<p>This study explores the strategies to use low-grade glauconite rock as a potential source of potash to minimize the import dependency and reduce the cost of import in developing countries. The valorization glauconite was done using physical, chemical, and biological methods and tested its efficacy in maize and wheat under pot experiments in K deficient Alfisol and K responsive Vertisol soils. Calcium chloride–blazed glauconite-charged composted residue (G_CalCR) or calcium chloride–blazed acidified glauconite-charged composted residue (G_AciCalCR) significantly enhanced biomass yield and K uptake in maize and wheat across both soils. The application of G_AciCalCR resulted in a notable enhancement in K fractions: available K (NH₄OAc-K) increased by 177%, water soluble-K (WS-K) by 516%, exchangeable-K (Exch-K) by 328%, non-exchangeable-K (HNO₃-K) by 16%, and total K (TK) by 28% compared to the control. Significant improvements in pH, cation exchange capacity (CEC), and exchangeable Ca²⁺, Mg²⁺, and K⁺ were observed in Alfisol compared to Vertisol. Greater increases in N fractions, dehydrogenase activity (DHA), and soil microbial biomass carbon (SMBC) were observed in Alfisol. Structural Equation Model (SEM) indicated soil K fractions as key predictors of biomass yield and K uptake in both soils. The significant positive correlation between yield, K uptake and K fractions suggests K nutrition is critical in Alfisol. Based on the findings, the application of GCR or G_CalCR proved most effective for crop K nutrition and crop productivity in Alfisol, with the concomitant benefit of improvement in soil chemical and biological properties.</p>