The global biogeography of soil priming effect intensity

9 páginas.- 4 figuras.- 41 referencias.- Additional supporting information may be found in the online version of the article at the publisher’s website.-

Aim Fresh carbon (C) inputs to the soil can have important consequences for the decomposition rates of soil organic matter (priming effect), thereby impacting the delicate global C balance at the soil-atmosphere interface. Yet, the environmental factors that control soil priming effect intensity remain poorly understood at a global scale. Location Global. Time period 1980-2020. Major taxa studied Soil priming effect intensity. Methods We conducted a global dataset of CO2 effluxes in 711 pairwise soils with C-13 or C-14 simple C sources inputs and without C inputs from incubation experiments in which isotope-labelled C was used to quantify fresh C-induced rather than exudate-induced priming. Results Soil priming effect intensity is predominantly positive. Soil texture and C content were identified as the most important factors associated with priming effects, with sandy soils from tropical and mid-latitudes supporting the highest soil priming effect intensity, and soils with greater C content and fine textures from high latitudes maintaining the lowest soil priming effects. The negative association between C content and soil priming effect intensity was also indirectly driven by changing mean annual temperature, net primary productivity, and fungi : bacteria ratio. Using this information, we generated a global map of soil priming effect intensity, and found that the priming was lower at high latitudes and higher at lower latitudes. Main conclusions Global patterns of soil priming effect intensity can be predicted using environmental data, with soil texture and C content playing a predominant role in explaining in priming effects. These effects were also indirectly driven by climate, vegetation and soil microbial properties. We present the first global atlas of soil priming effect intensity and advance our knowledge on the potential mechanisms underlying soil priming effect intensity, which are integral to improving the climate change and soil C dynamics components of Earth System models.

National Natural Science Foundation of China, Grant/Award Number: 41907031; China Postdoctoral Science Foundation, Grant/Award Number: 2021T140565; Natural Science Basic Research Plan in Shaanxi Province of China, Grant/Award Number: 2020JQ-272; Forest and Grass Technology Innovation Development and Research Projects from National Forestry and Grassland Administration, Grant/Award Number: 2020132111; China Postdoctoral Science Foundation, Grant/Award Number: 2019M650276; Chinese Academy of Sciences “Light of West China” Program for Introduced Talent in the West, Grant/Award Number: 31570440

Peer reviewed