LOCATION LATOM                   TX+OK

Established Series


The Latom series consists of very shallow to shallow, well drained, moderately permeable soils that formed in loamy residuum weathered from strongly cemented sandstone. These nearly level to very steep soils occur on interfluves and side slopes of hills on dissected plains. Slope ranges from 0 to 50 percent. Mean annual precipitation is about 559 mm (22 in), and mean annual temperature is about 16.7 degrees C (62 degrees F).

TAXONOMIC CLASS: Loamy, mixed, active, calcareous, thermic Aridic Lithic Ustorthents

TYPICAL PEDON: Latom fine sandy loam--in rangeland at an elevation of 723.9 m (2375 ft).
(Colors are for dry soil unless otherwise stated.)

A--0 to 20 cm (0 to 8 in); brown (7.5YR 5/4) fine sandy loam, dark brown (7.5YR 4/4) moist; weak granular stucture; soft, very friable; few fine roots; few fine pores; common strongly cemented fragments of sandstone up to about 3 inches across the long axis; calcareous; moderately alkaline; abrupt smooth lower boundary. Thickness is 10 to 51 cm (4 to 20 in)

R--20 to 51 cm (8 to 20 inches; very pale brown (10YR 8/3) strongly cemented calcareous sandstone; thin discontinuous coatings of calcium carbonate on the upper surface and in crevices.

TYPE LOCATION: Howard County, Texas; in range pasture 200 feet south of State Highway 350; 0.5 mile south and 3.5 miles southwest of Vincent, Texas; 1.2 miles southwest of the northeast corner, sec. 30, block 27, H & TC RR Survey.
USGS topographic quad: Big Spring North NE, Texas;
Latitude, 32 degrees, 26 minutes, 32.87 seconds N;
Longitude, 101 degrees, 16 minutes, 31.05 seconds W.
Datum: WGS84.
UTM Easting 286101 m, UTM Northing 3591761 m, UTM Zone 14.

Depth to lithic contact: typically 10 to 36 cm (4 to 14 in) but ranges up to 51 cm (20 in)

A horizon
Hue: 2.5YR to 10YR
Value: 4 to 6
Chroma: 2 to 6
Texture: loam, sandy loam, fine sandy loam, and their gravelly counterparts; some pedons may have loamy fine sand in the upper part of the horizon
Clay content: 5 to 18 percent
Organic matter: less than 1 percent
Rock fragments: 0 to 35 percent total; 0 to 35 percent sandstone or quartzite gravel; 0 to 5 percent sandstone cobbles or stones

C horizon (where present)
Partially weathered, calcareous, reddish or brownish sandstone and loamy soil materials.

R horizon:
Color: varies from red to very pale brown in hue 2.5YR through 10YR.
Texture: Sandstone or sandy conglomerate
Cementation: strongly to very strongly and has a hardness of 3 to 4, Moh's scale.

COMPETING SERIES: There are no series in the same family. Similar soils are the Quinlan and Spade series.
Quinlan soils: are shallow over noncemented densic sandstone
Spade soils: are more than 51 cm (20 in) deep over paralithic sandstone bedrock and have cambic horizons

Parent material: residuum derived from sandstone or conglomerate of Triassic or Permian age
Landscape: dissected plains
Landform: interfluves and side slopes of hillslopes or ridges
Slope: 0 to 50 percent
Mean annual precipitation: 483 to 686 mm (19 to 27 in)
Thornthwaite P-E Index: 25 to 38
Mean annual air temperature: 15.6 to 17.8 degrees C (60 to 64 degrees F)
Frost-free period: 190 to 240 days
Elevation: 411.5 to 914.4 m (1350 to 3000 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are Cobb, Miles, Quinlan, Spade, and Vernon series.
Cobb and Miles soils: have argillic horizons
Vernon soils: have a fine textured particle-size control section and are moderately deep to noncemented claystone

DRAINAGE AND PERMEABILITY: Well-drained; moderate to high runoff; moderate permeability.

USE AND VEGETATION: Rangeland - sparse cover of grasses such as sideoats grama, blue grama, little bluestem, and buffalograss, with some catclaw and yucca shrubs and mesquite trees.

DISTRIBUTION AND EXTENT: Western Texas and possibly Oklahoma. The soil is extensive.


SERIES ESTABLISHED: Howard County, Texas, 1965.

REMARKS: These soils were originally included in the Travessilla series.

Edited 01/2017 (RFG-ROG): Changed classification from Lithic Ustic Torriorthents to Aridic Lithic Ustorthents. Changed to tabular format. Added metric measurements. Updated competing series, geographic setting, and associated soils sections.

Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 8 inches.
The pedon does not have a diagnostic subsurface horizon.
Lithic contact of sandstone at 8 inches.
Other features: The soil is calcareous throughout.

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

National Cooperative Soil Survey