The distribution of solute processes on an acid hillslope and the delivery of solutes to a stream: II. Exchangeable Al3+

✍ Scribed by Park, S. J.; Burt, T. P.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 751 KB
• Volume: 24
• Category: Article
• ISSN: 0360-1269
• DOI: 10.1002/(sici)1096-9837(199909)24:10<851::aid-esp11>3.0.co;2-8

✦ Synopsis

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.