Final Report Summary - QUASOM (Quantifying and modelling pathways of soil organic matter as affected by abiotic factors, microbial dynamics, and transport processes)
One main outcome was SOMPROF, a parsimonious model of vertical transport of SOM across the soil profile. The depth explicit description allows improved representation other processes, e.g. the thermal insulation of the soil by an organic layer or energy-limitation of microbes responsible for SOM stabilization in the subsoil. By implementing the SOMPROF into the global ecosystem model JSBACH these interactions can now be simulated and studied at a global scale and can be better benchmarked with globally distributed soil maps.
Another finding was the strong but complicated control of living microbes on the dependence of SOM dynamics on environmental conditions. Therefore, detailed models describing microbial dynamics on small scales have been simplified to represent the most important effects on SOM decomposition. Usually the interactions between the fresh carbon from plants and the older soil carbon cannot be neglected, as is currently done in most models.
Furthermore, patterns of carbon turnover have been compiled that help benchmarking and improving earth system models.
Overall the QUASOM project gained and combined insight of SOM dynamics at different scales. These insights resulted in improved parsimonious descriptions and models that are useful to a broader scientific community especially in the climate modelling community.