Correlation Among K Forms with Soil Physical-Chemical Properties and Clay Mineral Diversity in Some Soils of Khuzestan

The knowledge about K forms and its distribution in different soils can help to apply properly K fertilizers. This study was performed to investigate the different K forms in the soil and their relationship with physical-chemical properties and clay mineral diversity of the soil. The results showed that the amount of soluble K had negative correlation with clay content but exchangeable or available K value had positive correlation with clay content. Also, the fixed K value had good correlation with type and among clay content in these soils. Structural K had positive and significant correlation with Fe and clay content but negative correlation with gypsum. Total K had good correlation with clay content and consequently with Fe, Al, and Si that are the main performed elements of the clay particles. The amount of K in the soil was increased with increasing of illite content but it was decreased with increasing the chlorite and palygorskite. The results showed a significant difference between the K values with the presence and absence of OM, CCE, and gypsum in the soils. Generally speaking, the available K content was corresponded to the parent material (clay mineral type), cultivation type and age, heavy irrigation and leaching which causes a reduction in illite clay mineral in these soils.