Simulating Biological Dynamics Using Partial Differential Equations: Application to Decomposition of Organic Matter in 3D Soil Structure

The majority of carbon on earth is in the form of soil organic matter. And its degradation by microorganisms leads to the remineralization of carbon as carbon dioxide. The microbial activity causes a reduction of soil carbon and increases atmospheric carbon. However, most models of organic matter do not explicitly take into account this reality. We try to answer these questions by developing and validating a model describing the action of microorganisms on degradation of organic matter. We use simulation domain as the pores in the soil modeled by a network of balls. The model is solved numerically in the balls by the finite element method with the solver of partial differential equations (PDEs) Freefem3d. We compare the numerical results with experimental data on the mineralization of soil carbon.