pH changes and K uptake by nine rice varieties in a solution containing 0.1 mmol/L K₂SO₄ plus 0.2 mmol/L CaSO₄ were measured in the study. Changes of pH and K concentration were strongly correlated over 2 and 4 hours, which could be the basis for the establishment of a rapid and simple method for screening, selecting rice varieties with a high rate of K uptake. Based on the total K uptake by rice in a successive cropping experiment, the greater part of its K requirement was obtained from non-exchangeable sources. Total K uptake by rice varieties was significantly correlated with non-exchangeable potassium and potassium in extractable with 1 mol/L HNO₃ and mineral potassium, which could be used as criteria for screening high potassium-absorbing rice varieties. Yield responses of rice varieties to K application were studied as well.