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 SO42−strongly influenced the amount of soil base cation released; Ca2+was much lower in the H2SO4extracted solutions (maximum 20.0 versus 110 μeq. g−1from the 0 horizon and 0.40 versus 2.0 μeq·g−1from the B horizon for H2SO4and HNO3solutions, respectively). Gypsum formation was suggested as a possible explanation for the decreased Ca2+levels; however, SO42−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 SO42−adsorption. Differences in contact time and solution composition were deemed to be important factors in cation release from these soils.
ASJC Scopus subject areas
- Soil Science