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The distribution of solute processes on an acid hillslope and the delivery of solutes to a stream: II. Exchangeable Al 3+
Author(s) -
Park S. J.,
Burt T. P.
Publication year - 1999
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/(sici)1096-9837(199909)24:10<851::aid-esp11>3.0.co;2-8
Subject(s) - throughflow , saturation (graph theory) , podzol , chemistry , geology , pedogenesis , mineralogy , soil science , soil water , mathematics , combinatorics
In order to identify the distribution of aluminium (Al) within an acid hillslope and its release to a stream, the spatial distribution of acid ammonium oxalate extractable Al (Al o ) and exchangeable Al 3+ have been investigated on a podzolized hillslope in Bicknoller Combe, Somerset, UK. The eluviated Al from topsoils is mainly deposited in the lower soil horizons forming podzolic B horizons, but some Al flows downslope carried by lateral throughflow. Al oxides may provide the main source of exchangeable Al 3+ on the study slope due to high soil acidity. Examination of the spatial distribution of exchangeable Al 3+ suggests that the slope hollow, where active convergent throughflow occurs, and the saturation wedge at the base of the slope are the main delivery routes of dissolved Al 3+ to the stream. Divalent base cations (Ca 2+ and Mg 2+ ), supplied from atmospheric input and organic decomposition and carried by throughflow, exchange Al 3+ via cation exchange reactions under high water content. Laterally illuviated Al oxides in the lower hollow adjacent to the saturation wedge probably provide a pool for continuous delivery of Al either as soluble or complexed forms to the stream via the saturated wedge. Copyright © 1999 John Wiley & Sons, Ltd.