Correlation between Mineral Composition and Potassium Quantity- Intensity Parameters and available potassium in Calcareous Soils

Ammonium Acetate extracted soil potassium is the most common plant available potassium evaluation method in soils, but it has been shown that this method was not been suitable to fertilization recommendation of potassium in calcareous soils. This study was conducted to determine correlation between soil mineralogical combinations, potassium Q/I parameters with potassium extracted by normal extraction method determination. Therefore, 18 different soil samples collected from farms of different provinces. Beside difference in physical, chemical and mineralogical characteristics, soils were in different available potassium categories (low, medium, high). Dominant clay minerals of soil samples were identified by X-Ray, then the Q/I parameters were calculated. The results showed no significant correlation between the types of dominant minerals with available potassium. But, some of the Q/I parameters, potassium absorbed by specific sites (KX), labile potassium (KL), and free energy of potassium replacement (ΔG°) were highly correlated with potassium ammonium extractable. Difference in physical, chemical and mineralogical properties could explain different Q/I parameters in soils. Results showed that different soil characteristics could directly affect Q/I parameters, so that it can give a better estimation of soil potassium availability than ammonium acetate extraction.