Potassium Fractionation and Stock in Clay Soils: Influence of Geochemical and Mineralogical Properties in Yogyakarta Region, Indonesia

• DOI: 10.20961/carakatani.v40i2.93721
• Publication Date: 2025-04-17T03:31:52Z
• Authors: Eko Hanudin; Padana Aperta Barus; Makruf Nurudin; Sri Nuryani Hiday...
• Keywords: geochemical indices; geological formations; upland clay soils; S; k fractions; feldspars; Agriculture

Research on potassium (K) dynamics in upland clay soils, particularly those derived from tertiary-aged rocks, remains limited Yogyakarta. This study aimed to investigate the relationships among geochemical indices, K fractions, and stock considering influence of their physical, chemical, mineralogical properties. Thirty soil samples were collected five geological formations at two depths (0 20 40 cm), with three replicates selected each formation through purposive sampling. Soil characterization was performed using routine methods, energy-dispersive X-ray fluorescence (EDXRF), diffraction (XRD) analyses. Geochemical indices such as chemical index alteration (CIA), Vogt residual (VR), alumina oxide ratio (AKN), silica sesquioxide (Si/Seq), Ruxton (R) calculated, determined. The results showed that feldspar contributes soils. Spearman’s correlation analysis revealed only AKN significantly correlated K-pseudo-total K-non-exchangeable (<em>p</em> < 0.01). highest concentration found P4-Sentolo (1,326 1,715 mg kg<sup>-</sup>¹) concentrations observed P5-Kebobutak (1.37 1.78 cmolc kg<sup>-</sup>¹). Significant correlations between K-exchangeable K-water-soluble total organic carbon also identified recorded P2-Nglanggran (0.17 0.33 kg<sup>-</sup>¹), while lowest P1-Wonosari (0.04 0.09 kg<sup>-1</sup>). All soils exhibited below critical deficiency level. Understanding these is crucial for effective management sustainable agricultural production. Targeted fertilization strategies can be developed based dominant fraction soil.