AUTHOR=Lei Jilin , Fan Qianyi , Yu Jingyao , Ma Yan , Yin Junhui , Liu Rui 

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

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.962146

DOI=10.3389/fmicb.2022.962146

ISSN=1664-302X

ABSTRACT=<p>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 (N<sub>2</sub>O) and perform the first step of nitrification, but their contribution to N<sub>2</sub>O 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 <italic>amo</italic>A 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 N<sub>2</sub>O emissions and increased 71.4% of soil <inline-formula><mml:math id="INEQ1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>NH</mml:mn><mml:msubsup><mml:mi /><mml:mn>4</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:math></inline-formula> 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 N<sub>2</sub>O emissions than in acidic soils. The abundance of AOB <italic>amo</italic>A genes was dramatically reduced by about 50% with NI application in most soil types. Decrease in N<sub>2</sub>O emissions with NI addition was significantly correlated with AOB changes (<italic>R</italic><sup>2</sup> = 0.135, <italic>n</italic> = 110, <italic>P</italic> &lt; 0.01) rather than changes in AOA, and there was an obvious correlation between the changes in <inline-formula><mml:math id="INEQ2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>NH</mml:mn><mml:msubsup><mml:mi /><mml:mn>4</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:math></inline-formula> concentration and AOB <italic>amo</italic>A gene abundance after NI application (<italic>R</italic><sup>2</sup> = 0.037, <italic>n</italic> = 136, <italic>P</italic> = 0.014). The results indicated the principal role of AOB in nitrification, furthermore, AOB would be the best predictor of NI efficiency.</p>