Nitrous oxide represents a powerful greenhouse gas with a global warming potential nearly three hundred times greater than carbon dioxide over a century. Agricultural and natural soils serve as the primary global source of these emissions, which are driven by temperature-sensitive microbial processes including nitrification and denitrification. While biochar made from pyrolyzed organic matter is widely utilized to improve soil fertility and suppress greenhouse gas output, its influence on how emissions react to rising temperatures remains complex and inconsistent across different ecosystems. To evaluate these thermal interactions, researchers incubated agricultural and forest soils at ten, twenty, and thirty degrees Celsius. The soil samples were amended with wood or rice husk biochar at application rates of one percent and three percent, alongside unamended control treatments. Over the incubation period, gas fluxes, mineral nitrogen availability, microbial biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More, and functional gene abundances were tracked to quantify temperature sensitivity coefficients and map the underlying biogeochemical pathways.

The findings revealed that temperature sensitivity responded uniquely to biochar depending on the underlying soil environment. Only the three percent wood biochar treatment produced a statistically significant change in temperature sensitivity. In agricultural soil, wood biochar lowered nitrate availability across all temperatures, creating substrate limitations that suppressed microbial responsiveness to warming. In contrast, the same treatment in forest soil accelerated ammonium consumption and altered nitrate accumulation dynamics, strengthening the coupling between nitrification and denitrification pathways under higher temperatures. Lower biochar application rates and rice husk biochar failed to alter temperature sensitivity significantly in either soil type.

Path modeling confirmed that rising temperatures played the dominant direct role in driving total nitrous oxide emissions by altering soil pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More, carbon sources, and functional gene abundances. Biochar functioned as a secondary modulator rather than the primary driver, regulating emission rates through soil-specific substrate constraints and microbial shifts. Because biochar can either suppress or amplify emission responses to warming depending on local soil conditions, land management strategies must tailor biochar selection and application rates to specific target environments under changing climate scenarios.

Source: Luo, S., Li, Z., Hu, J., & Liao, X. (2026). Biochar modulates temperature sensitivity of soil N2O emissions: soil-specific mechanisms. Biochar, 8, 81.