Potassium Distribution and Retention in Pine Bark and Sand Media1

Abstract

Abstract Potassium concentration was highest in the upper 5 cm of medium after leaching with 10 cm H 2 O, lowest in the middle of the soil column (10 and 15 cm depths), and intermediate at the bottom of the column. Increasing concentrations of applied K (336, 671, and 1007 kg/ha) increased the K level in each medium tested, except 100% sand, and at each depth in the soil column. After leaching, media containing high percentages of sand (75 and 100%) had a lower K concentration at all applied K rates than media containing high percentages of bark (0 and 25% sand). Cation exchange capacity was greater in bark than sand and is probably the most important factor influencing the movement of K in pine bark and sand media.