LOCATION REHM TXEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, active, hyperthermic Aridic Calciustolls
TYPICAL PEDON: Rehm gravelly clay loam--rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 11 inches; dark grayish brown (10YR 4/2) gravelly clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; hard, friable; many fine roots, fine pores, and old root channels; contains an estimated 20 percent by volume of rounded pebbles of chert mainly 1/2 to 2 inch diameter; calcareous; moderately alkaline; clear smooth boundary. (10 to 16 inches thick)
Bw1--11 to 20 inches; brown (10YR 5/3) extremely gravelly clay loam, dark brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; hard; friable; many fine roots, fine pores, and old root channels; contains an estimated 75 percent by volume of pebbles of chert mainly 1 to 3 inch diameter; calcareous; moderately alkaline; gradual wavy boundary. (8 to 20 inches thick)
Bw2--20 to 28 inches; pale brown (10YR 6/3) extremely gravelly clay loam, brown (10YR 5/3) moist; moderate fine and medium subangular blocky structure; hard, friable; few roots; contains an estimated 75 percent by volume of rounded pebbles of chert; few pebbles are coated with calcium carbonate; few calcium carbonate concretions in lower part; calcareous; moderately alkaline; gradual wavy boundary. (0 to 10 inches thick)
Bk1--28 to 34 inches; pale brown (10YR 6/3) extremely gravelly clay loam, brown (10YR 5/3) moist; moderate fine subangular blocky structure; hard, friable; contains an estimated 75 percent by volume of pebbles of chert that are partly coated with calcium carbonate; contains an estimated 10 percent by volume of strongly cemented calcium carbonate concretions; calcareous; moderately alkaline; clear wavy boundary. (0 to 18 inches thick)
Bk2--34 to 44 inches; very pale brown (10YR 7/4) very gravelly clay loam, light yellowish brown (10YR 6/4) moist; weak fine subangular blocky structure; hard, friable; contains an estimated 25 percent by volume of soft lumps and strongly cemented concretions of calcium carbonate; contains an estimated 50 percent by volume of pebbles of chert that are coated with calcium carbonate; calcareous; moderately alkaline; abrupt smooth boundary. (8 to 30 inches thick)
Crk--44 to 96 inches; light yellowish brown (2.5Y 6/4) soft shale bedrock that slakes in water, light olive brown (2.5Y 5/4) moist; massive; many streaks and splotches of olive yellow and yellowish brown; many pockets of soft whitish calcium carbonate that diminish with depth; calcareous; moderately alkaline.
TYPE LOCATION: Medina County, Texas; 5.3 miles south of D'Hanis on Farm Road 2200, then 220 feet south of fenceline in rangeland (about 400 feet northwest of windmill).
RANGE IN CHARACTERISTICS: Thickness of the solum and depth to soft bedrock ranges from 40 to 60 inches. Depth to the calcic horizon ranges from 22 to 40 inches. Coarse fragments, mainly of rounded chert, comprise 35 to 80 percent by volume of the 10- to 40-inch control section. The soil is calcareous and moderately alkaline throughout.
The A horizon has hue of 10YR or 2.5Y, value of 3 through 5, and chroma of 2 or 3. It is loam or clay loam or their gravelly counterparts.
The B horizons have hue of 10YR or 2.5Y, value of 4 through 6, and chroma of 2 through 4. The fine earth fraction of the 10- to 40-inch control section is loam or clay loam and the clay content ranges from 25 to 35 percent. Calcium carbonate content in the Bk horizon ranges from 20 to 40 percent visible lumps and concretions.
The Crk horizon ranges from clayey shale to weakly consolidated sandstone with seams and pockets of limy material.
COMPETING SERIES: There are no other series in this family. Soils in similar families are the Caid, Elindio, Hathaway, Jimenez, Olmos, Quihi, Somervell, Tascosa, and Uvalde series. Caid, Elindio, and Uvalde soils contain less than 35 percent coarse fragments. Hathaway, Somervell, and Tascosa soils have mean annual soil temperatures less than 72 degrees F. Jimenez, Olmos, and Quihi soils have a petrocalcic horizon. In addition, Jimenez and Olmos soils have sola less than 20 inches thick. Quihi soils have sola 20 to 40 inches thick and are more clayey.
GEOGRAPHIC SETTING: Rehm soils are on undulating to rolling uplands. Slopes are dominantly less than 4 percent but range from 0 to 8 percent. The soil formed in calcareous gravelly loamy alluvium of the Uvalde Gravel Formation of Pliocene or early Pleistocene time, mainly in areas where the Uvalde Gravel overlies the Escondido Formation of the Gulf series. The climate is dry subhumid or semiarid. Mean annual precipitation is 21 to 26 inches and the mean annual air temperature ranges from 70 to 73 degrees F. Frost free days range from 235 to 260 days and elevation ranges from 600 to 1200 feet. Thornthwaite P-E indices range from 26 to 36.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Caid, Olmos, and Uvalde series, and the Yologo series. Yologo soils have an argillic horizon over a petrocalcic horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: Used for rangeland. Present native grasses consist mostly of red grama, threeawn, bristlegrass, Hall's panicum, fall witchgrass, sideoats grama, and curlymesquite grass. Woody vegetation is mostly mesquite, blackbrush, whitebrush, guayacan, guajillo, Texas persimmon, and twisted acacia.
DISTRIBUTION AND EXTENT: Mainly in the northern Rio Grande Plains. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Uvalde County, Texas; 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the A horizon from 0 to 11 inches.
Cambic horizon - the Bw horizons from 11 to 28 inches.
Calcic horizon - The Bk horizons from 28 to 44 inches.
Paralithic contact at 44 inches.