KINETICS OF POTASSIUM ADSORPTION AND DESORPTION IN SOME NINEVEH GOVERNORATE SOILS

Abstract

This research was conducted to study physico – chemical behavior of potassium adsorption–desorption phenomena in some soils of Nineveh Governorate. To fulfill the mentioned target above 10 different locations in their rainfall and land management. Series chemical experiments were done . The results of the above experiments revealed the following: 1- Potassium adsorption was ranged between 32 – 64% of added potassium while K – desorption was ranged between 22 – 56% of added potassium. 2- The adsorption amounts were significantly correlated with Cation Exchange capacity (r = 0.48*) and organic matter (r = 0.36*). 3- According to kinetic approach showed a significant effect of time on potassium adsorption and soils a different pathways of adsorption curves, the first order equation was the best to describe the adsorption of potassium. The studied soils appeared to be high in potassium adsorption rate (310-3  6610-3 min-1). 4- Potassium desorption according to kinetic approach showed a significant effect of time on potassium desorption, there are two stages of K release, and first order equation was the best to describe the desorption of potassium by using missible displacement. Rate coefficient of K – desorption according to first order equation were range between (1.7 – 2.510-3) min-1. Studied soils appeared to be low in potassium desorption rate coefficient as well. 5- Desorption index ranged between 0.2 – 0.9 according to (Kd/Ka) by using first order equation. Studied soils appeared to be high–moderate fixing.