LOCATION ECKRANT TXEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, thermic Lithic Haplustolls
TYPICAL PEDON: Eckrant very gravelly clay--rangeland. (Colors are for dry soil unless otherwise stated.)
A1--0 to 4 inches; very dark gray (10YR 3/1) very gravelly clay, black (10YR 2/1) moist; moderate fine subangular blocky and fine granular structure; very hard, firm; common fine roots; common fine pores; estimated 15 percent by volume fragments of limestone larger than 3 inches and 20 percent smaller than 3 inches; moderately alkaline; clear irregular boundary. (4 to 15 inches thick)
A2--4 to 12 inches; very dark gray (10YR 3/1) very cobbly clay, black (10YR 2/1) moist; moderate fine subangular blocky and fine granular structure; very hard, firm; common fine roots; common fine pores; estimated 35 percent fragments of limestone larger than 3 inches and 20 percent smaller than 3 inches; fragments are mainly horizontally oriented with soil fines between; moderately alkaline; abrupt wavy boundary. (0 to 11 inches thick)
R--12 to 30 inches; coarsely fractured indurated limestone bedrock.
TYPE LOCATION: Uvalde County, Texas; 7.5 miles northwest of Sabinal on Texas Highway 127; 5.0 miles north on county road to cattleguard; 0.1 mile north across small creek to gate on right; 0.5 mile east on small ranch road; 150 feet south in rangeland.
RANGE IN CHARACTERISTICS: Solum thickness and depth to limestone ranges from 4 to 20 inches. Coarse fragments in the form of subrounded to angular pebbles, cobbles, and stones of limestone comprise 35 to 80 percent by volume of the pedon and increase with depth. Cobbles and stones comprise from 15 to 60 percent of the pedon. The soil is moderately alkaline through neutral.
The A horizon has color in hue of 7.5YR or 10YR, value of 2 to 4, and chroma of 1 to 3. The browner colors are usually confined to the lower part of the A horizon. The fine-earth fraction is clay, silty clay, or clay loam with 35 to 60 percent clay. Cobbles or stones dominate the fraction larger than 2 mm. Secondary calcium carbonate coats some of the limestone along fractures.
The upper 1/2 to 1 inch of the bedrock is often less hard than that below. In some pedons, the underlying limestone is interbedded with softer limy materials.
COMPETING SERIES: There are no soils in the same family. Similar soils include Aledo, Austin, Binnsville, Bolar, Eckert, Ector, Maloterre, Purves, Real, Stephen, Talpa, and Tarrant series. Aledo, Eckert, Ector, and Real soils contain less than 35 percent clay in the fine-earth fraction. In addition, Ector soils are dry in the moisture control section for longer periods and Real soils have a paralithic contact of softer limestone. Austin and Bolar soils have sola thicker than 20 inches. Binnsville, Maloterre, Purves, Stephen, and Talpa soils contain less than 35 percent coarse fragments. Tarrant soils have calcic horizons and calcareous sola.
GEOGRAPHIC SETTING: Eckrant soils are on convex to plane slopes in undulating to very steep uplands. Slopes are mainly 1 to 8 percent but range from 0 to 60 percent. The soil formed in residuum weathered mainly from limestone of Lower Cretaceous age, and includes interbedded chalks, marls, and marly earths. The mean annual precipitation ranges from 22 to 32 inches. Thornthwaite annual P-E indices are about 31 to 54, and mean annual temperature is about 66 to 69 degrees F. Frost free days range from 210 to 240 days. Elevation ranges from 1000 to 2400 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the similar Real and Tarrant series and Brackett, Comfort, Pratley, Somervell, and Tarpley series. Comfort, Real, Somervell, and Tarrant soils occur on similar surfaces. Brackett soils occur as side slopes of hills, have ochric epipedons and lack a lithic contact. Pratley and Tarpley soils occur at slightly higher elevations on smooth plateaus and low ridges, and in addition, Tarpley soils have Bt horizons. Somervell and Pratley soils have sola more than 20 inches thick and they have calcic horizons.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is negligible on 0 to 1 percent slopes, very low on 1 to 3 percent slopes, low on 3 to 5 percent slopes, medium on 5 to 20 percent slopes and high on 20 to 60 percent slopes. Permeability is moderately slow.
USE AND VEGETATION: Used for rangeland and wildlife. Present vegetation includes live oak, cedar, Texas persimmon, flameleaf sumac, mountain laurel, guajilo, algerita, pricklypear, red grama, threeawn, curlymesquite, fall witchgrass, Texas wintergrass, sideoats grama, plains lovegrass, Texas cupgrass, and forbs.
DISTRIBUTION AND EXTENT: Edwards Plateau and Grand Prairie of Texas. The series is of large extent with over 1 million acres.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Uvalde County, Texas; 1970.
REMARKS: These soils have been mapped in the Tarrant series. Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 12 inches
Lithic contact - at 12 inches; interface of soil and limestone