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Solution Sulfate Chemistry in Three Sulfur‐Retentive Hydrandepts
Author(s) -
Wolt J. D.,
Hue N. V.,
Fox R. L.
Publication year - 1992
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/sssaj1992.03615995005600010014x
Subject(s) - sorption , langmuir , chemistry , gravimetric analysis , gibbsite , soil water , moisture , montmorillonite , langmuir adsorption model , sulfur , sulfate , precipitation , alunite , adsorption , mineralogy , environmental chemistry , analytical chemistry (journal) , soil science , kaolinite , geology , meteorology , hydrothermal circulation , organic chemistry , physics , seismology
Highly S‐retentive Hydrandepts frequently contain large quantities (> 200 mmol kg ‐1 ) of sorbed S while exhibiting low S intensities in soil solution. Solution‐solid phase S relations for three representative Hydrandepts from Hawaii were investigated in terms of the nature of sorption isotherms and the role of basic Al hydroxysulfate precipitation as a mechanism for S retention. Sorption data were fit to linear, Langmuir, and multisite Langmuir isotherms using a modeling routine that performed parameter estimates and model optimization using weighted nonlinear fitting. Best‐fit models indicated sorption data were adequately described by Langmuir isotherms. Total P‐extractable SO 4 ‐S increased markedly at depths > 45 cm and tended to decline at depths > 120 cm. Extractable SO 4 ‐S was strongly regressed on gravimetric moisture content, a relative indicator of reactive surface for these thixotropic soils. Soil solution SO 4 ‐S concentrations were consistent with alunite or basaluminite solubility when gibbsite controlled solution Al 3+ .