LOCATION CATTO TXEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, active, nonacid, thermic Lithic Ustic Torriorthents
TYPICAL PEDON: Catto very gravelly loam - rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 7 inches; brown (7.5YR 4/2) very gravelly loam, dark brown (7.5YR 3/2) moist; moderate medium granular and subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; 50 percent angular chert gravel; slightly alkaline; abrupt irregular boundary (4 to 20 inches thick).
R--7 to 60 inches; fractured chert bedrock with angular fragments; small amount of A horizon in seams in upper 4 inches.
TYPE LOCATION: Brewster County, Texas; in Marathon from the junction of U. S. Highway 90 and U. S. Highway 385; 15.1 miles south on U. S. Highway 385; 0.5 miles east to ranch headquarters; 1.3 miles east on ranch road to corrals; 0.8 miles east along south side of mountain on ranch road; 530 feet north of road in range. (Latitude: 29 degrees, 59 minutes, 47 seconds North; Longitude: 103 degrees, 13 minutes, 59 seconds West.)
RANGE IN CHARACTERISTICS:
Soil moisture - Intermittently moist in the soil moisture control section during July-September. The soil is moist for less than 90 cumulative days during the growing season in the control section. Ustic aridic soil moisture regime.
Depth to chert bedrock: 4 to 20 inches
A horizon
Hue: 5YR, 7.5YR, 10YR
Value: 2 to 4, dry or moist
Chroma: 2 or 3, dry or moist
Texture: loam, clay loam
Clay content: 20 to 35 percent
Angular chert coarse fragment content: 35 to 65 percent and is 0 to 15 percent stones; 5 to 50 percent cobbles; and 25 to 60 percent gravel
Reaction: slightly alkaline or moderately alkaline
In some pedons, the chert bedrock is stratified with shale. Hardness is between 5 and 7 on Moh's scale.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Catto soils are on chert hills and ridges along the tilted uplift of the Oauchita Formation in the Trans-Pecos of Texas. Slopes are dominantly 12 to 30 percent but range from 5 to 45 percent. Rock outcrops are common along ridges. Mean annual precipitation ranges from 10 to 15 inches, with most occurring in the summer months. Mean annual air temperature ranges from 61 to 68 degrees F. Frost free period ranges from 210 to 240 days and elevation ranges from 3,500 to 4,700 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bullis, Buckear, Coyanosa, Sanderson, Stovall, and Upton series. Bullis soils have sola greater than 60 inches, and have clayey particle size control sections. Bullis soils are on footslope positions lower in the landscape. Buckear soils are on similar positions in the landscape. Coyanosa soils are on adjacent sandstone mountains and hills. Sanderson soils are very deep and have greater than 35 percent coarse fragments in the control section. Sanderson soils are in valleys and on foot slopes. Stovall soils are very deep soils, and do not contain coarse fragments. Stovall soils are in adjacent valleys and broad flats. Upton soils are shallow over a petrocalcic horizon and are on adjacent hills and ridges.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate over moderately slowly permeable bedrock. Runoff is medium on 5 to 20 percent slopes, and high on slopes greater than 20 percent.
USE AND VEGETATION: Used for livestock grazing. Typical vegetation now growing on most rangelands is grama, threeawns, tanglehead, silver bluestem, skeletonleaf goldeneye, ephedra, catclaw, and sotol.
DISTRIBUTION AND EXTENT: The Trans-Pecos of Texas. This soil occurs in LRR-D, MLRA 42. The series is of minor extent.
MLRA OFFICE RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Brewster County, Texas, 1996
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 0 to 7 inches (A horizon)
Lithic contact: The boundary at 7 inches
Ustic feature - Soil has an aridic moisture regime that borders on an ustic regime
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.
Updates and revisions for recorrelation Brewster County, TX, Main Part, 2/8/08, CEM.
Active cation exchange activity class is assigned to seperate this soil from the Reduff series. this is based on a difference in production capacity. 2/8/08, CEM.