An attempt was made to correlate data on available soil potassium as determined with rice seedlings by the Neubauer's method with determinations carried out with the help of various extracting solutions. In increasing extracting power these solutions were the following: distilled water, 0,002 N sulfuric acid, 0,5 N magnesium acetate, 0,5 N acetitc acid, 0,2 N nitric acid, 0,05 N sulfuric acid, 1 N ammonium acetate, 0,05 N hydrochloric acid, 0,5 N ammonium acetate, 0,05 N nitric acid, and 0,5 N sodium chloride. Data obtained indicated that the extracting solutions that resembled most closely the rice seedlings power to extract potassium from the soil were 0,5 N magnesium acetate, 0,5 N acetic acid, 0,2 N nitric acid, 0,05 N sulfuric acid, and 1 N ammonium acetate.