LOCATION GREDGE TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Udic Paleustalfs
TYPICAL PEDON: Gredge fine sandy loam--rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 7 inches; very pale brown (10YR 7/3) fine sandy loam, brown (10YR 5/3) moist; weak coarse subangular blocky structure; very hard, firm; many fine, medium and coarse roots; common fine pores; very strongly acid; abrupt wavy boundary. (3 to 13 inches thick)
Bt1--7 to 13 inches; dark red (2.5YR 3/6) clay, dark red (2.5YR 3/6) moist; moderate fine angular blocky structure; very hard, very firm; many fine, medium and coarse roots; continuous clay films on faces of peds; very strongly acid; clear smooth boundary. (5 to 14 inches thick)
Bt2--13 to 21 inches; reddish brown (5YR 5/4) clay, reddish brown (5YR 5/4) moist; common medium distinct light brownish gray (10YR 6/2) redox depletions; moderate medium angular blocky structure; very hard, very firm; common fine, medium and few coarse roots; continuous clay films on faces of peds, very strongly acid; clear smooth boundary. (6 to 18 inches thick)
Bt3--21 to 27 inches; light brownish gray (10YR 6/2) clay loam, grayish brown (10YR 5/2) moist; common medium distinct strong brown (7.5YR 5/8) and common fine prominent red (2.5YR 4/8) redox concentrations inside peds; moderate coarse angular blocky structure parting to moderate fine angular blocky; very hard, very firm; few fine, and medium roots; continuous clay films on faces of peds; strongly acid; gradual smooth boundary. (5 to 12 inches thick)
Bt4--27 to 40 inches; light brownish gray (10YR 6/2) clay loam, grayish brown (10YR 5/2) moist; few fine distinct strong brown (7.5YR 5/8) redox concentrations; moderate coarse angular blocky structure; very hard, very firm; few fine roots; patchy clay films on faces of peds; few white salt crystals (barite); strongly acid; gradual smooth boundary. (0 to 20 inches thick)
BCt1--40 to 57 inches; mixed brownish yellow (10YR 6/8), gray (10YR 6/1), and light gray (2.5Y 7/2) clay loam; moderate and weak coarse angular blocky structure; hard, firm; few fine roots; few patchy clay films on faces of peds; few sand coatings or fillings between peds; slightly acid; gradual wavy boundary. (0 to 18 inches thick)
BCt2--57 to 68 inches; mixed yellowish brown (10YR 5/4), very pale brown (10YR 7/3), and gray (10YR 6/1) sandy clay loam; weak medium and coarse subangular blocky structure; hard, firm; few fine roots; few patchy clay film on faces of peds; moderately alkaline.
TYPE LOCATION: Brazos County, Texas; from the intersection of Texas Highway 30 and the Navasota River in east Brazos County; 2.4 miles west on Texas Highway 30; north 1,000 feet in pasture.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. The boundary between the A and Bt horizons is abrupt to clear, with some waviness evident. Clay content decreases by 20 percent or more within a depth of 20 to 35 inches of the surface. Calcium carbonate concretions range from none to few below a depth of 30 inches.
The A horizon averages less than 10 inches thick but is 15 inches thick in some subsoil troughs. It has hue of 7.5YR or 10YR, value of 4 to 7, and chroma of 2 to 4. A thin E horizon is present in some pedons. Siliceous pebbles range from 0 to 60 percent by volume. Reaction ranges from very strongly acid to slightly acid.
The Bt1 horizon has hue of 2.5YR or 5YR, value of 3 to 5, and chroma of 4 to 8. Some pedons are mixed with these colors and, in addition, have hue of 5YR or 10YR, value of 4 to 6, and chroma of 1 to 4. The low chroma colors are not indicative of current wetness conditions. Texture is sandy clay or clay. Reaction ranges from very strongly acid to moderately acid.
The Bt2 horizon has hue of 2.5YR to 10YR, value of 4 to 6, and chroma of 1 to 8. All pedons are mixed in shades of brown, red and yellow. If not mixed the matrix is light brownish gray or grayish brown. Texture is sandy clay loam, clay loam, or clay. Reaction ranges from very strongly acid to slightly acid.
The Bt3 and Bt4 horizons have hue of 5YR, 7.5YR, and 10YR, value of 4 to 6, and chroma of 1 to 8. Texture is sandy clay loam or clay loam. Mottles are in shades of brown, gray, red, or yellow. Reaction ranges from strongly acid to slightly alkaline.
The BCt horizon is mottled in shades of brown, yellow, red, and gray. Some pedons have a matrix color of grayish brown, light gray, or reddish yellow with or without mottles. Texture is fine sandy loam, loam, sandy clay loam, or clay loam. Reaction ranges from moderately acid to moderately alkaline. The matrix is typically noncalcareous.
Some pedons have a geologic 2C horizon of shale, mudstone or stratified soil materials below a depth of 60 inches. These materials have texture mainly of loam, clay loam or clay. The reaction ranges from slightly acid to moderately alkaline. Some spots are calcareous.
COMPETING SERIES: These are the Cadell, Chazos, Payne, and Zack series. Similar soils are the Axtell, Burlewash, Crockett, Edge, and Tabor series. Cadell soils are 40 to 60 inches thick over tuffaceous clay. Chazos soils have a loamy fine sand surface layer 10 to 20 inches thick. Payne soils do not have an abrupt textural change between the epipedon and argillic horizon. Zack soils have sola 20 to 40 inches thick over weakly consolidated mudstones. The Axtell, Crockett, and Tabor soils classify in a vertic subgroup. Burlewash soils have a paralithic contact of tuffaceous sandstone and siltstone at a depth of 20 to 40 inches. Edge soils are on uplands and have sola 40 to 60 inches thick over geologic materials.
GEOGRAPHIC SETTING: Gredge soils are on convex and linear gently sloping to moderately sloping erosional terraces associated with uplands. Slopes are mainly 1 to 3 percent but range from 1 to 8 percent. The soil formed in slightly acid to alkaline loamy and clayey sediments of Pleistocene Age mainly over the Yagua geology. The mean annual temperature ranges from about 64 to 69 degrees F., and mean annual precipitation ranges from 32 to 42 inches. Frost free days range from 240 to 280 days and elevation ranges from 250 to 450 feet. The Thornthwaite P-E indices range from 48 to 64.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the similar Axtell, Edge and Crockett soils and the Gasil, Silawa and Lufkin soils. The Axtell, Edge, Crockett, Gasil and Silawa soils are on similar landscape positions. Gasil and Silawa soils have fine-loamy control sections. Lufkin soils are on slightly lower nearly level positions or in depressions. They have grayish colors throughout, and are in a vertic subgroup.
DRAINAGE AND PERMEABILITY: Well drained and the permeability is very slow. Runoff is medium on 1 to 3 percent slopes; high on 3 to 5 percent slopes; and very high on slopes more than 5 percent.
USE AND VEGETATION: Native vegetation is a Savannah consisting of post oak and blackjack oak trees with yaupon, little bluestem, longleaf uniola, panicums and paspalums. Many areas have been cultivated in the past. Improved pastures of coastal bermudagrass and bahiagrass are the dominant use.
DISTRIBUTION AND EXTENT: Mainly in East Central Texas. The series is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Freestone County, Texas; 1986.
REMARKS: The soils were formerly included in the Axtell and Edge series (Brazos County, 1958). Gredge soils have a high shrink-swell in the Bt1, then decrease in clay so that the shrink-swell potential is moderate to low in the remainder of the solum. They lack the necessary PLE to classify as vertic.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 7 inches (A horizon).
Argillic horizon - 7 to 68 inches (Bt Horizons).
The low chroma colors are not indicative of current wetness.
Abrupt texture change - at 7 inches.