In the context of anthropogenic environmental impact analysis, there is a need to study soil carbon dynamics. Since CO 2 transport and production depend on soil texture, air humidity, rainfall frequency, and other factors, mathematical description of the gaseous phase of soils in a specific area is a topical task. This work is based on a mathematical model of the production and transport of carbon dioxide in the circadian time range in forest soils typical of Eastern Fennoscandia. The model is focused on a comparative quantitative analysis of diffusive and convective components to assess the dynamics of soil respiration and changes in flow directions (towards the atmosphere and deep-lying horizons, to groundwater). In this paper, the transition to the dimensionless form of the model was implemented, an explicit–implicit difference scheme and an iterative computational algorithm for solving the boundary value problem of carbon dioxide transport in a soil horizon were proposed.