Nitrous oxide (N₂O) emissions from arable soils are predominantly caused by denitrifying microbes, of which fungal denitrifiers are of particular interest, as fungi, in contrast to bacteria, terminate denitrification with N₂O. Reduced tillage has been shown to increase gaseous nitrogen losses from soil, but knowledge of how varying tillage regimes and associated soil physical and chemical alterations affect fungal denitrifiers is limited. Based on results from a long-term (>40 years) tillage experiment, we show that non-inversion tillage resulted in increased potential denitrification activity in the upper soil layers, compared to annual or occasional (every 4–5 years) conventional inversion tillage. Using sequence-corrected abundance of the fungal nirK gene, we further identified an increased genetic potential for fungal denitrification, compared to that caused by bacteria, with decreasing tillage intensity. Differences in the composition and diversity of the fungal nirK community imply that different tillage regimes select for distinct fungal denitrifiers with differing functional capabilities and lifestyles, predominantly by altering carbon and nitrogen related niches. Our findings suggest that the creation of organic hotspots through stratification by non-inversion tillage increases the diversity and abundance of fungal denitrifier communities and modifies their composition, and thus their overall relevance for N₂O production by denitrification, in arable soils.

耕地土壤中的一氧化二氮 (N ₂ O) 排放主要是由反硝化微生物引起的，其中真菌反硝化菌尤其令人感兴趣，因为与细菌相比，真菌会用 N ₂ O 终止反硝化作用。减少耕作已被证明会增加气态土壤中的氮损失，但关于不同的耕作方式和相关的土壤物理和化学变化如何影响真菌反硝化菌的知识是有限的。基于长期（>40 年）耕作实验的结果，我们表明，与每年或偶尔（每 4-5 年）的常规反耕相比，非反耕导致上层土层潜在的反硝化活动增加. 使用真菌nirK的序列校正丰度基因，我们进一步确定了真菌反硝化的遗传潜力，与细菌引起的反硝化相比，随着耕作强度的降低。真菌nirK群落的组成和多样性的差异意味着不同的耕作方式选择具有不同功能能力和生活方式的不同真菌反硝化菌，主要是通过改变碳和氮相关的生态位。我们的研究结果表明，通过非反转耕作的分层产生的有机热点增加了真菌反硝化菌群落的多样性和丰度，并改变了它们的组成，从而改变了它们与可耕土壤中通过反硝化作用产生N _{2 O 的整体相关性。}