LOCATION NOBSCOT OK+TXEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, thermic Arenic Paleustalfs
TYPICAL PEDON: Nobscot fine sand, on a convex 4 percent slope, in range. (Colors are for dry soil unless otherwise stated.)
A--0 to 5 inches; brown (7.5YR 5/2) fine sand, brown (7.5YR 4/2) moist; weak fine granular structure; soft, very friable; many fine and medium roots; slightly acid; gradual wavy boundary. (4 to 6 inches thick)
E--5 to 23 inches; pink (7.5YR 7/4) fine sand, light brown (7.5YR 6/4) moist; single grained; loose; many fine and medium roots; slightly acid; clear wavy boundary. (14 to 36 inches thick)
Bt1--23 to 36 inches; red (2.5YR 4/6) sandy loam, dark red (2.5YR 3/6) moist; weak coarse prismatic structure; hard, friable; with a few bands about 1/4 inch thick of dark reddish brown (2.5YR 3/4) sandy loam; sand grains coated and bridged with clay; few very fine pores; few fine root channels filled or partially filled with clean sand grains; few fine and medium roots; slightly acid; gradual smooth boundary. (8 to 20 inches thick)
Bt2--36 to 53 inches; red (2.5YR 5/6) loamy sand, red (2.5YR 4/6) moist; weak coarse prismatic structure; hard, very friable; with thin bands of dark red (2.5YR 3/6) sandy loam about 1/4 inch thick and 4 to 6 inches apart between layers of loamy sand; sand grains coated and bridged with clay; few fine pores; few fine roots; slightly acid; gradual smooth boundary. (12 to 25 inches thick)
Bt3--53 to 71 inches; reddish yellow (5YR 6/6) loamy sand, yellowish red (5YR 5/6) moist; weak coarse prismatic structure; hard, very friable; with thin bands of red (2.5YR 4/6) sandy loam about 1/8 to 1 inch thick and 5 inches apart between layers of loamy sand; sand grains coated and bridged with clay; about 5 percent by volume of pockets of clean sand grains; few fine roots; slightly acid; diffused smooth boundary. (10 to 20 inches thick)
BC--71 to 80 inches; reddish yellow (5YR 6/6) fine sand, yellowish red (5YR 5/6) moist; weak coarse prismatic structure; slightly hard, loose; with thin bands of red (2.5YR 4/6) loamy fine sand about 1/8 inch thick and 5 inches apart between layers of fine sand; about 5 percent by volume of pockets of clean sand grains; slightly acid.
TYPE LOCATION: Beckham County, Oklahoma; 6 miles south and 2 miles east of Sayre; 600 feet east and 80 feet north of the southwest corner of sec. 35, T. 9 N., R. 23 W.
RANGE IN CHARACTERISTICS:
Particle-size control section (weighted average)
Clay content: 8 to 15 percent
Coarse Fragments: 0 to 3 percent
CEC/clay ratio: more than 0.6
Solum thickness: more than 60 inches
Combined thickness of the A and E horizons: 20 to 40 inches
A Horizon
Hue: 7.5YR or 10YR
Value: 4 or 5
Chroma: 2 to 4
In cultivated areas, the Ap horizon is as much as 2 units higher in value and 1 unit higher in chroma.
Texture: sand, fine sand, loamy fine sand, or loamy sand
Coarse fragments: 0 to 3 percent by volume, 2 to 5 mm in diameter
Effervescence: Noneffervescent
Reaction: Moderately acid to neutral in areas that have not been limed
E Horizon
Hue: 7.5YR or 10YR
Value: 5 to 8
Chroma: 2 to 4
Texture: sand, fine sand, loamy fine sand, or loamy sand
Coarse fragments: 0 to 3 percent by volume, 2 to 5 mm in diameter
Effervescence: Noneffervescent
Reaction: Moderately acid to neutral in areas that have not been limed
Upper Bt Horizon
Hue: 2.5YR to 7.5YR
Value: 4 to 6
Chroma: 6 to 8
Texture: sandy loam or fine sandy loam
Clay content: 8 to 15 percent
Coarse fragments: 0 to 3 percent by volume, 2 to 5 mm in diameter
Effervescence: Noneffervescent
Reaction: Strongly acid to neutral
Lower Bt Horizons
Hue: 2.5YR to 7.5YR
Value: 4 to 7
Chroma: 6 to 8
Texture: fine sandy loam, loamy fine sand, loamy sand or fine sand with lamellae of sandy loam or sandy clay loam. The lamellae range from 1/8 inch to 6 inches thick and 2 to 6 inches apart. Pockets of clean sand grains occur in the lower portion of most pedons.
Clay content: 2 to 15 percent
Coarse fragments: 0 to 3 percent by volume, 2 to 5 mm in diameter
Effervescence: Noneffervescent
Reaction: Strongly acid to neutral
BC Horizons
Hue: 2.5YR to 7.5YR
Value: 4 to 7
Chroma: 6 to 8
Texture: loamy fine sand, loamy sand or fine sand with lamellae that range from 1/8 inch to 2 inches thick and 4 to 12 inches apart. The lamellae have more clay content and lower color values than the matrix. Pockets of clean sand grains occur in most pedons.
Clay content: 2 to 10 percent
Coarse fragments: 0 to 3 percent by volume, 2 to 5 mm in diameter
Effervescence: Noneffervescent
Reaction: Slightly acid to neutral
Some pedons have a C horizon that is similar in color, texture, and reaction to the BC horizon. The lamellae decrease in thickness and increase in distance apart with depth.
COMPETING SERIES: The
Heatly series is the only series in the same family. Series in similar families are the
Dougherty and
Stidham series.
Heatly soils have a sandy clay loam argillic horizon.
Dougherty and Stidham soils are moist for longer periods of time during the growing season.
GEOGRAPHIC SETTING:
Parent material: Loamy and sandy alluvial sediments of Pleistocene age that have been reworked by the wind.
Landform: undulating to hilly sand sheets or stream terraces on alluvial plains of the Central Rolling Red Plains.
Slope: 0 to 20 percent
Mean annual air temperature range: 57 to 64 degrees F.
Mean annual precipitation range: 21 to 27 inches
Frost-free period: 185 to 230 days
Elevation: 1300 to 2500 feet
Thornthwaite annual P-E indices: 32 to 44
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Delwin,
Devol,
Eda,
Grandfield,
Springer, and
Tivoli series.
Delwin and Grandfield series: These soils occur on adjacent or slightly lower areas that are slightly concave, have a sandy clay loam argillic horizon, and do not have a sandy surface layer greater than 20 inches thick.
Devol and Springer series: These soils occur on slightly lower undulating to hummocky areas and do not have a sandy surface layer greater than 20 inches thick.
Eda and Tivoli series: These soils occur on slightly higher hummocky or dune areas, do not have an argillic horizon, and are sandy throughout.
DRAINAGE AND PERMEABILITY: Nobscot soils are well drained; permeability is moderately rapid. Runoff is negligible on slopes less than 1 percent, very low on 1 to 5 percent slopes, and low on 5 to 20 percent slopes.
USE AND VEGETATION: Used mainly as native range for beef cattle. Some of the undulating and hummocky areas are cultivated to sorghums, small grains, and alfalfa. Some areas are used for improved pasture. Native vegetation consists of shinnery oak with an understory of tall grasses. Near the eastern extent of these soils, the shinnery oak ranges up to 25 feet tall and are in small circular areas intermingled with shrubby plants 2 to 5 feet tall.
DISTRIBUTION AND EXTENT: Central Rolling Red Plains (MLRA 78B, 78C) of Oklahoma and Texas. The series is extensive.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Roger Mills County, Oklahoma; 1959.
REMARKS: Soil Interpretation Record: Series OK0057
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon- the zone from the soil surface to a depth of 23 inches. (the A and E horizons)
Argillic horizon- The zone from 23 inches to a depth of 71 inches (the Bt horizons).
ADDITIONAL DATA: Sample No. 72-OK-05-01 by Oklahoma State University, Stillwater Oklahoma. Sample No. S59-OK-77-2 by National Soil Survey Laboratory, Lincoln, Nebraska. Sample No. S00-OK-055-005 by National Soil Survey Laboratory, Lincoln, Nebraska.