LOCATION DIBOLL TXEstablished Series
TAXONOMIC CLASS: Fine-silty, siliceous, superactive, thermic Albic Glossic Natraqualfs
TYPICAL PEDON: Diboll very fine sandy loam, on a forested 0.7 percent slope.
(Colors are for moist soil.)
A1--0 to 9 inches; grayish brown (10YR 5/2) very fine sandy loam; weak medium granular structure; soft, friable; many fine, medium and coarse roots; very strongly acid; clear smooth boundary. (3 to 12 inches thick)
E1--9 to 17 inches; light brownish gray (10YR 6/2) very fine sandy loam with many medium distinct strong brown (7.5YR 5/8) mottles and stains along root channels; massive but porous; soft, friable; common medium and fine roots; very strongly acid; gradual wavy boundary. (4 to 14 inches thick)
E2--17 to 29 inches; light brownish gray (10YR 6/2) very fine sandy loam with common medium distinct strong brown (7.5YR 5/8) mottles and stains along root channels; massive but porous; slightly hard, friable, slightly sticky and nonplastic; common fine and medium roots; common rounded crayfish burrows filled with light gray (10YR 7/2) silt loam with thin (less than 1 cm thick) cups of dark gray (10YR 4/1) silty clay material with a slick soapy consistency; strongly acid; clear irregular boundary. (5 to 20 inches thick)
Btn/E--29 to 36 inches; mottled light brownish gray (2.5Y 6/2) and light yellowish brown (2.5Y 6/4) clay loam, dark grayish brown (10YR 4/2) clayey material about 6 mm thick surround most peds, about 40 percent tongues of light gray (10YR 7/2) loam (E) between peds; moderate medium columnar parting to weak medium angular blocky structure; hard, friable, sticky and plastic; few fine roots mainly in E material; common rounded crayfish burrows filled with E material and having cups of dark gray (10YR 4/1) clayey material at bottom of burrows; Bt materials occupy about 40 percent and have a slick soapy consistency; about 20 percent of the matrix ped interiors is a siltstone that breaks conchoidal; ECe 1.8 mmhos/cm medium acid; clear irregular boundary. (5 to 25 inches thick)
2Cr/Btn--36 to 43 inches; light olive brown (2.5YR 5/4) siltstone with spots of light brownish gray (2.5Y 6/2) and strong brown (7.5YR 5/6); the siltstone has conchoidal fractures; fracture planes have coatings about 2 mm thick of dark gray (10YR 4/1) silty clay loam (Bt); and interfingers 2 to 5 mm thick of light gray (10YR 7/2) silt loam (E) are in cracks and crevices; very hard, very firm; few fine roots along cracks; few crayfish burrows filled with light gray (10YR 7/2) dark gray (10YR 4/1) clay cups; burrows lined with grayish brown (10YR 5/2) silty clay loam; Bt part has slick soapy consistency; thin black coatings (FeMn) covers some horizontal faces; few masses of powdery barite; ECe 2.3 mmhos/cm; neutral; gradual wavy boundary. (3 to 8 inches thick)
3Cr1--43 to 55 inches; pale olive (5Y 6/3) siltstone; few crayfish burrows lined with grayish brown (10YR 5/2) and filled with light gray (10YR 7/2) silt loam; few masses of powdery barite; many rock faces covered with a thin black coating (FeMn); few faces have thin layer of reddish to yellowish natrojarosite and jarosite; few flat roots on rock faces; ECe 2.8 mmhos/cm; neutral; gradual wavy boundary. (7 to 20 inches thick)
3Cr2--55 to 67 inches; pale olive (5Y 6/3) siltstone; thin black coatings (FeMn) cover most rock faces; few masses of powdery barite; some faces have reddish to yellowish coating of jarosite and natrojarosite; few spots of calcite and gypsum; few fine flat roots in upper part on rock faces; ECe 2.3 mmhos/cm; neutral.
TYPE LOCATION: Angelina County, Texas; about 25 miles southeast of Lufkin; from Zavalla 5 miles east on Texas 147; 0.3 mile south on logging road; this is 75 feet south into National Forest.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 30 to 50 inches. Depth to paralithic contact ranges from 40 to 60 inches. Pebbles at the contact of the 2Cr/Bt range from none to common.
The combined thickness of the A and E horizons range from 25 to 45 inches. Aluminum saturation of the A horizon and upper part of the E horizon ranges from 20 to 65 percent. The A horizon is very fine sandy loam, silt loam, or loam. It has hue of 10YR, value of 3 to 5, and chroma of 1 or 2. If values are 3, the horizon is less than 6 inches thick. Reaction is very strongly acid to slightly acid, unless limed.
The E horizon is very fine sandy loam or loam and has hue of 10YR with value of 5 or 6, and chroma of 1 or 2. Stains along roots are in shades of red and brown. Reaction is very strongly acid to slightly acid. Exchangeable sodium in the lower part of the E horizon ranges from 2 to 10 percent.
The Bt/E and 2Cr/Bt horizons are varigated with ped interiors of siltstone parent materials seemingly little weathered, surrounded by darker and grayish argillic materials, with sandy E materials between peds. This gives a color pattern with yellowish or olive
interiors, dark gray rinds and grayish filling between the rinds. The Bt part consists of streaks and masses of silty clay loam, loam, or clay loam. It has hue of 10YR, value of 3 to 5, and chroma of 1 or 2. The E part consists of tongues, filled crayfish holes and streaks of very fine sandy loam or loam. It has hue of 10YR, value of 5 or 6, and chroma of 2 or 3. Mottles in shades of brown or yellow range from none to common, and are mainly in interior of peds. Reaction is very strongly acid to neutral. Average clay content of the horizon averages 18 to 35 percent and the silt content ranges from 30 to 55 percent. Electrical conductivity is less than 4 mmhos/cm. Exchangeable sodium ranges from 18 to 30 percent.
The 3Cr horizon is a clayey siltstone, mudstone, or shale which naturally contains many salts, some of which are barite, gypsum, calcite, jarosite, and natrojarosite. It has hue of 10YR to 5Y, value of 5 to 7, and chroma of 2 to 5. Exchangeable sodium
ranges from 20 to 30 percent. Reaction ranges from strongly acid
to neutral.
COMPETING SERIES: There are no competing seies in the same family. Similar series are Bonn, Colita, Fuller, Moten, Ozan, Plank, Sorter, and Verdum series. Bonn and Verdun soils have natric horizons within 16 inches and do not have a paralithic contact within 60 inches of the soil surface. In addition, Bonn soils are poorly drained. Colita soils do not have a natric horizons. Fuller soils are in a fine-loamy family. Moten, Ozan, and Sorter soils are in a coarse-loamy family, and do not have a paralithic contact. Plank soils are in a coarse-loamy family, are poorly drained, and do not have a paralithic contact.
GEOGRAPHIC SETTING: Diboll soils are on slightly concave to smooth, nearly level and gently sloping uplands. They formed in loamy sediments deposited over siltstone mainly of the Caddell, Manning, and Whitsett geological formations. The siltstone is thought to have been exposed, then reinundated by high tides and shallow bays during past geologic activity. Slopes are dominantly less than 3 percent, but range from 0 to 5 percent. Mean annual rainfall ranges from 40 to 55 inches. Frost-free rainfall ranges from 25 to 30 inches. Mean annual temperatures range from 65 to 68 degrees F., and Thornthwaite annual P-E indices exceed 64.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Herty and Keltys series. Herty soils are higher lying, have thin A horizons, are in a fine family, and have a dense clayey substratum. Keltys soils occur on similar landscape positions, are better drained, and contain less than 18 percent clay in the control section.
DRAINAGE AND PERMEABILITY: Diboll soils are somewhat poorly drained. Permeability is moderately slow in the A and E horizons and are very slow in the Bt and Cr horizons. A perched water table is at 6 to 18 inches during the winter and spring.
USE AND VEGETATION: This soil is used mainly for pasture and woodland. Much of this soil was previously used for cropland. Improved pastures are difficult to maintain and manage due to the concentration of crayfish mounds. Native vegetation is mixed pine-hardwood forest with an understory of grasses and shrubs. The understory is usually quite dense with hawthorn and other thorny shrubs.
DISTRIBUTION AND EXTENT: Eastern Texas. This series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Polk and San Jacinto Counties, Texas; 1983.
REMARKS: This soil was formerly considered a thick surface phase of Rains series. Crayfish activity in these soils is extreme and hinder management. In one pastured area there were over 1100 crayfish mounds per acre on the surface. These mounds averaged over 5 inches high and over 11 inches across and amounted to more than 19 tons per acre of soil moved. Local slick spots in pastures with electrical conductivity of 20 to 40 mmhos/cm have been measured.
ADDITIONAL DATA: NSSL Data from Angelina County, Texas, 80TX-005-4(type); 80TX-005 and 80TX-005-6. Reaction of Bt horizon when measured with Hellige-Truog kit is not reliable. Readings with kit are greater than 8.5. Soil reactions in this description are in water dilution and measured with glass electrods (method 8cia in SSIR No. 1).