POTASSIUM IN SOILS

Different forms of Potassium (K) could exist in soils, contributing to total K pool. The study aims at evaluating the forms and distribution of K in soils planted to plantain in University of Benin, Nigeria. Soil samples were collected in April, 2025, from four (0 - 30, 30- 60, 60 - 90 and 90 - 120 cm) depths in three replicates, making a total of 12 samples, the samples were air-dried, crushed, passed through 2 mm sieve and analyzed for some chemical and physical properties, using standard operating methods. Water soluble, exchangeable, difficultly exchangeable, fixed and total K forms, were determined in 1:10 soil:xtractants ratio diluted to 25 ml volume, while the relationship between some physical and chemical properties and forms of K were determined using simple linear correlation. The result showed that sand was the dominant soil separate with grand mean values of 71.37%, while the pH (H2O) showed slightly acidic soil reaction, and ranged between 5.00 - 5.15 with grand mean value of 5.06. The water soluble and exchangeable K were very low and ranged between 0.01 - 0. 03 and 0.01 - 0.05 cmol/kg with grand mean value of 0.02 and 0.03 cmol/kg respectively. Highest value of 0.10 cmol/kg at 30 - 60 cm soil depth and 0.07 cmol/kg at 60 - 90 cm soil depth with a grand mean values of 0.06 and 0.08 cmol/kg was obtained for difficultly exchangeable K and fixed form of K, respectively. Positively and negatively significant relationships was obtained between some soil physical and chemical properties, and different forms of K, indicating the influence of soil properties on forms, distribution and availability of K. Water soluble and exchangeable forms of K were very low in the soils studied.