LOCATION CHILDRESS TX+OKTentative Series
TAXONOMIC CLASS: Fine-loamy, gypsic, thermic Gypsic Haplustepts
TYPICAL PEDON: Childress silt loam--cropland. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 5 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak fine and medium granular structure; soft, very friable; few very fine and fine roots, few medium roots: about 13 percent gypsum by weight and 1 percent calcium carbonate equivalent; EC is 2.4 dS/m; strongly effervescent; slightly alkaline; abrupt smooth boundary. (4 to 9 inches thick)
Bky1--5 to 23 inches; very pale brown (10YR 8/2) gypsiferous loam, very pale brown (10YR 8/2) dry; weak medium prismatic structure parting to weak medium subangular blocky; slightly hard, friable; common very fine and fine roots; few fine and medium pores; vertical 1/4 inch (6mm) thick seams spaced about 2 feet apart of petrogypsic material; about 66 percent gypsum by weight and 5 percent calcium carbonate equivalent; EC is 2.2 dS/m; strongly effervescent; moderately alkaline; clear smooth boundary.
Bky2--23 to 30 inches; very pale brown (10YR 8/4) gypsiferous loam, very pale brown (10YR 7/4) moist; few fine distinct light brown (7.5YR 6/4) mottles; weak coarse prismatic structure; friable, hard, very firm; few fine roots and few very fine roots; many fine pores; about 25 percent visible masses and threads of gypsum; few quartz gravels less than 2cm across long axis; vertical 1/4 inch (6mm) thick seams spaced about 2 feet apart of petrogypsic material; About 61 percent gypsum by weight and 4 percent calcium carbonate equivalent; EC is 2.2 dS/m; strongly effervescent; moderately alkaline; clear smooth boundary. (Combined thickness of the Bky1 and Bky2 horizons is 15 to 45 inches)
Bky3--30 to 80 inches; light brown (7.5YR 6/4) gypsiferous loam, brown (7.5YR 5/4) moist; weak coarse prismatic structure; hard, very firm; few very fine roots; few very fine and fine pores; about 25 percent masses and threads of gypsum; few quartz pebbles less than 2cm across long axis; about 51 percent gypsum by weight and 9 percent calcium carbonate equivalent; EC is 2.2 dS/m; strongly effervescent; moderately alkaline.
TYPE LOCATION: Childress County, Texas; from intersection of Farm Road 2530 and U.S. Highway 287 in Childress; 1.2 miles north on farm Road 2530, 5.8 miles east on farm Road 268, 1150 feet south on county road and 100 feet east in cropland. Latitude: 34 degrees, 26 minutes, 0.30 seconds N; Longitude: 100 degrees, 5 minutes, 22.4 seconds W.) Kirkland North, Texas topographic quadrangle; NAD 1927.
RANGE IN CHARACTERISTICS:
Depth to gypsic horizon: 4 to 9 inches
Thickness of the solum ranges from 60 to more than 80 inches
Particle-size control section (weighted average)
Clay content: 18 to 35 percent
Coarse fragments: 0 to 2 percent
EC (dS/m): 2 to 4
Depth to secondary carbonates: 0 to 9 inches
A Horizon
Hue: 7.5YR or 10YR
Value: 5 to 7
Chroma: 2 to 4
Texture: loam, silt loam, or clay loam
Clay content: 12 to 30 percent
Coarse fragments: 0 to 2 percent
Calcium carbonate equivalent: 0 to 5 percent
Gypsum: Weighted average of 5 to 20 percent
SAR: 0 to 2
Effervescence: noneffervescent to strongly effervescent
Reaction: neutral to moderately alkaline
Bky1 and Bky2 horizons
Hue: 7.5YR to 2.5Y
Value: 6 to 8
Chroma: 1 to 3
Mottles: Some pedons contain a few brownish mottles
Texture: Gypsiferous materials of loam, silt loam, clay loam
Clay content: 18 to 35 percent
Coarse fragments: 0 to 2 percent
Calcium carbonate equivalent: 3 to 10 percent
Gypsum: Weighted average of 55 to 80 percent and may include a few vertical and horizontal discontinuous lenses of petrogypsic material less than 1 cm thick
SAR: 0 to 2
Effervescence: Slightly effervescent to violently effervescent
Reaction: slightly alkaline to moderately alkaline
Bky3 horizon
Hue: 5YR to 10YR
Value: 5 to 8
Chroma: 2 to 4
Mottles: Some pedons are mottled with these colors
Texture: Gypsiferous materials of loam, silt loam, clay loam or silty clay loam
Clay content: 18 to 40 percent clay
Coarse fragments: 0 to 2 percent
Calcium carbonate equivalent: 1 to 10 percent
Gypsum: Weighted average of 40 to 75 percent and may include selenite crystals and a few vertical and horizontal discontinuous lenses of petrogypsic material less than 1 cm thick. The content of gypsum commonly decreases with depth.
SAR: 0 to 2
Effervescence: noneffervescent to violently effervescent
Reaction: slightly alkaline to moderately alkaline
COMPETING SERIES: There are no competing series in this family. Similar soils are the Cornick, Cottonwood, and Vinson soils. These soils are underlain by bedrock gypsum at very shallow to moderate depths.
GEOGRAPHIC SETTING:
Landform: Stream terraces or dissected remnants of old lakebeds or other outwashes within or from the Blaine Formation. Childress soils commonly occur as small rounded or oblong areas within areas of Acme soils.
Parent material: sediments high in gypsum
Slope: 0 to 3 percent.
Mean annual temperature: 61 to about 66 degrees F.
Mean annual precipitation: 20 to 25 inches
Frost-free period: 205 to 230 days
Elevation: 1600 to 1850 feet
Thornthwaite annual P-E indices: 32 to 37
GEOGRAPHICALLY ASSOCIATED SOILS: These include the
Abilene,
Acme,
Kingco and
Rowena soils.
Abilene, Kingco, and Rowena series: These soils occur slightly higher in the landscape. These very deep soils have a mollic epipedon more than 20 inches thick and a clayey particle-size class.
Acme Series: These very deep soils have a mollic epipedon and afine-silty particle-size class.
DRAINAGE AND PERMEABILITY: Well drained. Moderate permeability. Runoff is negligible on 0 to 1 percent slopes and low on 1 to 3 percent slopes.
USE AND VEGETATION: This soil is mainly used as rangeland. Short grasses are prevalent where grazing is continuous, but some tall grasses grow in protected areas. Where the soil is intermingled with deeper and more productive soils, small areas are cultivated. Some areas are mined for the soft impure gypsum. This material is used for making sheetrock wall board.
DISTRIBUTION AND EXTENT: Rolling Red Plains of north central Texas; LRR H; MLRA 78B and 78C. Small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas.
SERIES PROPOSED: Childress County, Texas; 2003
REMARKS: This soil was formerly included with the Cottonwood series. Cottonwood soils formed in residuum over crystalline or alabaster gypsum. The Childress soil has concentrations of gypsum throughout the By horizons believed to be formed by upwards capillary action of water high in dissolved gypsum from a previous or present fluctuating water table from lower strata.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 5 inches
Gypsic horizon: 5 to 80 inches
Particle-size-control section: 10 to 40 inches
Range Site: Gyp - 078BY076TX
ADDITIONAL DATA: National Soil Survey Lab Data Nos.
Childress Co. TX. (S99TX-075-001), and Foard Co. TX. (S01TX-155-002).
TAXONOMIC VERSION: Keys to Soil Taxonomy, Ninth Edition, 2003