LOCATION BULLIS TXEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive, thermic Ustic Calciargids
TYPICAL PEDON: Bullis extremely gravelly fine sandy loam - rangeland. (Colors are for dry soil unless otherwise stated.)
A1--0 to 1 inch; brown (7.5YR 4/4) extremely gravelly fine sandy loam, dark brown (7.5YR 3/2) moist; weak very fine granular and subangular blocky structure; slightly hard, very friable; few fine roots; 65 percent chert gravel; neutral; abrupt smooth boundary (1 to 3 inches thick).
A2--1 to 7 inches; dark reddish brown (5YR 3/3) extremely gravelly fine sandy loam, dark reddish brown (5YR 3/2) moist; weak fine granular structure; slightly hard, very friable; many fine and very fine roots; 65 percent chert gravel; neutral; clear smooth boundary (4 to 12 inches thick).
Bt1--7 to 14 inches; dark reddish brown (5YR 3/3) extremely gravelly clay loam, dark reddish brown (5YR 3/3) moist; weak fine subangular blocky structure; very hard, firm; many fine roots; thin continuous clay films on surfaces of peds; 75 percent chert gravel; neutral; clear smooth boundary (4 to 18 inches thick).
Bt2--14 to 33 inches; reddish brown (2.5YR 4/4) extremely gravelly clay, dark reddish brown (2.5YR 3/4) moist; moderate medium subangular blocky structure; extremely hard, very firm; common fine roots; many continuous clay films on surfaces of peds and coarse fragments; 60 percent chert gravel; neutral; clear smooth boundary (6 to 19 inches thick).
Bk--33 to 65 inches; light reddish brown (5YR 6/4) very gravelly sandy clay loam, reddish brown (5YR 5/4) moist; weak fine subangular blocky structure; very hard, firm; common films and threads of calcium carbonate; few calcium carbonate concretions; 60 percent chert gravel; coarse fragments have patchy discontinuous coatings of calcium carbonate; strongly effervescent; moderately alkaline.
TYPE LOCATION: Brewster County, Texas; from the junction of U.S. Highway 385 and U.S. Highway 90 in Marathon; 10.5 miles south on U.S. Highway 385; 20 feet west of fence in rangeland (latitude: 30 degrees, 03 minutes, 35 seconds North; Longitude: 103 degrees, 16 minutes, 37 seconds West).
RANGE IN CHARACTERISTICS:
Soil moisture - control section is moist for less than 20 cumulative days during July through September. The soil is moist in the epipedon for less than 90 cumulative days in 7 out of 10 years during the growing season. Ustic aridic moisture regime.
Solum thickness ranges: 60 to more than 80 inches
Depth to secondary carbonates: 15 to 35 inches
Particle-size control section: averages 35 to 55 percent clay
Coarse fragment content: 35 to 80 percent
A horizon
Hue: 5YR, 7.5YR, 10YR
Value: 3 or 4, dry or moist
Chroma: 2 to 4, dry or moist
Texture: fine sandy loam, loam
Clay content: 10 to 25 percent clay
Reaction: neutral to slightly alkaline
Bt horizon
Hue: 2.5YR, 5YR, 7.5YR
Value: 3 to 6, dry or moist
Chroma: 2 to 6, dry or moist
Texture: clay loam, sandy clay, clay
Clay content: 35 to 55 percent
Reaction: neutral to slightly alkaline
Bk horizon
Hue: 5YR, 7.5YR, 10YR
Value: 4 to 6, dry or moist
Chroma: 3 to 6, dry to moist
Texture: fine earth fraction is loam, clay loam, sandy clay loam
Clay content: 15 to 30 percent
Calcium carbonate: in the form of film, masses, and concretions range from 15 to 40 percent by volume
Other features: films, threads, and concretions of calcium carbonate range from few to common
Reaction: slightly alkaline or moderately alkaline
BCk horizon (when present)
Hue: 5YR, 7.5YR, 10YR
Value: 4 to 8, dry or moist
Chroma: 3 to 6, dry or moist
Texture: loam, clay loam, sandy clay loam
Clay content: 15 to 30 percent
Films, threads and concretions of calcium carbonate range from common to many
Reaction: slightly alkaline or moderately alkaline
COMPETING SERIES: This is the Ryallen (AZ) series. Ryallen soils have lacustrine deposits at moderate depths and silty clay or silty clay loam textures in the particle control section.
GEOGRAPHIC SETTING: Bullis soils are on Pleistocene piedmont fans and footslopes of chert hills. Slopes range from 1 to 8 percent. The soils developed from alluvium and colluvium weathered primarily from chert of the Ouachita formation and, to a lesser extent, shale associated with this formation. Mean annual precipitation range from 10 to 15 inches, mostly occurring July through September. Mean annual air temperature ranges from 60 to 68 degrees F. Frost free period ranges from 210 to 260 days and elevation ranges from 3,400 to 4,500 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Buckear, Catto, and Coyanosa series. Buckear soils are shallow to a paralithic contact with shale and are in similar or slightly higher positions. Catto soils are shallow to a lithic contact with chert and are on sideslopes and ridgetops above. Coyanosa soils are shallow to a lithic contact with sandstone and are on adjacent sideslopes and ridgetops.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately slow. Runoff is very low on 1 to 3 percent slopes, low on 3 to 5 percent slopes, and medium on slopes greater than 5 percent.
USE AND VEGETATION: Used mainly for livestock grazing and wildlife habitat. Native vegetation consists of black grama, bush muhly, sideoats grama, slim tridens, plains bristlegrass, cane bluestem, Arizona cottontop, and blue grama. Woody species consist of creosotebush, white thorn acacia, range ratny, cat claw acacia, and mariola.
DISTRIBUTION AND EXTENT: Trans-Pecos area of Texas in MLRA 42. The series is of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Brewster County, Texas, 1996
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 7 inches (A horizons)
Argillic horizon: 7 to 33 inches (Bt horizons)
Ustic feature: The soil has an aridic moisture regime that borders the ustic regime
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.
Updates and revisions for Brewster County, TX, Main Part, 2/8/08, CEM