Modelling priming effect to explain the effect of DOC input quality on soil C turnover

Even though priming effects (PE) could reduce soil organic C gains from enhanced ecosystem productivity under global change, the PE has been introduced to few models only recently. Both particulate organic matter (POM) and mineral-associated organic matter (MAOM) decomposition may be increased by DOC (dissolved organic carbon) inputs via the priming effect (PE) which is stronger in less-protected fractions (i.e., POM) and is also influenced by the DOC input quality. In our previous study, we showed that spruce litter leachates induced a higher PE than root exudates and could track their utilization by fungi and bacteria using isotope labelling, 13C-PLFA and 13C in respired CO2 and soil C fractions (Jílková et al. 2022) Here we use components from the KEYLINK model to develop a model that can be optimized using data from the experiment of Jílková et al. (2022) and used to predict outcomes of ongoing follow up incubation experiments using 13C-labelled spruce and beech litter leachates and root exudates on soils and fractions alone. We use this approach to test our understanding of the mechanisms of the microbially-driven soil C turnover under contrasting quality of DOM inputs.