LOCATION AROL TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Udic Paleustalfs
TYPICAL PEDON: Arol fine sandy loam--pasture. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 6 inches; dark grayish brown (10YR 4/2) fine sandy loam, grayish brown (10YR 5/2) dry; massive; hard, friable; many fine roots; moderately acid; abrupt smooth boundary. (3 to 12 inches thick)
Bt1--6 to 18 inches; black (10YR 2/1) clay, very dark gray (10YR 3/1) dry; moderate medium angular blocky structure; very hard, very firm, sticky and plastic; common fine roots; thin patchy clay films on surfaces of peds; few shiny pressure faces; moderately acid; gradual wavy boundary.
Bt2--18 to 30 inches; very dark gray (10YR 3/1) clay, dark gray (10YR 4/1) dry; moderate coarse angular blocky structure; very hard, very firm, sticky and plastic; common fine roots; thin patchy clay films on surfaces of peds; few shiny pressure faces; few fine distinct light gray (10YR 7/2) and pinkish gray (7.5YR 7/2) redox depletions with sharp boundaries; slightly acid; abrupt smooth boundary. (combined Bt subhorizons are 15 to 32 inches thick)
Cr--30 to 45 inches; pale olive (5Y 6/3) weakly cemented clayey tuff; massive and weakly bedded; extremely hard, extremely firm; can be cut with a spade; gray stains between cleavage planes; neutral.
TYPE LOCATION: Walker County, Texas; from the intersection of Interstate 45 and Texas Highway 30 in Huntsville, Texas; 4.6 miles north along west access road of I-45 and northwest on Texas Highway 75 to the intersection on Wire Road; 2.7 miles west on Wire Road and 320 feet south in pasture.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 20 to 40 inches. Weighted average clay content of the particle- size control section ranges from 35 to 45 percent. The COLE may exceed 0.07 in the Bt subhorizons of some pedons, but the potential linear extensibility is less than 6 cm. Redox features are mainly relic or lithochromic.
The A horizon has hue of 10YR or 2.5Y, value of 4 to 6 and chroma of 1 or 2. The E horizon, where present, has value that are one or two units of value higher than the A horizon. Texture is fine sandy loam or loam. Reaction ranges from strongly acid to slightly acid.
The upper part of the Bt horizon has hue of 7.5YR or 10YR, value of 2 or 3 and chroma of 1 or 2. Reaction ranges from strongly acid to neutral. The lower part of the Bt horizon has hue of 7.5YR or 10YR, value of 2 to 6 and chroma of neutral to 2. The Bt subhorizons are clay or clay loam. Redox features or mottles in shades of gray, yellow and red range from few to common. Reaction ranges from moderately acid to slightly alkaline.
A BC horizon, where present, has hue of 10YR or 2.5Y, value of 5 to 7 and chroma of 1 to 3. Reaction ranges from slightly acid to slightly alkaline.
The Cr layer has hue of 10YR, 2.5Y or 5Y, values of 5 to 8 and chroma of 1 to 3. It ranges from clayey tuff to mudstone, containing small amounts of volcanic materials, to very fine grained weakly cemented sandstone or siltstone. Reaction ranges from moderately acid to moderately alkaline. Some pedons are very slightly or slightly effervescent. Roots seldom enter this material, but are along cleavage planes or fractures in some pedons.
COMPETING SERIES: These are the Chazos, Falba, Gredge, Payne, Singleton and Zack soils. Similar soils are the Burlewash, Lufkin, Shalba, and Zulch soils. Chazos, Gredge, Payne, and Lufkin soils have sola thicker than 40 inches. Falba soils have colors with value more than 3 throughout the argillic horizon. Singleton soils have a Bt horizon with more than 40 percent of the matrix with chroma of 3 or 4. Burlewash soils are well drained and have higher chroma colors in the Bt horizon. Shalba soils have sola less than 20 inches thick. Zack soils do not have a paralithic contact of tuffaceous materials. Zulch soils have distinct vertic properties and do not have a paralithic contact.
GEOGRAPHIC SETTING: Arol soils are on uplands. Slopes range from 0 to 5 percent and are plane to weakly concave. The soils formed in interbedded tuffaceous clays, ash beds, sandstones, and pyroclastics as typified by the Catahoula and associated formations. The mean annual precipitation ranges from 35 to 45 inches and mean annual temperature ranges from 67 to 70 degrees F. Frost free days range from 260 to 280 days and elevation ranges from 250 to 600 feet. Thornthwaite annual P-E indices range from 55 to 72. The soils occur in areas with a summer moisture deficit of 6 to 8 inches on the average.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Burlewash, Lufkin, and Shalba series and the Elmina, Leson, Mabank, and Redco series. Burlewash soils are on nearby sloping areas. Shalba soils are on similar landscape positions. Elmina soils have sandy surface layers 20 to 40 inches thick and are on slightly higher positions. Leson and Redco soils have intersecting slickensides and are clayey throughout and are on similar to slightly higher positions. Lufkin and Mabank soils have sola thicker than 60 inches and have vertic properties. These soils are on adjoining nearly level Pleistocene terraces.
DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is very slow. Runoff is low on slopes less than 1 percent, medium on 1 to 3 percent slopes, and high on 3 to 5 percent slopes. Slow internal drainage.
USE AND VEGETATION: Used mainly as pastureland. Large acreages were once planted to cotton and corn, but are now idle or in low quality pastures of threeawn grasses and annuals. Improved pastures are mainly coastal bermudagrass. Native grasses are little bluestem, indiangrass, switchgrass, big bluestem, and sideoats grama with scattered post oak trees.
DISTRIBUTION AND EXTENT: Southeastern Claypan area of Texas (MLRA 87A). The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Walker County, Texas; 1975.
REMARKS: These soils do not have an aquic moisture regime. Classification change from Typic Albaqualfs is due to interpretation that the low chroma matrix is due to organic matter accumulations in conjunction with gray colored parent material. Field observations, water table studies from Texas A&M University, landscape position and climate indicate the soil is typically not saturated long enough to be reduced in most years. Arol soils were formerly included in the Wilson series.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 6 inches (Ap horizon)
Abrupt textural change from A to Bt horizon
Argillic horizon - 6 to 30 inches (Bt horizon)
Paralithic Contact - at depth of 30 inches weakly cemented tuff.
ADDITIONAL DATA: National Soil Survey Laboratory - S70TX-236-4.
SOIL INTERPRETATION RECORD NUMBER: TX0309