Nitrogen addition to soil affects microbial carbon use efficiency: Meta‐analysis of similarities and differences in 13 C and 18 O approaches

作者：Junxi Hu, Congde Huang, Shixing Zhou, Yakov Kuzyakov · 发表于：Global Change Biology · 年份：2022 · DOI：10.1111/gcb.16226 · 被引用次数：108 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil and Water Nutrient Dynamics、Peatlands and Wetlands Ecology

Abstract The carbon use efficiency (CUE) of soil microorganisms is a critical parameter for the first step of organic carbon (C) transformation by and incorporation into microbial biomass and shapes C cycling in terrestrial ecosystems. As C and nitrogen (N) cycles interact closely and N availability affects microbial metabolism, N addition to soil may shift the microbial CUE. We conducted a meta‐analysis (100 data pairs) to generalize information about the microbial CUE response to N addition in soil based on the two most common CUE estimation approaches: (i) 13 C‐labelled substrate addition ( 13 C‐substrate) and (ii) 18 O‐labelled water addition ( 18 O‐H 2 O). The mean microbial CUE in soils across all biomes and approaches was 0.37. The effects of N addition on CUE, however, were depended on the approach: CUE decreased by 12% if measured by the 13 C‐substrate approach, while CUE increased by 11% if measured by the 18 O‐H 2 O approach. These differences in the microbial CUE response depending on the estimation approach are explained by the divergent reactions of microbial growth to N addition: N addition decreases the 13 C incorporation into microbial biomass (this parameter is in the numerator by CUE calculation based on the 13 C‐substrate approach). In contrast, N addition slightly increases (although statistically insignificant) the microbial growth rate (in the numerator of the CUE calculation when assessed by the 18 O‐H 2 O approach), significantly raising the CUE. We e...