Predicting Boron Adsorption by Soils Using Soil Chemical Parameters in the Constant Capacitance Model

The constant capacitance model, a chemical surface complexation model, was applied to B adsorption on 17 soils selected for variation in soil properties. A general regression model was developed for predicting soil B surface complexation constants from easily measured soil chemical characteristics. These chemical properties were cation‐exchange capacity (CEC), surface area, organic carbon content (OC), and inorganic carbon content (IOC). The prediction equations were used to obtain values for B surface complexation constants for 15 additional soils, thereby providing a completely independent evaluation of the ability of the constant capacitance model to fit B adsorption. The model was well able to predict B adsorption on the 15 soils. Incorporation of these prediction equations into chemical speciation–transport models will allow simulation of soil solution B concentrations under diverse environmental and agricultural conditions without the requirement of soil specific adsorption data and subsequent parameter optimization.