Abstract:【Objective】The relative contribution of ammonia oxidizing microorganisms determines the ammonia oxidation rate and N2O emission. However, the composition of their relative contribution to N2O emission in different soils and agricultural management has not been systematically studied.【Method】We studied the contributions of AOB, AOA+comammox and heterotrophic nitrifiers to the potential nitrification rate, net nitrification rate and N2O emission in typical upland surface soils (fluvo-aquic soil, black soil, latosol), and in latosols from soil profile under organic fertilizer amendment.【Result】In the surface fluvo-aquic soil, black soil and latosol, pH was 8.0, 6.7 and 5.7, potential nitrification rate was N 32.5, 6.6 and 4.8 mg?kg-1?d-1, net nitrification rates was N 7.1, 3.0 and 0.5 mg?kg-1?d-1, and N2O emission was N 38.0, 35.4 and 8.7 μg?kg-1, respectively. AOB dominated potential nitrification rate in the above surface soils, with contributions of 82%, 58% and 100%, respectively. For net nitrification rate, AOB and AOA+comammox contributed equally (30%-40%) in the fluvo-aquic soil and latosol, while AOB dominated in the black soil (72%). AOB dominated N2O emission from the above surface soils, contributing 72%, 92% and 58%, respectively. In the latosols from soil profile, at the 0-20 cm, 20-40 cm and 40-60 cm layers, pH was 7.0, 5.5 and 4.9, potential nitrification rate was N 6.6, 2.0 and 1.1 mg?kg-1?d-1, net nitrification rate was N 4.1, 0.9 and 0.2 mg?kg-1?d-1, and N2O emission was N 16.3, 6.5 and 2.8 mg?kg-1?d-1, respectively. The increase in potential nitrification rate and net nitrification rate at the 0-20 cm layer was dominated by AOA+comammox (contributing 63% and 54%) and the increase in N2O emissions was dominated by AOB (contributing 54%).【Conclusion】This study provides new evidence for developing reduction measures of N2O emissions that match the soil ammonia oxidation characteristics and soil properties.