Reduction of exchangeable calcium and magnesium in soil with increasing pH

A laboratory study was conducted with soil samples and synthetic solutions to investigate possible mechanisms related with reduction in KCl exchangeable Ca and Mg with increasing pH. Increasing soil pH over 5.3 with CaCO3 added to the soil and with NaOH solution added to soil/KCl suspension increase...

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Bibliographic Details
Main Authors: Miyazawa Mário, Pavan Marcos A., Ziglio Cláudio O., Franchini Júlio C.
Format: Article
Language:English
Published: Instituto de Tecnologia do Paraná (Tecpar) 2001-01-01
Series:Brazilian Archives of Biology and Technology
Subjects:
Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132001000200007
Description
Summary:A laboratory study was conducted with soil samples and synthetic solutions to investigate possible mechanisms related with reduction in KCl exchangeable Ca and Mg with increasing pH. Increasing soil pH over 5.3 with CaCO3 added to the soil and with NaOH solution added to soil/KCl suspension increased adsorptions of Ca and Mg. The reduction of Mg was greater than Ca and was related to the concentration of soil exchangeable Al. The decreases of soluble Ca and Mg following addition of Al in synthetic solution were at pH > 7.5. The isomorphic coprecipitation reaction with Al compounds may be the most possible mechanism responsible for the decrease of exchangeable Ca and Mg with increasing pH. Possible chemical reactions are presented.
ISSN:1516-8913
1678-4324