A recent study conducted by researchers at the University of California, Merced shows that the addition of even a small amount of biochar, which is a material similar to charcoal that is produced by burning organic matter, to the manure-composting process at a dairy can reduce methane emissions by 84%.
One of the most significant contributors to methane emissions in California is the dairy business, which is responsible for fifty percent of the state’s total methane output. The efforts being made by the state and the federal government to combat climate change must include the reduction of these emissions.
Rebecca Ryals, a professor of life and environmental sciences, referred to this phenomenon as a “great example of an undiscovered climate solution.” “Pollutant emissions from open burning of biomass and methane emissions from decomposing biomass are both reduced by using biochar,” says one study.
It is not common for dairies to have equipment like anaerobic digesters, but the dairy that the researchers worked on did so that it could properly manage the waste produced by its livestock. To achieve the climate goals that have been set, it is anticipated that most dairies will have digesters by the year 2030; however, at the moment, only a small fraction of dairies actually have them. One of the most significant contributors of organic waste in the state is manure from dairy farms. According to Brendan Harrison, a graduate student in his fourth year who is studying agroecology under Ryals and explains that farmers drain the waste from their barns and the liquids go into enormous uncovered ponds, while the solids are built up, the ponds are not covered. The farmers may sometimes cover the ponds in order to collect the methane emissions, which are then piped into generators and burned in order to produce energy.
According to Harrison, with the technology that are currently available, this strategy for cutting methane emissions is “really a pretty good way to reduce methane emissions.” “However, it does not account for any of the solids, which is an issue since in order to get rid of it, they either pile it up in large mounds or spread it out over areas that are close to the one in which it was produced. When you drive by a dairy, you’ll notice them covered in white plastic and kept down by tyres; they’re easy to spot. They are capable of generating so much heat that it causes them to spontaneously ignite.
Instead of hoarding the manure, the researchers looked into the possibility of composting it with biochar. According to Mechanical Engineering Professor Gerardo Diaz, biochar enhances the quality of composted manure, making it a more effective fertiliser for farmers to use on other portions of their land. This is one of the many benefits of using biochar.
“We were looking at ways to minimise emissions, but we were also looking at ways to bring some value to the community, particularly in areas that are disadvantaged,” Diaz said. “We investigated the potential of creating a mobile machine that we might take to various locations in order to process part of the material there.”
According to the findings of the study, smaller farmers would be able to utilise the improved fertiliser on their own farms to raise production or sell it to other people who have a requirement for it.
The study was made possible by funding from the California Strategic Growth Council. The research team, which was directed by Diaz, collaborated with Philip Verwey Dairy as well as industrial partners such as Golden State Carbon, LLC, and made use of the biomass that was found locally.
According to Diaz, “there is an urgent need to do something with that biomass because open-air burning is going to be banned in 2025.” Burning in an enclosed environment is required for the production of biochar.
The researchers, which included Diaz, Ryals, and professors Teamrat Ghezzehei, Asmeret Asefaw Berhe, YangQuan Chen, and Catherine Keske, examined the project from a variety of perspectives, such as emissions, a life-cycle analysis, the economic viability of such work, and how it affected the soil. The researchers also looked at how the project affected the soil.
Biochar, which was used by Indigenous people in their own farming practises, has the propensity to stay in the soil for much longer than other types of compounds, but the length of time it spends there is contingent on how the biochar is interacted with by the ecosystem of the soil, which includes the myriad of different microbes that can be found there. According to Ryals’ explanation, the longevity of any carbon that does remain in the soil is dependent on the ecosystem.
The conclusion that can be drawn from this research is that biochar is beneficial to dairy farmers as well as the environment. Diaz stated that additional research will investigate the various types of biochar that are composted together with dairy manure in an effort to encourage farmers to adopt this technology.
“Composting the solid manure isn’t the common practice, but if we go from stockpiling to composting, now we’ve gone from a carbon source to a carbon sink,” said Ryals. “If we go from stockpiling to composting, now we’ve gone from a carbon source to a carbon sink.” “Composting, by its very nature, is an activity that is incredibly good to the environment. And if you add just a tiny bit of biochar to that compost, you can basically double the impact that you have.
