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Sulfate Adsorption in Forest Soils of the Great Lakes Region
Author(s) -
MacDonald Neil W.,
Burton Andrew J.,
Witter John A.,
Richter Daniel D.
Publication year - 1994
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1994.03615995005800050039x
Subject(s) - sulfate , soil water , adsorption , leaching (pedology) , environmental chemistry , environmental science , soil science , deciduous , deposition (geology) , chemistry , soil horizon , acid neutralizing capacity , hydrology (agriculture) , mineralogy , acid deposition , geology , ecology , structural basin , biology , geomorphology , geotechnical engineering , organic chemistry
Sulfate adsorption by forest soils modifies the impact of pollutant deposition on cation leaching processes. We examined relationships among SO 2− 4 adsorption, soil properties, and seasonal variation in soil solution chemistry at 13 sites representing deciduous forest ecosystems common in the Great Lakes region. Objectives of the study were to test the validity of previously proposed SO 2− 4 adsorption indices, to examine within‐ and among‐site variability in SO 2− 4 adsorption potential, and to investigate the effects of seasonal changes in soil solution chemistry on SO 4 2‐ retention. Mineral soils were sampled by horizon at all sites, and soil solutions were sampled at lower E and lower B horizon boundaries at 10 sites. Proposed indices overpredicted sulfate adsorption in certain SO 2− 4 releasing subsurface horizons, seriously limiting the applicability of the published regression equations. We developed improved regression equations using the sum of initial extractable SO 2− 4 and additional SO 2− 4 adsorbed under laboratory conditions as the dependent variable. Sulfate retention indices predicted by the improved equations were independent of existing levels of extractable SO 2− 4 and past history of atmospheric SO 2− 4 deposition. Examination of within‐ and among‐site variability in SO 2− 4 adsorption potentials suggested that soils need to be grouped tightly on a taxonomic basis for modelling purposes. Seasonal variation in soil solution SO 2− 4 concentration and fluxes was consistent with an annual cycle of SO 2− 4 retention and release. Although seasonal patterns in SO 2− 4 concentrations and fluxes appeared to be controlled by hydrologic and S‐cycling processes, the magnitude of SO 2− 4 fluxes was primarily related to atmospheric SO 2− 4 deposition rates.