Kinetics of potassium desorption from entisol, vertisol and mollisol using miscible displacement technique in Sulamani Governorate

الملخص EN

Kinetics of desorption were conducted on soil samples previously examined for adsorption characteristics from the surface horizon of seven soils of Sulaimani governorate in Kurdistan region of Iraq by using miscible displacement technique .

The soil samples were leached with 0.001M CaCl2.

The solution of CaCl2 was passed through the soil at flow velocities of 1ml min-1.

Ten- milliliter aliquots were collected until K was not detected in the leachate.

Potassium desorption conformed to Elovich and Parabolic diffusion equations kinetics.

Potassium desorption as plotted by Elovich and parabolic diffusion equations in Ca- saturated soils was rapid at first and leveled off with the time indicating more difficult desorption reaction.

Apparent desorption rate coefficient (Kd) for Elovich equation ranged from 0.0604 to 0.0441 cmol kg-1 min-1, while the rate coefficient K desorption (Kd) according to parabolic diffusion equation ranged from 0.0188 to 0.0476 cmol kg-1 min-1/2.