LOCATION COMFORT            TX

COMFORT SERIES

TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive, thermic Lithic Argiustolls

TYPICAL PEDON: Comfort stony clay--rangeland. (Colors are for dry soil unless otherwise stated.)

A--0 to 5 inches; dark grayish brown (10YR 4/2) stony clay, very dark grayish brown (10YR 3/2) moist; moderate medium angular blocky structure parting to moderate fine subangular blocky; very hard, very firm; many fine roots; few very fine tubular pores; 15 percent by volume angular limestone pebbles, 40 percent by volume cobbles and stones partially on the surface and in the soil; slightly alkaline; clear wavy boundary. (3 to 10 inches thick)

Bt--5 to 17 inches; dark reddish gray (5YR 4/2) stony clay, dark reddish brown (5YR 3/2) moist; moderate medium subangular and angular blocky structure parting to moderate fine angular blocky; very hard, very firm; few fine and medium roots; patchy clay films; 40 percent by volume cobble and stone size angular limestone fragments, many roots matted at soil rock interfaces; slightly alkaline; abrupt wavy boundary. (7 to 14 inches thick)

R--17 to 20 inches; indurated crystalline dolomitic limestone with irregular veins filled with soil.

TYPE LOCATION: Kendall County, Texas; from the intersection of Ranch Road 474 and U.S. Highway 87 in Boerne, northwest on U.S. 87 to Interstate Highway 10 west access road, then northwest 1 mile to Cibolo Creek Road, then west approximately 3 miles to entrance to a subdivision, then south on a paved road, 1.3 miles, then west 0.3 mile on top of a ridge in rangeland.

RANGE IN CHARACTERISTICS: Solum thickness ranges from 9 to 20 inches and corresponds to the depth to bedrock. Soil reaction ranges from neutral through moderately alkaline. Coarse fragments of stone, cobble, and pebble size range from 35 to 70 percent on the surface and in the soil. Cobbles and stones are crystalline dolomitic limestone and pebbles are dominantly chert.

The A horizon has hue of 5YR, 7.5YR or 10YR with chroma of 3 or 4 and value of 2. Texture of the fine earth fraction is clay or clay loam.

The Bt horizon has hue of 2.5YR, 5YR, or 7.5YR, chroma of 3 or 4 and value of 2 to 6. Texture of the fine earth fraction is clay, with clay. Clay content ranges from 55 to 75 percent.

COMPETING SERIES: Ridgelite is the only series in the same family. Similar series in other families are Bexar, Eckrant, Hensley, Rumple, Speck, Spicewood, Tarpley, and Tarrant series. Ridgelite soils have lower soil temperatures and moisture. Bexar, Rumple, and Spicewood soils have sola more than 20 inches thick. Eckrant and Tarrant soils do not have Bt horizons. Hensley soils lack mollic epipedons. Speck and Tarpley soils have less than 35 percent coarse fragments.

GEOGRAPHIC SETTING: Comfort soils are on nearly level to sloping upland plateaus and low ridges. Slopes are plane to convex and gradients range from 0 to 8 percent, but are mostly less than 5 percent. The soils formed in clayey residuum over crystalline dolomitic limestone of Lower Cretaceous age. The climate is dry subhumid with a mean annual precipitation of 23 to 36 inches and average annual air temperature of 65 to 69 degrees F. The Thornthwaite annual P-E index ranges from 42 to 50. Frost free days range from 210 to 260. Elevation ranges from 1000 to 2300 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Eckrant, Speck, Spicewood, Tarpley, and Tarrant series and Brackett and Real series. Eckrant, Speck, Spicewood, Tarpley, and Tarrant soils are on similar surfaces. Brackett and Real soils do not have Bt horizons and are on slopes below plateaus. In addition, Brackett soils do not have mollic epipedons.

DRAINAGE AND PERMEABILITY: Well drained. Runoff is low on 0 to 1 percent slopes, medium on 1 to 5 percent slopes and high on 5 to 8 percent slopes; Permeability is medium.

USE AND VEGETATION: Mostly used for rangeland and rural homesites. Native vegetation consists mostly of Texas wintergrass, threeawns, sideoats grama, little bluestem, and indiangrass. Woody vegetation consists of Texas oak, shin oak, liveoak, Texas persimmon and pricklypear.

DISTRIBUTION AND EXTENT: Central Texas; mainly in the southeastern part of the Edwards Plateau. The soils of this series are moderately extensive, about 100,000 acres.

MLRA OFFICE RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Kendall County, Texas; 1979.

REMARKS: Comfort series was formerly included in the Tarrant series. Diagnostic horizons and features recognized in this pedon are:

Mollic epipedon - 0 to 17 inches (A and Bt horizon)
Lithic Contact - 17 inches (R horizon)
Argillic horizon - 5 to 17 inches (Bt horizon)

ADDITIONAL DATA: none

TAXONOMIC VERSION: Keys to Soil Taxonomy, Ninth Edition 2003.