Potassium Relationships of Three Ohio Soils

Abstract

Three Ohio soils, Hoytville clay, Brookston silty clay loam, and Wooster silt loam located at various branches of the Ohio Agricultural Research and Development Center, were studied. Bulk samples from each horizon were tested for exchangeable basic cations, pH, sulfuric acid extractable potassium (K+), and particle-size distribution. The surface horizons of each soil were characterized by measurement of cation exchange capacity, quantity-intensity adsorption isotherms for K+ and x-ray diffraction of the clay (<2 /J.) fraction. The Hoytville soil was highest in exchangeable and sulfuric acid extractable K+; Wooster was lowest; and Brookston was intermediate but closer to Wooster than to Hoytville. Hoytville and Brookston had high quantityintensity labile buffer capacities for K+, the values being 2-23^> times greater than that for Wooster. Hoytville clay was predominantly illitic while the Brookston and Wooster clays were of a more mixed mineralogical nature. The potassium content and crystallinity of the illite in the Hoytville clay is lower than those of the Brookston and Wooster clays.