Source and Distribution of Sodium in Solonetzic Soils in Illinois
1963
Wilding, L. P. | Odell, R. T. | Fehrenbacher, J. B. | Beavers, A. H.
Possible sources of extractable Na (water-soluble plus exchangeable) considered for Illinois solonetzic soils were: Pennsylvanian bedrock, Illinoian till, Farmdale and Peorian loess, and ocean spray salts from rain. Extractable Na in Illinois sononetzic soils originated chiefly from the weathering in situ of Na-rich feldspars of the parent loess. Members of the albite series (namely, albite and oligoclase) and the Na-rich microcline, anorthoclase, aggregate 70 to 80% of the silt-sized Na-bearing minerals which comprise 75 to 90% of the total mineral Na in these soils. Sufficient Na has weathered from the 50 to 5µ silt fraction in solonetzic soils to account for accumulations of extractable Na currently present in their B horizons. Little evidence of local variability in loess or differential weathering between solonetzic and associated soils suggests that differential redistribution of soluble products of weathering is responsible for extractable Na accumulations in Illinois solonetzic soils. It is believed that the local distribution of solonetzic soils is correlated with more permeable till zones of the highly impervious, underlying Illinoian till paleosol. Based on this assumption, a redistribution mechanism involving aqueous movement and differential segregation of soluble products of weathering is presented.
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