Exchangeable K values and X-ray diffraction patterns were obtained for soil samples from several modal profiles of nine different soil series in Iowa. Exchangeable K in "moist" subsoils was consistently low and almost always lower than in the "moist" surface soil. Drying increased exchangeable K in all the soils, but the increase due to drying varied between soil series and with depth in the profile of each series. Reversion of exchangeable K to a non-exchangeable form on rewetting the oven-dry samples generally increased with depth in the profile but the exchangeable K never decreased to the original "moist" level. X-ray diffraction analyses showed the presence of montmorillonite, chorlite, illite and/ or mica, and kaolinite in all the profiles, with mortmorillonite predominating. Vermiculite was present in some of the soil series. No relationship between the clay mineral content and the amount of exchangeable K could be established.
Proceedings of the Iowa Academy of Science
©1960 Iowa Academy of Science, Inc.
Hanway, J. J.; Handy, R. L.; and Scott, A. D.
"Exchangeable Potassium and Clay Minerals in Selected Iowa Soil Profiles,"
Proceedings of the Iowa Academy of Science, 67(1), 215-231.
Available at: https://scholarworks.uni.edu/pias/vol67/iss1/32