Assessing different forms of potassium in relation to clay minerals in different physiographies of Eskan Ashaier region, Nour-Abad Mammasani in Fars Province

This study was carried out to determine different forms of potassium in relation to chemical and mineralogical properties of soils of Eskan Ashaier region, Nour-Abad Mammasani of Fars Province. For this study after field studies and preparing soil maps, four soil profiles have been selected. Some physical, chemical, different forms of potassium (soluble, exchangeable, non-exchangeable and total) and types and relative amounts of clay minerals of selected soils were determined. The results showed that the soils of hills and alluvial-colluvial fans are Entisols, while in piedmont plains they are Inceptisols and Mollisols. The results of mineralogy of clay showed that the dominant mineralogy of soils of hill physiographic unit are illite, chlorite, smectite and quartz. The dominant minerals of alluvial-colluvial fans are illite, chlorite, smectite and kaolinite and finally the dominant minerals of piedmont plains physiographic unit are smectite, illite, chlorite, kaolinite and vermiculite minerals. The Mollisols order located on piedmont plains by having a high clay content, high cation enchange capacity and dominant smectite mineral, have also higher amounts of structural and total potassium than in any other orders. The Entisols order located on piedmont plains have a greater relative amounts of illite and chlorite, exchangeable and nonexchangeable potassium than in the other other orders. The Entisols located on hill have higher soluble potassium content than the other order and Inceptisols located on the piedmont plains, by having more than 55 percent carbonates and less than 25 percent clay content, have the lowest amounts of different potassium forms.