Plenty of research has amassed on the benefits of applying biochar to soil to lock in carbon. Now, an unusual new study looks at a novel way to get it there: feed biochar to cows, it says, and they’ll do the work for you.
The new research finds that when cows consume and excrete biochar, it remains almost completely intact and stable, suggesting that cows could spread biochar across the land and become architects of better soil health while tackling their own climate impacts.
Led by a team of Swiss researchers, the study took a group of eight dairy cows and fed them a diet containing trace amounts of biochar, about 1%. The feeding trial had two periods of 35 days each. In one, half the cows received the biochar additive, and the other half did not. In the second, the researchers switched the two groups of cows, so that each cow ultimately acted as its own control.
The researchers then gathered cow dung for several days over the course of the experiment. These samples were dried and three different methods used to analyze the biochar fragments within the dung. The goal was to determine how much of that biochar had remained intact, both structurally and chemically.
The answer was: a surprising amount. From the analysis, the researchers calculated that between 70 and 90% of the biochar that cows consumed in the study survived their famously robust digestion, resisting decomposition. What’s more, an estimated 98% of that biochar which made it out the other side was intact—both in terms of its physical structure and its chemical makeup.
The three analytical methods revealed that most of the surviving biochar was also chemically stable, meaning it contained characteristics such as a condensed carbon structure, enabling it to persist for long periods in the soil without breaking down and releasing the carbon it contains.
There was some variation: biochar that was more oxygen-rich was more easily decomposed during digestion. Importantly, the researchers note that the quality and composition of the biochar does affect how robust it will ultimately be in the cow’s gut.
The benefits of biochar may go beyond carbon storage and boosting nutrients in the soil: the study mentions previous research showing that biochar could even reduce methane emissions from cattle dung, adding to biochar’s many talents.
There’s something satisfying about the idea of cows dispersing this wonder ingredient into the soil, and helping to offset their own environmental damage. Whether this idea can be taken mainstream remains to be seen, but for now it adds to the burgeoning evidence that biochar could be a real agricultural solution — in many different forms.
Leifeld et. al. “Recovery and composition of biochar after feeding to cattle.” Biochar. 2026.
Image: ©Anthropocene Magazine
