LOCATION BUNTON TX
Tentative Series
LEL/JAC/MRM
05/2020
BUNTON SERIES
The Bunton series consists of very deep, well drained, moderately slowly permeable soils formed in clayey alluvium derived from igneous rocks. These soils are on nearly level basin floors. Slope gradient ranges from 0 to 3 percent. Mean annual precipitation is 330 mm (13 inches). Mean annual air temperature is 18.3 degrees C (65 degrees F).
TAXONOMIC CLASS: Fine, smectitic, thermic Ustertic Haplocambids
TYPICAL PEDON: Bunton silty clay loam--native rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 12 centimeters (0 to 5 inches); brown (7.5YR 4/3) silty clay loam, dark brown (7.5YR 3/3), moist; weak fine subangular blocky structure; slightly hard, friable, moderately sticky, moderately plastic; common fine roots; noneffervescent; neutral; clear smooth boundary. (5 to 24 cm [2 to 10 inches] thick)
Bw1--12 to 43 centimeters (5 to 17inches); dark brown (7.5YR 3/3) clay, very dark brown (7.5YR 2.5/3), moist; strong medium subangular blocky structure; hard, very firm, very sticky, very plastic; common fine roots and common medium roots; 8 percent distinct pressure faces on all faces of peds; noneffervescent; neutral, clear smooth boundary.
Bw2--43 to 87 centimeters (17 to 34 inches); brown (7.5YR 4/3) clay, dark brown (7.5YR 3/3), moist; moderate fine subangular blocky structure; moderately hard, firm, very sticky, very plastic; common fine roots; 5 percent distinct pressure faces on all faces of peds; noneffervescent; neutral, clear smooth boundary.
Bw3--87 to 152 centimeters (34 to 60 inches); brown (7.5YR 4/4) clay, dark brown (7.5YR 3/4), moist; moderate fine subangular blocky structure; slightly hard, friable, very sticky, very plastic; common fine roots; slight effervescence; slightly alkaline. (combined thickness of Bw horizons is 176 to 195 centimeters [69 to 77 inches])
TYPE LOCATION: Jeff Davis County, Texas; from the intersection of US Highway 90 and Eighth Street in Valentine, 0.9 mile northwest on US Highway 90 to Chilicote Ranch Road, 1.7 miles west and 0.3 mile south on Chilicote Ranch Road to cattle guard, 4.2 miles west on ranch road, 2.4 miles southwest on ranch road, 0.1 mile southeast on ranch trail, then 50 feet south in range,. USGS 7.5 minute topographic quadrangle: Vieja Pass, Texas; Latitude: 30 degrees, 34 minutes, 18.9 seconds North; Longitude: 104 degrees, 37 minutes, 42.8 seconds West, WGS84; UTM coordinates: 535237 m E, 3382219 m N, NAD 83, Zone 13N
RANGE IN CHARACTERISTICS:
Soil moisture: Soil moisture control section is dry in all parts for less than 270 days per year; Ustic aridic moisture regime.
Soil temperature - 17 to 19 degrees C (62 to 67 degrees F).
Soil depth: 150 to more than 200 cm (60 to more than 80 inches).
Cracks: when dry, cracks 0.5 to 5 cm (0.25 to 2 inches) wide extend 50 to about 90 cm (20 to about 36 inches) depth; cracks remain closed for less than 60 consecutive days per year.
Particle-size control section (weighted average):
Clay content: 35 to 60 percent
COLE value: 0.07 to 0.09
A horizon
Hue: 7.5YR, 10YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 2 through 4, dry or moist
Texture: silty clay loam, clay loam, silty clay, clay
Reaction: neutral to moderately alkaline
Bw horizons
Hue: 7.5YR, 10YR
Value: 3 through 5 dry, 2.5 through 4 moist
Chroma: 2 through 4, dry or moist
Texture: clay, silty clay
Rock fragments: some pedons may contain up to 5 percent by volume igneous gravel
Reaction: neutral to moderately alkaline
Some pedons may contain a few visible accumulations of carbonates, gypsum, or salts in the lower horizons.
COMPETING SERIES: This is the
Wagonbow (AZ) series. Wagonbow soils formed in colluvium on hillslopes and contain at least 5 percent cobbles. Furthermore, they occur in areas with summer-winter bimodal precipitation pattern. Wagonbow soils are intermittently moist in some part of the soil moisture control section during December through February and are dry in
May and June.
GEOGRAPHIC SETTING: Bunton soils are on basin floors and fan skirts in semi-bolsons. Slope gradient ranges from 0 to 3 percent. These soils developed in clayey alluvium derived from igneous rocks. Mean annual precipitation ranges from 305 to 380 mm (12 to 15 inches). Most precipitation occurs as high intensity rain during afternoon convective thunderstorms from June to September. Precipitation during the months of December, January, February, and March is less than 13 percent of the annual total. Mean annual temperature ranges from 16.7 to 19.4 degrees C (62 to 67 degrees F), and frost-free period range from 210 to 250 days. Elevation ranges from 1,070 to 1,525 m (3,500 to 5,000 feet).
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Antbed (TX),
Michigan (TX), and
Verhalen (TX) series. Antbed soils are on more proximal piedmont slope landforms and have an argillic horizon. Michigan soils are on similar fan skirt and basin floor landforms, but formed in alluvium derived from limestone and have mixed mineralogy. They support burrograss rather than tobosa vegetation. Verhalen soils lie in more distal basin floor landforms and have slickensides.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately slow. Runoff is low on slopes less than 1 percent, and medium on 1 to 3 percent slopes. The soil is subject to occasional, very brief overflow.
USE AND VEGETATION: The main use is livestock grazing and wildlife habitat. The soils support a dense grass cover dominated by tobosa with scattered western honey mesquite.
DISTRIBUTION AND EXTENT: LRR D, MLRA 42, Southern Desertic Basins, Plains, and Mountains, Desert Grassland LRU. The series is moderately extensive.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Phoenix, Arizona.
SERIES PROPOSED: Jeff Davis County, Texas; 2018.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 12 cm (0 to 5 inches) (A horizon).
The soil may meet all requirements for a mollic epipedon except that some part of the epipedon is moist for less than 90 days (cumulative) in normal years.
Cambic horizon - the zone from 12 to 152 cm (5 to 60 inches) (Bw horizons).
Ustertic feature - Smectitic mineralogy, trans-horizon cracks wide and deep enough for vertic, and the soil moisture control section is dry in all parts less than 270 days per year.
Areas of Bunton soil were formerly mapped as Phantom and Verhalen.
The soil occurs on water-receiving landforms.
Soil classified according to Keys to Soil Taxonomy, Twelfth Edition, 2014.
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National Cooperative Soil Survey
U.S.A.