Global ecological predictors of the soil priming effect

Abstract

Identifying the global drivers of soil priming is essential to understanding C cycling in terrestrial ecosystems. We conducted a survey of soils across 86 globally-distributed locations, spanning a wide range of climates, biotic communities, and soil conditions, and evaluated the apparent soil priming effect using 13 C-glucose labeling. Here we show that the magnitude of the positive apparent priming effect (increase in CO 2 release through accelerated microbial biomass turnover) was negatively associated with SOC content and microbial respiration rates. Our statistical modeling suggests that apparent priming effects tend to be negative in more mesic sites associated with higher SOC contents. In contrast, a single-input of labile C causes positive apparent priming effects in more arid locations with low SOC contents. Our results provide solid evidence that SOC content plays a critical role in regulating apparent priming effects, with important implications for the improvement of C cycling models under global change scenarios.

Regulation of priming effect by soil organic matter stability over a broad geographic scale

“…Particularly, the 13 C-labelled CaCO 3 experiment revealed that CaCO 3 -derived CO 2 only accounted for 1.0% of the total CO 2 release. These analyses demonstrated a minor contribution of carbonates to the CO 2 production and also its δ 13 C. Therefore, as done in most priming studies on soil with pH > 7.0 11,55 , the effects of soil carbonates on CO 2 release were considered limited in this study. The fractions of CO 2 -C derived from the added 13 C-glucose ( f glucose ) and from the SOM pool ( f SOM ) were then determined by Eqs.…”

Soil priming effect and its responses to nutrient addition along a tropical forest elevation gradient

“…spheric CO 2 can induce positive priming effects, accelerating soil C losses (Keuper et al, 2020;Sayer et al, 2011). It has been shown that priming effects on average can increase SOM decomposition by 15%-59% as indicated by previous studies at regional or global scale (Bastida et al, 2019;Chen et al, 2019;Huo et al, 2017;Perveen et al, 2019;Sun et al, 2019). In addition, regional-and global-scale modeling studies showed that incorporating the priming effect into earth system models could improve the predictions of soil C losses and soil C stocks under future global changes (Guenet et al, 2018;Keuper et al, 2020).…”

Soil microbial diversity–biomass relationships are driven by soil carbon content across global biomes

“…The diversity and biomass of soil microbial communities are the major regulators of fundamental ecosystem processes, such as organic matter decomposition, nutrient cycling, and gaseous fluxes [14][15][16]. However, although our understanding of biotic and abiotic factors controlling soil microbial diversity and biomass is increasingly growing [17][18][19], remarkably little is known about how soil microbial diversity and biomass are related across global biomes, and the factors that control such relationships [20,21].…”