LOCATION UVALDE                  TX

Established Series
Rev. EHT-HCD-JWS-WJG
02/2018

UVALDE SERIES

The Uvalde series consists of very deep, well drained, moderately slowly or moderately permeable soils that formed in calcareous alluvium. These nearly level to gently sloping or gently undulating soils are on stream terraces of piedmont alluvial plains below limestone hills. Slope ranges from 0 to 3 percent. Mean annual precipitation is about 584 mm (23 in) and mean annual air temperature is about 21.7 degrees C (71 degrees F).

TAXONOMIC CLASS: Fine-silty, mixed, active, hyperthermic Aridic Calciustolls

TYPICAL PEDON: Uvalde silty clay loam--pasture. (Colors are for dry soil unless otherwise stated.)

A--0 to 43 cm (0 to 17 in); dark grayish brown (10YR 4/2) silty clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky and granular structure; hard, friable; 20 percent calcium carbonate equivalent; calcareous; moderately alkaline; gradual smooth boundary. Thickness is 25 to 51 cm (10 to 20 in)

Bk1--43 tp 86 cm (17 to 34 in); brown (10YR 5/3) silty clay loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; hard, firm; few fine roots; few fine pores; few films and threads of segregated calcium carbonate; 30 percent calcium carbonate equivalent; calcareous; moderately alkaline; gradual wavy boundary. Thickness is 20 to 66 cm (8 to 26 in)

Bk2--86 to 127 cm (34 to 50 in); very pale brown (10YR 7/4) silty clay loam, light yellowish brown (10YR 6/4) moist; moderate very fine subangular blocky structure; hard, friable; 15 to 20 percent by volume of strongly cemented concretions of calcium carbonate; 40 percent calcium carbonate equivalent; calcareous; moderately alkaline; diffuse wavy boundary. Thickness is 15 to 76 cm (6 to 30 in)

Bk3--127 to 213 cm (50 to 84 in); very pale brown (10YR 7/4) silty clay loam, light yellowish brown (10YR 6/4) moist; weak very fine subangular blocky structure; hard, friable; few fine weakly cemented concretions and soft lumps of calcium carbonate; 50 percent calcium carbonate equivalent; calcareous; moderately alkaline.

TYPE LOCATION: Zavala County, Texas; Approximately 7.3 miles south of the Uvalde-Zavalla County line on U.S. Highway 83; From the intersection of U.S. Highway 83 and U.S. Highway 57 in La Pryor, Texas; 3.1 miles north on U.S. Highway 83; 50 feet east of highway in cropland.
USGS topographic quadrangle: LaPryor, Texas;
Latitude: 28 degrees 59 minutes 10.9 seconds N;
Longitude: 99 degrees 50 minutes 54.45 seconds W;
Datum: WGS84

RANGE IN CHARACTERISTICS:
Soil Moisture: An Aridic-Ustic soil moisture regime. The soil moisture control section is moist in some or all parts for fewer than 90 consecutive days in normal years.
Depth to calcic horizon: 25 to 51 cm (in)
Thickness of the mollic epipedon: 25 to 51 cm (10 to 20 in)
Limestone and chert gravel underlie some pedons below 60 inches.

Particle-size control section (weighted average)
Total clay content: 35 to 50 percent
Silicate clay content: 22 to 35 percent
Sand content coarser than very fine sand: 5 to 15 percent
Rock fragments: 0 to 7 percent
Calcium carbonate equivalent: 20 to 40 percent

A Horizon
Hue: 10YR or 7.5YR
Value: 4 or 5
Chroma: 2 or 3
Texture: clay loam, loam, silt loam, or silty clay loam
Total clay content: 25 to 40 percent
Carbonate clay content: 1 to 10 percent
Sand content: 10 to 35 percent
Calcium carbonate equivalent: 5 to 25 percent
Reaction (pH): slightly alkaline to moderately alkaline (7.4 to 8.4)

Upper Bk Horizon
Hue: 10YR or 7.5YR
Value: 4 through 7
Chroma: 2 through 4
Texture: clay loam, silty clay loam, silty clay, or clay
Total clay content: 35 to 50 percent
Carbonate clay content: 5 to 20 percent
Sand content: 10 to 35 percent
Identifiable secondary carbonate: 1 to 15 percent, masses and/or concretions
Calcium carbonate equivalent: 20 to 40 percent
Reaction (pH): slightly alkaline to moderately alkaline (7.4 to 8.4)

Lower Bk Horizon
Hue: 10YR or 7.5YR
Value: 4 through 7
Chroma: 2 through 4
Texture: clay loam, silty clay loam, silty clay, or clay
Total clay content: 28 to 50 percent
Carbonate clay content: 5 to 20 percent
Sand content: 10 to 35 percent
Identifiable secondary carbonate: 1 to 30 percent, masses and/or concretions
Calcium carbonate equivalent: 30 to 75 percent
Reaction (pH): slightly alkaline to moderately alkaline (7.4 to 8.4)

COMPETING SERIES: These are Elindio series of the same family. Similar soils are the Acuna, Angelo, Castroville, and Nuvalde series.
Acuna and Elindio soils: are dry in the moisture control section for longer periods. In addition, Acuna soils have carbonatic mineralogy.
Angelo and Nuvalde soils: have mean annual soil temperatures less than 22 degrees C. (72 degrees F.)
Castroville soils: are moist in the moisture control section for longer periods.

GEOGRAPHIC SETTING:
Parent material: calcareous alluvium
Landscape: inland, dissected coastal plains
Landform: stream terraces on piedmont alluvial plains below limestone hills
Slope: 0 to 3 percent, but is mainly less than 1 percent
Mean annual precipitation: 508 to 660 mm (20 to 26 in)
Thornthwaite P-E Index: 26 to 34
Mean annual air temperature: 21.1 to 22.8 degrees C (70 to 73 degrees F)
Frost-free period: 255 to 280 days
Elevation: 122.0 to 518.2 m (400 to 1700 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These include Atco, Bookout, Caid, Chacon, Knippa, Montell, Pryor, Sabenyo, and Valco series.
Atco, Bookout, Pryor, and Sabenyo soils: do not have mollic epipedons
Caid soils: have argillic horizons
Valco soils: have petrocalcic horizons
Chacon and Knippa soils: have vertic properties with COLE values greater than 0.07
Montell soils: have vertic properties with COLE values greater than 0.07 and have intersecting slickensides.
All of these soils occur on surfaces similar to Uvalde soils.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately slow or moderate. Runoff is low on 0 to 1 percent slopes and medium on 1 to 3 percent slopes.

USE AND VEGETATION: Used mostly for rangeland and for irrigated vegetables, cotton, corn, and grain sorghum. Some areas are used for nonirrigated grain sorghum and small grain. The potential native plant community include grasses such as plains lovegrass, trichloris, Arizona cottontop, pinhole bluestem and plains bristlegrass and they are the dominant vegetation. Perennial forbs make up about 5 percent of the community and shrubs make up about 3 percent. With retrogression, plants such as threeawn, curlymesquite, hooded windmillgrass, Hall's panicum, fall witchgrass, and red grama increase or invade and are dominant in most areas. A wide array of brush plants such as mesquite, guajillo, condalia, paloverde, guayacan, twisted acacia, white brush and pricklypear also increase or invade.

DISTRIBUTION AND EXTENT: Southern Texas; Land Resource Region: I, Southwest Plateaus and Pains Range and Cotton Region; MLRA: 83A, Northern Riogrande Plain; the series is of large extent.

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

SERIES ESTABLISHED: Uvalde County, Texas; 1911.

REMARKS:

Edited 11/2016 (RFG-GWH): Converted to tabular format and added metric units. Updated competing series, geographic setting, and associated soils sections.

Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 25 to 100 cm (Bk horizon)
Mollic epipedon: 0 to 43 cm (0 to 17 in). (A horizon)
Calcic horizon: 43 to 213 cm (17 to 84 in). (Bk horizons)

ADDITIONAL DATA: National Soil Survey Lab: S1963TX507002 (40A1647-1653), S1963TX507001 (40A34549-34557) and S84TX463001 (84P2429-2434)

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

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National Cooperative Soil Survey
U.S.A.