LOCATION DUNN NEEstablished Series
TAXONOMIC CLASS: Sandy over loamy, mixed, superactive, mesic Oxyaquic Haplustolls
TYPICAL PEDON: Dunn loamy sand - on a 1 percent convex slope in native grass. When described, the soil was dry throughout. (Colors are for dry soil unless otherwise stated)
A--0 to 12 inches; dark grayish brown (10YR 4/2) loamy sand, very dark gray (10YR 3/1) moist; weak fine and medium granular structure; soft, very friable; moderately acid; clear smooth boundary. (7 to 14 inches thick)
AC--12 to 17 inches; grayish brown (10YR 5/2) sand, very dark grayish brown (10YR 3/2) moist; weak fine and medium granular structure; soft, very friable; moderately acid; gradual smooth boundary. (5 to 9 inches thick)
C--17 to 28 inches; pale brown (10YR 6/3) sand, brown (10YR 5/3) moist; common medium faint yellowish brown (10YR 5/6) moist redoximorphic concentrations in the soil matrix; single grain; loose; moderately acid; abrupt smooth boundary. (8 to 14 inches thick)
2Bwb--28 to 42 inches; light brownish gray (10YR 6/2) sandy clay loam, grayish brown (10YR 5/2) moist; common medium faint brownish yellow (10YR 6/6) moist redoximorphic concentrations in the soil matrix; moderate coarse prismatic structure parting to strong medium and coarse angular blocky; very hard, firm; common pressure faces, many fine roots, sandy material in vertical cracks and cleavages; slightly acid; gradual smooth boundary. (7 to 20 inches thick)
2C--42 to 60 inches; light gray (2.5Y 7/2) sandy clay loam, light brownish gray (2.5Y 6/2) moist; many coarse faint brownish yellow (10YR 6/6) moist redoximorphic concentrations in the soil matrix; moderate coarse prismatic structure; very hard, firm; many fine roots; sandy material in vertical cracks and cleavages; neutral.
TYPE LOCATION: Holt County, Nebraska; 8 miles west and 4 miles north of O'Neill; 1,300 feet east and 50 feet north of the southwest corner, sec. 2, T. 29 N., R. 13 W.
RANGE IN CHARACTERISTICS: Mollic epipedons are 10 to 20 inches thick. Depth to the 2Bwb horizon is from 20 to 37 inches. Depth to carbonates is 20 to 60 inches or more and carbonates, when present, generally occur as a layer of accumulations in the 2Bwb or 2C horizons.
The A horizon has hue of 10YR, value of 3 to 5 and 2 or 3 moist and chroma of 1 to 3. It is loamy fine sand or loamy sand. Reaction is moderately acid through neutral.
The AC horizon has hue of 10YR, value of 4 to 6 and 3 to 5 moist and chroma of 2 or 3. It is sand, fine sand, loamy sand, or loamy fine sand. Reaction is moderately acid through neutral.
The C horizon has a hue of 10YR, value of 5 to 7 and 4 to 6 moist and chroma of 2 to 4. It is sand, fine sand, loamy sand or loamy fine sand. Reaction is medium acid through neutral. It has faint yellowish brown, reddish brown or brownish yellow redoximorphic concentrations in the soil matrix.
The 2Bwb and 2C horizons have hues of 7.5YR, 10YR, 2.5Y or 5Y, value of 5 to 8 and 3 to 6 moist, and chroma of 2 to 4. Texture is typically sandy clay loam, but includes loam and clay loam. Clay content ranges from 24 to 35 percent and averages about 30 percent. Dark colored sandy material is in the vertical cleavages and cracks. Yellowish, reddish and brownish redoximorphic concentrations are many or common in the soil matrix. Reaction is slightly acid to moderately alkaline. A gravelly substratum phase with gravelly coarse sand at 40 to 60 inches is recognized.
COMPETING SERIES: This is the Libory series. Libory soils contain less sand and are more friable in the 2Bw and 2C horizons.
GEOGRAPHIC SETTING: Dunn soils are on concave or low hummocky slopes on uplands and stream terraces. Slope gradients are dominantly 0 to 3 percent but range 2 to 20 percent. These soils formed in eolian sands deposited a few feet thick over dense, firm, loamy alluvium. Mean annual precipitation ranges from 18 to 24 inches, and mean annual air temperature ranges from 47 to 50 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Libory soils and the Boelus, Dunday, Elsmere, Pivot and Valentine soils. The Libory and Boelus soils are on similar landscapes. Elsmere, Dunday, Pivot and Boelus soils do not have aquic soil conditions and a perched water table within a depth of 40 inches. Valentine soils have a sandy particle size control section. Dunday, Pivot and Valentine soils are higher on the landscape. Elsmere soils are lower on the landscape.
DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is rapid in the solum and moderately slow or slow in the underlying material. Water is ponded for a brief duration in some of the swales and low areas during wet periods. There is a perched water table that ranges from about 1.5 feet to 3.5 feet during spring and early summer when rainfall is highest. Runoff is low to negligible.
USE AND VEGETATION: The Dunn soils are used for rangeland and cropland. A large acreage of cropland areas are irrigated. Corn and alfalfa are the major crops. Native vegetation is switchgrass, sand bluestem, little bluestem, needleandthread, and prairie sandreed.
DISTRIBUTION AND EXTENT: North-central Nebraska. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Holt County, Nebraska, 1981.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon--the zone from 0 to 17 inches (A and AC horizons); aquic soil conditions--the zone from 17 to 28 inches (C horizon) is saturated for 1 month or more in 6 out of 10 years.
Description supports aquic instead of oxyaquic subgroup (2 chroma with redoximorphic concentrations in 28 to 42 inch zone (2Bwb horizon). Consideration should be given to obtaining a different representative pedon or reclassifying to the aquic subgroup.
ADDITIONAL DATA: Lab data available. Sample No. S75NE89-2(1-4) (Type Location) and Sample No. S78NE89-4(4-5).