Soil potassium (K) dynamics are governed by the distribution of K among soluble, exchangeable, non-exchangeable and mineral pools, as well as by the capacity of soil to release reserve K. A study was conducted to characterize soil K fractions and to determine the release characteristics of non-exchangeable K under natural farming (NFS), organic farming (OFS), conventional farming (CFS) and integrated farming systems (IFS) across the North East Transition, North Eastern Dry and Northern Dry zones of Kalyana Karnataka, India. Forty-eight soil samples were collected from surface (0-15 cm) and subsurface (15-30 cm) layers under established production systems and analysed using standard procedures. Potassium fractions followed the order total K > mineral K > non-exchangeable K > exchangeable K > water-soluble K. Total K ranged from 3286 to 3980 mg kg⁻¹ in surface soil and 3427 to 4122 mg kg⁻¹ in subsurface soil. Sequential extraction with boiling 1 N HNO₃ showed rapid K release during the first seven extractions, followed by a gradual decline and a near-constant release during the later extractions. Total step-K ranged from 652 to 748 mg kg⁻¹ in surface soil and 740 to 939 mg kg⁻¹ in subsurface soil. Cumulative K release ranged from 671 to 825 mg kg⁻¹ in surface soil and 820 to 1051 mg kg⁻¹ in subsurface soil. Constant-rate K ranged from 2 to 6 mg kg⁻¹ in surface soil and 7 to 9 mg kg⁻¹ in subsurface soil.