RT - Journal Article T1 - Kinetics of Non-exchangable Potassium Release in Aggregates with Different Sizes in a Number of Calcareous Soils JF - JSTNAR YR - 2018 JO - JSTNAR VO - 22 IS - 1 UR - http://jstnar.iut.ac.ir/article-1-3202-en.html SP - 267 EP - 278 K1 - Release of none exchangeable potassium K1 - Aggregates K1 - Calcium chloride K1 - Kinetics equations. AB - 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. LA eng UL http://jstnar.iut.ac.ir/article-1-3202-en.html M3 10.29252/jstnar.22.1.267 ER -