LOCATION ECTOR                   TX+NM

Established Series
Rev. ERB-JLR-WJG
01/2016

ECTOR SERIES

The Ector series consists of very shallow to shallow, well drained soils that are moderately permeable above a moderately slowly permeable limestone bedrock. They formed in calcareous loamy residuum derived from limestone. These gently sloping to very steep soils occur on ridges on dissected plateaus. Slope ranges from 1 to 60 percent. Mean annual precipitation is about 381 mm (15 in), and mean annual air temperature is about 18 degrees C (64 degrees F).

TAXONOMIC CLASS: Loamy-skeletal, carbonatic, thermic Lithic Calciustolls

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

A--0 to 10 cm (0 to 4 in); dark grayish brown (10YR 4/2) very gravelly loam; very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; slightly hard, friable, nonsticky and nonplastic; common fine roots; 25 percent limestone gravel, 5 percent limestone cobbles; violently effervescent; moderately alkaline; clear wavy boundary. Thickness is 5 to 38 cm (2 to 15 in)

Bk--10 to 20 cm (4 to 8 in); dark grayish brown (10YR 4/2) very gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium granular and subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; 40 percent limestone gravel 15 percent limestone cobbles; the fragments of limestone are coated with secondary carbonates on the lower side; violently effervescent; moderately alkaline; abrupt irregular boundary. Thickness is 5 to 38 cm (2 to 15 in)

Rk/Bk--20 to 38 cm (8 to 15 in); fractured hard limestone with fractures less than 4 inches apart; coatings of calcium carbonate on surface of fragments; cracks and fractures are filled and partially sealed with calcium carbonate in the upper 4 inches; in some cracks a thin seam of dark earth 3 mm thick is present; moderately alkaline; gradual wavy boundary. Thickness is 0 to 30 cm (0 to 12 in)

R--38 to 102 cm (15 to 40 in); fractured limestone bedrock; few seams of calcium carbonate in fractures in the upper part.

TYPE LOCATION: Terrell County, Texas; from the intersection of U.S. Highway 90 and Texas Highway 349 in Dryden, TX; 14 miles north on Texas Highway 349, located 100 feet west in rangeland.
USGS topographic quadrangle: Dryden NE, Texas;
Latitude: 30 degrees, 13 minutes, 26.95 seconds N;
Longitude: 102 degrees, 2 minutes, 5.78 seconds W;
Datum: WGS 84.

RANGE IN CHARACTERISTICS:
Soil Moisture: Ustic Aridic soil moisture regime.
Mean annual soil temperature: 18 to 22 degrees C (64 to 72 degrees F)
Depth to lithic contact: 15 to 50 cm (6 to 20 in)
Depth to calcic horizon: 5 to 43 cm (4 to 17 in)
Thickness of the mollic epipedon: 10 to 38 cm (4 to 15 in)
Thickness of the calcic horizon: 15 to 38 cm (6 to 15 in)
Surface fragments: 25 to 80 percent total; 15 to 60 percent gravel, 10 to 30 percent cobbles, 0 to 20 percent stones; limestone

Particle-size control section (weighted average)
Total clay content: 20 to 40 percent
Silicate clay content: 18 to 35 percent
Rock fragments: 35 to 80 percent

A Horizon
Hue: 7.5YR or 10YR
Value: 3 to 5, 2 or 3 moist
Chroma: 2 or 3 dry or moist
Texture: very gravelly, extremely gravelly, very cobbly, or extremely cobbly phases of loam, clay loam, silty clay loam, or silt loam
Total clay content: 20 to 40 percent
Carbonate clay content: 1 to 4 percent
Sand content: 12 to 40 percent
Rock fragments: 35 to 80 percent total; 30 to 75 percent gravels, 5 to 35 percent cobbles, and 0 to 20 percent stones; limestone
Calcium carbonate equivalent (< 20 mm fraction): 40 to 70 percent
Electrical conductivity (mmhos/cm): 0 to 2
Effervescence: violent
Reaction (pH): slightly alkaline to moderately alkaline (7.4 to 8.4)

Bk Horizon
Hue: 7.5YR or 10YR
Value: 3 to 5, 2 or 3 moist
Chroma: 2 or 3 dry or moist
Texture: very gravelly, extremely gravelly, very cobbly, or extremely cobbly phases of loam, clay loam, silty clay loam, or silt loam
Total clay content: 20 to 40 percent
Carbonate clay content: 3 to 12 percent
Sand content: 12 to 40 percent
Rock fragments: 35 to 80 percent total; 30 to 75 percent gravels, 5 to 35 percent cobbles, and 0 to 20 percent stones; limestone
Calcium carbonate equivalent (< 20 mm fraction): 40 to 80 percent
Electrical conductivity (mmhos/cm): 0 to 2
Effervescence: violent
Reaction (pH): slightly alkaline to moderately alkaline (7.4 to 8.4)

R Horizon
Cementation: strongly cemented to indurated, fractured
Fractures: may be filled with Bk material in upper part
Secondary calcium carbonate: surface fractures may have coats in upper part

COMPETING SERIES: These are the Aledo (TX), Altuda (TX), Lueders (TX), and Oplin (TX) series. Similar soils are the Eckrant, Langtry, and Tarrant series.
Aledo, Lueders, and Oplin soils: are moist in the moisture control section for longer periods of time
Altuda soils: have mean annual soil temperatures from 15 to 18 degrees C (59 to 64 degrees F)
Eckrant and Tarrant soils: contain more than 35 percent clay in the fine earth fraction
Langtry soils: have a mean annual soil temperature great than 22 degrees C (72 degrees F)

GEOGRAPHIC SETTING:
Parent material: calcareous loamy residuum derived from limestone mostly of Cretaceous age, but some are of Permian or Pennsylvanian age
Landscape: dissected plateaus
Landform: ridges
Slope: 1 to 60 percent
Mean annual precipitation: 305 to 660 mm (12 to 26 in)
Precipitation Pattern: falls mostly during the months of May through October.
Thornthwaite P-E Index: 18 to 35
Mean annual air temperature: 16.1 to 21.1 degrees C (61 to 70 degrees F)
Frost-free period: 210 to 270 days
Elevation: 350.5 to 1676.4 m (1150 to 5500 feet)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dev, Reagan, Sanderson, and Upton series.
Dev soils: very deep gravelly loamy soils and occur on floodplains on dissected plateaus
Reagan soils: very deep loamy soils and occur on toeslopes or stream terraces on dissected plateaus
Sanderson soils: very deep loamy soils and occur on footslopes on dissected plateaus
Upton soils: shallow to a petrocalcic horizon and occur on similar positions

DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate above a moderately slowly permeable limestone bedrock. Runoff is low on 1 to 5 percent slopes, medium on 5 to 20 percent slopes, and high on slopes greater than 20 percent.

USE AND VEGETATION: Used entirely for livestock and wildlife grazing. Native vegetation is short and mid grasses with some low desert shrubs. Grasses are mainly grama, triden, or threeawn. Shrubs are juniper, lotebush, dalea, guajillo, and blackbrush. Ecological site: Limestone Hills (R081AY566TX).

DISTRIBUTION AND EXTENT: Texas and New Mexico; Land Resource Region I; MLRA 81A; the series is extensive, comprising several million acres

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Reeves County, Texas; 1922.

REMARKS:
Edited 01/2016 (RFG-THW): Changed to tabular format. Added metric measurements. Updated competing series, geographic setting, and associated soils sections.

Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 0 to 38 cm (0 to 15 in)
Mollic epipedon: 0 to 38 cm (0 to 15 in) (A and Bk horizons)
Calcic horizon: 10 to 38 cm (4 to 15 in) (Bk and Bk portion of Rk/Bk layer)
Lithic contact: 38 cm (15 in) (top of the R horizon)

ADDITIONAL DATA:
The data is supported by three KSSL pedons: 91TX043001 and 92TX043013 from Brewster County, Texas and 92TX137001 from Edwards County, Texas

Taxonomic Version: Keys to Soil Taxonomy, Twelfth Edition, 2014

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National Cooperative Soil Survey
U.S.A.