LOCATION PRYOR TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, hyperthermic Ustertic Haplargids
TYPICAL PEDON: Pryor clay loam--rangeland. (Colors are for dry soil unless otherwise stated.)
A1--0 to 8 inches; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; weak medium platy structure in upper 1 inch, weak fine and medium subangular blocky structure below; very hard, friable; many fine roots; many fine pores and root channels; few chert pebbles in soil mass and on surface; about 12 percent calcium carbonate equivalent; calcareous; moderately alkaline; clear smooth boundary. (5 to 20 inches thick)
Bt--8 to 18 inches; pale brown (10YR 6/3) clay loam, brown (10YR 5/3) moist; moderate fine and medium subangular blocky structure; very hard, firm; common fine roots; few fine pores and root channels; few films and threads of calcium carbonate; about 14 percent calcium carbonate equivalent; calcareous; moderately alkaline; gradual smooth boundary. (7 to 20 inches thick)
Btk1--18 to 30 inches; light yellowish brown (10YR 6/4) clay, yellowish brown (10YR 5/4) moist; moderate fine and medium subangular blocky and angular blocky structure; very hard, firm; few fine pores and root channels; few soft masses of calcium carbonate with few films and threads; about 19 percent calcium carbonate equivalent; calcareous; moderately alkaline; gradual wavy boundary. (0 to 17 inches thick)
Btk2--30 to 42 inches; light yellowish brown (2.5Y 6/4) clay loam, light olive brown (2.5Y 5/4) moist; moderate fine and medium angular blocky structure; very hard, firm; few roots; few fine pores; contains about 5 percent soft masses of calcium carbonate; about 18 percent calcium carbonate equivalent; calcareous; moderately alkaline; clear wavy boundary. (8 to 26 inches thick)
Cd--42 to 72 inches; pale yellow (2.5Y 7/4) claystone, light yellowish brown (2.5Y 6/4) moist; rock structure of moderate, fine, and medium platy parting to moderate, fine, and medium blocky; extremely hard, very firm; few soft masses of calcium carbonate; few gypsum crystals; about 12 percent calcium carbonate equivalent; calcareous; moderately alkaline.
TYPE LOCATION: Maverick County, Texas, 2.3 miles east of courthouse in Eagle Pass on US Highway 277, 14.6 miles northeast on US Highway 57, 5.2 miles southwest on pipeline road to metal gate, 3.5 miles west by southwest on pipeline road, 100 feet south in rangeland.
RANGE IN CHARACTERISTICS: Solum thickness is 40 to 60 inches. The electrical conductivity ranges from 0 to 4 millimhos in the upper 12 inches, from 2 to 8 millimhos in the 12 to 24 inch zone, from 4 to 16 millimhos in the 24 to 48 inch zone, and 8 to 16 millimhos below 48 inches. COLE below the A horizon is 0.06 to 0.11.
The A horizon is grayish brown, brown, or light olive brown in hue of 10YR and 2.5Y, with value of 4 and 5, and chroma of 2 through 4. When color values are less than 5.5, when dry, and 3.5, when moist, it is less than 10 inches thick. It is sandy clay loam, clay loam, or clay. Calcium carbonate equivalent ranges from 2 to 15 percent.
The upper B horizon is light brownish gray, brown, pale brown, yellowish brown, light yellowish brown, light olive brown, very pale brown, or pale yellow in hue of 10YR and 2.5Y, with value of 5 through 7, and chroma of 2 through 6. It is clay loam or clay with clay content ranging from 35 to about 55 percent clay. Calcium carbonate equivalent ranges from 4 to 25 percent.
The lower B horizon is light yellowish brown, very pale brown, brownish yellow, olive yellow, pale yellow, or yellow in hue of 10YR, 2.5Y, and 5Y, with value of 5 through 8, and chroma of 4 through 6. Soft masses and concretions of calcium carbonate comprise from about 1 to about 15 percent by volume. Calcium carbonate equivalent ranges from 10 to 25 percent.
The Cd horizon is non-cemented claystone or interbedded noncemented claystone and sandstone. Cracks that roots can enter are more than 4 inches apart. Excavation difficulty when moist is low to moderate.
COMPETING SERIES: These are Dant, Garceno, Hinman, Mavco, Maverick, and Viboras series. Dant soils have mollic epipedons and lack Bt horizons. Garceno, Maverick, and Viboras soils lack Bt horizons and Garceno and Viboras soils have mixed mineralogy. Hinman soils have mean annual soil temperatures less than 59 degrees F. Mavco soils lack prominent soil cracking and have carbonatic mineralogy.
GEOGRAPHIC SETTING: Pryor soils occur on nearly level to gently sloping uplands. Surfaces mainly are plain to convex. Slope gradients range from 0 to 5 percent but are mainly 1 to 3 percent. The soils formed in calcareous clays and clay loams over shale. The climate is hot and dry subhumid or semiarid. Average annual precipitation is 20 to 24 inches. Mean annual air temperature is 70 to 74 degrees F. Frost free period is 270 to 300 days, and elevation ranges from 150 to 1000 feet. Thornthwaite P-E index is 20 to 31.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Dant, Garceno, Mavco, Maverick, and Viboras series of the competing series and Copita, Tonio, and Verick series. Dant, Garceno, Mavco, and Viboras soils occur on similar surfaces. Maverick soils occur at slightly higher elevations. Copita, Tonio, and Verick soils occur on similar surfaces and have less than 35 percent silicate clay in their control sections.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; slow permeability.
USE AND VEGETATION: Used mostly as rangeland. A few small areas are cultivated to grain sorghum or small grain. The original plant community was an open grassland, dominated by mid grasses, with an occasional mesquite tree or woody shrub which make up about 5 percent of the vegetation. About 5 percent were present originally. With retrogression, woody plants such as blackbrush, guyacan, whitebrush, condalias, and spiny hackberry increase or invade. Herbaceous plants which increase or invade are red grama, threeawn, Hall's panicum and annual weeds.
DISTRIBUTION AND EXTENT: The northwestern and central Rio Grande Plain of Texas and probably Mexico. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Maverick County, Texas, 1972.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 8 inches. (A horizon)
Argillic horizon - 8 to 42 inches. (Bt, Btk1 and Btk2 horizons)
Calcic horizon - 18 to 42 inches. (Btk1 and Btk2 horizons)
Densic Contact - 42 inches. (Cd horizon)