Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, 100871, China.
Department of Environmental Studies, University of California, Santa Cruz, CA, 95064, USA.
New Phytol. 2023 Jan;237(1):88-99. doi: 10.1111/nph.18458. Epub 2022 Sep 21.
Soil organic carbon (SOC) is a mixture of various carbon (C) compounds with different stability, which can be distinctly affected by the priming effect (PE). However, little is known about how the PE changes with SOC stability. We address this issue by combining results from two experiments and a metaanalysis. We found that the PE increased with the prolongation of soil preincubation, suggesting that higher PE occurred for more stable SOC than for labile SOC. This was further supported by the metaanalysis of 42 observations. There were significant negative relationships between the difference in PE (ΔPE) between labile and more stable SOC and their differences in SOC, microbial biomass C and soil C : N ratio, indicating that soil C availability exerts a vital control on ΔPE. We conclude that, compared with labile SOC, stable SOC can be more vulnerable to priming once microbes are provided with exogenous C substrates. This high vulnerability of stable SOC to priming warrants more attention in future studies on SOC cycling and global change.
土壤有机碳（SOC）是各种具有不同稳定性的碳（C）化合物的混合物，它会受到激发效应（PE）的显著影响。然而，人们对于激发效应如何随 SOC 稳定性而变化知之甚少。我们通过结合两项实验和荟萃分析的结果来解决这个问题。我们发现，随着土壤预培养时间的延长，激发效应会增加，这表明更稳定的 SOC 比不稳定的 SOC 会产生更高的激发效应。荟萃分析的 42 个观测结果进一步支持了这一点。激发效应（ΔPE）在不稳定 SOC 和更稳定 SOC 之间的差异与 SOC、微生物生物量 C 和土壤 C:N 比之间的差异呈显著负相关，这表明土壤 C 的有效性对 ΔPE 起着至关重要的控制作用。我们得出结论，与不稳定 SOC 相比，一旦微生物获得外源 C 底物，稳定 SOC 更容易受到激发。因此，在未来关于 SOC 循环和全球变化的研究中，稳定 SOC 对激发效应的高敏感性需要引起更多关注。
