Established Series


The Palopinto series consists of well drained, moderately permeable, shallow and very shallow soils over limestone bedrock that formed in residuum from Pennsylvanian limestone bedrock. These soils occur on ridges of hills.. Slope ranges from 1 to 20 percent. Mean annual precipitation is about 787 mm (31 in), and mean annual air temperature is about 17.8 degrees C (64 degrees F).

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Lithic Haplustolls

TYPICAL PEDON: Palopinto stony clay loam, on a 2 percent slope, in rangeland.
(Colors are for dry soil unless otherwise stated.)

A1--0 to 10 cm (0 to 4 in); dark grayish brown (10YR 4/2) very stony clay loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky and moderate fine granular structure; hard, friable; many fine roots; many fine pores; few wormcasts; about 30 percent fragments of limestone from 6 to 30 inches across, and 5 percent less than 3 inches across; moderately alkaline; clear smooth boundary. Thickness is 5 to 30 cm (2 to 12 in)

A2--10 to 30 cm (4 to 12 in); dark grayish brown (10YR 4/2) extremely stony clay loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky and moderate fine granular structure; hard, friable; common fine roots; common fine pores; few wormcasts; about 70 percent of fragments of limestone that are from 6 to 30 inches across; moderately alkaline; abrupt wavy boundary. Thickness is 10 to 41 cm (4 to 16 in)

R--30 to 102 cm (12 to 40 in); indurated limestone; coarsely fractured; contains less than 5 percent fine-earth in fractures and crevices.

TYPE LOCATION: Palo Pinto County, Texas; from the intersection of U.S. Highway 180 and U. S. Highway 281 in Mineral Wells, Texas; 8 miles north on U. S. Highway 281; 3.6 miles west and north on Texas Highway 254 and 1600 feet east of highway in rangeland.
USGS topographic quadrangle: Graford East, Texas;
Latitude: 32 degrees, 55 minutes, 38.5 seconds N;
Longitude: 98 degrees, 7 minutes, 41.0 seconds W;
Datum: WGS84

Depth to Lithic bedrock: 15 to 51 cm (6 to 20 in)
Mollic epipedon: 15 to 51 cm (6 to 20 in)
Effervescence: noncalcareous to weakly

A Horizon
Hue: 5YR to 10YR
Value: 3 to 4
Chroma: 2 to 3
Texture: clay loam, silty clay loam, loam, silt loam
Clay content: 18 to 35 percent
Rock fragments: averages 35 to 85 percent in the solum; the A1 horizon ranges from 15 to 60 percent and the A2 horizon ranges from 50 to 90 percent; size ranges from 12 to 915 mm (0.5 to 36 in), dominantly 150 to 510 mm (6 to 20 in), across the long axis; nonflat subangular to flat limestone
Effervescence: none to slight
Reaction (pH): neutral to moderately alkaline (6.6-8.4)

R Layer
Kind: coarsely fractured, indurated limestone mainly of the Strawn and Canyon groups of Pennsylvanian age

COMPETING SERIES: These include the Kiti, and Timhill series in the same family. Similar soils include the Aledo, Eckert, Eckrant, Rayford, and Tarrant series.
Kiti soils: are moist in the soil moisture control section for longer periods.
Timhill soils: have sola 10 to 20 inches thick over rhyolite.
Aledo soils: have carbonatic mineralogy.
Eckert soils: are formed in residuum derived from limestone of Ordovician and Cambrian age.
Eckrant and Tarrant soils: contain more than 35 percent clay in the particle-size control section.
Rayford soils: have an active clay activity class

Parent material: stony loamy residuum weathered from hard crystalline limestone mainly of the Strawn and Canyon groups of Pennsylvanian age
Landscape: Hills
Landform: Summits, shoulders, and backslopes of ridges
Slope: 1 to 20 percent, but are dominantly about 2 percent
Mean annual precipitation: 660 to 864 mm (26 to 34 in)
Thornthwaite P-E Index: 40 to 50
Mean annual air temperature: 16.7 to 18.3 degrees C (62 to 65 degrees F)
Frost-free period: 210 to 230 days
Elevation: 243.8 to 548.6 m (800 to 1800 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hensley, Leeray, Lindy, Owens, and Set series.
Hensley soils: have red argillic horizons and occur on stream divides usually above Palopinto soils.
Leeray soils: are clayey throughout and occur below on stream divides or in valleys.
Lindy soils: have sola 20 to 40 inches thick and are below on stream divides.
Owens soils: are shallow clayey soils and occur on higher hillsides.
Set soils: have sola more than 40 inches thick and occur below on knolls or intermingled with Palopinto soils.

DRAINAGE AND PERMEABILITY: Well drained. Permeability of the soil is moderate above a slowly permeable bedrock. Runoff is high on 1 to 5 percent, and very high on slopes greater than 5 percent.

USE AND VEGETATION: Used for rangeland. Native vegetation includes sideoats grama, little bluestem, and annual grasses. There are scattered liveoak, juniper, tasajillo, and pricklypear. Whitebrush and sumac are usually present. Forbs include bushsunflower, western ragweed, and gayfeather.

DISTRIBUTION AND EXTENT: North-central Texas; LRR H - Central Great Plains Winter Wheat and Range Region, MLRA 80B - Texas north-central prairies; The series is of large extent.


SERIES ESTABLISHED: Palo Pinto County, Texas; 1979.

REMARKS: This soil has formerly been included in the Tarrant series.

Edited 01/2017 (RFG-SCP): 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:
Mollic epipedon - 0 to 30 cm (0 to 12 in) (A1 and A2 horizons).
Lithic contact - 30 cm (12 in) (top of R layer).

ADDITIONAL DATA: NSSL sample 384TX-429-1.

Taxonomic Version: Keys to Soil Taxonomy, 12th Edition, 2014

National Cooperative Soil Survey