Effects and Mechanisms of Different Biological Nitrification Inhibitors on N2O Emissions from Red Paddy Soil
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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