LOCATION COMFORT TX
The Comfort series consists of soils that are shallow to indurated limestone bedrock. These well drained, slowly permeable soils that formed in clayey residuum derived from dolomitic limestone of Lower Cretaceous period. These nearly level to moderately sloping soils occur on ridges on dissected plateaus. Slopes are 0 to 8 percent. Mean annual temperature is about 18.9 degrees C (66 degrees F), and mean annual precipitation is about 914 mm (36 in).
TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive, thermic Lithic Argiustolls
TYPICAL PEDON: Comfort very stony clay--rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 13 cm (0 to 5 in); dark grayish brown (10YR 4/2) very 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, 2 to 75 mm, non-flat, angular, limestone gravel; 40 percent, 76 to 600 mm, non-flat, limestone partially on the surface and in the soil; slightly alkaline; clear wavy boundary. (Thickness is 8 to 25 cm [3 to 10 in])
Bt--13 to 43 cm (5 to 17 in); dark reddish gray (5YR 4/2) very 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, 76 to 600 mm, non-flat, angular limestone; many roots matted at soil rock interfaces; slightly alkaline; abrupt wavy boundary. (Thickness is 18 to 36 cm [7 to 14 in])
R--43 to 69 cm (17 to 27 in); indurated crystalline dolomitic limestone bedrock with irregular seams 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.
USGS topographic quadrangle: Ranger Creek, TX;
Latitude: 29 degrees, 49 minutes, 17.9 seconds N;
Longitude: 98 degrees, 48 minutes, 48.3 seconds W;
RANGE IN CHARACTERISTICS:
Soil moisture: Typic ustic soil moisture regime. The soil moisture control section is dry in some or all parts for more than 90 but less than 150 cumulative days in normal years.
Depth to lithic contact: 25 to 51 cm (10 to 20 in)
Thickness of mollic epipedon: 18 to 51 cm (7 to 20 in)
Surface rock fragments: 0 to 90 percent, limestone, 2mm to more than 600 mm
Particle-size control section (weighted average):
Clay content: 40 to 60 percent
Fragments: 35 to 75 percent by volume, crystalline dolomitic limestone and chert, 2 mm to 600 mm
Hue: 5YR to 10YR
Value: 2 dry
Chroma: 3 or 4 dry
Texture: Clay loam or clay; with the very gravelly, very cobbly, or very stony phases.
Clay content: 30 to 50 percent
Rock fragments: 35 to 60 percent total by volume, limestone; 5 to 25 percent, 2 to 75 mm, chert; 15 to 50 percent, 76 to 600 mm, crystalline dolomitic limestone
Effervescence: none or very slight
Reaction: Slightly acid to slightly alkaline
Hue: 2.5YR to 7.5YR
Value: 2 to 6
Chroma: 3 or 4
Texture: Clay; very gravelly, very cobbly, or very stony phases
Clay content: 55 to 75 percent
Rock fragments: 35 to 75 percent total by volume, limestone; 5 to 25 percent, 2 to 75 mm, chert; 15 to 50 percent, 76 to 600 mm, crystalline dolomitic limestone
Effervescence: none or slight
Reaction: Slightly acid to slightly alkaline
Bedrock kind: Dolomitic limestone bedrock
Cementation: Strongly cemented or indurated
COMPETING SERIES: There are no other series in the same family. Similar series include the
Spicewood soils: are more than 51 cm (20 in) deep to bedrock.
Tarrant soils: do not have argillic horizons.
Hensley soils: do not have mollic epipedons.
Roughcreek soils: have smectitic mineralogy.
Tarpley soils: have less than 35 percent coarse fragments in the particle-size control section.
Parent material: The soil formed in residuum weathered from dolomitic limestone of Lower Cretaceous age.
Landscape: Dissected plateaus
Landform: Summits, shoulders, and backslopes of ridges
Slope: 0 to 8 percent, mostly less than 5 percent
Climate: Dry subhumid
Precipitation Pattern: The majority of the yearly amount occurs during the fall and spring months. The winter and summer months are normally drier.
Mean annual precipitation: 584 to 914 mm (23 to 36 in)
Thornthwaite P-E indices: 42 to 50
Mean annual temperature: 17.8 to 20.6 degrees C (64 to 69 degrees F)
Frost-free periods: 210 to 260 days
Elevation: 304.8 to 731.5 m (1,000 to 2,400 ft)
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Real soils: do not have argillic horizons and occur on side slopes of ridges on dissected plateaus. In addition, Brackett soils do not have mollic epipedons.
Tarpley soils: occur on similar positions.
DRAINAGE AND PERMEABILITY:
Drainage class: Well.
Permeability class: Slow.
Runoff: high on 0 to less 1 percent slopes, high on 1 to 5 percent slopes, and very high on 5 to 8 percent slopes.
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; Southwest Plateaus and Plains Range and Cotton Region, LLR I: MLRA 81B-Edwards Plateau, Central Part; MLRA 81C-Edwards Plateau, Eastern Part; MLRA 82A-Texas Central Basin. This series is extensive, over 100,000 acres.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Kendall County, Texas; 1979.
REMARKS: Comfort series was formerly included in the Tarrant series.
Edited 10/2016 (RFG-THW): Updated competing series, geographic setting, and associated soils sections.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 0 to 43 cm (0 to 17 in) (A and Bt horizon)
Argillic horizon: 13 to 43 cm (5 to 17 in) (Bt horizon)
Lithic Contact: 43 cm (17 in) (top of R layer)
ADDITIONAL DATA: none
Taxonomic Version: Keys to Soil Taxonomy, Twelfth Edition, 2014.
National Cooperative Soil Survey