LOCATION ESCOBAS TXEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, hyperthermic Aridic Argiustolls
TYPICAL PEDON: Escobas fine sandy loam--rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 28 cm (0 to 11 in); grayish brown (10YR 5/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist: weak fine subangular blocky structure; soft, very friable; about 5 percent medium and 2 percent fine roots; about 3 percent fine tubular pores; neutral; clear smooth boundary. (25 to 33 cm [10 to 13 in] thick)
Bt--28 to 66 cm (11 to 26 in); brown (10YR 5/3) fine sandy loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable; about 2 percent medium and 2 percent fine roots; about 3 percent fine tubular pores; few distinct clay films on faces of peds; neutral; clear smooth boundary. (31 to 53 cm [12 to 21 in] thick)
Btk--66 to 127 cm (26 to 50 in); pale brown (10YR 6/3) fine sandy loam, brown (10YR 5/3) moist; weak coarse prismatic structure parting to weak medium subangular blocky; moderately hard, friable; 1 percent fine roots; about 1 percent very fine tubular pores, few distinct clay film on faces of peds; 2 percent fine threads and masses of calcium carbonate on ped faces; slightly alkaline; very slightly effervescent; clear smooth boundary. (12 to 24 inches thick)
Bk--127 to 203 cm (50 to 80 in); very pale brown (10YR 7/3) fine sandy loam, pale brown (10YR 6/3) moist; weak coarse prismatic structure parting to weak fine subangular blocky; slightly hard, friable; 1 percent very fine roots; about 8 percent threads and masses of calcium carbonate; strongly alkaline; strongly effervescent.
TYPE LOCATION: Zapata County, TX., from the intersection of U. S. Highway 83 and Texas Highway 16 in Zapata; about 8.2 miles east on Texas Highway 16 to unpaved county road; 7.1 miles north on unpaved county road to Goodwin ranch gate entrance; 0.94 mile northwest along east fence, 150 feet west in rangeland. Mogotes Hill USGS Quadsheet; Latitude: 27 degrees, 4.0 minutes, 47.817 seconds N; Longitude: 99 degrees, 9.0 minutes, 4.434 seconds W; NAD 83.
RANGE IN CHARACTERISTICS:
Solum thickness is more than 203 cm (80 in).
Soil Moisture: An ustic soil moisture regime bordering on aridic. The soil moisture control section, 20 to 61 cm (8 to 24 in), is moist in some or all parts for less than 90 consecutive days in normal years.
Mean annual soil temperature: 22 to 23 degrees C (72 to 74 degrees F).
Depth to argillic horizon: 25 to 33 cm (10 to 13 in).
Depth to secondary calcium carbonate: 61 to 127 cm (24 to 50 in).
Particle-size control section (weighted average).
Clay content: 14 to 18 percent.
A Horizon
Hue: 10YR
Value: 3 to 5
Chroma: 1 to 3
Texture: fine sandy loam or loamy fine sand
Clay content: 8 to 20 percent
Effervescence: non-effervescent
Reaction: Neutral
Bt Horizon
Hue: 10YR
Value: 4 or 5
Chroma: 2 or 3
Texture: fine sandy loam or sandy clay loam
Clay content: 14 to 20 percent
Clay films: few to common, on faces of peds and lining pores, faint or distinct
Effervescence: non-effervescent
Reaction: neutral or slightly alkaline
Btk Horizon
Hue: 10YR
Value: 4 to 6
Chroma: 3 or 4
Texture: fine sandy loam or loam
Clay content: 11 to 18 percent
Base saturation: 100 percent
Clay films: common on faces of peds, faint or distinct
Identifiable secondary carbonate: 1 to 19 percent, fine to medium in the form of threads or masses on faces of peds.
Effervescence: very slightly or slightly effervescent
Reaction: slightly or moderately alkaline
Bk Horizon
Hue: 10YR
Value: 5 to 7
Chroma: 3 or 4
Texture: fine sandy loam
Clay content: 10 to 18 percent
Base saturation: 100 percent
Calcium carbonate equivalent: 3 to 14 percent
Identifiable secondary carbonate: 1 to 19 percent, fine and medium threads and masses, located on faces of peds
Effervescence: strongly or violently effervescent
Reaction: moderately or strongly alkaline
COMPETING SERIES: There are the no series in the same family. Similar soils are the
Brennan (TX),
Comitas (TX),
Hebbronville (TX),
Julesburg (CO)
Nueces (TX),
Salco (T-TX),
Tela (TX), and
Vitrina (NM) series.
Brennan, Salco, and Tela soils: have fine-loamy particle size control sections.
Comitas and Nueces soils: surface textures coarser than loamy very fine sand that extend to depths of more than 51 cm (20 in).
Hebbronville soils: have an ochric epipedon.
Julesburg and Vitrina soils: have a mesic soil temperature regime.
GEOGRAPHIC SETTING:
Parent material: eolian sands over calcareous loamy sediments.
Landform: vegetated sand sheet.
Slope: 0 to 5 percent.
Mean annual air temperature range: 22 to 23 degrees C (72 to 74 degrees F).
Mean annual precipitation range: 508 to 584 mm (20 to 23 in)
Precipitation Pattern: The majority of the yearly rainfall occurs during the spring and fall month. The summer months are normally dry with infrequent showers. December and January are usually the driest months.
Frost-free period: 290 to 320 days.
Elevation: 107 to 145 m (350 to 475 ft).
Thornthwaite annual P-E indices: 20 to 28.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Brennan,
Comitas,
Hebbronville,
Nueces, and
Sarita series.
All these soils have an ochric epipedon.
Brennan soils: fine-loamy particle size control section and are on similar to slightly higher positions.
Comitas, Nueces, and Sarita soils: surface texture coarser than loamy fine sand that extend to depth of more than 51 cm (20 in) and are on similar or slightly higher positions.
Hebbronville soils: do not have a mollic surface and are on similar to slightly higher positions.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately rapid. Runoff is negligible on slopes less than 1 percent and very low on 1 to 5 percent slopes.
USE AND VEGETATION: Used mainly as rangeland and wildlife habitat. The native vegetation consists of four-flower trichloris, Arizona cottontop, Plains bristlegrass, hooded windmillgrass, pink pappusgrass and woody shrubs such as mesquite, pricklypear, Texas ebony, tasajillo, and spiny hackberry. The ecological site is Sandy Loam, 25-35 PZ (R083EY702TX).
DISTRIBUTION AND EXTENT: Sandsheet Prairie, Texas, LRR I; MLRA 83E; the series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas.
SERIES ESTABLISHED: Zapata County, Texas, in 2009. This series was proposed in Zapata County, Texas, 2000. The name is comes from a small community in eastern Zapata County, Texas.
REMARKS: These soils were formerly included in the Hebbronville series. The Hebbronville series has an ochric epipedon.
Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 28 to 79 cm (11 to 31 in) (Bt horizons).
Mollic epipedon: 0 to 28 cm (0 to 11 in) (A horizon).
Argillic horizon: 28 to 127 cm (11 to 50 in) (Bt horizons).
ADDITIONAL DATA: Particle-size analysis, calcium carbonate equivalent, sieve analysis and pH tests were performed at the project office on 3 pedons. The assignment of the cation-exchange activity class is inferred from lab data from geographically associated soils.
Taxonomic version: Keys to Soil Taxonomy, Ten Edition, 2006.