New research shows biochar works in acidic soils by generating hydroxyl radicals that suppress enzymes responsible for decomposing soil organic carbon. In two acidic soil types, untreated biochar cut CO2 emissions by up to 12.9 percent, while quenched biochar increased emissions. The effect did not hold in calcareous soil, where biochar accelerated carbon loss despite the radicals. The study, published in Biochar, highlights that biochar's carbon storage benefit is soil-specific, not universal. It adds a chemical preservation mechanism to biochar's known physical sorption. This means land managers should tailor biochar application based on soil pH and type, rather than expecting uniform results.
