Depth profiles of potassium and its isotope ratio (40K/K) in several forest soils

Depth profiles potassium and its isotope ratio ( 40 K/K) were investigated in several forest soils from different geological and climatic backgrounds. The ratio was found not to be constant (0.0117%) but varied appreciably from 0.0085% to 0.0167% among different soils. Possible factors affecting variability of 40 K/K values were considered by a multivariate factor analysis which suggested that aqueous parameters like humidity and pH might be a controlling factor in the surface soils. The amount (and probably chemical forms) of iron oxide may be another one influencing 40 K/K values in mineral components at deeper portions.