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
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.
