Department of Agricultural Chemistry & Soil Science, Institute of Agricultural Science, University of Calcutta, 51/2, Hazra Road, Kolkata-700 019, India E-mail : priyamaroy@gmail.com College of Agriculture, Orissa University of Agriculture and Technology, Bhubaneshwar-751 003, Odisha, India Water Management Research Centre, Department of Agriculture, Ranaghat, Government of West Bengal, India Manuscript received 08 April 2015, revised 24 June 2015, accepted 01 July 2015 The interaction study between potassium and zinc was conducted with an inceptisol under submerged soil condition at ambient laboratory conditions with their nine different treatment combinations. It was found that exchangeable K increased gradually till 42 days of incubation before decreasing and was maintained highest (189.20 mg kg–1) in the treatment T6 where both K and Zn were applied combinedly at 60 and 5 mg kg–1 respectively. But regarding changes with respect to the cationic micronutrients it was observed that the amount of Fe, Mn, Cu and Zn was highest with the values 152.94, 64.94, 2.64 and 10.18 mg kg–1 respectively in the treatment T9 where K and Zn were applied combinedly at their highest level (K @ 60 mg kg–1 soil and Zn @ 10 mg kg–1 soil) at 42 days of incubation for Fe and Mn, 35 days of incubation for Cu and 14 days of incubation for Zn. From the present investigation it is concluded that both Zn and K has a positive synergistic effect on one another under submerged soil conditions.