LOCATION AGUILARES               TX

Established Series
Rev. RRS-RM-JAG
11/2010

AGUILARES SERIES

The Aguilares series consists of very deep, well drained soils. These nearly level to gently sloping soils formed in calcareous, loamy residuum weathered from sandstone predominantly from the Jackson Formation. Slope ranges from 0 to 3 percent. Mean annual temperature is about 23 degrees C (73 degrees F) and mean annual precipitation is about 585 mm (23 in).

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, hyperthermic Aridic Calciustepts

TYPICAL PEDON: Aguilares sandy clay loam, on a south-southeast facing, 2 percent slope in rangeland; elevation is 159 meters (520 feet). (Colors are for dry soil unless otherwise stated.)

A--0 to 20 cm (0 to 8 in); grayish brown (10YR 5/2) sandy clay loam, dark grayish brown (10YR 4/2) moist; weak coarse prismatic structure parting to weak fine subangular blocky and weak fine granular; slightly hard, friable, slightly sticky and slightly plastic; surface has a 1.0 inch thick hard surface crust; many fine roots; common fine and medium pores; few snail shell fragments; 9 percent calcium carbonate equivalent; strongly effervescent; moderately alkaline; clear smooth boundary. (13 to 30 cm [5 to 12 in] thick)

Bk1--20 to 33 cm (8 to 13 in); light brownish gray (10YR 6/2) clay loam, grayish brown (10YR 5/2) moist; weak coarse prismatic structure parting to weak fine and medium subangular blocky; slightly hard, friable, sticky and plastic; common fine and medium roots; few fine and medium pores; 2 percent threads and films of calcium carbonate; 15 percent calcium carbonate equivalent; violently effervescent; moderately alkaline; clear wavy boundary.

Bk2--33 to 58 cm (13 to 23 in); pale brown (10YR 6/3) clay loam, brown (10YR 5/3) moist; weak coarse prismatic structure parting to weak fine subangular blocky; slightly hard, friable, sticky and plastic; few fine roots; few fine pores; 5 percent threads, films and masses of calcium carbonate; 20 percent calcium carbonate equivalent; violently effervescent; moderately alkaline; clear wavy boundary.

Bk3--58 to 91 cm (23 to 36 in); pale brown (10YR 6/3) clay loam, brown (10YR 5/3) moist; weak fine subangular blocky structure; slightly hard, friable, sticky and plastic; few fine roots; few fine pores; 10 percent threads, films, and masses of calcium carbonate; 35 percent calcium carbonate equivalent; violently effervescent; moderately alkaline; clear wavy boundary. (combined thickness of the Bk horizon is 38 to 165 cm [15 to 65 in] thick)

BCknz1--91 to 117 cm (36 to 46 in); very pale brown (10YR 7/3) sandy clay loam, pale brown (10YR 6/3) moist; weak medium and coarse subangular blocky structure; slightly hard, friable; few fine and very fine roots; 10 percent threads, films, and masses of calcium carbonate; 30 percent calcium carbonate equivalent; moderately saline; ESP is 18; violently effervescent; moderately alkaline; gradual wavy boundary.

BCknz2--117 to 150 cm (46 to 59 in); very pale brown (10YR 8/3) sandy clay loam, very pale brown (10YR 7/3) moist; weak medium and coarse subangular blocky structure; slightly hard, friable; 15 percent light gray (5Y 7/2) sandstone pararock fragments; few fine and very fine roots; 5 percent threads, films, and masses of calcium carbonate; 25 percent calcium carbonate equivalent; moderately saline; ESP is 25; violently effervescent; moderately alkaline; clear wavy boundary. (combined thickness of BC horizon is 30 to 71 cm [12 to 28 in] thick)

BCknyz--150 to 203 cm (59 to 80 in); very pale brown (10YR 8/3) sandy clay loam, very pale brown (10YR 7/3) moist; weak medium and coarse subangular blocky structure; slightly hard, friable; 30 percent light gray (5Y 7/2) sandstone pararock fragments; few very fine roots; 3 percent threads, films, and masses of calcium carbonate; 17 percent calcium carbonate equivalent; about 10 percent masses and crystals of gypsum and other salts; moderately saline; ESP is 22; violently effervescent; moderately alkaline.

TYPE LOCATION: Webb County, Texas; from the intersection of Interstate Highway 35 and U. S. Highway 59 in Laredo, 36.6 miles northeast on U. S. Highway 59 to intersection with Welhausen Road, 4.25 miles northeast from intersection on U. S. Highway 59, 50 feet south of fence in rangeland (west of gas pipeline). Biel Lake South, Texas USGS topographic quadrangle; Latitude: 27 degrees, 45 minutes, 4 seconds N; Longitude: 98 degrees, 53 minutes, 53.3 seconds W; NAD 27.

RANGE IN CHARACTERISTICS:

Soil Moisture: An aridic ustic moisture regime. The soil moisture control section is moist in some or all parts for less than 90 consecutive days in normal years. June to August and December to February are the driest months, while September to November and March to May are the wettest months.
Mean annual soil temperature: 22 to 24 degrees C (72 to 76 degrees F).
Depth to calcic horizon: 25 to 89 cm (10 to 35 in)
Depth to salt accumulations: 51 to 102 cm (20 to 40 in)
CEC/clay ratio: 0.60 to 0.90

Solumn thickness: 152 to 203 cm (60 to 80 in)
Particle-size control section (weighted average)
Clay content: 25 to 40 percent total clay content, 18 to 30 percent silicate clay.
Coarse Fragments: 0 to 15 percent within any horizon

A horizon

Hue: 10YR
Value: 4 to 6, when moist value less than 3, horizon is less than 18 cm (7 in) thick.
Chroma: 2 or 3
Texture: fine sandy loam or sandy clay loam
Clay content: 10 to 30 percent
Base saturation: 100 percent
Calcium carbonate equivalent: 0 to 10 percent
EC (dS/m): 0 to 2
Gypsum: 0 to 1 percent
SAR: 0 to 2
Effervescence: slight to strong
Reaction: slightly or moderately alkaline

Bk horizon

Hue: 7.5YR, 10YR, or 2.5Y
Value: 5 to 7
Chroma: 2 to 4
Texture: sandy clay loam or clay loam
Clay content: 20 to 40 percent total clay, 1 to 20 percent carbonate clay.
Pararock fragments: 0 to 5 percent
Base saturation: 100 percent
Calcium carbonate equivalent: 15 to 35 percent
Gypsum: 0 to 1 percent
EC (dS/m): 1 to 4 above 76 cm (30 in), increasing with depth to more than 16 below 76 (30 in).
SAR: 10 to 40
Effervescence: strong or violent
Reaction: moderately alkaline

BC horizon

Hue: 7.5YR or 10YR
Value: 6 to 8
Chroma: 3 or 4
Texture: fine sandy loam, sandy clay loam, or clay loam
Clay content: 10 to 40 percent total clay, 1 to 20 percent carbonate clay
Pararock fragments: 5 to 35 percent
Base saturation: 100 percent
Calcium carbonate equivalent: 15 to 35 percent
Gypsum: 0 to 10 percent
EC (dS/m): 8 to more than 16
SAR: 10 to 40
Effervescence: strong or violent
Reaction: moderately alkaline

COMPETING SERIES: These are the Mcallen (TX) and Moglia (TX) series in the same family. Similar soils are the Brennan (TX), Brundage (TX), Coconino (AZ), Copita (TX), Drake (TX), Hebbronville (TX), and Midessa (TX) series.
McAllen soils: are very slightly saline in control section
Moglia soils: have SAR greater than 13 within 64 cm (25 in) of the soil surface.
Brennan soils: have an argillic horizon
Brundage soils: have a natric horizon
Coconino soils: have a mesic soil temperature regime
Copita soils: are 51 to 102 cm (20 to 40 in) to weathered sandstone bedrock
Drake and Midessa soils: have thermic soil temperature regime
Hebbronville soils: are in the coarse-loamy family and have an argillic horizon

GEOGRAPHIC SETTING:
Parent material: calcareous loamy residuum weathered from sandstone predominantly from the Jackson Formation.
Landform: plane to convex, nearly level to very gently sloping interfluves
Slope: 0 to 3 percent
Mean annual temperature: 21 to 23 degrees C (70 to 74 degrees F)
Mean annual precipitation: 483 to 610 mm (19 to 24 in)
Frost-free period: 280 to 325 days
Elevation: 500 to 900 feet

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brundage (TX), Copita (TX), Hebbronville (TX), Jimenez (TX), Moglia (TX), Montell (TX), and Quemado (TX) series.

Brundage soils: have nitric horizons; are on lower positions
Copita soils: are on similar positions
Hebbronville soils: are on lower positions and sandy surfaces.
Jimenez and Quemado soils: have loamy-skeletal control sections and are on similar to higher positions on gravelly ridges and hilltops.
Montell soils: are clayey and are in lower positions.

DRAINAGE AND PERMEABILITY: Well drained. Moderate permeability. Runoff is negligible on slopes less than 1 percent and low on 1 to 3 percent slopes.

USE AND VEGETATION: Used mainly for rangeland and wildlife habitat. The native vegetation in excellent condition is 90 percent grasses, 5 percent woody plants, and 5 percent forbs. In excellent condition, mid-grasses such as four-flower trichloris, plains bristlegrass, Arizona cottontop, and pink pappusgrass dominate; guajillo, blackbrush, and coma are dominant woody plants; the major forbs are velvet bundleflower, bushsunflower, daleas, and orange zexmenia. As retrogression occurs, woody plants, especially guajillo, blackbrush, mesquite, and cenizo increase in density. Grasses which increase or invade are Texas bristlegrass and Hall's panicum.

DISTRIBUTION AND EXTENT: Western and Central Rio Grande Plain, Texas; LRR I; MLRA 83B and 83C; The series is of large extent.

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

SERIES ESTABLISHED: Webb County, Texas, 1982.

REMARKS: Classification change from Ustic Haplocalcids to Aridic Calciustepts based on geographic distribution of the series, rainfall patterns, and vegetative production and composition. The soil has an ustic soil moisture regime that borders an aridic moisture regime.

Diagnostic horizons and features recognized in this pedon are:

Particle size control section: 25 to 102 cm (10 to 40 in).
Ochric epipedon: 0 to 20 cm (0 to 8 in) (A horizon).
Calcic horizon: 33 to 150 cm (13 to 59 in) (Bk2, Bk3, BCknz horizons).

The assignment of the cation-exchange activity class is supported by laboratory data number S79TX-479-007 from Webb County, Texas.

ADDITIONAL DATA: Texas A&M University SCL data on pedon S79TX-479-007 from Webb County, Texas

TAXONOMIC VERSION: Keys to Soil Taxonomy, Eleventh Edition, 2010.

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National Cooperative Soil Survey
U.S.A.