A Comparative Assessment of Potassium Mineralization from Waste Mica by Application of KSB and FYM in Alluvial and Black Soils

Potassium (K) deficiency poses a major challenge to sustainable agriculture, affecting crop productivity and soil fertility. Conventional K fertilizers are costly and environmentally harmful, highlighting the need for alternative sustainable sources. Mica (K-bearing mineral) occurs naturally and remains underutilized due to its slow-release nature. This study investigates whether potassium solubilizing bacteria (KSB), specifically Enterobacter wuhouensis , can enhance K availability from mica in alluvial and black soils. A 60-day incubation experiment was formulated and conducted using a complete randomized design (CRD) with 9 treatments and 3 replications, varying the proportions of mica, farmyard manure (FYM), and KSB. The treatments were assessed for key soil properties, including pH, available potassium, microbial populations (bacteria, fungi, actinomycetes, and KSB), dehydrogenase enzyme activity, and potassium solubilizing power. Results showed that the addition of KSB and FYM significantly improved K solubilization compared to mica alone, with the highest effects observed when KSB was combined with 75% mica and 25% FYM. This combination led to the greatest increases in available potassium, reaching 322.67 kg ha⁻¹ in alluvial soil and 398.00 kg ha⁻¹ in black soil at 60 days. Microbial activity also showed substantial enhancement, with bacterial counts reaching 50.00 × 10⁶ cfu g⁻¹ in alluvial soil and 123.30 × 10⁶ cfu g⁻¹ in black soil. Dehydrogenase activity peaked at 25.34 µg TPF g⁻¹ hr⁻¹ in alluvial soil and 75.33 µg TPF g⁻¹ hr⁻¹ in black soil. These findings suggest that integrating KSB with mica and FYM provides a viable, eco-friendly, and low-cost approach to enhance soil K availability, thereby promoting sustainable crop production.