A meta-analysis to examine whether nitrification inhibitors work through selectively inhibiting ammonia-oxidizing bacteria

Abstract

Nitrification inhibitor (NI) is often claimed to be efficient in mitigating nitrogen (N) losses from agricultural production systems by slowing down nitrification. Increasing evidence suggests that ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) have the genetic potential to produce nitrous oxide (N2O) and perform the first step of nitrification, but their contribution to N2O and nitrification remains unclear. Furthermore, both AOA and AOB are probably targets for NIs, but a quantitative synthesis is lacking to identify the “indicator microbe” as the best predictor of NI efficiency under different environmental conditions. In this present study, a meta-analysis to assess the response characteristics of AOB and AOA to NI application was conducted and the relationship between NI efficiency and the AOA and AOB amoA genes response under different conditions was evaluated. The dataset consisted of 48 papers (214 observations). This study showed that NIs on average reduced 58.1% of N2O emissions and increased 71.4% of soil NH4+ concentrations, respectively. When 3, 4-dimethylpyrazole phosphate (DMPP) was applied with both organic and inorganic fertilizers in alkaline medium soils, it had higher efficacy of decreasing N2O emissions than in acidic soils. The abundance of AOB amoA genes was dramatically reduced by about 50% with NI application in most soil types. Decrease in N2O emissions with NI addition was significantly correlated with AOB changes (R2 = 0.135, n = 110, P < 0.01) rather than changes in AOA, and there was an obvious correlation between the changes in NH4+ concentration and AOB amoA gene abundance after NI application (R2 = 0.037, n = 136, P = 0.014). The results indicated the principal role of AOB in nitrification, furthermore, AOB would be the best predictor of NI efficiency.

Inhibition profile of three biological nitrification inhibitors and their response to soil pH modification in two contrasting soils

“…Although the incubation conditions used in this study might have altered the proportion of AOB/comammox and AOA activities compared to the more competitive interactions observed in whole soil incubations (Prosser and Nicol 2012 , Rütting et al 2021 ). This trend of higher NI efficacy in more neutral soils, where net nitrification potential is AOB driven, compared to AOA dominated or more ASs has been observed previously (Guardia et al 2018 , Lu et al 2019 , Lei et al 2022 ).…”

Impacts of Climate Change and Agricultural Practices on Nitrogen Processes, Genes, and Soil Nitrous Oxide Emissions: A Quantitative Review of Meta-Analyses

“…In general, AOB tends to dominate nitrification in neutral and alkaline soils, while AOA is more prevalent in acidic environments [106]. Increasing the NH 4 + concentrations can enhance the nitrification activity of AOB [106], while AOA prefers environments with lower NH 4 + concentrations. Furthermore, many studies showed that NIs effectively decreased the AOB population but not AOA [30,65,106].…”

“…However, results have been inconsistent [30]. In general, AOB tends to dominate nitrification in neutral and alkaline soils, while AOA is more prevalent in acidic environments [106]. Increasing the NH 4 + concentrations can enhance the nitrification activity of AOB [106], while AOA prefers environments with lower NH 4 + concentrations.…”

“…Increasing the NH 4 + concentrations can enhance the nitrification activity of AOB [106], while AOA prefers environments with lower NH 4 + concentrations. Furthermore, many studies showed that NIs effectively decreased the AOB population but not AOA [30,65,106]. In contrast, for alkaline paddy soil in China, nitrapyrin decreased the rates of nitrification and denitrification by limiting the abundances of AOA and nirK, respectively [30].…”

The addition of discrimination inhibitors stimulations discrimination potential and N2O emissions were linked to predation among microorganisms in long term nitrogen application and straw returning systems

“…3,4-dimethylpyrazole phosphate (DMPP) is a highly soluble compound with high stability and persistent suppression effects ( Li et al, 2023 ). Studies have shown that DMPP effectively inhibited the metabolic activity of AOB rather than AOA, which in turn led to a reduction of nitrification rate ( Lei et al, 2022 ). Furthermore, in calcareous soils where the nitrification process was regulated by AOB, the addition of DMPP significantly suppressed N 2 O emissions ( Bai et al, 2020 ).…”