Summary:

Soil Layers

The soil column can be divided into multiple layers for modeling purposes. The default configuration uses 25 layers, with the deepest 5 layers included only for thermodynamic calculations. 

The key characteristics of the soil layer structure are:

1. Node depth (zi): The depth of each layer node
2. Layer thickness (Δzi): The thickness of each soil layer
3. Layer interface depth (zh,i): The depth at the interface between each soil layer

The table provided outlines the specific values for these parameters in the default soil layer structure, with layer depths ranging from 0.02 m for the top layer to 49.556 m for the bottom layer.

This layered soil representation allows for detailed modeling of soil processes, including hydrology and biogeochemistry, within the top 20 active layers, as well as thermodynamic calculations in the deeper layers.