LOCATION DERLY TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Typic Glossaqualfs
TYPICAL PEDON: Derly silt loam--pasture. (Colors are for moist soil unless otherwise stated.)
A--0 to 3 inches; grayish brown (10YR 5/2) silt loam, light brownish gray (10YR 6/2) dry; common medium faint dark grayish brown (10YR 4/2) redox concentrations; weak fine subangular blocky structure; slightly hard, friable; common fine and medium roots; few fine pores; few wormcasts; moderately acid; clear smooth boundary. (2 to 7 inches thick)
Eg--3 to 8 inches; light brownish gray (10YR 6/2) silt loam, white (10YR 8/2) dry; common medium distinct light yellowish brown (10YR 6/4) redox concentrations; weak coarse prismatic structure parting to weak fine subangular blocky structure; slightly hard, friable; common fine and medium roots; common fine pores; few wormcasts; very strongly acid; clear wavy boundary. (0 to 8 inches thick)
Btg/E1--8 to 12 inches; light brownish gray (10YR 6/2) clay loam, light gray (10YR 7/2) dry; common medium distinct light olive brown (2.5Y 5/4) redox concentrations within peds; weak coarse prismatic structure parting to moderate fine and medium subangular blocky; very hard, firm; common fine and medium roots; common fine and medium pores; about 25 percent streaks, pockets, and coatings on surfaces of prisms of light brownish gray (10YR 6/2) albic material (E); few wormcasts; very strongly acid; clear irregular boundary. (3 to 17 inches thick)
Btg/E2--12 to 31 inches; grayish brown (10YR 5/2) clay, light brownish gray (10YR 6/2) dry; moderate coarse angular blocky structure parting to moderate medium angular blocky structure; extremely hard, very firm, sticky and plastic; common fine and medium roots; few clay films; few pressure faces 1 to 2 cm across; light brownish gray (10YR 6/2) streaks, pockets, and coatings of albic material (E) make up about 10 percent of the upper part and about 3 percent of the lower part; very strongly acid; gradual wavy boundary. (0 to 23 inches thick)
Btg1--31 to 42 inches; grayish brown (10YR 5/2) clay, light brownish gray (10YR 6/2) dry; moderate coarse angular blocky structure parting to weak medium subangular blocky structure; extremely hard, very firm, sticky and plastic; few medium roots mostly on surfaces of peds; few clay films; few slickensides 2 to 4 inches across; few thin streaks of albic material; very strongly acid; gradual wavy boundary. (7 to 18 inches thick)
Btg2--42 to 50 inches; grayish brown (2.5Y 5/2) clay; few medium distinct yellowish brown (10YR 5/6) redox concentrations; some ped surfaces are coated with dark grayish brown (10YR 4/2); moderate coarse angular blocky structure parting to moderate medium subangular blocky structure; extremely hard, very firm, sticky and plastic; few medium roots mainly on surfaces of peds; few slickensides 3 to 4 inches across; few clay films; few black concretions 1 to 4 mm in diameter; few fine masses of gypsum; strongly acid; gradual wavy boundary. (0 to 15 inches thick)
Btg3--50 to 74 inches; light brownish gray (2.5Y 6/2) clay; few medium distinct light olive brown (2.5Y 5/4) redox concentrations; moderate coarse angular blocky structure; extremely hard, very firm, sticky and plastic; few medium roots mainly on surfaces of peds; few pressure faces 1 to 2 cm across; many clay films; few black concretions 1 to 4 mm in diameter; few fine masses of gypsum; slightly acid; diffuse wavy boundary. (0 to 27 inches thick)
Btg4--74 to 84 inches; mottled light gray (2.5Y 7/2) and light brownish gray (2.5Y 6/2) clay; common medium distinct brownish yellow (10YR 6/6) redox concentrations; weak medium prismatic structure; extremely hard, very firm, sticky and plastic; few fine roots; few clay films and gray (10YR 5/1) clayflows; few black concretions 2 to 4 mm in diameter; few fine masses of gypsum; neutral.
TYPE LOCATION: Lamar County, Texas; from the intersection of U.S. Highway 82 and Farm Road 195 in Paris, 3.1 miles northeast on Farm Road 195; 3.0 miles north on county road, 0.13 mile east; 1.8 miles north, 0.7 mile east and 350 feet south in pasture.
RANGE IN CHARACTERISTICS: Solum thickness is more than 80 inches. The control section averages 35 to 45 percent clay. Pressure faces and small slickensides ranges from none to a few in the Bt horizons.
The A horizon has hue of 10YR or 2.5Y, value of 3 to 5, and chroma of 2 or 3. Horizons with value of 3 are less than 7 inches thick. Grayish or brownish redoximorphic features range from none to common. Yellowish, brownish, or reddish coatings are along root channels and pores during wet periods. It is very fine sandy loam, loam or silt loam. The reaction ranges from very strongly acid to slightly acid unless limed.
The E horizon has hue of 10YR or 2.5Y, value of 5 to 7, and chroma of 2 or 3. Grayish, brownish or yellowish redoximorphic features range from few to common in most pedons. Yellowish, brownish, or reddish coatings are along root channels and pores during wet periods. Texture is very fine sandy loam, loam or silt loam. The reaction ranges from very strongly acid to moderately acid.
The Btg/E horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 1 or 2. Brownish, yellowish, or reddish redoximorphic features and/or coatings along root channels range from few to common in most pedons. Texture is clay loam, silty clay loam, or clay. Albic material (E) in the form of streaks, pockets, and coatings make up 5 to 35 percent of this horizon. In some part of the pedon this horizon has 15 percent or more albic materials. The reaction ranges from very strongly acid to moderately acid.
The Btg horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 1 or 2. Redoximorphic features or coatings along root channels in shades of gray, brown, red, or yellow range from few to common in some part of this horizon. Some pedons have a mottled matrix in some part. Texture is clay or clay loam in the upper part and clay, silty clay loam, clay loam, or loam in the lower part. The reaction of the upper part ranges from very strongly acid to moderately acid. The lower part ranges from strongly acid to neutral. Gypsum crystals or masses range from none to common. Some pedons contain a few calcium carbonate concretions in the lower part. Typically, they are hard and pitted. Some pedons have BCt horizons with high value colors and loamy textures.
COMPETING SERIES: These are the Aris, Encrow, and Mowata series in the same family and the Alusa, Crowley, Evadale, Lufkin, Panola, Mollville, and Wrightsville. Aris soils are moist in the moisture control section for longer periods and have annual temperatures of 68 to 70 degrees F. The Mowata soils have sola less than 60 inches thick. Encrow soils have a lithologic discontinuity in the argillic horizon and an ESP of 5-15 percent in the lower part of the argillic horizon. Alusa, Crowley, Lufkin, and Panola soils do not have a glossic horizon. Evadale and Wrightsville soils have mixed mineralogy. Mollville soils have a fine-loamy control sections.
GEOGRAPHIC SETTING: Derly soils are on nearly level to concave areas, typically between mounds. These soils formed in loamy and clayey sediments on Pleistocene Age Terraces about 30 to 80 feet above present flood plains. They are commonly on second or third terrace levels of rivers or on slightly higher terrace smears associated with uplands. The average annual temperature ranges from 63 to about 68 degrees F.; the average annual rainfall ranges from 36 to 46 inches. Frost free days ranges from 230 to 275, and the elevation ranges from 150 to 400 feet above sea level. Thornthwaite P-E index ranges from 60 to 68.
GEOGRAPHICALLY ASSOCIATED SOILS: Associated soils are those of the Annona, Freestone, Hicota, Rader, Raino, and Woodtell series. Annona and Woodtell soils have redder hues and do not have albic materials in the argillic horizon and are on uplands. Freestone, Hicota, Rader and Raino soils are on mounds or other slightly higher positions and have fine-loamy control sections.
DRAINAGE AND PERMEABILITY: Derly soils are poorly drained and have very slow permeability. They have negligible runoff. Water is ponded on the surface for brief to long periods during the winter and spring seasons of most years. A perched water table is in the Eg and the Btg/E horizons for more than 30 consecutive days from October to May during most years.
USE AND VEGETATION: Derly soils are used mainly for pasture and woodland. Native vegetation is an overstory of elm, post oak, willow oak, and water oak. Grasses include such species as beaked panicum, longleaf uniola, and sedges. Bermudagrass, dallisgrass, and fescuegrass are the dominant pasture plants.
DISTRIBUTION AND EXTENT: These soils are in the northeastern and east central part of Texas and possibly in the southern part of Oklahoma. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Lamar County, Texas; 1975.
REMARKS: These soils are in the Western Coastal Plain and Texas Claypan MLRA's. They were formerly included with the Wrightsville or Lufkin series.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - A and E horizons from 0 to 8 inches.
Argillic horizons - the Bt horizons from 8 to 84 inches.
Aquic feature - low chromas and mottles caused by wetness in the 3 to 84 inch layers.
Glossic feature - has 15 percent or more albic material in the upper part of the argillic horizon.
ADDITIONAL DATA: Data from Lincoln Laboratory, March 1966, LSL 20866 (Btg/E horizon) and samples from two pedons in Smith County indicate the clay is dominantly montmorillonite with small amounts of kaolinite and quartz.
Madison County characterization data by TAMU S-85TX-313-001.