【Objective】Combined application of nitrification inhibitors and ammonium-containing fertilizers is considered an effective means for improving N utilization efficiency and reducing pollution risk. To determine effects of the use of two nitrification inhibitors: dicyandiamide (DCD) and 3,4-dimethylpyrazole phosphate (DMPP), separately, on N₂O emission, nitrogen transformation rate, and community structure and abundance of ammonia-oxidizing bacteria (AOB)） and ammonia-oxidizing archaea (AOA) in soils applied with ammonium-containing fertilizers.【Method】 An in-lab incubation test was conducted of soil samples collected from an extensively managed Phyllostachys edulis plantation. The soil samples were subjected to six treatments, separately, that is (1) CK(no fertilizer); (2)）Urea (Urea); (3) Urea 1% DMPP (1% of Urea in quantity); (4) Urea 1.5% DMPP; (5) Urea 10% DCD; (6) Urea 15% DCD. Dynamics of N₂O emission and soil parameters at the time of N₂O emission turning point (10 d, 50 d and 90 d) were determined. 【Result】Results show that both of the two nitrification inhibitors greatly reduced N₂O emission during the 160 days of incubation. The reduction rate in Treatments Urea DMPP (both 1% and 1.5%), Treatment Urea 10% DCD, and Treatment Urea 15% DCD was 54%, 28%, and 41%, respectively. Significant differences were found in cumulative emission of N₂O (p<0.05) between the treatments, but not between the two Urea DMPP treatments. The treatments in which urea was combined with nitrification inhibitors were similar to Treatment CK in N₂O emission rate during the first 40 days of incubation, and then the formers began to rise gradually with the incubation going on and exceeded CK. Significantly lower N₂O cumulative emission was observed in Treatment Urea 15% DCD than in Treatment Urea 10% DCD. Soil NH₄⁺-N levels due to urea application increased rapidly to a maximum and then decreased gradually, with Treatment Urea being lower than all the urea inhibitor treatments on D50 and D90 of incubation; NO₃^--N concentrations exhibited an opposite trend. The DGGE profiles of soil ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) revealed that DCD and DMPP significantly inhibited AOB in abundance. The effect began to be obvious on D10 of incubation and remained to be significant on D50 and D90 in Treatments Urea MPP, but faded on D90 in Treatments Urea DCD. Treatment Urea was obviously much higher than all the urea inhibitor treatments in abundance of AOB amoA except for Treatment Urea 10% DCD on D 90 of incubation. In contrast, little effect of the use of inhibitors was detected on AOA community, with AOA amoA copy number actually increasing in all treatments. In summary, the dynamics of N₂O emission, soil NH₄⁺-N content, and abundance of AOB amoA and AOA amoA did vary synchronously, indicating that N₂O emission was controlled by different factors in different time periods for the two bacterial groups. The effect of nitrification inhibitors suppressing AOB led to low N₂O emission during the first 40 days of incubation. Although the soil was sufficient in ammonium content and abundant in AOA, the slightly acidic condition (pH about 6.0) may have limited nitrification activity of the group. During the period of D50-D90 of incubation, Changes in AOA triggered by decrease in soil pH with time may be responsible for the increase in N₂O emission because the AOB amoA abundance was still low. 【Conclusion】In conclusion, nitrification was mainly controlled via inhibition of AOB activity and application of DMPP at a 1% rate appears to be sufficient to reduce nitrification. It is also suggested that adjusting soil pH to nearly neutral may prolong the effect of the inhibitor DMPP.