Niche Differentiation Among Canonical Nitrifiers and N2O Reducers Is Linked to Varying Effects of Nitrification Inhibitors DCD and DMPP in Two Arable Soils

• Published in: Microbial ecology 2023-05, Vol.85 (4), p.1434-1447
• Main Authors: Fan, Xiaoping, Chen, Hao, Yan, Guochao, Ye, Mujun, Yin, Chang, Li, Tingqiang, Wakelin, Steven A., Liang, Yongchao
• Format: Article
• Language: English
• Subjects: Abundance; Acidic soils; Alkaline soils; Ammonia; Ammonia-oxidizing bacteria; Arable land; Archaea; Biomedical and Life Sciences; Community composition; Community structure; Correlation; Differentiation; Ecology; Effectiveness; Emission; Emissions; Geoecology/Natural Processes; Guilds; Inhibitors; Life Sciences; Microbial Ecology; Microbiology; Microbiota; Microorganisms; Nature Conservation; Niches; Nitrification; Nitrobacter; Nitrospira; Nitrous oxide; Oxidation; Oxidizing agents; Phosphates; Soil; Soil Microbiology; Soil structure; Soil types; Soils; Urea; Water Quality/Water Pollution
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s00248-022-02006-8

The efficacy of nitrification inhibitors (NIs) dicyandiamide (DCD) and 3,4-dimethylpyrazole phosphate (DMPP) varies with soil types. Understanding the microbial mechanisms for this variation may lead to better modelling of NI efficacy and therefore on-farm adoption. This study addressed the response patterns of mineral nitrogen, nitrous oxide (N 2 O) emission, abundances of N-cycling functional guilds and soil microbiota characteristics, in relation to urea application with or without DCD or DMPP in two arable soils (an alkaline and an acid soil). The inhibition of nitrification rate and N 2 O emission by NI application occurred by suppressing ammonia-oxidizing bacteria (AOB) abundances and increasing the abundances of nosZ I-N 2 O reducers; however, abundances of ammonia-oxidizing archaea (AOA) were also stimulated with NIs-added in these two arable soils. DMPP generally had stronger inhibition efficiency than DCD, and both NIs’ addition decreased Nitrobacter , while increased Nitrospira abundance only in alkaline soil. N 2 O emissions were positively correlated with AOB and negatively correlated with nosZ I in both soils and AOA only in acid soil. Moreover, N 2 O emissions were also positively correlated with nirK -type denitrifiers in alkaline soil, and clade A comammox in acid soil. Amendment with DCD or DMPP altered soil microbiota community structure, but had minor effect on community composition. These results highlight a crucial role of the niche differentiation among canonical ammonia oxidizers (AOA/AOB), Nitrobacter and Nitrospira , as well as nosZ I- and nosZ II-N 2 O reducers in determining the varying efficacies of DCD and DMPP in different arable soils.