Simulation and sensitivity analysis of N2O emissions in dryland wheat fields at different fertilization levels using the DNDC model
[Objective]To study the emission characteristics of soil N2O and verify the adaptability of the DNDC model to N2O emission under different fertilization levels on the Loess Plateau of Longzhong.[Method]Wheat fields in Dingxi City,Gansu Province,were set up with no nitrogen fertilizer(0 kg/hm2),low nitrogen fertilizer(55 kg/hm2),medium nitrogen fertilizer(110 kg/hm2)and high nitrogen fertilizer(220 kg/hm2).Soil N2O emission flux was measured in situ by static box gas chromatography.Combined with the measured data of N2O emission flux continuously monitored at the test site,the DNDC model was used to investigate the sensitivity of several factors to simulated N2O emission.[Result]Under different fer-tilization levels,the trend of soil N2O emission was basically the same,and the emission flux was positively correlated with the nitrogen application rate.The DNDC model has a good simulation effect on N2O emis-sion under four fertilization levels,which is manifested as no nitrogen fertilizer(R2=0.88,EF=0.84,P=0.002),low nitrogen fertilizer(R2=0.92,EF=0.82,P=0.001),and low nitrogen fertilizer(R2=0.92,EF=0.82,P=0.001).Medium nitrogen(R2=0.86,EF=0.81,P=0.003)and high nitrogen(R2=0.84,EF=0.74,P=0.004)showed that the DNDC model could be used to simulate soil N2O emission under dif-ferent fertilization levels.Sensitivity analysis showed that compared with other factors,soil pH value was the most sensitive parameter to affect N2O emission from farmland in the study area.[Conclusion]This study can provide the theoretical basis and technical support for local application of the regional N2O emis-sion model and optimization of farmland management measures.
万方数据
维普
