LOCATION REK TXEstablished Series
TAXONOMIC CLASS: Fine, mixed, semiactive, thermic Typic Haplustults
TYPICAL PEDON: Rek extremely gravelly coarse sandy loam on a 2 percent slope. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 3 inches; pink (7.5YR 7/4) extremely gravelly coarse sandy loam, brown (7.5YR 5/4) moist; massive; soft, loose; many fine, few medium and few coarse roots; 5 percent cobbles, 75 percent pebbles; very strongly acid; abrupt wavy boundary. (0 to 6 inches thick)
Bt1--3 to 7 inches; red (2.5YR 4/6) gravelly clay, red (2.5YR 4/6) moist; many medium prominent light brownish gray (10YR 6/2) and few fine distinct yellowish brown (10YR 5/6) mottles; moderate medium prismatic structure parting to moderate medium angular blocky; extremely hard, very firm; few coarse, common fine and medium roots; common thick continuous light gray (10YR 6/1) clay films on ped faces; many thick continuous dark red (2.5YR 3/6) clay films on rock fragments; 5 percent cobbles, 25 percent pebbles; extremely acid; clear wavy boundary.
Bt2--7 to 12 inches; light gray (10YR 7/1) clay, gray (10YR 6/1) moist; many coarse prominent red (10R 4/8) and few fine prominent light red (2.5YR 6/6) mottles; weak medium prismatic structure parting to moderate coarse angular blocky; extremely hard, very firm; few coarse, common fine and common medium roots; common thick continuous light gray (10YR 6/1) clay films on ped faces; 2 percent cobbles, 5 percent pebbles; extremely acid; clear wavy boundary.
Bt3--12 to 22 inches; light gray (10YR 7/1) clay, gray (10YR 6/1) moist; many coarse prominent dark red (10R 3/6) and many medium prominent red (10R 4/6) mottles; weak medium prismatic structure parting to moderate coarse angular blocky; extremely hard, very firm; common fine and medium roots; few medium pores; common distinct discontinuous patchy gray (10YR 6/1) clay films on ped faces; 5 percent pebbles in lower part; extremely acid; gradual wavy boundary. (Combined thickness of Bt horizons range from 15 to 30 inches)
2Bt4--22 to 37 inches; light brownish gray (2.5Y 6/2) sandy clay, gray (2.5Y 5/2) moist; common medium prominent dark red (10R 3/6) and medium distinct yellowish brown (10YR 5/6) mottles; weak medium prismatic structure parting to moderate coarse angular blocky; extremely hard, very firm; common fine and common medium roots; few medium pores; many distinct continuous light gray (10YR 6/1) clay films on ped faces; 2 percent pebbles; extremely acid; gradual smooth boundary.
2Bt5--37 to 49 inches; light gray (2.5Y 7/2) sandy clay loam, light brownish gray (2.5Y 6/2) moist; moderate medium prismatic structure parting to moderate coarse angular blocky; very hard, very firm; few fine and medium roots; few medium pores; many thick continuous light brownish gray (10YR 6/2) clay films on ped faces; common dark gray (10YR 4/1) stains along root channels; many medium prominent dark red (10R 3/6), few fine prominent brownish yellow (10YR 5/6) and common brownish yellow (10YR 6/6) masses of iron accumulation; extremely acid; gradual smooth boundary.
2Bt6--49 to 63 inches; light gray (2.5Y 7/2) sandy clay loam, light brownish gray (2.5Y 6/2) moist; moderate medium prismatic structure parting to moderate coarse angular blocky; very hard, very firm; few fine and medium roots; many thick continuous light brownish gray (2.5Y 6/2) clay films on ped faces; thin discontinuous layer of clayey material just above C horizon; common dark gray (10YR 4/1) stains along root channels; many medium prominent dark red (10R 3/6) and few fine prominent brownish yellow (10YR 6/8) masses of iron accumulation; extremely acid; abrupt irregular boundary. (8 to 15 inches thick)
2Cr--63 to 80 inches; grayish brown (2.5Y 5/2) weakly cemented sandstone, grayish brown (2.5Y 5/2) moist; few fine and medium roots along fracture prism faces; few dark gray (10YR 4/1) stains on vertical prism faces; common coarse prominent yellowish red (5YR 5/6) and common medium prominent red (2.5YR 4/8) masses of iron accumulation; extremely acid.
TYPE LOCATION: Fayette County: In Fayetteville, from the intersection of Farm Road 159 and Farm Road 1291, 1.8 miles north on Farm Road 1291, 2,000 feet northeast on private gravel road, and 200 feet northwest in desurfaced area. (Latitude: 30 degree, 56 minutes, 04 minutes North; Longitude: 96 degrees, 40 minutes, 18 seconds West.)
RANGE IN CHARACTERISTICS: Solum thickness and depth to a paralithic contact ranges from 60 to about 80 inches. Rounded siliceous pebbles and cobbles are on the surface and in the A and upper Bt horizons. COLE is less than 0.07. Clay content in the upper 20 inches of the argillic ranges from 50 to 70 percent. Base saturation at 50 inches below the top of the argillic horizon or immediately above a paralithic contact ranges from 15 to 35 percent.
The A horizon has hue of 7.5YR or 10YR, value of 4 to 7, and chroma of 3 to 6. The texture is variable consisting of extremely gravelly loamy coarse sand, extremely gravelly loamy sand or extremely gravelly coarse sandy loam. Gravel and cobble content ranges from 65 to 80 percent. About 5 to 10 percent of the volume of the coarse fraction is composed of cobbles, mainly less than 5 inches across their long axis. Reaction ranges from extremely acid to strongly acid. The boundary is abrupt.
The Bt1 horizon has hue of 2.5YR to 10YR, value of 3 to 7, and chroma of 1 to 6. There are few to many redoximorphic features in shades of red, gray, brown or yellow. Texture is gravelly sandy clay or gravelly clay. Coarse fragments range from 15 to 35 percent. Reaction ranges from extremely acid to strongly acid.
The Bt2 and Bt3 horizons have hue of 2.5YR to 10YR, value of 3 to 7 and chroma of 1 to 6. There are few to many redoximorphic features in shades of red, gray, brown or yellow. Texture is sandy clay or clay. Coarse fragments range from 0 to 15 percent. Reaction ranges from extremely acid to slightly acid.
The 2Bt horizons have hue of 10YR or 2.5Y, with value of 6 to 8, and chroma of 1 to 4. There are redoximorphic features in shades of red, gray, brown or yellow. Texture is sandy clay loam, clay loam or sandy clay. Coarse fragments ranges from 0 to 15 percent by volume. Reaction ranges from extremely acid to slightly acid.
The 2Cr or 2C horizons have hue of 10YR to 5Y, value of 5 to 8, and chroma of 1 to 3. Redoximorphic features in shades of red occur in most pedons. It is shale or weakly cemented sandstone that has texture of fine sandy loam, sandy clay loam, sandy clay or clay. Siliceous pebbles range from 1 to 3 percent by volume. Reaction ranges from extremely acid to slightly acid.
COMPETING SERIES: These are the Aubrey, Hearne and Marquez, and Stein series. Similar families are the Cuthbert, Kirvin, Straber, and Tremona series. Aubrey and Hearne soils have sola 20 to 40 inches thick. Marquez soils do not have zones of iron depletions in the upper Bt horizons. Stein soils do not have a paralithic contact within 80 inches of the soil surface. Cuthbert and Kirvin soils are well drained and are in the udic moisture regime. Straber and Tremona soils have sandy surface textures and have base saturation greater than 35 percent.
GEOGRAPHIC SETTING: Rek soils are on upland ridges on Quaternary terraces. Slopes range from 1 to 5 percent. Mean annual temperature ranges from 67 to 70 degrees F., and mean annual precipitation ranges from 34 to 40 inches. Frost free days range from 260 to 280 days, and elevation ranges from 300 to 500 feet. Thornthwaite P-E indices range 52 to 60.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Straber and Tremona series. Straber and Tremona soils have sandy and gravelly surfaces greater than 10 inches thick and are on similar positions.
DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is very slow. Runoff is medium on 1 to 3 percent slopes and high on 3 to 5 percent slopes.
USE AND VEGETATION: This soil is used as rangeland and wildlife habitat. Because of the removal of the surface layer and the highly acidic and droughthy subsoil, these areas are slow to revegetate. Most areas are dominated by annual threeawns. Other species include broomsedge bluestem, brownseed paspalum, prickly pear cactus, false indigo, broomweed and juniper.
DISTRIBUTION AND EXTENT: Mainly on the High Gravelly Quaternary terraces in the Texas Claypan Land Resource Area. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Fayette County, Texas; 1992. The name is from Rek Hill community located in the eastern part of Fayette County.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 3 inches. (Ap horizon)
Argillic horizon - 3 to 63 inches. (Bt horizons)
Paralithic contact at 63 inches.
Base saturation less than 35 percent at 50 inches below the top of the argillic horizon or immediately above a paralithic contact.
The soil originally had a gravelly surface that has been mechanically removed for resource material. This has caused a change in the soil hydrology. Redoximorphic features are relic and are not related to present wetness condition.
The soil does not have hue that becomes redder with depth.
ADDITIONAL DATA: A complete characterization report was provided by the Texas Agricultural Experiment Station Soil Characterization Laboratory from a 1988 pit study in Fayette County. Limited characterization data in a report to LCRA, "Comparison of Physical and Chemical Properties and Production Capacity of Overburden and Land-Surface Soils from Proposed Mine Site, Fayette County, Texas", Texas Tech University. (S88TX-149-003-1-8)