LOCATION STRAWHOUSE TX

Established Series
RAC-GSD
10/2012

STRAWHOUSE SERIES

The Strawhouse series consists of soils that are very shallow and shallow to a petrocalcic horizon. They are well drained, and are moderately permeable soils above very slowly permeable petrocalcic horizon. The soils formed in old gravelly alluvium and pedisediment derived from limestone, and occur on pediment remnants. Slope ranges from 1 to 16 percent. Mean annual precipitation is about 280 mm (11 in) and the mean annual air temperature is about 21.1 degrees C (70 degrees F).

TAXONOMIC CLASS: Loamy-skeletal, carbonatic, hyperthermic, shallow Calcic Petrocalcids

TYPICAL PEDON: Strawhouse very gravelly loam - rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 13 cm (0 to 5 in); pale brown (10YR 6/3), very gravelly loam, brown (10YR 5/3), moist; weak medium subangular blocky structure; very friable, slightly hard; few fine roots; 60 percent distinct carbonate coats on rock fragments; 40 percent subrounded limestone gravel; violently effervescent; moderately alkaline; clear smooth boundary. (Thickness is 5 to 17 cm [2 to 7 in])

Bk--13 to 38 cm (5 to 15 in); pink (7.5YR 7/4), very gravelly loam, brown (7.5YR 5/4), moist; weak medium subangular blocky structure; very friable, slightly hard; few fine roots; 100 percent prominent carbonate coats on rock fragments; 5 percent distinct carbonate masses around rock fragments and 2 percent distinct weakly cemented carbonate nodules on bottom of rock fragments; 40 percent subrounded limestone fragments and 1 percent subrounded limestone cobbles; violently effervescent; moderately alkaline; abrupt wavy boundary. (Thickness is 18 to 30 cm [7 to 12 in])

Bkkm--38 to 48 cm (15 to 19 in); white (10YR 8/1), cemented material, very pale brown (10YR 7/3), moist; massive; extremely firm, extremely hard, strongly cemented by carbonates; 50 percent subrounded limestone gravel; violently effervescent; moderately alkaline; clear smooth boundary. (Thickness is 10 to 30 cm [4 to 12 in])

CBk--48 to 203 cm (19 to 80 in); pinkish white (7.5YR 8/2), very gravelly loam, light brown (7.5YR 6/4), moist; massive; firm, slightly hard; 50 percent subrounded limestone gravel; violently effervescent; moderately alkaline.

TYPE LOCATION: Brewster County, Texas; from the junction of U.S. Highways 285 and 90 just east of Marathon; 54.5 miles south on U.S. Highway 290 to intersection with Dagger Flat Road; 2.1 miles east on Dagger Flat Road to intersection with Old Ore Road; 0.15 mile south on Old Ore Road; 100 feet west in rangeland. McKinney Springs, Texas USGS 7.5 minute quadrangle Latitude: 29 degrees, 29 minutes, 12.5 seconds N., and Longitude: 103 degrees, 5 minutes, 51.3 seconds W. NAD83. UTM Coordinates: 684438 meters E, 3263429 meters N; Zone 13

RANGE IN CHARACTERISTICS:

Soil moisture: The moisture control section is dry in all parts more than three fourths of the time the soil temperature exceeds 5 degrees C (41 degrees F). Intermittently moist in some part of the soil moisture control section during June-September. More than 60 percent of the annual rainfall occurs during that period. The soil does not receive significant amounts of moisture during winter months. Ustic aridic soil moisture regime.

Mean annual soil temperature: 22.2 to 25.6 degrees C (72 degrees to 78 degrees F)

Depth to petrocalcic horizon: 10 to 50 cm (4 to 20 in)

Particle-size control section (weighted average):
Texture of the fine-earth fraction: sandy loam, loam
Clay content: 15 to 27 percent
Calcium carbonate equivalent: more than 40 percent
Rock fragments: 35 to 60 percent limestone and petrocalcic fragments, mainly gravel

A and Bk Horizon
Hue: 7.5YR or 10YR
Value: 6 to 8 dry, 4 or 6 moist
Chroma: 2 to 4, dry or moist
Texture of the fine-earth fraction: sandy loam or loam
Clay content: 15 to 27 percent
Rock fragments: 35 to 60 percent limestone and petrocalcic fragments, mainly gravel
Effervescence: violent
Reaction: moderately alkaline

Bkkm Horizon
Hue: 7.5YR or 10YR
Value: 7 or 8 dry, 6 to 8 moist
Chroma: 1 to 5, dry or moist
Cementation: strong in upper part, decreasing with depth; some pedons have an indurated laminar cap 2 to 5 mm thick
Effervescence: violent
Reaction: moderately alkaline

BCk or CBk Horizon
Hue: 7.5YR or 10YR
Value: 6 to 8 dry, 4 to 6 moist
Chroma: 1 to 5, dry or moist
Texture of the fine-earth fraction: stratified coarse sandy loam, sandy loam, or loam
Rock fragments: more than 35 percent
Effervescence: violent
Reaction: moderately alkaline

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Parent material: Pleistocene-age gravelly alluvium and pedisediment derived from limestone.
Landscape: piedmont slope
Landform: erosional remnants of mid-Pleistocene
Slopes: 1 to 16 percent
Mean annual air temperature: 20.0 to 22.2 degrees C (68 to 72 degrees F)
Mean annual precipitation: 250 to 330 mm (10 to 13 in)
Precipitation pattern: Most precipitation falls as intense rain during convectional afternoon thunderstorms from June to September. Precipitation during the months of January, February, and March is less than 13 percent of the total.
Frost-free period: 240 to 280 days
Elevation: 457 to 1,219 m (1,500 to 3,995 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Corazones (TX), Stillwell (TX), Blackgap (TX) and Geefour (TX) soils.
Blackgap soils are very shallow and shallow to limestone bedrock and occur on hillslopes and mountainsides.
Corazones and Stillwell soils occur on similar pediment landforms. They are very deep and do not have petrocalcic horizons. In addition, Corazones soils have mixed mineralogy.
Geefour soils occur on lower, younger hillslopes. They are clayey and shallow to densic claystone.

DRAINAGE AND PERMEABILITY: Well drained; very high runoff; moderate permeability over very slowly permeable petrocalcic horizon.

USE AND VEGETATION: Rangeland used for ephemeral livestock grazing, wildlife habitat, and recreation. Vegetation physiognomy is desert shrubland. Woody plants include creosotebush, lechuguilla, and ocotillo. Grasses include Chino grama, black grama, tridens, and fluffgrass. Other characteristic plants are candelilla and leatherstem.

DISTRIBUTION AND EXTENT: West Texas. MLRA 42. The series is moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Big Bend National Park, Texas; 2010; the name is taken from a trail in the vicinity of the type location.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon: the zone from 0 to 13 cm (0 to 5 in). (A horizons)

Calcic horizon: the zone from 13 to 38 cm (5 to 15 in). (Bk horizon)

Petrocalcic horizon: the zone from 38 to 48 cm (15 to 19 in). (Bkkm horizon)

Strawhouse soils were formerly included in the Upton and Tencee series

Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Eleventh Edition, 2010

Revised for the correlation of Presidio County, Texas ; Oct, 2012, WWJ

National Cooperative Soil Survey
U.S.A.