The objective of this study was to determine the potassium (K) release kinetics of clay samples from 10 agricultural representative soils of Arizona by successive extraction using Ca-saturated cation resin. A 1993 physical and chemical characterization of the soils revealed that all soils contain smectite-mica K bearing minerals. Four mathematical models (power function, Elovich, parabolic diffusion and first-order) were used to describe the nonexchangeable K release reaction involving 700-hr cumulative reaction time. Comparison of the models using the coefficient of determination (r²) and the standard error of the estimate (SE) indicated that the Elovich and the power function equations overall displayed the best fit. The first-order rate and for the most part, the parabolic diffusion equation did not describe the K release very well. The constants a and b for the Elovich and the power function equations, which represent the intercept and the release rate of the nonexchangeable K respectively, are at least in the order of magnitude as those found by others in several previous studies.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/210381 |
| Date | 04 1900 |
| Creators | Galadima, A., Silvertooth, J. C. |
| Contributors | Silvertooth, Jeff |
| Publisher | College of Agriculture, University of Arizona (Tucson, AZ) |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Article |
| Relation | AZ1006 |
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