Shelburne Farms hopes ‘biochar’ eases methane emissions

Shelburne Farms is experimenting with a charcoal-like material known as biochar in its dairy operations as part of reaching a net-zero emissions goal.

The 1,400-acre working farm and education center is primarily using biochar on the surface of its manure pits, with early indications suggesting it has reduced odors along with potentially reducing greenhouse gas emissions.

Biochar is a kind of a charcoal, made from excess organic material that is often used for its ability to sequester carbon. Studies also suggest biochar can help soils retain moisture and nutrients.

“It’s considered a soil amendment, and it’s produced by heating wood in very, very hot temperatures, called pyrolysis,” explained Molly Webb, a climate action adviser for Shelburne Farms. “Therefore, the release of carbon dioxide and gases that would normally happen as biomass degrades would be captured or sequestered in the biochar.”

Shelburne Farms is home to animals including a herd of 110 milking cows, whose milk is used in the cheese-making operation on site. The biochar project, which started four years ago, is designed to help reduce methane emissions from cow manure at the sprawling property along Lake Champlain. Methane is another greenhouse gas, like carbon dioxide, that gets released into the atmosphere and contributes to global warming by trapping heat.

In Vermont, agriculture is a major source of methane. Methane is naturally emitted from cows in a process called eructation — belching. Methane can also be observed bubbling off of the surface of manure storage lagoons.

“Methane in agriculture is biogenic,” said Alex DePillis, senior agricultural development coordinator for the Vermont Agency of Agriculture, Food and Markets. “It comes from plants, it can go back to plants.”

Agriculture accounts for over 16 percent of Vermont’s greenhouse gas emissions, according to the updated Vermont Greenhouse Gas Emissions Inventory and Forecast.

“We’re doing the mitigation, reducing greenhouse gases because we have a responsibility to do it,” said DePillis. “There’s been good work done to really think about: ‘How does this help us adapt to what is gonna happen, and how do we help nature be more resilient, and how do we help our working lands be more resilient?’”

Shelburne Farms began using biochar as part of a multiphased climate initiative to reach a 2028 net-zero emissions goal. Other initiatives included replacing gas-reliant lawnmowers with electric ones, a reforestation project aimed at increasing carbon sequestration and the creation of more educational spaces around the importance of a net-zero goal. The work around soils is an important part of the effort.

“The key thing is everyone’s getting more excited about soils. It’s part of the story of how regenerating land and soils is part of net-zero storage,” Webb said.

Biochar has several additional benefits besides potential emissions reductions. Many of the dairy farmworkers at Shelburne Farms have observed significantly less odors coming from the manure pits in which biochar was applied.

“One of my favorite things that Shelburne Farms is doing with biochar is covering their manure pit,” DePillis said. “And this has two really great effects. One, it reduces the ammonia smell, so it reduces odors from the manure pit. … It’s a solid that’s glomming onto that ammonia gas. That’s why it reduces ammonia odor and this is really well proven.”

Most of the data Shelburne Farms has collected is largely anecdotal. Webb said that areas where biochar-rich manure had been spread, the land was often more fertile, and plants appeared to be flourishing. So far, the pilot project with biochar has not yielded conclusive data on reducing emissions at Shelburne Farms, according to Webb.

But studying its potential and sharing the experience is important to the organization’s broader vision.

“We have a net-zero goal, and we’re — I don’t want to say gunning for it — but we’re really committed to it. Part of that commitment is based on the lessons that we’ve learned on this journey and sharing those lessons,” said Holly Brough, director of communications for Shelburne Farms.

Shelburne Farms recently applied for a grant with the University of Vermont to conduct more research on the impacts of biochar. The nonprofit farm hopes to conduct more field trials, as well as host a series of activities at the property around a biochar summit, designed to connect major stakeholders within the industry.

In August 2024, the farm hosted a roundtable workshop with the Northeast Climate Hub and UVM Extension around what are called smart commodities in Vermont, namely biochar.

“Having the ability to share what we’re doing in a few different ways is part of the climate action goal,” Webb said. “It’s not just visibly doing net-zero at the farm, it’s also being able to amplify that or create audiences, you know, find audiences for that that might benefit from our learning.”

(Via Community News Service, a University of Vermont journalism internship.)