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Field‐Extracted Spodosol Solutions and Soils: Aluminum, Organic Carbon, and pH Interrelationships
Author(s) -
Ross Donald S.,
Bartlett Richmond J.
Publication year - 1996
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/sssaj1996.03615995006000020036x
Subject(s) - soil water , chemistry , dissolved organic carbon , podzol , total organic carbon , environmental chemistry , ionic strength , soil ph , inorganic chemistry , soil science , aqueous solution , environmental science
Abstract Using the syringe‐pressure technique, we field‐extracted soil solution from Spodosol horizon samples in a high‐elevation forested watershed. Dissolved organic carbon (DOC) was negatively correlated with solution pH. Solution reactive Al (catechol‐violet labile) was strongly correlated with total solution Al (graphite furnace), averaging 71% of the total. Except in extremely acidic, low‐Al Oa horizons, both forms of solution Al were positively correlated with DOC. Exchangeable Al, measured in subsamples of the same horizons from which soil solutions were extracted, correlated with total and reactive solution Al. The Oa horizons that were relatively low in solution and exchangeable Al were also low in total, acid‐digestible Al. Soil pH in water was generally higher than soil solution pH while soil pH in 2.5 m M CaCl 2 was always lower, consistent with the well‐documented decrease in most soils' pH under increasing ionic strength (the “salt effect”). Organic C, Al, and H + are interrelated in these soils. These interrelationships support current hypotheses that organics control the concentration of solution Al.