Goethite promoted N2O emissions via increasing autotrophic nitrification dominated by ammonia oxidizing bacteria in paddy soils

• Published in: Applied soil ecology : a section of Agriculture, ecosystems & environment Vol. 201; p. 105479
• Main Authors: Zuo, Jichao, Fu, Qingling, Hu, Hongqing, Zhu, Jun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2024
• Subjects: AOA; AOB; Fe oxides; N2O emissions; Nitrification; Nitrifying microorganisms; Fe oxides; AOA; AOB; Nitrifying microorganisms; N2O emissions; Nitrification
• ISSN: 0929-1393; 1873-0272
• DOI: 10.1016/j.apsoil.2024.105479

Fe oxides play a crucial role in the biogeochemical processes of nitrous oxide (N2O) emissions. However, the role of Fe in affecting the quantitative contribution of ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) to N2O production has not been well understood. To clarify the effects of goethite on relative contribution of AOB and AOA to N2O production, acetylene and 1-octyne inhibition culture experiment was conducted in two paddy soils with contrasting pH (pH 5.5 and pH 7.9). The results showed that goethite increased cumulative N2O emissions by 13.5 %–39.9 % and 2.7 %–27.2 % in acidic and alkaline paddy soils, respectively. In both paddy soils with nitrogen (N) application, AOB contributed more to N2O emissions than AOA, while the trend was opposite in the treatment without N application. Goethite increased the relative contribution of AOB to N2O production from 41 % to 56 % in acidic paddy soil and from 54 % to 59 % in alkaline paddy soil, respectively. The main genera involved in N2O emissions in the two paddy soils were Nitrosospira-AOB and Nitrososphaera-AOA, and goethite increased their abundance in alkaline paddy soil. Overall, goethite mainly increased the N2O emissions by promoting the autotrophic nitrification processes dominated by AOB. The findings of our study provide new insights into the development of strategies to reduce N2O emissions by steering the microbiome responsible for N2O emissions by regulating soil iron oxide in paddy soils. [Display omitted] •Goethite increased cumulative N2O emissions in paddy soils.•AOB, rather than AOA, was the main contributor to N2O emissions in both soils.•Goethite increased the abundance of AOB and its contribution to N2O emissions.•Goethite increased Nitrosospira-like AOB and Nitrososphaera-like AOA in alkaline paddy soil.