LOCATION BASTSIL TXEstablished Series
TAXONOMIC CLASS: Fine-loamy, siliceous, active, thermic Udic Paleustalfs
TYPICAL PEDON: Bastsil loamy fine sand--cropland. (Colors are for dry soil unless otherwise stated.)
A--0 to 6 inches; light brown (7.5YR 6/4) loamy fine sand, brown (7.5YR 4/4) moist; single grained; loose, very friable; many very fine and fine roots; few siliceous pebbles; slightly acid; clear smooth boundary. (4 to 8 inches thick)
E--6 to 16 inches; light brown (7.5YR 6/4) loamy fine sand, brown (7.5YR 5/4) moist; single grained; loose, very friable; many very fine and fine roots; few coarse roots; few siliceous pebbles; slightly acid; abrupt smooth boundary. (0 to 12 inches thick)
Bt1--16 to 31 inches; red (2.5YR 4/6) sandy clay loam, dark red (2.5YR 3/6) moist; common medium faint to coarse yellowish red (5YR 4/6) mottles; weak coarse prismatic structure parting to moderate medium and coarse subangular blocky; very hard, friable; common fine roots; many fine pores; few wormcasts; common thin patchy clay films on faces of peds and bridging sand grains; few siliceous pebbles; slightly acid; gradual wavy boundary. (12 to 25 inches thick)
Bt2--31 to 43 inches; strong brown (7.5YR 5/6) sandy clay loam, strong brown (7.5YR 5/6) moist; common fine and medium faint yellowish red (5YR 5/6, 5/8) mottles; moderate coarse prismatic structure parting to weak and moderate medium and coarse subangular blocky; very hard, friable; common fine roots; many fine and very fine pores; few wormcasts; common clay films on faces of peds and bridging sand grains; few siliceous pebbles; few black masses up to 1 cm in diameter; slightly acid; gradual wavy boundary. (10 to 26 inches thick)
Bt3--43 to 52 inches; strong brown (7.5YR 5/6) sandy clay loam, strong brown (7.5YR 5/6) moist; common medium distinct dark red (2.5YR 3/6) mottles in interior of peds; moderate coarse prismatic structure parting to weak and moderate medium and coarse subangular blocky; extremely hard, friable; common fine roots and many fine and very fine pores in strong brown part; common thin patchy clay films on faces of prisms and bridging sand grains; few smooth, rounded siliceous pebbles; slightly acid; gradual irregular boundary. (0 to 15 inches thick)
Bt/E--52 to 80 inches; red (2.5YR 4/6) sandy clay loam, red (2.5YR 4/6) moist (Bt part); common faint medium and coarse red (10R 4/6) and few medium distinct strong brown (7.5YR 6/6) mottles in interiors of peds; moderate and strong coarse prismatic structure parting to medium prismatic and coarse blocky; extremely hard, firm; coarse prisms coated with light gray (10YR 7/2) sand grains l mm thick (E part); medium prisms and coarse blocks coated with light gray (10YR 7/2) clay films; common fine roots in light gray areas; common very fine pores in light gray areas; few siliceous pebbles; slightly acid.
TYPE LOCATION: Hill County, Texas, about 17 miles west of Hillsboro in coastal bermudagrass field. North from Whitney on Farm Road 933 for 5 miles, west on Farm Road 1713 for 5.5 miles into McCown Park, south on sand road for 0.5 mile, east 0.15 mile, south 0.25 mile, west 0.25 mile and south 0.15 mile. Site is 375 feet west of road and 75 feet south of wooded area.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. The average clay content of the control section ranges from 20 to 30 percent. Most pedons contain a few siliceous pebbles and they range up to 15 percent by volume in some horizons. Beds of siliceous gravel and sand are typically within a depth of 5 to 12 feet. The gravel are mainly smooth, rounded, and less than three inches across.
The A horizon has hue of 5YR, 7.5YR, or 10YR, value of 4 to 6, and chroma of 2 to 6. It is loamy fine sand or fine sandy loam. The reaction ranges from medium acid to neutral unless limed.
The E horizon has colors with 1 to 2 value or more than the A horizon. The chroma however are typically 4 or less. It is loamy fine sand or fine sandy loam. Reaction ranges from strongly acid to slightly acid unless limed. The E horizon is absent in some pedons as a result of being mixed with the A horizon by cultivation.
The Bt horizon has colors in shades of red or brown with hue of 2.5YR, 5YR, or 7.5YR, value of 4 to 6, and chroma of 4 to 8. Typically there are mottles of these colors or in other shades of red and yellow. The texture is mainly sandy clay loam, but the range includes fine sandy loam, loam, and clay loam. The reaction ranges from medium acid to mildly alkaline. In some pedons the reaction increases with depth.
The Bt/E horizon has reddish or brownish matrix colors. Grayish uncoated sand and silt particles are on the surface of peds and in streaks or pockets. These soil materials (E) range from a few coatings between peds to about 15 percent by volume. The texture is most commonly sandy clay loam but ranges from sandy loam to clay loam. The reaction ranges from medium acid to mildly alkaline. However, parts or spots in this horizon of some pedons are strongly acid.
Some pedons have a 2C horizon below a depth of 60 inches. It is loamy fine sand, loamy sand or stratified beds of sand and gravel. The reaction is variable and ranges from medium acid to moderately alkaline. Some pedons are calcareous.
COMPETING SERIES: These include the Duffau and the Flynn series. Other similar soils include Bastrop, Delwin, Gasil, Gholson Konawa, and Silawa series. Bastrop, Delwin, and Konawa soils have mixed mineralogy. Duffau soils are on uplands formed in the cretaceous Paluxy sand and does not have B/E horizons and does not have sandy or gravelly sediments below the solum. Flynn soils have fragments of weathered glaucontic materials in the lower argillic horizon. Gasil soils have control sections with hue of 7.5YR or 10YR and base saturation less than 75 percent throughout the argillic horizon. Gholson soils have a clay decrease of more than 20 percent of the maximum within 60 inches. Silawa soils are more acid throughout the argillic horizon and have less clay in the lower part.
GEOGRAPHIC SETTING: Bastsil soils are on nearly level or gently sloping stream terraces. Slopes are typically 1 to 3 percent but range from 0 to 5 percent. The soil formed in loamy, alluvial sediments. The climate is subhumid. The normal annual precipitation ranges from 28 to 36 inches. Mean annual temperature ranges from 64 to 68 degrees F. The average summer moisture deficit is 7 to 9 inches. Frost free period is 220 to 250 days and elevation ranges from 350 to 1000 feet. Thornthwaite PE indices are 44 to 62.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Gasil series and Aquilla, Desan, Minwells, and Silstid series. Aquilla soils have a sandy control section and are on similar terrace positions. Desan soils have sandy grossarenic surfaces. Gasil and Silstid soils are on higher lying upland positions. Minwells soils have a clayey control section. Silstid soils have sandy arenic surfaces. These soils are on similar or slightly higher terrace positions.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability. There is a water table for short periods of less than 30 days below a depth of 48 inches in most years.
USE AND VEGETATION: Used mainly for crops and improved pastures. Crops include peanuts, grain sorghum, small grain, and truck crops. Pastures of improved bermudagrass or kleingrass are common. Native vegetation is mainly little bluestem with other perennial grasses and grape, greenbriar, low shrubs, with post oak and blackjack oak trees.
DISTRIBUTION AND EXTENT: Central Texas, mainly along terraces of the Brazos and Trinity Rivers or other rivers that have watersheds primarily with soils of Cretaceous age. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Hill County, Texas, 1975.
REMARKS: The soils were formerly included with Bastrop series.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface of the soil to a depth of 16 inches. (A & E horizons)
Argillic horizon - the zone from 16 to 80 inches.
Paleustalf feature - clay content does not decrease by more than 20 percent of the maximum content within 60 inches from the soil surface.
ADDITIONAL DATA: NSSL: S73TX-109-1; S74TX-113-1 & 2; S80TX-099-1 & 2; S80TX-099-6 & 7 & 8; S80TX-193-1 & 2. All are mineralogy determination or mineralogy and particle-size.