To reveal the differences in the effects and mechanisms of different biological nitrification inhibitors(BNIs)on N2O emissions from red paddy soil,a 21-day soil column flooding incubation experiment was conducted to compare three BNIs,1,9-decanediol(1,9-D),linolenic acid(LN)and methyl 3-(4-hydroxyphenyl)propionate(MHPP)with the chemically synthesized nitrification inhibitor dicyandiamide(DCD)on soil N2O emissions and associated nitrification and denitrification functional genes.The results showed that the different BNIs(1,9-D,LN,MHPP)significantly reduced peak N2O emissions by 40.1％on average;1,9-D and MHPP suppressed total N_θ emlssons by 44.5％and 43.9％,respectively,while DCD and LN had no sigififcant effects.Both 1,9-D and MHPP differed in their regulations of nitrifying and denitrifying bacteria,with 1,9-D inhibiting the growth of both AOA,AOB,and nirS microorganisms;MHPP only inhibited the growth of AOA;whereas the abundance of AOA-amoA and nirS genes were significant and positively correlated with soil N2O emissions.Meanwhile,both 1,9-D and MHPP increased nosZ gene abundances and their ratios to AOA-amoA+AOB-amoA,nirS+nirK and AOA-amoA+AOB-amoA+nirS+nirK,which were significantly negatively correlated with soil N2O emissions.In conclusion,changes in the abundance of AOA-amoA and nosZ genes caused by the biological nitrification inhibitors 1,9-D and MHPP play important roles in N2O reduction in red paddy soil.
Biological nitrification inhibitorsPaddy soil derived from red earthN2OAOA-amoAnosZ
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