Abstract:Based on the field plot experiments in Southeast China, N2O emissions from the rice—wheat rotation field under controlled irrigation of rice were simulated by using the DNDC model, and the applicability of this model in the region was analyzed. The results showed that N2O fluxes from controlled irrigation rice fields were generally higher than those from the following wheat fields, and the average flux was 3.0 times of that in the following wheat fields. DNDC model successfully simulated the rules of N2O emissions from controlled irrigation rice fields, and the correlation coefficient between the simulated and measured values was 0.79 (n=39, p<0.001). It could also simulate the relationship between the N2O fluxes and soil moisture regulation and fertilization. But the response of the model to the extent of soil dehydration was not sensitive enough, resulting in the slight lag of some N2O peaks. Simulated N2O fluxes from the following wheat fields were usually lower than the measured values. Compared with the measured values, the simulated value of the highest peak was increased by 14.96% (p<0.05), and the simulated value of the smaller peak was decreased by 18.10% (p<0.05). The relative errors between the simulated and measured values of the cumulative N2O emission during the rice season, wheat season and rice—wheat rotation period were 5.86%, -20.17% (p<0.05) and -4.97%, respectively. These results indicated that the DNDC model can well simulate the cumulative N2O emission from the rice fields under controlled irrigation, but the N2O emissions from the following wheat fields were significantly underestimated. The difference between the simulated and measured values of total N2O emission from rice—wheat rotation field was small. Thus, the DNDC model can be used to simulate the N2O emissions from controlled irrigation rice fields in Southeast China, but it can not accurately simulate the N2O emissions from the following wheat fields.