The release and leaching of base cations and aluminum by acid additions to O and B soil horizons was examined using both batch and column experimental methods. Solution and soil contact time was a significant factor in the amount of cation release and leaching from the B horizon. Increased acidity resulted in greater levels of base cations and aluminum being released or leached from all soils. The type of acid anion, NO3(-) or SO4(-2), strongly influenced the amount of soil base cation released; Ca(2+) was much lower in the H2SO4 extracted solutions. Gypsum formation was suggested as a possible explanation for the decreased Ca(2+) levels; however, SO4(-2) adsorption was also believed to contribute to the reduction in base cation release. Proton buffering was due to three soil processes which included: cation exchange reactions, protonation of organic constituents, and SO4(-2) adsorption. Differences in contact time and solution composition were deemed to be important factors in cation release from the soils. (Copyright (c) 1991 by Williams & Wilkins.)