Redoximorphic features as indicators of seasonal saturation, Lowndes County, Georgia

Redoximorphic features are generally accepted to be reliable indicators of seasonal saturation although little data exist to verify or refine the relationship in southern Georgia. This 2-yr study used nested piezometers to investigate the relationship between seasonal saturation and redoximorphic features in seven pedons of the middle Coastal Plain near Valdosta, GA. Three clayey pedons including two Plinthic Kandiudults and a Plinthaquic Paleudult were studied along a hillslope transect. Four sandy pedons including a Typic Quartzipsamment, a Grossarenic Kandiudult, a Grossarenic Kandiaquult, and an Ultic Alaquod were studied along an upland and river terrace transect. Results indicate that (i) pedons that experienced a seasonal high water table are endosaturated; (ii) a gray matrix is indicative of seasonal saturation, on average for >50% of the time, although some sandy horizons may be saturated much less; (iii) Fe depletions are associated with saturation an average of 18% of the study period, a value less than commonly reported; (iv) Fe-concentration features occur in horizons saturated on average for 24% of the time, although some shallow, especially sandy, horizons were never or only briefly saturated during the study period. Upland and backslope soils, especially Kandiudults with plinthite and reticulate mottling, do not show a consistent relationship between saturation and redoximorphic features; these features appear to be relict and more monitoring in a variety of landscape settings is needed to determine the origin and significance of these features.