Abstract
Different forms of potassium (K) are in a dynamic equilibrium in soils. Potassium supplying power of soil is, therefore, depends on the accurate determination the contribution of each form of K to plant nutrition. Numerous empirical techniques for the extraction and estimation of “available K” have been proposed and used to some extent in routine soil testing. Since K+ movement to plant roots is a dynamic process, true thermodynamic equilibrium of K+ with the soil probably never occurs in the active rhizosphere during crop growth. This study was carried out to compare the kinetic parameters and capsule resin data with some static soil test procedures for predicting the K uptake by rice plant in some paddy fields in the north of Iran. A pot experiment with 2 treatments (0 and 300 mg K per kg of soil), 3 replicates, and 10 soils were performed. Soil potassium was extracted by 0.01 molar of CaCl2, ammonium acetate, ammonium acetate from submerged soil samples, magnesium acetate, boiling nitric acid, distilled water, sulfuric acid, Morgan, Texas, Cellovana and by capsule resin. Resin adsorption quantity (RAQ) was a function of incubation time and may be best described with a fractional power equation. Results showed that RAQ1 (resin adsorption quantity for the first period) had higher correlation coefficient with mild extractants such as 0.01 M of CaCl2 and distilled water, while RAQ2 (resin adsorption quantity for the second period) showed lower correlation coefficient with mild extractants and higher correlation with stronger extractants such as ammonium acetate, Texas, and sulfuric acid. Parameter ai of the fractional power equation had also higher correlation with the mild extractants as compared with stronger ones. Resin adsorption quantity for the second period (RAQ2) had the highest correlation with total K uptake and K concentration of rice straw as compared to other periods. RAQ2 also predicted K uptake better than the kinetic parameters and the chemical extractants. In this study, ai parameter showed a relatively high correlation coefficient with K uptake by rice while bi parameter showed no correlation.
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.
