MOUNT AIRY, Md. — Over the past year or so, the company Lithos Carbon has been contacting farmers with an offer that sounds too good to be true.
Lithos offers to pay farmers about $50 per acre to spread finely ground basalt rock, a new soil amendment (though not one registered with the Maryland Department of Agriculture’s state chemist) that will store atmospheric carbon inorganically, creating carbon credits the company can sell.
More than that, Lithos will pay for the amendment and the applicator, and the company advertises the basalt as free lime.
“This is kind of coming from this idea of climate action and climate mitigation efforts from these larger entities,” said Mark Townsend, a University of Maryland Extension agent for Frederick County.
Mark Townsend, a University of Maryland Extension agent for Frederick County, shares a research update on Lithos Carbon during the Jan. 23, 2025, Central Maryland Forage Conference hosted in Mt. Airy, Md.
But what is basalt, and what does it do to the soil?
Townsend presented results from Extension’s first year of research Jan. 23 during the Central Maryland Forage Conference.
In summary, the amendment, which is just basalt rock ground very finely, had no immediate effects on the soil, but the long-term effects are unknown.
It didn’t help build soil fertility, as promised with the “free lime” advertisement, but it also didn’t change the field’s yield or quality, Townsend said, and it did not create any chemical problems as tested in a grain sample slurry.
There was a difference in the soil’s aggregate stability, with the basalt application appearing to increase compaction, but researchers haven’t run the numbers to see if the change was statistically significant.
Extension results also didn’t show any carbon sequestration in one year, Townsend said.
It’s unknown whether Lithos expects carbon sequestration in one year because the whole project is based on the silicate-carbonate cycle, which naturally takes hundreds or thousands of years to occur.
“We know that this happens, but we know this happens on incredibly long time scales,” Townsend said.
The company did not respond to a request for comment on the timeline.
Lithos’ expedited cycle is expected to sequester carbon more quickly than nature, but it’s unclear when results would be measurable.
In the silicate-carbonate cycle, carbon dioxide from the soil and the atmosphere — through rain water — work together to break down the silicate of the basalt rock.
The basalt must be finely ground for the process to occur more quickly than it does in nature.
Carbon dioxide and silicate combine to form a bicarbonate ion, Townsend said. This ion is what Lithos claims will raise soil pH, acting like lime.
The ion combines with calcium to form calcium carbonate, Townsend said.
The calcium carbonate will then end up in the ocean where the carbon will be stored, completing the process of permanent, inorganic carbon sequestration.
The inorganic method of Lithos’ carbon sequestration interested Townsend because of problems Maryland farmers have had participating in the organic carbon sequestration credit market.
Practices such as no-till farming and cover crop planting sequester carbon on which some brokerage companies will sell credits.
But in many cases, participating farmers need to start these practices after an agreement is made with a brokerage organization so the amount of carbon being sequestered can be quantified.
That means farmers already doing these practices can’t get in on the organic carbon market.
Lithos offers a way any farmer could participate.
But regardless of whether a farmer participates with Lithos or another company, the carbon credit market is unsettled and lacks a regulating agency.
As a result, Townsend said, there is no standard going rate for a credit or a cut of that credit designated for farmers.
It also means market operations could change at any time if a governing agency steps in.
“There’s a lot of funny money floating around,” Townsend said.
Lithos Carbon was built by two biogeochemical researchers, one from Georgia Tech and one from Yale University, who wanted to turn years of research into a business.
Most of their research since starting Lithos has been conducted in the Midwest or in California, so it may not reflect the function of the Mid-Atlantic’s acidic subsoil.
Certain management strategies, like nitrogen fertilizer application, may also affect results.
“There could be an argument to be made that we won’t see the accumulation (of pH) because, in fact, our management strategies often pull our pH down lower,” Townsend said.
Instead, the neutral results from Extension’s first year of testing seem to negate any initial panic over basalt as a soil amendment, Townsend said, but there are still a lot of unknowns.
What will the long-term soil effects be? Can it actually capture carbon? Would it work better in hay and pasture fields? Is it worth working with Lithos Carbon?
Extension has funding from the Maryland Soybean Board to continue testing for at least two more years in hopes of answering some of these questions.
For now, there are still many unknowns, and many farmers expressed continued skepticism during the conference, but Townsend hasn’t lost faith in Lithos Carbon’s potential positives for farmers.
“I don’t think it’s necessarily a good thing to liken this product to that which occurred in the Snake River or the Ohio. I think that’s a little too far,” Townsend said. “It’s something we need to keep in the back of our heads, but, again, it’s a rock.”
