Effects of long-term fertilization regime on denitrifying microbial community and denitrification potential of nirS, nirK and nosZ genotypes

Denitrification is an important process in the nitrogen cycle, and it is also one of the main processes causing N2O greenhouse gas emission and soil nitrogen loss. nirK, nirS and nosZ genotypes denitrifying microorganisms play a key role in this process. The purpose of this study was to study the effects of long-term fertilization on denitrifying microbial community and denitrification potential of nirK, nirS and nosZ genotypes in Chao brown soil in Shenyang, China. Five treatments were selected in this study, including no fertilizer (CK), chemical N fertilizer (N), chemical N, P and K fertilizers (NPK), recycled organic manure (M) and combined application of chemical N, P, K and recycled manure (MNPK). Methods of quantitative polymerase chain reaction (qPCR) and Illumina MiSeq sequencing were applied to assess the abundance and composition of Denitrifying microorganism. The results show that different long-term fertilization models will have a significant impact on the number and community structure of denitrifying microbial community. The response of nosZ gene abundance to the environment and the response of nirK and NIRnirS gene abundance to the environment are different. The long-term fertilization model of nitrogen fertilizer will significantly change the species composition of denitrifying microbial community, The long-term application of inorganic fertilizer significantly increased the denitrification potential of soil.