LOCATION COSH                    TX

Established Series


The Cosh series consists of shallow, well drained, moderately permeable soils that formed in weakly cemented sandstone. These soils are on gently sloping to sloping uplands. Slope ranges from 1 to 8 percent. Mean annual precipitation is about 635 mm (25 in), and mean annual air temperature is about 17.2 degrees C (63 degrees F).

TAXONOMIC CLASS: Loamy, mixed, active, thermic, shallow Typic Rhodustalfs

TYPICAL PEDON: Cosh fine sandy loam--rangeland.
(Colors are for dry soil unless otherwise stated.)

A1--0 to 15 cm (0 to 6 in); reddish brown (2.5YR 5/4) fine sandy loam, dark reddish brown (2.5YR 3/4) moist; weak very fine granular structure and single grained; hard, very friable; many grass roots; many very fine and few fine pores; neutral clear smooth boundary. Thickness is 10 to 25 cm (4 to 10 in)

Bt--15 to 41 cm (6 to 16 in); reddish brown (2.5YR 4/4) sandy clay loam, dark reddish brown (2.5YR 3/4) moist; moderate coarse prismatic structure, parting to fine and very fine subangular blocky structure; very hard, friable; many grass roots; many fin and very fine pores; few wormcasts; few faint clay films on prism faces; neutral; abrupt smooth boundary. Thickness is 15 to 36 cm (6 to 14 in)

Cr--41 to 61 cm (16 to 24 in); red (2.5YR 4/6) weakly cemented sandstone; massive; extremely hard; neutral.

TYPE LOCATION: Hardeman County, Texas; from the intersection of U.S. Highway 287 and Texas Highway 6 in Quanah, about 10 miles south on Texas Highway 6, then about 3.5 miles east on county road, then about 0.65 mile south on county road, 100 feet west of county road in rangeland.
USGS topographic quadrangle: Big Mound, Texas;
Latitude: 34 degrees, 07 minutes, 58.6 seconds N;
Longitude: 99 degrees, 40 minutes, 46.8 seconds W;
Datum: WGS84

Depth to paralithic bedrock: 30 to 51 cm (12 to 20 in)
Rock fragments: 0 to 5 percent gravel; 0 to 2 percent cobbles; strongly to very strongly cemented sandstone; in the soil and on the surface

Particle-size control section (weighted average)
Clay content: 18 to 35 percent

A Horizon
Hue: 2.5YR to 7.5YR
Value: 4 to 5
Chroma: 3 to 4
Texture: mostly fine sandy loam, but varies to loamy fine sand in some pedons that are winnowed
Organic Matter: less than 1 percent
Effervescence: none
Reaction (pH): slightly acid to slightly alkaline (6.1 - 7.8)

Bt Horizon
Hue: 10R to 2.5YR
Value: 3 to 5
Chroma: 4 to 6
Texture: sandy clay loam, fine sandy loam
Clay content: 18 to 35 percent
Calcium carbonate equivalent: 0 to 2 percent
Effervescence: none to slight
Reaction (pH): neutral to slightly alkaline (6.6 - 7.8)

Cr Horizon
Color: red to reddish brown
Texture: weakly consolidated to hard sandstone with a hardness of about 2 on Moh's scale
Cementation: extremely weakly to moderately
Identifiable secondary carbonate: typically none, but in a few places thin calcium carbonate coats occur in cracks and fractures
Effervescence: typically noncalcareous

COMPETING SERIES: There are no series in the same family. Similar soils are the Cobb, Dill, Jolly, Latom, Oben, Quinlan, and Spikebox series.
Cobb and Dill soils: are more than 51 cm (20 in) deep to bedrock and Dill soils do not have an argillic horizon
Latom, Quinlan, and Spikebox soils: do not have an argillic horizon
Oben soils: have argillic horizons in hues of 5YR or yellower

Parent material: typically noncalcareous, medium-grained sandstone of the San Angelo Sandstone of Permian age that are interbedded in places with calcareous clayey and silty redbeds, but is also mapped in Triassic age sandstone
Landscape: dissected plain
Landform: convex to plane interfluves and side slopes of hillslopes
Slope: 1 to 8 percent, but are mostly about 1 to 4 percent
Mean annual precipitation: 559 to 711 mm (22 to 28 in)
Thornthwaite P-E Index: 28 to about 40
Mean annual air temperature: 15.6 to 17.8 degrees C (60 to 64 degrees F)
Frost-free period: 210 to 240 days
Elevation: 304.8 to 762.0 m (1000 to 2500 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cobb, Decobb, Latom, and Spikebox series.
Cobb soils: occur on similar to slightly lower positions
Decobb soils: are deep to bedrock and occur on lower less sloping areas
Latom and Spikebox soils: occur on similar to slightly higher positions

DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow to rapid. Permeability is moderate.

USE AND VEGETATION: Dominantly used for rangeland. About 40 percent of these soils are in cultivation. Native grasses consist mainly of buffalograss, blue grama, sideoats grama, little bluestem, and threeawn. Mesquite trees occur in some areas.

DISTRIBUTION AND EXTENT: Western Texas and southwestern Oklahoma. Land Resource Region H - Central Great plains Winter Wheat and Range Region. The Central Rolling Red Plains (MLRA 78). The series is of small extent.


SERIES ESTABLISHED: Hardeman County, Texas; 1966.

REMARKS: These soils were formerly classified in the Reddish Chestnut great soil group.

Edited 01/2017 (RFG-ROG): Changed to tabular format. Added metric measurements. Updated competing series, geographic setting, and associated soils sections.

Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 15 to 41 cm (6 to 16 in). (Bt horizon)
Ochric epipedon: 0 to 15 cm (0 to 6 in). (A horizon)
Argillic horizon: 15 to 41 cm (6 to 16 in). (Bt horizon)
Paralithic contact: The contact with weakly cemented sandstone at 41 cm (16 in). (Cr horizon)


Taxonomic Version: Keys to Soil Taxonomy, Twelfth Edition, 2014

National Cooperative Soil Survey