Biochar application increased soil CO2 emissions (7.4%) and crop yield (9.4%), while decreasing methane (−13.0%) and nitrous oxide emissions (−26.8%), global warming potential (−7.7%), and greenhouse gas intensity (−14.3%). The changes in CO2 emissions were more pronounced in incubation and pot experiments compared to field studies. Soil pH change was a key factor affecting GHG fluxes. Biochar also enhanced the soil carbon pool significantly (38.1% in upland and 33.4% in paddy soils), highlighting its role in reducing CH₄ and N₂O emissions and providing insights for tailored biochar management strategies.