LOCATION CALLAHAN TX

Established Series
Rev. WMR-ACT-TEC-WJG
11/2013

CALLAHAN SERIES

The Callahan series consists of moderately deep, well drained, slowly permeable soils that formed in claystone interbedded with thin sandstone strata. These soils are on gently to strongly sloping ridges on hills. Slopes range from 1 to 12 percent. Mean annual precipitation is about 711 mm (28 in) and the mean annual air temperature is about 18.3 degrees C (65 degrees F).

TAXONOMIC CLASS: Fine, mixed, active, thermic Typic Haplustalfs

TYPICAL PEDON: Callahan loam--cultivated. (Colors are for dry soil unless otherwise stated.)

Ap--0 to 7 inches; reddish brown (5YR 4/4) loam, dark reddish brown (5YR 3/4) moist; massive; hard, firm; few fine roots; few fine pores; surface has 6 mm (1/4 in) crust that is very hard; moderately alkaline; clear smooth boundary. Thickness is 3 to 25 cm (1 to 10 in)

Bt--7 to 18 inches; reddish brown (5YR 4/3) clay, dark reddish brown (5YR 3/3) moist; compound moderate, medium prismatic structure, parting to moderate fine blocky structure; very hard, very firm; few fine roots; few fine pores; thin patchy clay films on faces of peds that are one- half value darker than the inside of the peds; few fine quartz gravel; moderately alkaline; clear smooth boundary. Thickness is 18 to 46 cm (7 to 18 in)

Btk--18 to 30 inches; reddish brown (5YR 4/4) clay, dark reddish brown (5YR 3/4) moist; moderate fine blocky structure; very hard, very firm; few fine roots; few fine pores; the surfaces of the peds are shiny; few fine quartz gravel; few films and threads of calcium carbonate; few strongly and weakly cemented concretions of calcium carbonate; slight effervescence; moderately alkaline; gradual wavy boundary. Thickness is 20 to 51 cm (8 to 20 in)

Btk/C--30 to 36 inches; yellowish red (5YR 5/6) clay, yellowish red (5YR 4/6) moist; weak medium blocky structure; very hard, firm; few thin patchy clay films on faces of peds; 10 percent by volume of partially weathered fragments of shale; few strongly and weakly cemented concretions of calcium carbonate; strong effervescence; moderately alkaline; clear smooth boundary. Thickness is 0 to 25 cm (0 to 10 in)

Cdk--36 to 70 inches; thin lenses and strata of pink, claystone bedrock, interbedded with weakly cemented sandstone and yellow clay loam; massive; extremely hard, very firm; cleavage planes and horizontal bedding are evident; few concretions of calcium carbonate and few soft bodies of calcium carbonate; strong effervescence; moderately alkaline.

TYPE LOCATION: Coleman County, Texas; about 15 miles south, 61 degrees east of the Coleman County Courthouse at a point in a cultivated field that is 150 feet south of U. S. Highway 84 and 67, and 0.2 mile west of the Brown-Coleman County Line post on U. S. Highway 84 and 67. USGS topographic quad: Bangs West, Texas; Latitude; 31 degrees 43 minutes 36.27 seconds N; Longitude; 99 degrees 12 minutes 42.26 seconds W; Datum: WGS84; UTM Easting: 479941.05 m, UTM Northing: 3510167.25 m, Zone 14N.

RANGE IN CHARACTERISTICS:
Soil Moisture: Typic-ustic soil moisture regime
Depth to Densic bedrock: 51-102cm (20 to 40in)
Depth to secondary calcium carbonate: 46 to 71cm (18 to 28 in)
Fragments: 1 to 10 percent by volume, quartzite and sandstone gravel

Particle-size control section (weighted average)
Clay content: 35 to 50 percent

A Horizon:
Hue: 5YR to 10YR
Value: 4 to 6
Chroma: 2 to 4; pedons with value and chroma of less than 3.5 are less than 8 inches thick.
Texture: loam, sandy clay loam, clay loam or their stony or cobbly counterparts
Clay Content: 15 to 27 percent
Reaction: neutral to moderately alkaline

Btk and Btk/C Horizons:
Hue: 2.5YR to 7.5YR
Value: 3 to 7
Chroma: 3 to 6
Texture: clay or clay loam
Clay Content: 35 to 50 percent
Reaction: neutral to moderately alkaline in the upper part and slightly alkaline to moderately alkaline in the lower part

Cd Horizon:
Texture: claystone bedrock or dense clay that is commonly interbedded
with thin strata of sandstone and alkaline loamy or clayey sediments
Clay content: 40 to 60 percent

COMPETING SERIES: These are the Acove, Bluegrove, and Lindale series in the same family.
Acove and Bluegrove: are underlain by paralithic sandstone and do not have secondary carbonates
Lindale: do not have densic bedrock within 102cm (40 in) of the surface and are moist for longer periods.

GEOGRAPHIC SETTING:
Parent Material: clayey residuum derived from claystone and sandstone of lower Permian and upper Pennsylvanian age.
Landscape: hills
Landform: side slopes of low ridges
Slope: 1 to 12 percent
Mean annual precipitation range: 686 to 787 mm (27 to 31 in)
Thornthwaite P-E index: 32 to 44
Mean annual air temperature: 17.2 to 18.9 degrees C (63 to 66 degrees F)
Frost Free Period: 210 to 250 days
Elevation: 259.1 to 650.8 m (850 to 2135 feet)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bonti, Owens, Throck, Truce, and Winters series.
Bonti soils: have less than 75 percent base saturation
Owens and Throck soils: do not have argillic horizons
Truce and Winters soils: do not have bedrock within 102 cm (40 in) of the surface and do not have secondary carbonates within 71 cm (28 in) of the surface

DRAINAGE AND PERMEABILITY: Well drained. Permeability is slow. Runoff is high on 1 to 5 percent slopes and very high on 5 to 12 percent slopes.

USE AND VEGETATION: Used for cultivation and rangeland. Cultivated crops are mostly small grains and grain sorghum. Native vegetation consists mostly of curlymesquite, buffalograss, and Texas wintergrass with a few scattered hackberry, post oak, and mesquite trees.

DISTRIBUTION AND EXTENT: Mainly in Central Texas, in the southern part of the North Central Prairies and Rolling Red Plains. The series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Coleman County, Texas; 1968.

REMARKS: Callahan soils were formerly included in the Windthorst series.

Edited 11/2013 (RFG-TRD): changed to tabular format, updated competing series, geographic setting and associated soils sections.

Diagnostic horizons and features recognized in this pedon:
Ochric epipedon: 0 to 18 cm (0 to 7 in) (A Horizon)
Argillic horizon: 18 to 91 cm (7 to 36 in) (Bt, Btk, BCtk Horizons)
Densic bedrock: 91 to 178 cm (36 to 70 in) (Cdk Horizon)

Taxonomic Version: Keys to Soil Taxonomy, Eleventh Edition, 2010

National Cooperative Soil Survey
U.S.A.