Stimulation of ammonia oxidizer and denitrifier abundances by nitrogen loading: Poor predictability for increased soil N 2 O emission

作者：Yong Zhang, Feng Zhang, Diego Ábalos, Yiqi Luo, Dafeng Hui, Bruce A. Hungate, Pablo García‐Palacios, Yakov Kuzyakov, Jørgen E. Olesen, Uffe Jørgensen, Ji Chen · 发表于：Global Change Biology · 年份：2021 · DOI：10.1111/gcb.16042 · 被引用次数：101 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil and Water Nutrient Dynamics、Agriculture, Soil, Plant Science

Abstract Unprecedented nitrogen (N) inputs into terrestrial ecosystems have profoundly altered soil N cycling. Ammonia oxidizers and denitrifiers are the main producers of nitrous oxide (N 2 O), but it remains unclear how ammonia oxidizer and denitrifier abundances will respond to N loading and whether their responses can predict N‐induced changes in soil N 2 O emission. By synthesizing 101 field studies worldwide, we showed that N loading significantly increased ammonia oxidizer abundance by 107% and denitrifier abundance by 45%. The increases in both ammonia oxidizer and denitrifier abundances were primarily explained by N loading form, and more specifically, organic N loading had stronger effects on their abundances than mineral N loading. Nitrogen loading increased soil N 2 O emission by 261%, whereas there was no clear relationship between changes in soil N 2 O emission and shifts in ammonia oxidizer and denitrifier abundances. Our field‐based results challenge the laboratory‐based hypothesis that increased ammonia oxidizer and denitrifier abundances by N loading would directly cause higher soil N 2 O emission. Instead, key abiotic factors (mean annual precipitation, soil pH, soil C:N ratio, and ecosystem type) explained N‐induced changes in soil N 2 O emission. Altogether, these findings highlight the need for considering the roles of key abiotic factors in regulating soil N transformations under N loading to better understand the microbially mediated soil N 2 O emissio...