采伐剩余物管理对杉木人工林土壤nosZ型反硝化细菌群落多样性的影响

反硝化细菌是土壤氧化亚氮(N₂O)排放的关键因子。以杉木人工林为研究对象，设置4种采伐剩余物处理方式(RF:对照；RB:火烧；MT:粉碎；NR:移除),采用高通量测序技术，以nosZ为标记基因，测定了自2018年9月—2020年9月，2年期间土壤nosZ型反硝化细菌群落的组成和丰度。研究结果显示，4种采伐剩余物处理中的土壤nosZ型反硝化细菌90%以上来自变形菌门，优势菌属包括固氮螺菌属、中慢生根瘤菌属、动胶菌属、伯克霍尔德菌属、嗜酸菌属、慢生根瘤菌属、假单胞菌属、固氮弧菌属以及无色杆菌属；样本间差异物种的显著性分析表明，在处理完成半年时，火烧相较于对照于β-变形菌纲水平显著增加了nosZ基因丰度；在处理完成一年时，火烧分别于红螺菌目、红螺菌科、固氮螺菌属水平显著高于粉碎；粉碎相较于移除在处理完成一年时，于γ-变形菌纲和产碱菌科水平显著增加了nosZ基因丰度；在处理完成两年时，粉碎处理的nosZ基因丰度在变形菌门水平显著高于对照和火烧。α多样性数据显示，处理完成一年时，粉碎处理相较于对照和移除显著增加了Shannon和Simpson指数；处理完成两年时，粉碎和火烧...

Effects of logging residue management on soil nosZ-type denitrifying bacteria community diversity in a Chinese fir plantation

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.