Following is the appearance of the Soil Layers tab of the Catchment Coefficients dialog with Adsorption selected:
Following is a description of the Adsorption parameters associated with Soil Layers. Refer to the main Catchment Coefficients page for information on other categories of coefficients. To save the changes made when closing this dialog, click OK. To ignore changes, click Cancel.
CEC is the cation exchange capacity of the soil layer (0-40 meq/100 g soil).
Max. PO4 is the maximum phosphate adsorption capacity of the soil layer (0-17600 mg PO4/kg soil)
For each cation, enter the adsorption isotherm. For the major ions (NH4, Ca, Mg, K, Na) their adsorbed concentrations are calculated using competitive ion exchange. Hydrogen ion will adsorb to those cation sites not adsorbed to by other cations. For other cations and all anions, enter the constant adsorption isotherm in liters per kg of soil.