Abstract
This research was conducted to study the K- kinetics’ adsorption- desorption phenomena in predominant soil orders (Mollisols, Entisols, Vertisols, Aridisols, and Inceptisols) of Kurdistan region- Iraq, Soil samples were taken from sixteen different locations at depth (0 – 30 cm) selected according to the variation in their soils order, physical, and chemical properties. The study included Kinetics of potassium adsorption and desorption were determined depending on miscible displacement techniques using 0.001M KCl and 0.01M CaCl2 respectively, by applying First order equation, and determine the desorption index (DI) depended on the ratio of potassium desorption and adsorption isotherm slopes: The main results refer, the adsorption capacity ranged from 2.52 to 4.46 cmolc kg-1 the lowest value was recorded in Inceptisols , while the highest value in recoded in Mollisols, but the desorption capacity was ranged from 1.11 to 2.67 cmolc kg-1 with the mean value 1.99 cmolc kg-1, the lowest value was recorded in Inceptisols while the highest value was recorded in Mollisols. Cumulative adsorption and desorption of potassium increased with increasing the time for all samples. The value of desorption index (DI) was ranged from 0.26 to 0.58. The low value of DI indicated increased hysteresis and increase difficulty of the sorbed K+ to desorb from soil surfaces.
