Conservation agriculture (CA) draws an attention towards maintaining sustainability with productivity enhancement and by applying principal of zero/minimum tillage. It plays a key role on the availability of potassium (K) contents in soil. It was observed that the release pattern of different forms of potassium is regulated by different tillage practices and cropping system. Keeping in these views, the present study has been designed targeting long-term CA experiment on "Resource conservation technologies for stabilizing yield under different cropping system" which was started in the year 2011 at Bihar Agricultural University research Farm, Sabour. It was concluded that there was significant increase inorganic carbon (OC) content in ZT system with M-C cropping sequences, Potassium content in soil showed significant relationship with cropping sequences and tillage system. Higher nutrient availability was recorded in ZT system followed by PB system, and the soil recorded different PBCK values but may be same activity ratio. Maximum soil have higher amount of non-specifically held potassium, it means greater release of greater release of K at time of stress.