The objective of this study is to establish controlled-release nitrogen fertilization technology for achieving high yield and reduce carbon emissions.Two late-maturing medium japonica rice varieties,Nanjing 9108 and Taixiangjing 1402,were se-lected in this study.The controlled-release fertilizer with resin-coated urea(N 43％,the longevity was 100 d)and common urea(46％N)were used as nitrogen fertilizers.Different ratios of basal and panicle nitrogen fertilizers were set for different treatments of 10∶0(NM1),8∶2(NM2),7∶3(NM3),and 6∶4(NM4).The basal fertilizer was applied using the side-deep fertilization method,with a ratio of 5:5 for resin-coated urea and common urea.The panicle nitrogen fertilizer was common urea.Conven-tional fertilization(FFT)and no nitrogen fertilizer(0N)control treatments were also included.The effect of different nitrogen fertilizer application methods on rice yield,NH3 volatilization,and greenhouse gas emissions were investigated.The results showed that the side-deep application of controlled-release nitrogen fertilizer delayed the peak of NH3 volatilization,preventing it from occurring at tillering stage compared to the FFT treatment.In addition,the flux of NH3 volatilization and the average flux after topdressing were significantly reduced by the side-deep application of controlled-release nitrogen fertilizer.The NH3 emis-sion accumulation,NH3 emission factor,and NH3 emission intensity were reduced by 25.33％-48.76％,29.14％-60.81％,and 29.60％-56.01％,respectively.Furthermore,the CH4 emission fluxes were significantly reduced at tillering stage and after head-ing stage.The N2O emission fluxes were also significantly reduced during the shelving and heading period.The CH4 and N2O emission accumulation were reduced by 20.20％-55.04％and 25.56％-61.56％,respectively.The CH4 emission reduction rate decreased as the proportion of basal and panicle fertilizer decreased.The N2O emission reduction rate followed the order of NM1＞NM3＞NM2＞NM4.The GWP and GHGI were reduced by 20.96％-53.35％and 25.91％-55.40％,respectively.Considering the economic and ecological benefits,NM1 treatment had the best effect on the reduction of NH3 volatilization and greenhouse gas emissions.NM1 treatment reduced the number of fertilization times 1-2 compared with the NM3 and FFT treatments,which was advantageous for achieving green,simple,and large-scale rice production.NM3 treatment exhibited the highest increase in yield,and its impact on reducing NH3 volatilization and greenhouse gas emissions was second only to NM1 treatment.In sum-mary,the present study explored a set of controlled-release nitrogen fertilization method(NM1 and NM3 focused on"light and simple+emission reduction"and"high yield+emission reduction",respectively)suitable for reducing emission and increas-ing yield of late-maturing medium japonica rice.
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