LOCATION MEDLIN TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Chromic Udic Haplusterts
TYPICAL PEDON: At center of microknoll--rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 6 inches; grayish brown (10YR 5/2) silty clay, dark grayish brown (10YR 4/2) moist; moderate fine subangular blocky and granular structure; extremely hard, very firm, sticky and plastic; many fine roots; few fine pebbles of quartz; common fine concretions of calcium carbonate; strong effervescence; moderately alkaline; gradual wavy boundary. (4 to 20 inches thick)
Bssk1--6 to 30 inches; grayish brown (10YR 5/2) silty clay, dark grayish brown (10YR 4/2) moist; moderate fine and medium blocky structure; extremely hard, very firm, sticky and plastic; few fine roots; few fine pebbles of quartz; common concretions of calcium carbonate; few fine slickensides below 26 inches; strong effervescence; moderately alkaline; gradual wavy boundary. (8 to 28 inches thick)
Bssk2--30 to 49 inches; grayish brown (2.5Y 5/2) silty clay, common fine distinct yellowish brown (10YR 5/6) mottles, dark grayish brown (2.5Y 4/2) moist; moderate coarse blocky structure; extremely hard, very firm, sticky and plastic; few fine roots; common coarse slickensides; common vertical streaks of brown clay; about 10 percent soft masses and concretions of calcium carbonate; violent effervescence; moderately alkaline; gradual wavy boundary. (0 to 30 inches thick)
C--49 to 70 inches; grayish brown (2.5YR 5/2) marly silty clay, common fine distinct yellowish brown (10YR 5/6) and gray (10YR 6/1) mottles, dark grayish brown (2.5Y 4/2) moist; massive; extremely hard, very firm, slightly sticky and plastic; about 20 percent soft masses and concretions of calcium carbonate; few fine black concretions; violent effervescence; moderately alkaline.
TYPE LOCATION: Denton County, Texas; from intersection of I-35E and I-35W in Denton, Texas; 3.5 miles south on I-35W, and 400 feet west of highway right-of-way into rangeland.
RANGE IN CHARACTERISTICS: This is a cyclic soil with solum 40 to more than 60 inches thick. The weighted average clay content of the particle size control section ranges from 40 to 60 percent. Cracks 1 to 3 inches wide extend from the surface to a depth of more than 20 inches when the soil is dry. In undisturbed areas there is gilgai microrelief with microknolls 4 to 12 inches higher than microdepressions. Cycles of knolls and depressions are repeated each 6 to 23 feet. Intersecting slickensides begin at depths of 15 to 24 inches. The soil is moderately alkaline and calcareous clay or silty clay throughout with clay content of 40 to 60 percent. Limestone fragments about 10 to 24 inches across the long axis cover 0 to 10 percent of the soil surface.
Thickness of the A horizon is variable within the pedon and ranges from about 3 to 8 inches thick on knolls and 8 to 20 inches thick in depressions. Colors are in hue of 10YR, 2.5Y, and 5Y; value of 4 or 5; and chroma of 2 through 4. Where moist color values are less than 4, the horizon is less than 12 inches thick or comprises less than 50 percent of the pedon.
The Bssk horizon has hue of 10YR, 2.5Y, and 5Y; value of 5 through 7; and chroma of 2 through 4. Some pedons contain grayish, brownish, or yellowish mottles. Concretions and soft masses of calcium carbonate range from 2 to 20 percent by volume. The calcium carbonate equivalent ranges from 30 to 45 percent in the lower part. Selenite gypsum crystals, larger than 2 mm, range from 0 to about 10 percent by volume and increase with depth.
Colors of the C horizon are in shades of gray, brown, or yellow with or without mottles. It is marly or shaley clay or silty clay with calcium carbonate equivalent of 45 to more than 60 percent.
COMPETING SERIES: These include the Deport, Frelsburg, Ferris, latium, and Depalt in the same family and the similar Sanger, Slidell, Ellis and McLennan. Deport soils have developed over clayey sediments and are over 80 inches thick. Frelsburg, Ferris, and Latium contain less than 30 percent calcium carbonate. In addition Ferris soils are underlain by shale, Frelsburg and latium have developed over Tertiary age material and are moist for slightly longer periods. Depalt soils have hues 7.5YR and redder. Sanger and Slidell contain less calcium carbonate and have moist color value less than 3.5 in the upper 12 inches. Ellis soils are noncalcareous in the surface layer. McLennan soils are in a fine-silty family and contain over 40 percent calcium carbonate.
GEOGRAPHIC SETTING: Medlin soils are on narrow stream divides or slopes along drainageways. These gently sloping to moderately steep soils have slopes from 1 to 20 percent, but slopes are mainly 5 to 12 percent. The soil formed in alkaline, clayey marine sediments of Lower Cretaceous systems like those of the Grayson Marl and, Del Rio Formation. The climate is warm subhumid. The mean annual precipitation is 28 to 34 inches. The mean annual temperature is 64 degrees to 67 degrees F. Thornthwaite P-E indices are 48 to 56.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bolar, Mingo, Sanger, Somervell and Slidell series.. Bolar and Somervell soils have limestone at depths of 20 to 40 inches. Mingo soils have mollic epipedons. Slidell soils have chroma less than 1.5 throughout the upper 12 inches. Bolar soils are on positions similar to Medlin soils. Mingo soils are above on convex ridgetops. Sanger, Slidell, and Somervell soils are usually above on broad stream divides.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; very slow permeability. Water enters rapidly when the soil is dry and cracked, and very slowly when the soil is moist.
USE AND VEGETATION: Used mainly for rangeland. Native vegetation is tall and mid grasses such as bluestems, indiangrass, sideoats grama, Texas wintergrass, and threeawn. Scattered elm, hackberry, and mesquite trees occur in places. A few areas are in improved bermudagrass pastures.
DISTRIBUTION AND EXTENT: Mainly in Grand Prairie of north-central Texas. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Denton County, Texas; 1975.
Diagnostic horizons and features in this pedon:
Ochric epipedon 0 to 6 inches
Cambic horizon - 6 to 49 inches.
Vertic features - Slickensides at a depth 26 to 49 inches. High Shrink-Swell potential and cracks that are 1 to 3 inches wide at a depth of 12 inches or more during dry periods.
SIR Number, TX0510, TX0570 (Stony)
REMARKS: These soils were formerly classified in the Regosol great soil group and included in the Ferris series. This series probably occurs only in the Grand Prairie Land Resource Area. The calcium carbonate equivalent increases with depth. This series has a lower liquid limit and plasticity index than the Ferris series.
ADDITIONAL DATA: Soil Mechanics Laboratory Data - Fort Worth
.002 .005 .02 .05 200 LL PI UNIF
6-30" 49 58 74 84 89 52 30 CH
30-49" 43 51 73 84 89 48 29 CL
49-70" 42 59 83 85 89 46 28 CL
Calcium carbonate equivalent - Field Method
6-30" 14 percent
30-49 30 percent
49-70 60 percent +