Local Soil-landscape Relationships in Western Iowa: II. Quantification of Pedologic and Geologic Effects
1975
Huddleston, J. H. (James Herbert) | Walsh, J. A. | Jowett, D. | Riecken, F. F.
The soil-landscape system consists of contiguous units of noncalcareous loess, calcareous loess, and alluvium. Soil data from each unit were subjected to a principal components analysis. The objective was to identify specific pedologic and geologic processes that have contributed to soil formation and to quantify the separate effects of each process. Factors generated by the analysis were interpreted as representing (i) processes of parent material formation, whose effects are inherited; (ii) processes of pedogenesis that modify initial-state distributions; (iii) processes of loess stratification; (iv) processes of hillslope erosion and footslope sedimentation; (v) processes of nutrient concentration; and (vi) processes of nitrate mobility. The percentage variance removed by each factor indicates the relative strength of each process. Parent material effects dominate in calcareous loess, but pedogenic profile modifications dominate in noncalcareous loess. In both materials, the effects inherited from geologic processes of loess stratification could also be identified. Two processes in alluvium express effects of erosion-sedimentation and of nutrient concentration in the waterway center. Pedogenesis is of tertiary importance to soil formation in alluvium.
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