The absorption of potassium as influenced by its concentration in the nutrient medium

Summary Barley plants were grown, for periods of up to eleven weeks duration, in culture solutions in which the potassium concentrations were maintained at 0.01, 0.10, 1.0, and 50.0 ppm. Potassium added continuously during the day was augmented night and morning, as determined by solution analysis. The following observations were made:Plants grew equally well at pH levels of 5.5 and 7.0. Variations in root temperature between 15° and 25°C had no effect on K-content of tissue at either pH level. Yields were large as were the quantities of potassium absorbed from the solutions. No potassium-deficiency symptoms were observed at any of the concentrations used.Considerable variation in yield was observed between tanks and between plants growing in the same tank. The variation appeared to be due to a difference in the amount of tillering per plant.The results indicate that plants grow well in culture solutions at potassium concentrations approaching 0.01 ppm and this may have some implications on the mechanism of uptake of potassium by plant roots growing in a soil system.