In Lab Tests, a Fix for One Farm Greenhouse Gas Slows the Soil's Methane Cleanup

Plant compounds promoted as a way to cut nitrous oxide emissions from farmland also suppressed the soil bacteria that consume methane, researchers at Kansas State University report in a study published August 25, 2026, in Communications Earth & Environment.

The compounds come from biological nitrification inhibition, in which plant roots release substances that slow the soil microbes converting fertilizer nitrogen into forms lost as nitrous oxide, a greenhouse gas. Seongmin Yang and colleagues tested what else those substances do.

Suppression of methane oxidation was consistent in two setups, the authors report: soil bioreactors containing Brachiaria, a grass whose roots release the inhibitors, and pure cultures of methanotrophs, the bacteria that live on methane, exposed to representative inhibitor compounds. Both are laboratory systems, and the paper reports no field measurements.

The team traced where the effect acts. Kinetic analysis indicated an uncompetitive-like inhibition pattern, reversibility assays showed the bacteria remained viable rather than being killed, and experiments run with and without copper pointed to particulate methane monooxygenase (the copper-dependent enzyme methanotrophs use to break down methane) as the site.

That combination names a trade-off between two greenhouse gases: the same compounds credited with reducing nitrous oxide may weaken the soil's ability to remove methane. The authors write that the inhibitors "may" have this effect in farm soil (a hedge their laboratory scale requires, since nothing here was measured in a field).

The study lists support from US National Science Foundation grants 2144189 and 2435179, and the authors declare no competing interests. The paper was published as an accepted manuscript, ahead of the final version of record.