Many soils have clay-enriched horizons that are thought to result from pedogenic processes. Various hypotheses are proposed for expected clay size-distributions in soil profiles. The average size of clay crystallites determined by the amount of broadening of x-ray diffraction peaks ranged from 160 to >2000Aº , but the lack of trends in four loess-derived soils did not permit the hypotheses to be evaluated. An unexpected relationship in a well expressed illuvial horizon was noted: as the percent of accumulated clay increased to the observed maximum the average crystallite size also increased rather than decreased as proposed. This suggests that small-sized illuvial clay particles undergo reorganization to form larger stable crystallites. Knowledge of clay crystallite size is expected to supplement other data in interpreting soil genesis.
Proceedings of the Iowa Academy of Science
©1967 Iowa Academy of Science, Inc.
Arnold, R. W.
"Application of Clay Crystallite-Size in Soil Genesis Studies,"
Proceedings of the Iowa Academy of Science, 74(1), 122-129.
Available at: https://scholarworks.uni.edu/pias/vol74/iss1/22