LOCATION CIRCLEBACK TXEstablished Series
TAXONOMIC CLASS: Siliceous, thermic Lamellic Ustipsamments
TYPICAL PEDON: Circleback fine sand--rangeland.
(Colors are for dry soil unless otherwise stated.)
A--0 to 6 inches; brown (7.5YR 5/4) fine sand, dark brown (7.5 4/4) moist; massive; soft, very friable; common fine roots; neutral; clear smooth boundary. (3 to 8 inches thick)
E--6 to 30 inches; reddish yellow (7.5YR 6/6) fine sand, strong brown (7.5YR 5/6) moist; massive; slightly hard and soft, very friable; common roots; neutral; clear wavy boundary. (6 to 35 inches thick)
E and Bt1--30 to 46 inches; reddish yellow (7.5YR 6/6) fine sand, strong brown (7.5YR 5/6) moist; massive; slightly hard, very friable; few fine roots; several 1 to 5 mm thick bands of reddish yellow (5YR 6/8) loamy fine sand; yellowish red (5YR 5/8) moist, bands from 2 to 20 mm apart; mildly alkaline; clear wavy boundary.
E and Bt2--46 to 80 inches; light brown (7.5YR 6/4) fine sand, brown (7.5YR 5/4) moist; massive; slightly hard, very friable; few woody shin oak roots; many wavy horizontal bands of reddish yellow (5YR 6/8) loamy fine sand, yellowish red (5YR 5/8) moist, that are 1 to 10 mm thick and 5 to 20 mm apart; mildly alkaline.
TYPE LOCATION: Cochran County, Texas; from the intersection of Texas Highway 125 and Farm Road 592 in Bledsoe, east 1 block, 0.4 mile south on county road; 0.3 mile west and south along turn row through fields; 0.9 mile south on private ranch trail; then 20 feet west. This site is about 1.6 miles south of Bledsoe, Texas.
RANGE IN CHARACTERISTICS: Depth of solum is 80 inches or more. Combined thickness of the A and E horizon is 10 to 40 inches. Mixed texture of all horizons is sand or fine sand with a clay content of about l to about 8 percent. Reaction is slightly acid to moderately alkaline and noncalcareous throughout.
The A horizon has hue of 7.5YR or l0YR, value 4 to 6, and chroma of 2 or 3.
The E horizon has hue of 7.5YR or 10YR, value of 5 through 7, and chroma of 3 through 6.
The E and Bt horizons alternate. The Bt lamellae layers have hue dominantly of 5YR, value of 5 or 6, and chroma of 4 through 6. At least one E and Bt horizon occurs in the solum which contains at least 2 lamellae that are l mm or more in thickness. The total thickness of lamellae more than l cm thick to a depth of 60 inches is less than l5 cm. The lamellae are too thin or too few to be an argillic horizon. Lamella are from l to 30 mm thick and loamy fine sand or fine sandy loam in texture. Some pedons also have an E' and Bt' horizon. Some pedons have buried fine sandy loam or sandy clay loam Btb horizons below 80 inches.
COMPETING SERIES: These are the Derby series of the same family and the similar Aline, Arenosa, Eufaula, Goltry, Likes, McCaffery, Nutivoli, Penwell, Pratt, and Tivoli series. Derby soils are mosit for longer periods. Aline, Eufaula, and Goltry have lamellae that total more than 15 cm thick. Arenosa soils have more than 95 percent quartz in the sand fraction. Likes soils are calcareous and lack lamellae. McCaffery soils are in the frigid temperature zone. Nutivoli, Penwell, and Tivoli soils do not contain lamellae and, in addition, Penwell soils are dry for longer periods. Pratt soils have argillic horizons.
GEOGRAPHIC SETTING: Circleback soils are on nearly level to steep areas with undulating to duned ridges on uplands in the Southern High Plains and western Rolling Plains. Slopes are 0 to about 35 percent. The soil formed in sandy eolian sediments, usually many feet thick, of the Pleistocene and Holocene epochs. Mean annual precipitation ranges from l4 to 22 inches. Mean annual temperature ranges from 57 to 65 degrees F. Thornthwaite annual P-E indices range from 22 to 34.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the similar Nutivoli soil and the Amarillo, Brownfield, Patricia and Springer series. Amarillo, Brownfield, Patricia, and Springer soils have argillic horizons.
DRAINAGE AND PERMEABILITY: Circleback soils are excessively drained. Runoff is very slow and permeability is rapid. Most of the rainfall water soaks in rapidly and little runs off the surface.
USE AND VEGETATION: Used mainly for grazing beef cattle. Native climax vegetation is dominantly little bluestem, sand bluestem, sand lovegrass, sand dropseed, and sideoats grama. Sand sagebrush and shin oak are woody increasers. Yucca, snakeweed, annuals, and a few small mesquite invade the site when the range condition deteriorates under continued heavy grazing.
DISTRIBUTION AND EXTENT: Southern High Plains and western Rolling Plains of west Texas and New Mexico. The series is extensive.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Bailey County, Texas; l984.
REMARKS: These soils were formerly included with the Tivoli series.
ADDITIONAL DATA: Laboratory data available is NSSL Sample Nos. 76028l-760290. Additional analysis of these samples indicated that the mineralogy is siliceous instead of mixed.