Abstract:Denitrifying bacteria was the key factor of soil nitrous oxide (N2O) emission. Taking Chinese fir plantation as the research object, four treatments of logging residues were set up (RF, reference; RB, residue burning; MT, mulching treatment; NR, no residues), using high-throughput sequencing technology and nosZ as marker gene, the composition and abundance of soil nosZ-type denitrifying bacteria community were determined from September 2018 to September 2020. The results showed that more than 90% of soil nosZ-type denitrifying bacteria came from Proteobacteria in the four treatments, and the dominant bacteria included Azospirillum, Mesorhizobium, Zoogloea, Burkholderia, Acidovorax, Bradyrhizobium, Pseudomonas, Azoarcus and Achromobacter. The results of significance analysis between samples in different species showed that the nosZ gene abundance at Betaproteobacteria level was significantly increased in RB compared with RF after the treatment of half a year. After one year, the Rhodospirillales, Rhodospirillaceae and Azospirillum in RB were significantly higher than those in MT. Compared with NR, the abundance of nosZ gene was significantly increased in Gammaproteobacteria and Alcaligenaceae in MT after one year of treatment. The nosZ gene abundance at Proteobacteria level was also significantly higher in MT than that in RF and RB after two years of treatment. The alpha diversity data showed that the Shannon and Simpson indexes in MT were significantly increased compared with those in RF and NR after one year of treatment. After two years of treatment, ACE and Chao1 indexes in MT and RB were significantly lower than those in RF. The four different logging residue treatments in Chinese fir plantation had significant effects on the composition and abundance of soil nosZ-type denitrifying bacteria community, which changed significantly with the study time, providing a data basis for comprehensively understanding of the microbial mechanism of N2O emission of soil nitrogen cycling process under different forest cutting and regeneration methodology.
