LOCATION AMPHION TXEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, hyperthermic Pachic Paleustolls
TYPICAL PEDON: Amphion clay loam--cropland. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 5 inches; very dark grayish brown (10YR 3/2) clay loam, very dark brown (10YR 2/2) moist; moderate fine and medium subangular blocky structure; hard, friable; many fine roots; neutral; abrupt smooth boundary. (3 to 8 inches thick)
A--5 to 10 inches; very dark gray (10YR 3/1) clay loam, black (10YR 2/1) moist; moderate fine and medium subangular blocky structure; hard, friable; many fine roots; few fine pores; neutral; clear smooth boundary. (4 to 8 inches thick)
BA--10 to 17 inches; very dark gray (10YR 3/1) clay, black (10YR 2/1) moist; moderate fine angular blocky structure; hard, firm; few patchy clay films on surfaces of peds; common fine roots; few fine pores; neutral; clear smooth boundary. (3 to 12 inches thick)
Bt1--17 to 26 inches; dark grayish brown (10YR 4/2) clay, very dark grayish brown (10YR 3/2) moist; weak medium prismatic parting to moderate medium angular blocky structure; very hard, very firm; clay films on surfaces of peds; few roots; few fine pores; mildly alkaline; gradual wavy boundary. (6 to 14 inches thick)
Bt2--26 to 39 inches; brown (10YR 5/3) clay, dark brown (10YR 4/3) moist; moderate medium prismatic parting to moderate fine and medium angular blocky structure; very hard, very firm; clay films on surfaces of peds; few fine roots mainly between peds; few fine pores; few old channels partially filled with darker material; few fine soft masses and concretions of calcium carbonate mostly in lower part; calcareous; moderately alkaline; gradual wavy boundary. (6 to 16 inches thick)
Btk1--39 to 68 inches; very pale brown (10YR 7/3) clay loam, pale brown (10YR 6/3) moist; common coarse reddish yellow (7.5YR 7/6) and yellow (10YR 7/6) mottles; moderate fine and medium subangular blocky structure; very hard, firm; clay films on surfaces of peds; very few roots; 15 percent soft masses and concretions of calcium carbonate; few old channels and cracks filled with darker material; calcareous; moderately alkaline; clear wavy boundary. (10 to 30 inches thick)
Btk2--68 to 80 inches; yellow (10YR 7/6) clay loam, brownish yellow (10YR 6/6) moist; few fine and medium reddish yellow (7.5YR 6/8) mottles; weak fine subangular blocky structure; hard, friable; 3 percent concretions and soft masses of calcium carbonate; calcareous; moderately alkaline.
TYPE LOCATION: Medina County, Texas; 13.8 miles south on Farm Road 462 from its intersection with U.S. Highway 90 in Hondo, Texas; 0.3 mile east on county road; 100 feet north in abandoned cropland.
RANGE IN CHARACTERISTICS: Solum thickness is 60 to 100 inches. Thickness of the mollic epipedon is 20 to 40 inches. Depth to secondary calcium carbonate is 28 to 50 inches.
The A and BA horizons have hue of 10YR, value of 2 to 4, and chroma of 1 to 3. Texture is clay loam, sandy clay loam, or loam. Reaction is neutral to moderately alkaline.
The Bt horizons have hue of 10YR or 2.5Y, value of 3 to 5, and chroma of 1 to 3. They are neutral to moderately alkaline. Texture is clay, clay loam, or sandy clay with a clay content of 35 to 50 percent.
The Btk horizons have hue of 10YR or 2.5Y, value of 4 to 8, and chroma of 2 to 8. In pedons with matrix colors containing chromas of 5 or less mottling is reddish or yellowish and always includes common or many coarse mottles with hue of 2.5YR to 7.5YR with chroma of 5 to 8 extending to depths below 60 inches. Texture is clay, clay loam, sandy clay loam, or loam. Some pedons have few to common crystalline gypsum bodies occurring below 36 inches.
COMPETING SERIES: Hanis is the only other series in the same family. Similar soils are the Abilene, Blanket, Clareville, Cuero, Elmendorf, Racombes, and Rotan series. Hanis soils have hues redder than 10YR. Abilene, Blanket, and Rotan soils have mean annual temperatures less than 72 degrees F. Clareville soils lack coarse mottles with chromas of 5 or more in the lower part of the argillic horizon. Cuero and Racombes soils have fine-loamy control sections. Elmendorf soils have a COLE of more than 0.07 in the upper 1.25 meters.
GEOGRAPHIC SETTING: Amphion soils are on nearly level to gently sloping uplands. Slope gradients are dominantly less than 2 percent but range up to 3 percent. The soil formed in calcareous clay loams and sandy clay loams. The climate is dry subhumid. Mean annual precipitation ranges from 26 to 34 inches and mean annual temperature ranges from 70 to 74 degrees F. Frost free days range from 240 to 290 days and elevation ranges from 500 to 1,500 feet. The annual Thornthwaite P-E indices range from 31 to 40.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Hanis series and the Caid, Duval, Webb and Zavco series. Caid soils are in similar positions and have fine-loamy control sections and are calcareous throughout. Duval and Webb soils occupy higher areas of the landscape. Duval soils have reddish less clayey subsoils, and Webb soils lack mollic epipedons. Zavco soils occur on similar or higher areas in the landscape and have hues redder than 10YR in the Bt horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately slow permeability.
USE AND VEGETATION: Used both as cropland and rangeland. Crops grown are mainly grain sorghum, small grains, corn, forage sorghum, and introduced grasses. Native grasses include trichloris, bristlegrass, feathery bluestem, fall witchgrass, curlymesquite, and threeawn. Woody invaders are mesquite, whitebrush, spiny hackberry, and lotebush condalia.
DISTRIBUTION AND EXTENT: Northern Rio Grande Plain of Texas. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Medina County, Texas; 1972.
REMARKS: These soils formerly were considered as part of the Clareville series.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 26 inches. (Ap, A, BA and Bt1 horizons)
Argillic horizon - 17 to 80 inches. (Bt1, Bt2, Btk1 and Btk2 horizons)
Calcic horizon - 39 to 68 inches. (Btk1 horizon)
Pale feature - clay content does not significantly decrease from the maximum above 60 inches and contains common coarse mottles with chroma of 5 or greater.