The application of nitrogen（N） fertilizer to increase crop yields has a significant influence on soil methane（CH_4） and nitrous oxide（N_2O） emission/uptake.A meta-analysis was carried out on the effect of N appl...The application of nitrogen（N） fertilizer to increase crop yields has a significant influence on soil methane（CH_4） and nitrous oxide（N_2O） emission/uptake.A meta-analysis was carried out on the effect of N application on（i） CH_4 emissions in rice paddies,（ii） CH_4 uptake in upland fields and（iii） N_2O emissions.The responses of CH_4 emissions to N application in rice paddies were highly variable and overall no effects were found.CH_4 emissions were stimulated at low N application rates（〈100 kg N ha^（-1）） but inhibited at high N rates（〉200 kg N ha^（-1）） as compared to no N fertilizer（control）.The response of CH_4 uptake to N application in upland fields was 15%lower than control,with a mean CH_4 uptake factor of-0.001 kg CH_4-C kg^（-1） N.The mean N_2O emission factors were 1.00 and 0.94%for maize（Zea mays） and wheat（Triticum aestivum）,respectively,but significantly lower for the rice（Oryza sativa）（0.51%）.Compared with controls,N addition overall increased global warming potential of CH_4 and N_2O emissions by 78%.Our result revealed that response of CH_4 emission to N input might depend on the CH_4concentration in rice paddy.The critical factors that affected CH_4 uptake and N_2O emission were N fertilizer application rate and the controls of CH_4 uptake and N_2O emission.The influences of application times,cropping systems and measurement frequency should all be considered when assessing CH_4 and N_2O emissions/uptake induced by N fertilizer.展开更多
Elevated CO_(2)(eCO_(2))and rice cultivars can strongly alter CH_(4)and N_(2)O emissions from paddy fields.However,detailed information on how their interaction affects greenhouse gas fluxes in the field is still lack...Elevated CO_(2)(eCO_(2))and rice cultivars can strongly alter CH_(4)and N_(2)O emissions from paddy fields.However,detailed information on how their interaction affects greenhouse gas fluxes in the field is still lacking.In this study,we investigated CH_(4)and N_(2)O emissions and rice growth under two contrasting rice cultivars(the strongly and weakly responsive cultivars)in response to eCO_(2),200μmol mol^(-1)higher than the ambient CO_(2)(aCO_(2)),in Chinese subtropical rice systems relying on a multi-year in-situ free-air CO_(2)enrichment platform from 2016 to 2018.The results showed that compared to aCO_(2),eCO_(2)increased rice yield by 7%-31%,while it decreased seasonal cumulative CH_(4)and N_(2)O emissions by 10%-59%and 33%-70%,respectively,regardless of rice cultivar.The decrease in CH_(4) emissions under eCO_(2)was possibly ascribed to the lower CH_(4)production potential(MPP)and the higher CH_(4)oxidation potential(MOP)correlated with the higher soil redox potential(Eh)and O_(2)concentration([O_(2)])in the surface soil.The mitigating effect of eCO_(2)on N_(2)O emissions was likely associated with the reduction of soil soluble N content.The strongly responsive cultivars had lower CH_(4)and N_(2)O emissions than the weakly re sponsive cultivars,and the main reason might be that the former induced higher soil Eh and[O_(2)]in the surface soil and had larger plant biomass and greater N uptake.The findings indicated that breeding strongly responsive cultivars with the potential for greater rice production and lower greenhouse gas emissions is an effective agricultural practice to ensure food security and environmental sustainability under future climate change scenarios.展开更多
基金financed by the Chinese Academy of Sciences for Strategic Priority Research Program(XDA05050602)the Key Technologies R&D Program of China during the 12th Five-Year Plan period of China(2012BAD14B01-1)
文摘The application of nitrogen（N） fertilizer to increase crop yields has a significant influence on soil methane（CH_4） and nitrous oxide（N_2O） emission/uptake.A meta-analysis was carried out on the effect of N application on（i） CH_4 emissions in rice paddies,（ii） CH_4 uptake in upland fields and（iii） N_2O emissions.The responses of CH_4 emissions to N application in rice paddies were highly variable and overall no effects were found.CH_4 emissions were stimulated at low N application rates（〈100 kg N ha^（-1）） but inhibited at high N rates（〉200 kg N ha^（-1）） as compared to no N fertilizer（control）.The response of CH_4 uptake to N application in upland fields was 15%lower than control,with a mean CH_4 uptake factor of-0.001 kg CH_4-C kg^（-1） N.The mean N_2O emission factors were 1.00 and 0.94%for maize（Zea mays） and wheat（Triticum aestivum）,respectively,but significantly lower for the rice（Oryza sativa）（0.51%）.Compared with controls,N addition overall increased global warming potential of CH_4 and N_2O emissions by 78%.Our result revealed that response of CH_4 emission to N input might depend on the CH_4concentration in rice paddy.The critical factors that affected CH_4 uptake and N_2O emission were N fertilizer application rate and the controls of CH_4 uptake and N_2O emission.The influences of application times,cropping systems and measurement frequency should all be considered when assessing CH_4 and N_2O emissions/uptake induced by N fertilizer.
基金supported by the National Key Research and Development Program of China(No.2017YFD0300105)the National Natural Science Foundation of China(No.41877325)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2018349)。
文摘Elevated CO_(2)(eCO_(2))and rice cultivars can strongly alter CH_(4)and N_(2)O emissions from paddy fields.However,detailed information on how their interaction affects greenhouse gas fluxes in the field is still lacking.In this study,we investigated CH_(4)and N_(2)O emissions and rice growth under two contrasting rice cultivars(the strongly and weakly responsive cultivars)in response to eCO_(2),200μmol mol^(-1)higher than the ambient CO_(2)(aCO_(2)),in Chinese subtropical rice systems relying on a multi-year in-situ free-air CO_(2)enrichment platform from 2016 to 2018.The results showed that compared to aCO_(2),eCO_(2)increased rice yield by 7%-31%,while it decreased seasonal cumulative CH_(4)and N_(2)O emissions by 10%-59%and 33%-70%,respectively,regardless of rice cultivar.The decrease in CH_(4) emissions under eCO_(2)was possibly ascribed to the lower CH_(4)production potential(MPP)and the higher CH_(4)oxidation potential(MOP)correlated with the higher soil redox potential(Eh)and O_(2)concentration([O_(2)])in the surface soil.The mitigating effect of eCO_(2)on N_(2)O emissions was likely associated with the reduction of soil soluble N content.The strongly responsive cultivars had lower CH_(4)and N_(2)O emissions than the weakly re sponsive cultivars,and the main reason might be that the former induced higher soil Eh and[O_(2)]in the surface soil and had larger plant biomass and greater N uptake.The findings indicated that breeding strongly responsive cultivars with the potential for greater rice production and lower greenhouse gas emissions is an effective agricultural practice to ensure food security and environmental sustainability under future climate change scenarios.
