Processes in SoilGen

This chapter specifies the processes in SoilGen. The (re-)distribution of mass of elements, gas and water requires the simulation of various transport processes, and these are driven by variations at the soil boundary. The landscape context affects effective infiltration per unit area and is mimicked by slope, its exposition and the main wind direction. Clay transport is simulated. Various processes influencing element cycling are included: the organic and inorganic C-cycles, and the effect of the plant-driven nutrient pump. Processes affecting the solid phase are chemical precipitation and dissolution, weathering and neoformation of minerals and physical weathering. Soil production from bedrock is simulated as a combination of these processes. Plant-related processes are including the water cycle, root distribution and its growth and the nutrient pump effect. Mixing processes such as bioturbation and tillage are an additional form of mass redistribution. Methods to update the CEC, soil texture, bulk density and transport parameters after mass redistributions are described. Simple case studies are included to illustrate weathering and neoformation of soil minerals and soil production.