Biochar amendment has been shown to reduce nitrous oxide (N₂O) emissions from acidic soils in tea plantations. Given that both soil bacterial and fungal denitrifications can produce N₂O, their relative contributions to the decrease in N₂O emissions following biochar amendment remain unclear. Here, we examined soils sampled from a subtropical tea plantation that had received 2 years of biochar amendment. Measurements of the relative contributions of fungi and bacteria to N₂O production were taken by the substrate-induced respiration method implemented with the addition of selective inhibitors. The abundances of total fungi, bacteria, and key N₂O-related bacterial genes were quantified by q-PCR, and the composition of the fungal community was analyzed by 18S rRNA amplicon sequencing. The results showed that the contribution of fungi to N₂O production (52%) was greater than that of bacteria (18%) for the N-applied acidic soils. Biochar amendment significantly decreased the fungal abundances and the fungal contribution to N₂O production (by 28%). In contrast, biochar amendment significantly increased the abundances of N₂O-related bacteria (e.g., ammonia-oxidizing bacteria (AOB), nirS, nosZ). Structural equation models (SEMs) revealed that biochar decreased the fungal contribution to N₂O production through enhancing the soil pH and shifting the fungal community composition. Our results highlight that the decreased N₂O emissions could be ascribed to the stimulated N₂O consumption process (driven by N₂O-consuming bacteria encoded by the nosZ gene) and suppressed fungal dominance in acidic soils from tea plantations. This study presents relatively comprehensive insights into the regulatory roles of biochar on soil microbe-mediated N₂O production processes.

生物炭改良剂已被证明可以减少茶园酸性土壤中的一氧化二氮 (N ₂ O) 排放。鉴于土壤细菌和真菌反硝化作用都可以产生 N ₂ O，它们对生物炭修正后N ₂ O 排放量减少的相对贡献仍不清楚。在这里，我们检查了从接受 2 年生物炭改良的亚热带茶园取样的土壤。真菌和细菌对 N ₂ O 产生的相对贡献的测量是通过添加选择性抑制剂实施的底物诱导呼吸方法进行的。总真菌、细菌和关键 N ₂的丰度通过q-PCR定量O相关细菌基因，通过18S rRNA扩增子测序分析真菌群落的组成。结果表明，对于施氮酸性土壤，真菌对N ₂ O 产生的贡献（52%）大于细菌（18%）。Biochar 修正剂显着降低了真菌丰度和真菌对 N ₂ O 生产的贡献（降低了 28%）。相比之下， biochar 修正显着增加了 N ₂ O 相关细菌（例如，氨氧化细菌 (AOB)、nirS、nosZ）的丰度。结构方程模型 (SEM) 显示 biochar 降低了真菌对 N _{2 的}贡献通过提高土壤 pH 值和改变真菌群落组成来产生 O。我们的结果强调，N ₂ O 排放量的减少可归因于受刺激的 N ₂ O 消耗过程（由nosZ基因编码的N ₂ O 消耗细菌驱动）并抑制了茶园酸性土壤中的真菌优势。本研究对生物炭对土壤微生物介导的 N ₂ O 生产过程的调节作用提出了相对全面的见解。