Valley farmer-owned dairy cooperative, and their cows are typically on pasture 90 percent of the year. Gary and Jarrid Bordessa, the father and son team at the helm of the farm’s operations, think a lot about balancing the ecological health of the land with economic viability. Managing manure is an important aspect of achieving this balance.
Because their cows are on pasture for so much of the year, most of the manure is distributed across the landscape, and Jarrid says the fertility the manure provides is one of the keys to the health and productivity of their pastures. Manure from the milking barns or free stalls where the cows are housed when the pastures are too wet to graze is flushed with recycled water and collected in cement pits. At the end of each pit is a low-tech “weeping wall,” a screen of wooden slats through which solids are separated as the water moves through the screen, pressurized by gravity. The liquid is either recycled for flushing barns or is used to fertigate pasture. The solids are dried, composted and used on pasture to enhance soil health and add fertility.
Gary says they are interested in exploring a transition to a dry scrape system that would reduce the need for flushing the barns and would minimize the anaerobic conditions in their manure pits and ponds that cause methane emissions. They are also planning on experimenting with a technology to aerate the ponds that hold the liquid slurry from the barns.
The Bordessas are not alone in their commitment to continually improve their manure management strategies for greater environmental benefit. To showcase examples of innovative approaches to manure management and related emission reductions, CalCAN produced a series of six case studies profiling dairy producers. The profiles feature manure management techniques that reduce methane emissions while providing numerous other benefits such as improved air and water quality and soil health. Click here to download a copy of the case studies.
The series includes three dairies in Sonoma County, one in Marin County and two in Stanislaus County, all of which incorporate some pasturing of cows in their operation. They illustrate various methods for shifting away from flushing manure into stagnant lagoons (as is the practice in large confined animal operations) to one or a combination of alternative manure management systems such as solid separation, dry scraping manure, composting, and increased pasturing of cows.
Though each of these case studies is unique and tailored to the operations’ opportunities and constraints, there are some similarities. All of the producers are striving to minimize not only methane emissions but also ammonia and odor.They all integrate some pasturing of cows in their system—to varying degrees depending on their available pasture area and weather conditions—which reduces the amount of manure they must manage near the barns and distributes it across the landscape under aerobic conditions. They are all continuously seeking improvements to their systems. And importantly, the initial capital costs of management practices they use are estimated to range from approximately $85 to $910 per cow, considerably cheaper than the installation of anaerobic digesters that can range from $1,350 to $3,400 per cow.
CalCAN has been a leading voice in deliberations about a new cap-and-trade funded state program to provide grants to dairy producers for reducing methane emissions using alternative manure management practices. It is called the Alternative Manure Management Practices (AMMP) program, and a call for proposals will likely be released this summer. Producers like Gary and Jarrid Bordessa may be eligible for grants to implement new manure management systems that reduce greenhouse gas emissions.
In 2015, under its Dairy Digester Program, CDFA incentivized only the installation of anaerobic digesters to capture methane and convert it to renewable energy as a strategy for reducing methane. However, since then CalCAN and others have advocated for a more diversified approach that is appropriate for a range of dairies and for strategies that cost less than expensive and technologically complex digesters that are best-suited to large confined animal feeding operations. CalCAN released a policy brief in late 2015 entitled Diversified Strategies for Reducing Methane Emissions from Dairy Operations, making recommendations to CDFA that informed their creation of AMMP.
This year, CDFA has earmarked $9-16 million for AMMP to fund grants for dairy producers. CalCAN and others have been providing input on the design of the program, including attending CDFA-hosted workshops and providing public comment (see here for a comment letter to CDFA). In May, CalCAN and Organic Valley also hosted a dairy farm tour in Sonoma County to help inform state agency staff about dairy manure management strategies to reduce methane emissions.
Stay tuned for developments on the AMMP design and rollout by signing up to subscribe to our blog or to receive notices on CDFA’s AMMP listserve.