Degree Type


Date of Award


Degree Name

Doctor of Philosophy



First Advisor

T. E. Fenton


This study was conducted to determine the saturated zone and its relationships to selected mineralogical and chemical properties in the Clarion catena. The Clarion catena predominantly includes Clarion, Nicollet, Webster, and Canisteo soil series, derived from the late Wisconsin glacial till and its sediments. These soils occur in north central Iowa, where they occupy all or parts of 29 counties;The amount of precipitation and the depth of water table were monitored for seven years in selected soils from the Clarion catena at the Agronomy farm in Boone County of central Iowa. Results show that the water table depth in each soil is a function of annual precipitation and landscape position. Redoximorphic features commonly are correlated with the fluctuating depth of the present day water table;Mineralogical composition of these soils were determined. There is a considerable difference in the amount of heavy minerals among soils at the study site. Clay minerals composition was very similar among the soils except for the presence of goethite in the B horizon of the Clarion soil on the summit position. The samples analyzed demonstrate the effect of topographic positions as well as varying saturation conditions on the distinctive mineralogical signature associated with the soils studied;The variability of different forms of extractable iron, manganese, and aluminum throughout the profile and their relationship to different moisture regimes was investigated. The distribution of pedogenic oxides of the above elements were applied for interpreting soil drainage classes as well as soil moisture regimes. Aluminum distributions did not differ significantly among these soils. This indicates that it was less affected as compared to Fe and Mn by differences in moisture conditions. There was a pronounced decrease of total iron as duration of saturation increased. With increased duration of saturation, Fe[subscript] d decreased and Mn[subscript] d increased;The quantitative ratio of Mn[subscript] d/Fe[subscript] d with its depth function separated aquic moisture regime from non-aquic regimes among the members of the Clarion catena. Therefore, quantification of soil moisture regimes of the Clarion catena may provide a better understanding of aquic and non-aquic environments.



Digital Repository @ Iowa State University,

Copyright Owner

Faruque A.Z.M. Khan



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174 pages