The availability of potassium to plants is related in many ways to the structure and morphology of soil minerals. The chemical composition profoundly affects K release. The soils of Kurdistan are characterized by high capacity of K fixation due to the presence of smectite mineral. Using thermodynamic and kinetics methods showed that the rate of release of K from soils of Kurdistan is very low and this may explain the response of most soils of Kurdistan to K- fertilizers application in spite of their high content of potassium. K fertilizers have been forgotten in fertilizers recommendation in Kurdistan due to the widespread belief that soils of Kurdistan are well supplied with nature K. It is necessary to shift from classical methods of K analyses into thermodynamic and kinetics approaches. This method could be regarded a good and safe way to discover the dynamic and transformations of this element in soil and to know the pathway reaction of adsorption-desorption phenomenon in the soil to determine the K fertilizer requirement of economics crops in the calcareous soil of Kurdistan region.

Dr. Ghafoor Ahmed Mam Rasul, (Assistant Professor)/ Department of Soil and Water Sciences, College of Agricultural Sciences, University of Sulaimani/ Kurdistan region