LOCATION SPIRES                  TX

Established Series
Rev. WCC-MLG-WJG-RM
08/2018

SPIRES SERIES

The Spires series consists of moderately deep, well drained, slowly permeable soils that formed in residuum over limestone. These soils are on nearly level to sloping interfluves and side slopes of dissected plateaus. Slope range from 1 to 8 percent. Mean annual precipitation is about 838 mm (33 in) and mean annual air temperature is about 18.3 degrees C (65 degrees F).

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

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

A--0 to 15 cm (0 to 6 in); reddish brown (5YR 4/4) loam, dark reddish brown (5YR 3/4) moist; weak fine granular structure; very hard, friable; many very fine and fine roots, 5 percent fragments of chert 15 to 100 mm (1/2 to 4 in) in diameter; neutral; clear smooth boundary. (Thickness is 10 to 18 cm [4 to 7 in])

Bt--15 to 71 cm (6 to 28 in); dark red (10R 3/6) clay, dark red (10R 3/6) moist; moderate fine and medium subangular blocky structure; very hard, very firm; few very fine and fine roots, many distinct clay films on vertical surfaces of peds; few distinct clay films on horizontal surfaces of peds; 10 percent fragments of chert and an occasional cobble of chert; few earthworm burrows; slightly alkaline; abrupt wavy boundary. (Thickness is 41 to 84 cm [16 to 33 in])

R--71 to 76 cm (28 to 30 in); indurated fractured crystalline limestone, partially weathered in upper one inch.

TYPE LOCATION: Bandera County, Texas; in native rangeland, approximately 60 feet west to pasture road; 0.6 mile south and 0.25 mile east to Ranch Road 187, which point is 10.6 miles south to Vanderpool, Texas.

USGS topographic quadrangle: Sabinal Canyon, Texas;
Latitude: 29 degrees, 51 mintues, 44.83 seconds N;
Longitude: 99 degrees, 33 minutes, 46.11 seconds W;
Datum: WGS84.
UTM Easting 445643.27 m,
UTM Northing 3303677.03 m,
UTM Zone 14.

RANGE IN CHARACTERISTICS:
Soil Moisture: Typic Ustic soil moisture regime
Depth to lithic contact: 51 to 102 cm (20 to 40 in)
Depth to argillic horizon: 10 to 18 cm (4 to 7 in)

Particle size control section (weighted average)
Clay content: 42 to 57 percent
Rock fragments: 2 to 20 percent

A Horizon
Hue: 5YR or 7.5 YR
Value: 3 to 5
Chroma: 1 to 4
Texture: loam or clay loam or their gravelly or cobbly counterparts
Clay content: 15 to 37
Rock fragments: 2 to 25 percent
Electrical conductivity (decisiemens per meter): 0 to 2
Reaction (pH): slighty acid to slightly alkaline (6.1 to 7.8)

Bt Horizon
Hue: 10R or 2.5YR
Value: 2 to 4
Chroma: 4 or 6
Texture: clay
Clay content: 42 to 57 percent
Rock fragments: 2 to 15 percent
Electrical conductivity (decisiemens per meter): 0 to 2
Reaction (pH): slightly acid to slightly alkaline (6.1 to 7.8)

R Horizon
Kind: limestone
Cementation: indurated

COMPETING SERIES: There are no other series in the same family. Similar series include Bexar, Hensley, Lindy, Pontotoc, and Scullin series.
Bexar soils: have a mollic epipedon and colors do not meet rhodic
Hensley soils: are less than 51 cm (20 in) deep over limestone.
Lindy soils: do not have an abrupt textural change between the A and the Bt horizons
Pontotoc soils: have less than 18 percent clay in the upper 51 cm (20 in) of the Bt horizon and are formed over sandstone
Scullin: soils have a mollic epipedon.

GEOGRAPHIC SETTING:
Parent material: residuum weathered from limestone
Landscape: dissected plateaus
Landform: summit, shoulder, and backslopes of interfluves and sideslopes
Slope: 1 to 8 percent
Mean annual precipitation: 610 to 889 mm (24 to 35 in)
Thornthwaite P-E Index: 36 to 44
Mean annual air temperature: 17.2 o 20.6 degrees C (63 to 69 degrees F)
Frost-free period: 210 to 250
Elevation: 487.7 to 731.5 m (1600 to 2400 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Comfort, Eckrant, Tarpley, and Tarrant series.
Comfort soils: occurs on similar landscape positions and are skeletal and shallow to limestone bedrock
Eckrant soils: occur on steeper sloping ridges, are shallow to limestone bedrock, and have no argillic horizon
Tarpley soils: occur on similar landscape positions and are shallow to limestone bedrock
Tarrant soils: occur on steeper sloping ridges and are skeletal calcic soils shallow to limestone bedrock

DRAINAGE AND PERMEABILITY:
Drainage class: Well.
Permeability class: very slow.
Runoff: high on slopes less than 1 percent and very high from 1 to 8 percent slopes.

USE AND VEGETATION: Principal use is for rangeland. This is a post oak, live oak savannah. Principal grasses are bluestems, Indiangrass, dropseed, and Texas wintergrass.

DISTRIBUTION AND EXTENT: Southwest Texas in the Edwards Plateau Land Resource Area (MLRAs 81B and 81C). The series is of moderate extent, exceeding an estimated 50,000 acres.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Bandera County, Texas; 1971.

REMARKS: These soils were formerly mapped in the Bexar series.

Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 15 cm (0 to 6 in) (A horizon)
Argillic horizon: 15 to 71 cm (6 to 28 in) (Bt horizon)
Lithic contact: 71 cm (28 in) (R)

ADDITIONAL DATA: None

TAXONOMIC VERSION: Keys to Soil Taxonomy, Twelfth Edition, 2014

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National Cooperative Soil Survey
U.S.A.