Abstract. The plant-soil interactions in a changing environment, such as the response of soil organic matter (SOM) decomposition, nutrient release, and plant uptake to elevated CO2 concentration, is essential to understand the global carbon (C) cycling and predict potential future climate feedbacks. These processes are poorly represented in current terrestrial biosphere models (TBMs) due to the simple linear approach of SOM cycling and the ignorance of variation within the soil profile. While the emerging microbially-explicit soil organic carbon models can better describe C formation and turnover processes, they lack so far a coupling to nutrient cycles. Here we present a new SOM model, JSM (Jena Soil Model), which is microbially-explicit, vertically resolved, and integrated with nitrogen (N) and phosphorus (P) cycle processes. JSM includes a representation of enzyme allocation to different depolymerisation sources based on the microbial adaptation approach, and a representation of nutrient acquisition competition based on the equilibrium chemistry approximation (ECA) approach. We present the model structure and basic features of the model performance against a German beech forest site. The model is capable of reproducing the main SOM stocks, microbial biomass, and their vertical patterns of the soil profile. We further test the model sensitivity to its parameterisation and show that JSM is generally sensitive to the change of microbial stoichiometry and microbial processes.
Supplementary material to "Jena Soil Model: a microbial soil organic carbon model integrated with nitrogen and phosphorus processes"
