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Showing 2 results for Kinetics Equations.
Kinetics of Nonexchangeable Potassium Release in Relation to Clay Mineralogy in Some Calcareous Soils of Kohgilouye Province
H. R. Owliaie, S. Heydarmah, E. Adhami, M. Najafi Ghiri,
Volume 18, Issue 68 (9-2014)
Abstract
Rate of nonexchangeable K release can significantly influence K availability. Kinetics of K+ release was studied by extraction using 0.01 M CaCl2 in 12 surface calcareous soils of Kohgilouye Province. Results showed that cumulative K release ranged from 89.9 to 460.9 mg kg-1(Average 195.4 mg kg-1). Calcium carbonate, nonexchangeable K, cation exchange capacity and mica showed a significant correlation with K release. Maximum of potassium release was observed in Alfisols, probably because of high amount of clay content and the clay mineral of mica. The amount of K release was in the following order: Alfisols> Entisols> Inceptisols. Elovich, parabulic diffusion and power function equations could reasonably describe the K release kinetics. Fitting the data to these equations indicated that release of K is controlled by diffusion process.
Kinetics of Non-exchangable Potassium Release in Aggregates with Different Sizes in a Number of Calcareous Soils
S. Z. Atar Shahraki, A. R. Hosseinpur, H. R. Motaghian, Sh. Ghorbani,
Volume 22, Issue 1 (6-2018)
Abstract
The study of the kinetics of non-exchangeable potassium (NEK) release is very important for a better understanding of K availability for plants in different soils. Moreover, aggregates with different sizes have different effects on the release of nutrients. Therefore, the aim of this study was to examine the release of NEK in 5 calcareous soils of chaharmahal-va- bakhtiari province, and small and large aggregates (<250 μm and >250 μm) using CaCl2 0.01 M at 25±1ºc for 2-2017 h. The results showed that cumulative released NEK in soils, and small and large aggregates was 173.5-372.7, 215.1-426.1 and 178.9-381.5 mg kg-1, respectively. The results revealed that coefficients of the cumulative released NEK in small aggregates was lower than those of the soils and large aggregates. Based on the coefficient of determination (R2) and standard error (SE), the released NEK was well described by the first order, the power function, parabolic diffusion, and simplified Elovich equations. The rate coefficients of the release of K were different in different soils. The cumulative released amount of K and its rate of release in a solution of calcium chloride in small aggregates was more than those of large aggregates.

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