Abstract
BECKETT1,2 has discussed potassium–calcium exchange energies in soil suspensions, using a development of a thermodynamic approach suggested by Woodruff3 and Schofield and Taylor4. He showed that a graph of the “activity ratio” (called ARK) in the solution plotted against the changes in exchangeable soil potassium (ΔK) is usually linear except at small values of ARK where it curves sharply and becomes asymptotic to the ΔK axis (Fig. 2). ARK is directly related to the change in free energy when equivalent amounts of potassium and calcium are exchanged between the soil and solution phases. Beckett2 considers that the curvature is produced by a small proportion of potassium ions held on discrete exchange sites with a greater preference for potassium relative to calcium. These sites determine the exchange energy when nearly all the exchangeable potassium is removed. Very recently he has found evidence of similar behaviour for calcium and magnesium5.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
