Kinetics of potassium desorption by Alfisols of Greece
作者:
A. Ioannou,
A. Dimirkou,
M. Doula,
Ch. Paschalidis,
期刊:
Communications in Soil Science and Plant Analysis
(Taylor Available online 1994)
卷期:
Volume 25,
issue 9-10
页码: 1355-1372
ISSN:0010-3624
年代: 1994
DOI:10.1080/00103629409369120
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
Kinetics of K desorption was studied on Alfisol Haploxeralf samples of central Greece. Calcium‐saturated samples were equilibrated with different potassium concentrations and pH for 96 hours at pH 5.0, 6.0, 7.0 and 8.0 and initial potassium concentrations of 7, 35, 54 and 112 ppm. Samples were continuously leached with 0.01 M CaCL2until K was not detected in the leachate. Desorption was nearly complete in approximately 3 to 4 hours for the Alfisol Haploxeralf. When the initial K concentrations varied between 0–7, 7–35, 35–54 and 54–112 ppm, then approximately 95–97%, 93–98%, 75–96% and 18–75%, respectively, was subsequently desorbed from Alfisol Haploxeralf samples. Three mathematical models (first order, power function and parabolic diffusion) were used to describe cumulative potassium release at different values of pH and initially adsorbed K. Comparisons of coefficients of determination (r2) indicated that the first order, power function and parabolic diffusion equations adequately described cumulative potassium release for all studied pH and initially adsorbed potassium. Apparent potassium desorption rate coefficients (k) ranged from 4.3 x 10‐3to 11.43× 10‐3min‐1. The magnitude of the k values decreased as adsorbed potassium and pH increased. Finally all the studied models were transformed to pH‐dependent forms.
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