LOCATION TOPIA                   TX

Established Series
Rev. ALN-JWS-CLG
10/2016

TOPIA SERIES

The Topia series consists of well drained, very slowly permeable soils that are moderately deep over limestone bedrock. The soils formed in clayey pedisediment over residuum from limestone bedrock. The soils occur on nearly level to gently undulating ridges on dissected plateaus. Slope ranges from 0 to 5 percent. Mean annual precipitation is about 686 mm (27 in), and mean annual air temperature is about 19 degrees C (66 degrees F).

TAXONOMIC CLASS: Very-fine, mixed, superactive, thermic Vertic Argiustolls

TYPICAL PEDON: Topia clay--rangeland.
(Colors are for dry soil unless otherwise stated.)

A--0 to 18 cm (0 to 7 in); very dark gray (10YR 3/1) clay, black (10YR 2/1) moist; moderate fine and medium subangular blocky and granular structure; very hard, firm; very sticky and plastic; many fine roots; few fine pores and old root channels; neutral; clear smooth boundary. Thickness is 10 to 25 cm (4 to 10 in)

Bt1--18 to 30 cm (7 to 12 in); dark reddish brown (5YR 3/2) clay; dark reddish brown (5YR 2/2) moist; moderate fine and very fine angular blocky structure; extremely hard, very firm, very sticky and plastic; many fine roots; clay films on peds; dark organic staining on few peds; few cracks partially filled with A material; few pockets of redder clay; neutral; gradual wavy boundary. Thickness is 13 to 43 cm (5 to 17 in)

Bt2--30 to 56 cm (12 to 22 in); dark reddish brown (5YR 3/3) clay, dark reddish brown (5YR 3/3) moist; moderate medium and fine angular blocky structure; extremely hard, very firm, very sticky and plastic; common fine roots; clay films on peds; distinct shiny pressure faces; dark organic stains on few peds; few vertical streaks one-inch wide of darker clay; few pockets of red clay; few fine limestone fragments; neutral; gradual wavy boundary. Thickness is 8 to 33 (3 to 13 in)

Bt3--56 to 69 cm (22 to 27 in); reddish brown (5YR 4/3) clay, dark reddish brown (5YR 3/3) moist; weak fine and medium angular blocky structure very hard, very firm, sticky and plastic; few fine roots; patchy clay films on peds; few distinct pressure faces; dark organic stains on few peds; few vertical streaks of darker clay; estimated 2 percent by volume of 1 to 2 mm weakly cemented limestone fragments; few larger fragments; strongly effervescent; moderately alkaline; clear wavy boundary. Thickness is 0 to 23 cm (0 to 9 in)

Bt4--69 to 76 (27 to 30 in); reddish brown (5YR 4/4) very gravelly clay, dark reddish brown (5YR 3/4) moist; weak fine and medium subangular blocky structure; very hard, firm; few fine roots; estimated 50 percent by volume of weakly cemented limestone pebbles; many of the fragments are coated with clay; violently effervescent; moderately alkaline; abrupt wavy boundary. Thickness is 0 to 20 cm (0 to 8 in)

2Cr--76 to 122 cm (30 to 48 in); very pale brown (10YR 7/4) and yellow (10YR 7/6) weakly cemented consolidated limestone bedrock; streaks and splotches of reddish yellow (7.5YR 6/6) and (5YR 6/6); upper one-half inch is slightly harder than that below.

TYPE LOCATION: Uvalde County, Texas; 1.4 miles west of Utopia on Farm to Market Road 1050, 0.75 mile south and west on county road, 400 feet south in rangeland, 285 feet southwest of old house and 80 feet west of post oak tree.
USGS topographic quadrangle: Utpoia, Texas;
Latitude: 29 degrees, 35 minutes, 53.30 seconds N;
Longitude: 99 degrees, 33 minutes, 10.40 seconds W;
Datum: WGS84

RANGE IN CHARACTERISTICS:
Soil moisture: Typic ustic moisture regime
Depth to limestone bedrock: 53 to 102 cm (21 to 40 in)
Mollic epipedon thickness: 25 to 102 cm (10 to 40 in)
Cracks: Cracks up to 5 cm (2 in) wide at the soil surface extend to 51 cm (20 in) or more when the soil is dry and are 6 mm (1/4 in) to 13 mm (1/2 in) wide at 51 cm (20 in).

Particle size control section (weighted average)
Clay content: 60 to 75 percent
Coarse fragments: 0 to 15 percent by volume

A horizon
Hue: 10YR to 5YR
Value: 3 or 4
Chroma: 1 or 2
Texture: clay loam or clay
Fragments: 0 to 15 percent by volume; limestone and chert
Reaction (pH): slightly acid to slightly alkaline (6.1 - 7.8)

Bt1 horizon
Hue: 5YR or 7.5YR
Value: 3 or 4
Chroma: 2 or 3
Texture: clay
Clay content: 60 to 75 percent
Fragments: 0 to 15 percent chert and limestone
Reaction (pH): slightly acid to slightly alkaline (6.1 - 7.8)

Bt2 horizon
Hue: 2.5YR, 5YR or 7.5YR
Value: 3 or 4
Chroma: 3 or 4
Texture: clay loam or clay
Reaction (pH): slightly acid to slightly alkaline (6.1 - 7.8)
Bt3 and Bt4 horizons
Hue: 2.5 YR or 5YR
Value: 4 or 5
Chroma: 3 or 4
Texture: clay, gravelly clay or very gravelly clay
Coarse fragments: 2 to 60 percent by volume mostly limestone gravel, but may include some chert gravel
Secondary carbonates: range from very thin coatings on coarse fragments to 10 percent by volume in the lower part of the Bt horizon
Reaction (pH): slightly alkaline or moderately alkaline (7.4 - 8.4)

2Cr horizon
Interbedded chalk, marl, weakly consolidated limestone and strongly cemented or indurated limestone

COMPETING SERIES: There are no other soils in this family. Similar series include the Anhalt, Bexar, Crawford, Lindy, Rumple, and Speck series.
Anhalt soils: have slickensides
Bexar and Lindy soils: do not have a mollic epipedon
Crawford soils: have slickensides, hard bedrock strata, and do not have an argillic horizon
Rumple soils: have more than 35 percent coarse fragments in the particle-size control section
Speck soils: are less than 51 cm (20 in) deep over limestone

GEOGRAPHIC SETTING:
Parent material: clayey pedisediment formed over residuum of limestone bedrock
Landscape: dissected plateaus
Landform: ridges
Slopes: 0 to 5 percent
Precipitation pattern: The majority of the yearly rainfall amount occurs during the fall and spring months with the winter and summer months typically being drier.
Mean annual precipitation: 610 mm to 813 mm (24 to 32 in)
Thornthwaite annual P-E index: 32 to 48
Mean annual air temperature: 17.2 to 21.1 decrees C(63 to 70 degrees F)
Frost free period: 235 to 255 days
Elevation: 274.3 to 678.2 m (900 to 2225 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Bexar, Crawford, Rumple, and Speck series, as well as the Brackett, Denton, Eckrant, Kavett, Pratley, San Saba, and Tarrant series.
Brackett, Denton, Eckrant, Kavett, San Saba, and Tarrant soils do not have an argillic horizon. In addition, Brackett, Eckrant, Kavett, and Tarrant soils are less than 51 cm (20 in) deep to bedrock.
Pratley soils: are calcareous throughout and have less than 60 percent clay in the particle-size control section.
San Saba soils: have intersecting slickensides.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is very slow. Runoff is high on 0 to 1 percent slopes and very high on 1 to 5 percent slopes.

USE AND VEGETATION: Mainly rangeland, but a few areas are used for growing small grains and grain sorghums. Present vegetation includes live oak, cedar, post oak, Texas persimmon, curlymesquite, Texas wintergrass, fall witchgrass, sideoats grama, little bluestem, and Indiangrass.

DISTRIBUTION AND EXTENT: Edwards Plateau and Grand Prairie of Texas. Topia soils are of moderate extent with about 13,000 acres.

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

SERIES ESTABLISHED: Uvalde County, Texas; 1970.

REMARKS: Topia soils were formerly included in the Crawford series.

Edited 10/2016 (RFG-JRJ): Changed to tabular format. Added metric measurements. Updated competing series, geographic setting, and associated soils sections.

Diagnostic horizons and feature recognized in this pedon are:
Mollic epipedon - 0 to 69 cm (0 to 27 in)
Argillic horizon - 18 to 76 cm (7 to 30 in)
Paralithic Contact at 76 cm (30 in).

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

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National Cooperative Soil Survey
U.S.A.