Enrichment of nosZ‐type denitrifiers by arbuscular mycorrhizal fungi mitigates N2O emissions from soybean stubbles

• Published in: Environmental microbiology Vol. 23; no. 11; pp. 6587 - 6602
• Main Authors: Zhao, Ruotong, Li, Xia, Bei, Shuikuan, Li, Dandan, Li, Haigang, Christie, Peter, Bender, S Franz, Zhang, Junling
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.11.2021; Wiley Subscription Services, Inc
• Subjects: Abundance; Agricultural practices; Arbuscular mycorrhizas; Community composition; community structure; Composition effects; Corn; denitrifying microorganisms; Emissions; Fertilizers; Fungi; Hyphae; Intercropping; Legumes; Microorganisms; nitrogen fertilizers; Nitrous oxide; Residues; Soil; Soil microorganisms; Soils; Soybeans; vesicular arbuscular mycorrhizae
• DOI: 10.1111/1462-2920.15815
• ISSN: 1462-2912

Summary Hotspots of N2O emissions are generated from legume residues during decomposition. Arbuscular mycorrhizal fungi (AMF) from co‐cultivated intercropped plants may proliferate into the microsites and interact with soil microbes to reduce N2O emissions. Yet, the mechanisms by which or how mycorrhizal hyphae affect nitrifiers and denitrifiers in the legume residues remain ambiguous. Here, a split‐microcosm experiment was conducted to assess hyphae of Rhizophagus aggregatus from neighbouring maize on overall N2O emissions from stubbles of nodulated or non‐nodulated soybean. Soil microbes from fields intercropped with maize/soybean amended with fertilizer nitrogen (SS‐N1) or unamended (SS‐N0) were added to the soybean chamber only. AMF hyphae consistently reduced N2O emissions by 20.8%–61.5%. Generally, AMF hyphae promoted the abundance of N2O‐consuming (nosZ‐type) denitrifiers and altered their community composition. The effects were partly associated with increasing MBC and DOC. By contrast, AMF reduced the abundance of nirK‐type denitrifiers in the nodulated SS‐N0 treatment only and that of AOB in the non‐nodulated SS‐N1 treatment. Taken together, our results show that AMF reduced N2O emissions from soybean stubbles, mainly through the promotion of N2O‐consuming denitrifiers. This holds promise for mitigating N2O emissions by manipulating the efficacious AMF and their associated microbes in cereal/legume intercropping systems.