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Aluminum Leaching by Mineral Acids in Forest Soils: I. Nitric‐Sulfuric Acid Differences
Author(s) -
James Bruce R.,
Riha Susan J.
Publication year - 1989
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/sssaj1989.03615995005300010047x
Subject(s) - leaching (pedology) , soil water , forest floor , environmental chemistry , nitric acid , sulfuric acid , soil horizon , leachate , chemistry , soil acidification , snowmelt , acid rain , soil ph , environmental science , soil science , geology , snow , inorganic chemistry , organic chemistry , geomorphology
In laboratory studies simulating snowmelt leaching of forest soils, HNO 3 leached more Al than did H 2 SO 4 from soil columns containing a forest floor‐spodic horizon sequence (FF/Bs) representative of high elevation forest soils and watersheds thought to be sensitive to acidification by acid precipitation. Increasing the HNO 3 concentration 100‐fold (pH 5 to 3) increased total Al concentration in leachates from 0.70 to 0.85 m M , while increasing H 2 SO 4 concentration had no effect. Addition of pH 3 H 2 SO 4 to the FF/Bs columns raised leachate pH relative to pH 3 HNO 3 and control treatments, and resulted in the lowest Al concentrations of all treatments in the first three of four sequential leachings. In albic (E) and ochric (A) mineral soil horizons below a forest floor, there were no differences between the acids and no effects of changing acid concentration. Concentrations of Al leached by the acids did not differ from those in control treatments. The differences in effects of HNO 3 and H 2 SO 4 on soluble Al and pH in the Bs horizon and the lack of effect of either acid in the E and A horizons imply that the type of mineral horizon below the forest floor and the kind of acid leaching through these horizons are pertinent to predicting lake acidification in diverse forested watersheds. The results also have implications for pollution control strategies focusing solely on SO 2 emissions and designed to mitigate lake acidification.