This investigation was carried out as separate four studies. In the first study, nonexchangeable K release from three micaceous minerals was investigated with sequential extraction using different extracting solutions. In the second and the third study, the effect of wheat and two pistachio cultivars on nonexchangeable K extraction from different types of micas and their transformation were examined. In the fourth study, changes of soil properties as well as different forms of K and related minerals were investigated. Selected biotite, phlogopite and muscovite were separated to 60 and 60-100 µm size muscovite. Mica transformation to vermiculite happened only in the growth media treated with the K-free nutrient solution. Muscovite was not as affected by Badami-Zarand cultivar after 6 months. In the fourth study, pistachio orchards with three different ages of 10, 20, and 40 years old and adjacent virgin lands were selected in three different regions in Rafsanjan area. Soil properties and different potassium forms were determined. Results indicated that pistachio plantation, irrigation and orchards management have improved soil properties as compared to virgin lands, whereas nonexchangeable K has reduced even in 10 years old pistachio orchards. Keywords: Biotite, Muscovite, Phlogopite, Pistachio, Potassium, Wheat
