LOCATION RAMADERO TXEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, hyperthermic Cumulic Haplustolls
TYPICAL PEDON: Ramadero sandy clay loam--native rangeland.
(Colors are for dry soil unless otherwise stated.)
A1--0 to 6 inches; dark grayish brown (10YR 4/2) sandy clay loam, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure; hard, friable; many fine roots; calcareous; moderately alkaline; clear smooth boundary. (4 to 8 inches thick)
A2--6 to 12 inches; very dark grayish brown (10YR 3/2) sandy clay loam, very dark brown (10YR 2/2) moist; weak coarse prismatic structure parting to weak fine subangular blocky; very hard, friable; many fine roots; few fine pores; calcareous; moderately alkaline; clear smooth boundary. (4 to 8 inches thick)
A3--12 to 24 inches; dark grayish brown (10YR 4/2) sandy clay loam, dark brown (10YR 3/3) moist; weak coarse prismatic structure parting to weak fine subangular blocky; very hard, friable; few fine roots, few fine pores; calcareous; moderately alkaline; gradual smooth boundary. (5 to 14 inches thick)
Bw--24 to 34 inches; brown (10YR 5/3) sandy clay loam, dark brown (10YR 4/3) moist; moderate medium subangular blocky structure; very hard, firm; few fine pores; few films and threads of calcium carbonate in lower part; calcareous; moderately alkaline; gradual smooth boundary. (8 to 16 inches thick)
Bk1--34 to 42 inches; pale brown (10YR 6/3) sandy clay loam, brown (10YR 5/3) moist; weak fine subangular blocky structure; very hard, friable; few fine pores; few films and threads of calcium carbonate; calcareous; moderately alkaline; gradual smooth boundary. (5 to 12 inches thick)
Bk2--42 to 54 inches; pale brown (10YR 6/3) sandy clay loam, brown (10YR 5/3) moist; weak fine blocky; few soft bodies and fine concretions of calcium carbonate; calcareous; moderately alkaline; gradual smooth boundary. (10 to 16 inches thick)
BCk--54 to 80 inches; light yellowish brown (10YR 6/4) sandy clay loam, yellowish brown (10YR 5/4) moist; weak fine subangular blocky structure; hard, friable; few films and threads of calcium carbonate; calcareous; moderately alkaline.
TYPE LOCATION: Starr County, Texas; about 15 miles north and 54 degrees east of Rio Grande City; in a pasture about 5.5 miles east of the intersection of Farm Road 490 and Farm Road 775 along Farm Road 490 to intersection with private road, then 0.3 mile north on private road and 50 feet west.
RANGE IN CHARACTERISTICS: Solum thickness is more than 60 inches. It is neutral through moderately alkaline and calcareous or noncalcareous in the A and B horizons. The mollic epipedon is 20 to 30 inches thick and organic carbon decreases irregularly with depth. Clay content in the 10 to 40 inch control section is 25 to 34 percent.
The A horizon has hue of 10YR, value of 3 or 4, and chromas of 1 to 3. It is sandy clay loam, clay loam, loam, or fine sandy loam.
The B horizons have hue of 10YR, value of 4 to 6, and chroma of 2 to 4. Some pedons have hue of 7.5YR in some part of the B horizon. It is sandy clay loam, clay loam, or loam. Some pedons contain Ab horizons below about 24 inches.
The BC horizon has hue of 7.5YR or 10YR, value of 5 to 7, and chroma of 3 or 4. It is sandy clay loam, clay loam, or loam. Segregated soft bodies and concretions of calcium carbonate range from 1 to 20 percent by volume.
COMPETING SERIES: These include the Degola and Sinton series in the same family and the Bippus, Bosque, Cuero, Laredo, Medley, Primer, and Tordia series. Bippus, Bosque, and Medley soils have mean annual soil temperatures less than 72 degrees F. Cuero soils have Bt horizons. Degola soils are moist in the control section for longer periods of time. Laredo and Primer soils have fine-silty control sections. Sinton soils are moist in the moisture control section for longer periods. Tordia soils have more than 35 percent clay in the their control sections and a COLE of more than 0.07 in the upper 1.25 meters.
GEOGRAPHIC SETTING: Ramadero soils occur in long, narrow and shallow valleys that serve as drainageways for the adjacent smooth upland plains. Surfaces are concave with slope gradients less than 1 percent. These soils receive extra water most years. The soil formed in alkaline loamy alluvium. The climate is semiarid. Mean annual precipitation ranges from 18 to 25 inches and mean annual air temperature ranges from 70 degrees to 74 degrees F., Frost free days range from 250 to 320 days and elevation ranges from 100 to 600 feet. Thornthwaite annual P-E index is 20 to 31.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Brennan, Catarina, Copita, McAllen, and Zapata series which occur in the adjacent uplands. Brennan, Copita, McAllen, and Zapata soils do not have mollic epipedons. In addition, Brennan soils have Bt horizons, Copita soils have a paralithic contact with sandstone at depths of less than 40 inches, and Zapata soils have sola less than 20 inches thick over a petrocalcic horizon. Catarina soils have more than 35 percent clay in their control sections and the soil cracks widely and deeply when dry.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.
USE AND VEGETATION: Used mostly for rangeland. A few areas are cropped in corn, grain sorghum, and vegetables. Rangeland vegetation consists of a dense stand of thorny brush, mesquite trees, with an understory of fourflower trichloris, plains bristlegrass, Arizona cottontop, cenchrus, windmillgrass, whorled dropseed, and threeawn.
DISTRIBUTION AND EXTENT: Northern and Central Rio Grande Plains and Lower Rio Grande Valley of Texas; probably in Mexico. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Uvalde County, Texas; 1970.
ADDITIONAL DATA: Lincoln Laboratory investigations for determination of particle size analysis, water content at 15 bar, carbonate, and organic matter is available on samples No. 72L277, 72L283.
REMARKS: Diagnostic horizons and features recognized in this pedon are: Mollic epipedon - 0 to 24 inches.
Cambic horizon - 24 to 54 inches.