LOCATION AOWA NE+SDEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, calcareous, mesic Mollic Ustifluvents
TYPICAL PEDON: Aowa silt loam - cultivated. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 7 inches; after mixing, dark gray (10YR 4/1) silt loam, very dark brown (10YR 3/2) moist; weak, fine, granular structure; slightly hard, very friable, strong effervescence, moderately alkaline, abrupt, smooth boundary. (7 to 10 inches thick)
C1--7 to 16 inches; stratified very dark grayish brown (10YR 3/2) and grayish brown (10YR 5/2) silt loam, very dark gray (10YR 3/1) and gray (10YR 5/1) moist; weak, fine, granular structure; slightly hard, very friable; slight effervescence; moderately alkaline; gradual wavy boundary. (10 to 50 inches thick)
C2--16 to 60 inches; stratified dark gray (10YR 4/1) and pale brown (10YR 6/3) silt loam, very dark gray, (10YR 3/1) and brown (10YR 5/3) moist; weak, fine, subangular blocky structure with some platy structure characteristics due to stratification, slightly hard, very friable; slight effervescence; moderately alkaline.
TYPE LOCATION: Dixon County, Nebraska; 3 miles south and 1/2 mile east of Concord, Nebraska; 150 feet north and 2630 feet west of the southeast corner, sec. 4, T. 27 N., R. 4 E.
RANGE IN CHARACTERISTICS: The solum thickness is 20 inches or less, and is the same as the thickness of the A1 or Ap horizon. Stratification occurs within 10 inches of the surface. Aowa soils are calcareous throughout, and are mildly alkaline or moderately alkaline.
The A horizon after mixing has a hue of 10YR, value of 3 through 5 and 2 or 3 moist, with chroma of 1 through 3 moist or dry. Texture is silt loam or silty clay loam.
The C horizon is stratified with light and dark colored strata. The C horizon has a hue of 10YR, value of 3 through 6 and 3 through 5 moist, with chroma of 1 through 3 moist or dry. It typically is silt loam; however, strata of silty clay loam or loam are present in some pedons. The control section typically averages between 20 and 28 percent clay. Dark brown silt loam or silty clay loam buried soils are below depths of 24 inches in some pedons. Few to common yellowish brown, brown, or strong brown mottles are present on the faces of stratification planes in some pedons. The lower part of the C horizon contains thin strata of fine sandy loam, silty clay loam, loam, or silty clay in some pedons.
COMPETING SERIES: This is the only series in this family. Other closely related soils are the Dorchester, Haynie, Hobbs, McPaul, and Nodaway series. Dorchester soils have a wetter climate. Haynie and McPaul soils are coarse-silty. Hobbs and Nodaway soils lack free carbonates within a depth of 40 inches.
GEOGRAPHIC SETTING: Aowa soils typically are on occasionally or frequently flooded drainageways or narrow flood plains of tributary streams. These soils have slope gradients ranging from 0 to 2 percent. Aowa soils formed in light and dark colored stratified calcareous alluvium from soils formed in the adjacent loess uplands. The mean annual precipitation ranges from 20 to 28 inches, and the mean annual temperature ranges from 47 to 54 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kennebec, Judson, and Omadi soils. All of these soils are on landscapes that are flooded less frequently.
DRAINAGE AND PERMEABILITY: Well and moderately well drained; runoff is medium; permeability is moderate; flooding is occasional or frequent, but flood waters generally recede within a few hours. Most areas are without a permanent water table within 6 feet.
USE AND VEGETATION: The principle crops are corn and soybeans. The most frequently flooded areas along narrow tributaries are in native grass or woodland.
DISTRIBUTION AND EXTENT: Moderately extensive in northeast Nebraska and southeast South Dakota.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Dixon County, Nebraska, 1975.
REMARKS: Aowa soils would have been classified as alluvial soils in the former system. The Aowa soils include soils formerly called McPaul and Kennebec overwash phase.