Among all essential plant nutrients, potassium is the 3^rd most likely, after nitrogen and phosphorus to limit plant productivity.  The production and productivity of onion is very sensitive to potassium status in soil. Thus, it has become essential to replenish the reserve of potassium which are removed or lost from the soil. Effect of organic and inorganic sources of potassium or alone influence on productivity and storability of kharif onion. A field experiment was conducted in split plot design with 15 treatments and 3 replications at Bihar Agricultural College Farm of BAU, Sabour, (Bhagalpur) during the year 2018-19. Three planting methods of kharifonion (T₁: Flat bed, T₂: Raised bed and T₃: Ridge bed) and five nutritional modules (C₁: Control, C₂: 100% K_Fert.,C₃: 100% K_VC, C₄ :50% K_Fert. + 50% K_VC and C₅: 75% K_Fert. + 25% K_VC) where allocated in main and sub-plots respectively. Results from field experiment indicated that planting methods did not influenced growth parameter, yield attributing characters and quality parameter of onion bulb, significantly. The maximum number of leaves at 70 DAT (5.99), 90 DAT (8.14) and 120 DAT (9.95) were recorded in plot receiving 50% recommended K through vermicompost and 50% recommended K through chemical fertilizer. The neck thickness was not influenced by nutritional modules. The maximum polar diameter of bulb (4.22 cm) was found with C₄ (50% K_Fert. + 50% K_VC) treatment. The highest TSS content of bulb (12.42 ^oBrix) was recorded with treatment C₃ (100% potassium through vermicompost). However, yield of kharif onion was augmented significantly by planting methods and the highest bulb yield (31.84 t ha^-1) was recorded in Raised bed method. The physiological weight losses were found the highest (34.81%) in C₂ and lowest (26.82%) in C₃ after 90 days of storage, as compared to the initial weight of bulbs. Rotting percentage of bulb was also recorded to be the lowest in C₃ treated onion bulb. After harvest, soil reaction (pH), Electrical conductivity (EC) and Cation exchange capacity (CEC) were not affected by planting methods and nutritional modules. The maximum value of SOC,available nitrogen and available phosphorus was obtained in that soil in which 100% of recommended K was supplied through vermicompost (VC).

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