LOCATION KURTH TX+LAEstablished Series
TAXONOMIC CLASS: Fine-loamy, siliceous, semiactive, thermic Oxyaquic Glossudalfs
TYPICAL PEDON: Kurth fine sandy loam, on a 2 percent slope in woods. (Colors are for moist soil conditions)
A--0 to 6 inches; brown (10YR 4/3) fine sandy loam; weak medium granular structure; soft, friable; slightly sticky and nonplastic; many fine and medium roots; slightly acid; clear smooth boundary.
E--6 to 18 inches; pale brown (10YR 6/3) fine sandy loam; weak medium granular structure; soft, friable; slightly sticky and nonplastic; common fine and medium roots; strongly acid; clear smooth boundary. (combined thickness of tha A and E horizons is 16 to 30 inches).
Bt/E1--18 to 30 inches; yellowish brown (10YR 5/6) sandy clay loam; weak medium subangular blocky structure; slightly hard, friable; slightly sticky and nonplastic; common fine roots; about 10 percent albic material of light brownish gray (10YR 6/2) (E); few patchy clay films on surface of peds; common medium distinct light brownish gray (10YR 6/2) iron depletions; few fine distinct strong brown (7.5YR 4/6) redox concentrations; very strongly acid; gradual wavy boundary.
Bt/E2--30 to 38 inches; yellowish brown (10YR 5/6) sandy clay loam; weak medium subangular blocky structure; slightly hard, firm; slightly sticky and nonplastic; few fine roots; few patchy clay films on surface of peds; about 20 percent albic material of light brownish gray (10YR 6/2) (E); common medium distinct light brownish gray (10YR 6/2) iron depletions; common medium distinct strong brown (7.5YR 4/6) and few fine distinct yellowish red (5YR 5/8) redox concentrations; very strongly acid; gradual wavy boundary.
Bt/E3--38 to 49 inches; variegated yellowish brown (10YR 5/6) and red (2.5YR 4/6) sandy clay loam; weak medium subangular blocky structure; hard, firm; slightly sticky and slightly plastic; few fine roots; few patchy clay films on surface of peds; about 25 percent light gray (10YR 7/1) albic materials (E); common medium distinct light gray (10YR 7/1) iron depletions; very strongly acid; clear smooth boundary. (combined thickness of the Bt/E horizons is 10 to 30 inches)
2Btg--49 to 69 inches; light brownish gray (10YR 6/2) clay loam; weak fine subangular blocky structure; hard, firm; slightly sticky and slightly plastic; few fine roots; few clay films on surface of peds; common medium prominent dark red (2.5YR 3/6) redox concentrations; very strongly acid; clear smooth boundary.
2C--69 to 80 inches; light yellowish brown (2.5Y 6/3) weakly consolidated mudstone with texture of clay loam; massive; very hard, firm; few streaks of dark gray (10YR 4/1); very strongly acid.
TYPE LOCATION: Angelina County, Texas; from Loop 287 in Lufkin, 6.3 miles west on Texas 103; 1.1 miles south and southeast on timber road; 1.8 miles southwest and south on adjoining timber road; 50 feet east in woods.
RANGE IN CHARACTERISTICS: Solum thickness usually is more than 60 inches, however some pedons have a 2C horizon within a depth of 60 inches. Weighted average clay content of the particle-size control section ranges from 20 to 30 percent. The silt content ranges from 15 to 30 percent. Depth to the clayey 2Btg horizon ranges from 40 to 60 inches. Base saturation ranges from 35 to 60 percent in the lower part of the argillic horizon.
The A horizon has hue of 10YR, value of 3 to 5, and chroma of 2 or 3. Reaction ranges from strongly acid to slightly acid.
The E horizon has hue of 10YR, value of 5 or 6, and chroma of 2 to 4. Reaction ranges from strongly acid to moderately acid.
A Bt horizon is present in some pedons. Where present, it has hue of 2.5YR to 10YR, value of 4 or 7, chroma of 5 to 8. Intrusions of albic material (E) make up less than 10 percent of the horizon. Texture is fine sandy loam or sandy clay loam. Reaction ranges from strongly acid to moderately acid.
The Bt/E horizon has hue of 2.5YR to 10YR, value of 4 or 7, chroma of 5 to 8. Iron depletions or masses in the upper part appear to be relic. Intrusions of albic material (E) make up 10 to 40 percent of the horizon, but are more than 15 percent in some subhorizon that is more than 2 inches thick. Texture is fine sandy loam or sandy clay loam. Reaction ranges from strongly acid to moderately acid.
2Btg horizon has hue of 10YR, value of 5 to 7, and chroma 1 or 2. Redox concentrations in masses range from few to many in shades of red or brown. Texture is sandy clay loam or clay loam. Reaction ranges from extremely acid to strongly acid.
The 2C horizon has matrix colors mainly in shades of brown or gray, with strata, streaks, or masses with these colors or shades of yellow or red. It is weakly consolidated sandstone or mudstone or is stratified with these materials. In some pedons, it is also stratified with shale and/or siltstone. Electrical conductivity ranges from 0.5 to 2.0 mmhos/cm. Reaction ranges from extremely acid to strongly acid.
COMPETING SERIES: This is the Batson series in the same family, and the Alazan, Freestone, Keltys, Metcalf, Penning, Sawlit and Sawtown soils in closely families. Batson soils formed in Pleistocene age alluvium on the flatwoods or coast prairie, and do not have a discontinuity to geologic materials within a dpeth of 80 inches. Alazan, Freestone, Metcalf, Sawlit and Sawtown soils have a solum thicker than 80 inches. In addition, Alazan, Freestone, Metcalf, Penning, and Sawlit soils have aquic conditions within the upper 10 inches of the argillic horizon, and Sawtown soils do not have a water table within 40 inches of the soil surface. Keltys soils have a coarse-loamy particle-size control section.
GEOGRAPHIC SETTING: Kurth soils are on slightly convex to smooth, gently sloping to moderately sloping interstream divides. They formed in loamy coastal plain sediments mainly of the Yegua geological formation, but also on the Whitset formation. Slopes range from 1 to 8 percent, but dominantly are from 2 to 4 percent. Mean annual precipitation ranges from 40 to 50 inches. Frost-free rainfall ranges from 25 to 30 inches. Frost free days range from 235 to 245. Elevation ranges from 250 to 500 feet above sea level. Mean annual temperature ranges from 65 to 68 degrees F., and the Thornthwaite annual PE indices range from 70 to 82.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the closely related Keltys and Penning series, and the Diboll, Herty, Lovelady, Moswell and Rosenwall series. Diboll, Herty and Penning soils are on slightly lower, wetter positions. In addition, Diboll soils have a fine-silty control section, and Herty soils have a fine control section with higher shrink-swell. Keltys, Lovelady, Moswell and Rosenwall soils are on positions similar to Kurth soils. Lovelady soils have a sandy epipedon 20 to 40 inches thick. Moswell and Rosenwall soils have a clayey control section.
DRAINAGE AND PERMEABILITY: Kurth soils are moderately well drained and slowly permeable. Runoff is medium on 1 to 5 percent slopes; and high on 5 to 8 percent slopes. A saturated zone is perched above the 2Btg horizon at a depth of 30 to 40 inches for brief to long periods during the late winter and early spring in normal years.
USE AND VEGETATION: This soil is used mainly for woodland and improved pasture. Woodland consists mainly of shortleaf pine, loblolly pine, sweetgum, red oak and water oak trees, with an understory of grasses and shrubs. Pastures include mainly improved bermudagrass and Pensacola bahiagrass.
DISTRIBUTION AND EXTENT: Western Coastal Plain (MLRA 133B) in Eastern Texas. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Angelina County, Texas; 1984.
REMARKS: These soils were formerly included with the Caddo or Summerfield series. Base saturation of the substrata is greater than 35 percent; data by Hach kit. A prior revision (1993) changed the subgroup classification from Aquic to Typic, then it was changed back to Oxyaquic (1/1999). Aquic conditions are below a depth of 40 inches when present. Redox depletions and concentrations in the upper part of the glossic horizon are relic.
Diagnostic horizons and features recognized in the type location pedon include:
Ochric epipedon -- 0 to 18 inches (A and E horizons).
Albic horizon -- 6 to 18 inches (E horizon).
Argillic horizon -- 18 to 69 inches (Bt/E and 2Btg horizons).
Glossic horizon - 18 to 49 inches (Bt/E horizons).
Lithologic discontinuity -- 49 inches (top of the 2Btg horizon).
ADDITIONAL DATA: Analyses were run on 2 pedons from Houston County, Tx. by the Texas Agricultural Experiment Station (S82TX-225-1, S84TX-225-1).