Biochar Addition Inhibits Nitrification by Shifting Community Structure of Ammonia-Oxidizing Microorganisms in Salt-Affected Irrigation-Silting Soil

Abstract

Biochar has been widely recognized as an effective and eco-friendly ameliorant for saline soils, but information about the mechanism of how biochar influences nitrification in salt-affected agroecosystem remains fragmented. An incubation experiment was performed on the salt-affected soil collected from a three-consecutive-year experiment at biochar application gradients of 7.5 t⋅ha−1, 15 t⋅ha−1 and 30⋅t ha−1 and under nitrogen (N) fertilization. Responses of the nitrification rate (NR), numbers of ammonia monooxygenase (amoA) gene copies, and community structures of ammonia-oxidizing bacteria (AOB) and archaea (AOA) to biochar application were investigated. The results indicated that, under N fertilization, the NR and numbers of amoA-AOB and amoA-AOA gene copies negatively responded to biochar addition. Biochar application increased the community diversity of AOB but decreased that of AOA. Biochar addition and N fertilization shifted the AOB community from Nitrosospira-dominated to Nitrosospira and Nitrosomonas-dominated, and altered the AOA community from Nitrososphaera-dominated to Nitrososphaera and Nitrosopumilus-dominated. The relative abundance of Nitrosospira, Nitrosomonas and Nitrosopumilus decreased, and that of Nitrosovibrio and Nitrososphaera increased with biochar application rate. Soil SOC, pH and NO3−-N explained 87.1% of the variation in the AOB community, and 78.1% of the variation in the AOA community was explanatory by soil pH and SOC. The SOC and NO3−-N influenced NR through Nitrosovibrio, Nitrosomonas, Norank_c_environmental_samples_p_Crenarchaeota and amoA-AOB and amoA-AOA gene abundance. Therefore, biochar addition inhibited nitrification in salt-affected irrigation-silting soil by shifting the community structures of AOB and AOA and reducing the relative abundance of dominant functional ammonia-oxidizers, such as Nitrosospira, Nitrosomonas and Nitrosopumilus.

The legacy effect of biochar application on soil nitrous oxide emissions

“…This is consistent with the finding that aging biochar reduced N 2 O emissions by reducing autotrophic nitrification via reduced bioavailability of NH 4 + (Liao, Müller, et al, 2021). Therefore, we conclude that the reduction in substrate effectiveness and microbial functional gene abundance may have affected soil nitrification, thereby suppressing its driven N 2 O emissions (Liao, Müller, et al, 2021;Yao et al, 2022).…”

Methane-Derived Zero-Valent Carbon Solids Differentially Impact Model Nitrogen Cycling Bacteria and Significantly Inhibit Nitrification

“…Estimated cell abundance dramatically decreased after 24 h before stabilizing and resuming slight growth between 72 and 96 h. The observed differences in growth and associated metabolic activity in the presence of ZVC were reflected by changes in the pH of the medium (Figure S2b), while charcoal treatments buffered pH changes under acidic conditions . Although it is unknown whether ZVC will impact all ammonia-oxidizing bacteria (AOB) similarly, Nitrosomonas is one of the most abundant genera of AOB in soils , and is sensitive to other carbon solid amendments. , While ammonia oxidation can be carried out by ammonia-oxidizing archaea (AOA) and comammox bacteria, AOB are generally favored in soils with high levels of fertilizers. − In such cases, inhibiting ammonia oxidation, the first and most rate-limiting step of nitrification, would be critical for restricting downstream nitrate production and denitrification.…”

“…44 Although it is unknown whether ZVC will impact all ammonia-oxidizing bacteria (AOB) similarly, Nitrosomonas is one of the most abundant genera of AOB in soils 45,46 and is sensitive to other carbon solid amendments. 47,48 While ammonia oxidation can be carried out by ammonia-oxidizing archaea (AOA) and comammox bacteria, AOB are generally favored in soils with high levels of fertilizers. 49−51 In such cases, inhibiting ammonia oxidation, the first and most rate-limiting step of nitrification, would be critical for restricting downstream nitrate production and denitrification.…”

Recent trends in nitrogen cycle and eco-efficient nitrogen management strategies in aerobic rice system

“…Considering the relative abundance of AOA under differential soil conditions, Nitrososphaera and Nitrosopumilus clusters have been indicated as the most abundant AOA communities ( Prosser and Nicol, 2012 ; Li et al, 2018 ; Yao et al, 2022 ). Structural composition and relative abundance of AOA communities are inclined to be less influenced by variations in soil N regimes and environmental conditions as compared to AOB ( Liu et al, 2014 ; Lu et al, 2018 ; Zou et al, 2022 ).…”