LOCATION NACLINA TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Chromic Hapluderts
TYPICAL PEDON: Naclina clay, on convex a 7 percent slope, in woodland. (Colors are for moist conditions unless otherwise noted.)
A1--0 to 5 inches; very dark grayish brown (10YR 3/2) clay; moderate medium subangular blocky parting to moderate medium granular structure; very hard, very firm; common medium and coarse roots; neutral; clear wavy boundary.
A2--5 to 9 inches; reddish brown (5YR 4/3) clay; moderate medium subangular blocky structure; extremely hard, very firm; common medium roots; few ironstone pebbles; neutral; clear wavy boundary. (combined A subhorizons are 4 to 16 inches thick)
Bw--9 to 14 inches; reddish brown (5YR 4/4) clay; moderate medium subangular blocky structure; extremely hard, very firm; common medium roots; few pressure faces; few coatings of dark grayish brown (10YR 4/2) on surfaces of some peds; few ironstone pebbles; neutral; clear wavy boundary. (0 to 12 inches thick)
Bss1--14 to 21 inches; light olive brown (2.5Y 5/4) clay; common medium distinct mottles of light brownish gray (2.5Y 6/2) with sharp boundaries; weak medium angular blocky structure; extremely hard, very firm; common fine and medium roots; few shiny ped surfaces and few grooved slickensides; slightly alkaline; gradual wavy boundary.
Bss2--21 to 36 inches; light olive brown (2.5Y 5/4) clay; common fine and medium distinct mottles of yellowish brown (10YR 5/6) and light brownish gray (2.5Y 6/2) with sharp boundaries; weak subangular blocky structure; extremely hard, very firm; few fine and medium roots; few pitted concretions of calcium carbonate; common grooved slickensides; spots in matrix has very slight effervescence; slightly alkaline; gradual wavy boundary. (combined Bss subhorizons are 20 to 40 inches thick)
Bkss--36 to 46 inches; olive yellow (2.5Y 6/4) clay; many medium and coarse distinct yellowish brown (10YR 5/6) and common medium and coarse distinct light brownish gray (2.5Y 6/2) mottles with sharp boundaries; weak medium and coarse angular blocky structure; very hard, very firm; few fine roots; common grooved slickensides; common masses and few pitted concretions of calcium carbonate; strong effervescence; moderately alkaline; gradual wavy boundary. (0 to 20 inches thick)
C--46 to 65 inches; variegated layers of strong brown (7.5YR 5/6) and light brownish gray (2.5Y 6/2) clayey shale; weak angular rock-like structure; very hard, very firm; few fine roots; strong effervescence; moderately alkaline.
TYPE LOCATION: Nacogdoches County, Texas; about 30 miles southeast of Nacogdoches from the intersection of Texas Highway 103 and Farm Road 95; 2 miles north on Farm Road 95; 50 feet east into woods.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to 60 inches. The weighted average clay content of the particle-size control section ranges from 40 to 60 percent. When dry, cracks 1/2 to more than 1 inch wide extend from the surface to a depth of more than 12 inches. Cracks remain open from 60 to 90 cumulative days in most years. Slickensides and wedge-shaped peds begin at a depth of 10 to 24 inches. Undisturbed areas have gilgai microrelief with microknolls about 4 to 12 inches above the microdepressions.
Distance from the center of the microknoll to the center of the microdepression ranges from 4 to about 15 feet. Colors with chroma of 2 or less in the subsoil are considered to be litho-chromic. Mottles with chroma of 3 or more, or redox concentrations, are considered to be relic or litho-chromic.
The A horizon has colors in shades of brown with hue of 5YR, 7.5YR, or 10YR, value of 3 to 5, and chroma of 2 or 3. Horizons with mollic colors are less than 12 inches thick in more than half the pedon. The texture is clay loam, silty clay loam, silty clay, or clay. The reaction ranges from moderately acid to neutral.
The Bw horizon has colors mainly in shades of red or brown with hue of 2.5YR to 7.5YR, value of 4 or 5, and chroma of 3 to 8. Mottles in shades of gray or brown range for none to common. The texture is silty clay or clay. The reaction ranges from strongly acid to neutral.
The Bss and Bkss horizons have colors mainly in shades of brown, olive, or yellow with hue of 7.5YR to 5Y, value of 4 to 6, and chroma of 3 to 8. Mottles with these colors and colors with chroma of 2 or less range from few to many and some subhorizons have a mottled matrix. The texture is silty clay or clay. Reaction ranges from strongly acid to neutral in the upper part of the Bss horizon and from slightly acid to slightly alkaline in the lower part. The reaction ranges from neutral to moderately alkaline in the Bkss horizon.
The C horizon has colors in shades of brown, gray, olive, and yellow. It is a shale or shale and marl with clay texture. The material is in variegated layers, platy, or weakly bedded. Effervesence ranges from very slight to strong in most pedons. The reaction is slightly alkaline or moderately alkaline.
COMPETING SERIES: There are no other series in this family. Closely similar soils include the Burkeville, Dylan, Hallsbluff, LaCerda, Morse, Redco, and Tahoula. Burkeville, Dylan, LaCerda, Redco, and Tahoula soils have very-fine particle-size control sections. In addition Burkeville, Dylan, LaCerda, and Redco soils have a solum thicker than 60 inches. Also, LaCerda soils are more acid in the surface layer. Hallsbluff soils have mollic colors from the surface to a depth of more than 12 inches. Morse soils have mixed mineralogy.
GEOGRAPHIC SETTING: Naclina soils are gently sloping to steep with convex surfaces. They are on stream divides and side slopes above drainageways. Slopes are mainly 5 to 10 percent but range from 1 to 35 percent. Mean annual rainfall ranges from 42 to 52 inches and is evenly distributed throughout the year. Mean annual temperature ranges from 65 to 67 degrees F., and the frost free days range from 230 to 245. The elevation ranges from 200 to 600 feet above sea level. Thornthwaite annual P-E indices exceed 66.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the LaCerda series from competing soils. They are on similar positions. Also, the Etoile and Woodtell series are associated. Etoile and Woodtell soils have a loamy epipedon and a clayey argillic horizon. Etoile soils commonly have slopes less than 5 percent with plane or concave surfaces and are on slightly higher positions. Woodtell soils are on similar positions in the landscape.
DRAINAGE AND PERMEABILITY: Naclina soils are well drained and very slowly permeable. Runoff is medium on 1 to 3 percent slopes, high on 3 to 5 percent slopes, and very high on 5 to 35 percent slopes.
USE AND VEGETATION: Used mainly for woodland. Trees include loblolly and shortleaf pine, red oak, and sweetgum. Most woodland areas have a dense understory of haw and other shrubs. Some areas are used for pasture. Adapted pasture grasses include common bermuda, improved bermuda, pensacola bahia, klein, and alamo switchgrass.
DISTRIBUTION AND EXTENT: Southeast Texas in MLRA 133B. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Nacogdoches County, Texas; 1976.
REMARKS: This soil was formerly mapped with the Susquehanna, Vaiden, or Oktibbeha soils. The classification is changed from Aquentic Chromuderts to Chromic Hapluderts based on the new classification for Vertisols. In addition, this soil does not have aquic soil conditions (January 1994).
Diagnostic horizons and features recognized in this pedon
are:
Ochric epipedon--the A1 and A2 horizon; also includes the chromic feature, a color value of 4 or more in some subhorizon within 12 inches of the surface.
Cambic horizon--the Bw, Bss, and Bssk horizons.
Vertic features--cracks when dry that are 1/2 inch wide to a depth of more than 12 inches; slickesides from a depth of 14 to 46 inches in the Bss subhorizons.
SOIL INTERPRETATION RECORD: TX0704