An incubation experiment was conducted to examine combined or individual impacts of biochar and/or 3,4-dimethylpyrazole phosphate (DMPP) on the net nitrification rates, the abundances of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB, a halophilic β-AOB) and TAO100 (a non-halophilic γ-AOB), and comammox Nitrospira in a highly acidic sugarcane soil. The net nitrification rates were markedly suppressed by biochar and/or DMPP application. Urea addition stimulated but DMPP alone significantly inhibited the growth of AOB, TAO100, total comammox Nitrospira, and clade A. The application of biochar alone increased AOA and AOB abundances, but reduced those of TAO100, total comammox Nitrospira, and clade A. Likely in the combined biochar and DMPP treatment, DMPP was absorbed by biochar then reducing its efficacy in suppressing the growth of AOB, total comammox Nitrospira, and clade A. Total comammox Nitrospira and clade A abundances were significantly correlated with NO3− concentrations (P < 0.001). Furthermore, biochar and/or DMPP addition had a significant effect on the composition of comammox Nitrospira community by PCoA. Phylogenetic analysis showed that all main comammox Nitrospira community fell within the clade A. Overall, our findings proved that the dynamics of total comammox Nitrospira resulting from the application of biochar and/or DMPP played a pivotal role in controlling soil nitrification in the highly acidic sugarcane soil with high N input.

中文翻译：

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生物炭和/或硝化抑制剂降低硝化作用与高酸性甘蔗土壤中 comammox Nitrospira 的丰度密切相关

进行孵化实验以检查生物炭和/或 3,4-二甲基吡唑磷酸盐 (DMPP) 对净硝化速率、氨氧化古菌 (AOA)、氨氧化细菌 (AOB, a嗜盐 β-AOB）和 TAO100（非嗜盐 γ-AOB），以及高酸性甘蔗土壤中的 comammox Nitrospira。生物炭和/或 DMPP 应用显着抑制了净硝化速率。添加尿素刺激但单独使用 DMPP 显着抑制 AOB、TAO100、总硝化螺旋藻和进化枝 A 的生长。单独使用 biochar 增加了 AOA 和 AOB 丰度，但降低了 TAO100、总硝化螺旋藻和进化枝 A结合生物炭和 DMPP 处理，DMPP 被 biochar 吸收，然后降低其抑制 AOB、总 comammox Nitrospira 和进化枝 A 生长的功效。总 comammox Nitrospira 和进化枝 A 丰度与 NO3− 浓度显着相关（P < 0.001）。此外，生物炭和/或 DMPP 添加对 PCoA 对 comammox Nitrospira 群落的组成有显着影响。系统发育分析表明，所有主要的 comammox Nitrospira 群落都落在进化枝 A 内。高氮输入的土壤。总 comammox Nitrospira 和进化枝 A 丰度与 NO3− 浓度显着相关（P < 0.001）。此外，生物炭和/或 DMPP 添加对 PCoA 对 comammox Nitrospira 群落的组成有显着影响。系统发育分析表明，所有主要的 comammox Nitrospira 群落都属于进化枝 A。 总的来说，我们的研究结果证明，应用 biochar 和/或 DMPP 产生的总 comammox Nitrospira 的动态在控制高酸性甘蔗中的土壤硝化作用中起着关键作用高氮输入的土壤。总 comammox Nitrospira 和进化枝 A 丰度与 NO3− 浓度显着相关（P < 0.001）。此外，生物炭和/或 DMPP 添加对 PCoA 对 comammox Nitrospira 群落的组成有显着影响。系统发育分析表明，所有主要的 comammox Nitrospira 群落都属于进化枝 A。 总的来说，我们的研究结果证明，应用 biochar 和/或 DMPP 产生的总 comammox Nitrospira 的动态在控制高酸性甘蔗中的土壤硝化作用中起着关键作用高氮输入的土壤。