A study on the adsorption of 2-methy-1-4-chlorophenoxyacetic acid (MCPA) on three different soils with different contents of organic matter was performed. Adsorption isotherms were obtained using batch equilibrium method, and adsorption constant were calculated. The value of organic carbon adsorption constant of MCPA in soil was 108. It is one molecular layer adsorption and belongs to physical adsorption.
