LOCATION ATASCO TX

Established Series
FFW-JKW-RM
07/2014

ATASCO SERIES

The Atasco series consists of very deep, moderately well drained soils. These nearly level to gently sloping soils formed in loamy fluvial deposits of Pleistocene age. Slope ranges from 1 to 8 percent. Mean annual temperature is about 19.5 degrees C (67 degrees F), and mean annual precipitation is about 1295 mm (51 in).

TAXONOMIC CLASS: Fine, smectitic, thermic Vertic Hapludalfs

TYPICAL PEDON: Atasco fine sandy loam in forest (Colors are for moist soil unless otherwise stated.)

A--0 to 15 cm, (0 to 6 in); brown (10YR 5/3) fine sandy loam; weak fine granular structure; very friable; common fine to very coarse roots throughout; common medium vesicular pores; very strongly acid; clear smooth boundary. (10 to 20 cm [4 to 8 in] thick)

E--15 to 36 cm, (6 to 14 in); light yellowish brown (10YR 6/4) fine sandy loam; weak fine subangular blocky structure; very friable; common fine to coarse roots throughout; common fine tubular pores; 1 percent medium spherical moderately cemented strong brown (7.5YR 4/6) ironstone nodules; strongly acid; very abrupt smooth boundary. (10 to 28 cm [4 to 11 in] thick)

Bt1--36 to 54 cm, (14 to 21 in); red (2.5YR 4/6) and 40 percent brownish yellow (10YR 6/6) clay; moderate medium angular blocky structure; firm; common very fine and fine roots throughout; common very fine and fine tubular pores; 10 percent distinct light yellowish brown (10YR 6/4) clay films on all faces of peds; few distinct pressure faces; extremely acid; clear smooth boundary. (combined thickness of the Bt horizons is 74 to 125 cm [29 to 49 in])

Bt2--54 to 83 cm, (21 to 33 in); brownish yellow (10YR 6/6) and 35 percent red (10R 4/6) sandy clay; moderate medium angular blocky structure; firm; common very fine roots between peds; 10 percent distinct yellowish brown (10YR 5/4) clay films on vertical faces of peds; few faint slickensides; common distinct pressure faces; 5 percent medium prominent gray (10YR 6/1) iron depletions with clear boundaries on faces of peds; extremely acid; gradual smooth boundary.

Bt3--83 to 123 cm, (33 to 49 in); 40 percent red (10R 4/6), 35 percent yellow (10YR 7/6), and 25 percent gray (10YR 6/1) sandy clay; moderate coarse angular blocky structure; firm; common very fine roots; common very fine tubular pores; 5 percent distinct gray (10YR 5/1) clay films on vertical faces of peds; common distinct pressure faces; 5 percent prominent yellowish red (5YR 4/6) masses of oxidized iron with sharp boundaries lining pores; extremely acid; gradual wavy boundary.

Btg1--123 to 179 cm, (33 to 71 in); light gray (N 7/) and 30 percent red (10R 5/8) sandy clay loam; weak coarse subangular blocky structure; firm; common very fine roots; 10 percent distinct gray (N 6/) clay films on vertical faces of peds; 10 percent medium prominent strong brown (7.5YR 5/8) masses of oxidized iron with clear boundaries; very strongly acid; gradual wavy boundary. (combined thickness of the Btg horizons is 57 to 89 cm [22 to 35 in])

Btg2--179 to 203 cm, (71 to 80 in); light greenish gray (10Y 8/1) and 45 percent yellowish red (5YR 5/6) clay; weak coarse subangular blocky structure; firm; common very fine roots; common very fine pores; 5 percent pale yellow (2.5Y 8/2) sand coats on all faces of peds; 10 percent light greenish gray (10Y 8/1) clay films; very strongly acid.

TYPE LOCATION: Montgomery County, Texas; from the intersection of U.S. Highway 59 and FM 1485 in New Caney, about 3.3 miles east on FM 1485 to Lake Houston City Park; south 0.2 mile; east 100 feet in forest. (Splendora USGS quad; Latitude: 30 degrees, 8 minutes 49.4 seconds N; Longitude: 95 degrees, 10 minutes, 5.6 seconds W; WGS84)

RANGE IN CHARACTERISTICS:
Soil Moisture: An udic soil moisture regime. The soil moisture control section is 10 to 30 cm (4 to 12 in) below the soil surface and remains dry less than 90 cumulative days in most years.
Mean annual soil temperature: 20.6 to 21.7 degrees C (69 to 71 degrees F)
Particle-size control section (weighted average)
Clay content: 40 to 50 percent

A Horizon
Hue: 10YR
Value: 3 to 5 (areas with value of 3 are less than 25 cm [10 in] thick)
Chroma: 2 or 3
Texture: fine sandy loam, very fine sandy loam, or loam
Clay content: 5 to 24 percent
Redox concentrations: amount-0 to 2 percent, location-lining pores, shades-brown
Reaction: very strongly acid to slightly acid

E Horizon
Hue: 10YR
Value: 4 to 6
Chroma: 3 or 4
Texture: fine sandy loam, very fine sandy loam, or loam
Clay content: 5 to 22 percent
Redox concentrations: amount-0 to 2 percent, location-lining pores, shades-brown
Reaction: very strongly acid to slightly acid

Bt Horizon
Variegated matrix in Hue: 10R to 10YR
Value: 4 to 6
Chroma: 1 to 8
Texture: clay loam, sandy clay, or clay
Clay content: 28 to 60 percent
Redox concentrations: amount-0 to 20 percent, location-lining pores and in matrix, shades-brown, red or yellow
Redox depletions: amount-0 to 20 percent, location-lining pores and in matrix, shades-blue, gray or green
Reaction: extremely acid to moderately acid

Btg Horizons
Variegated matrix in Hue: N to 10R
Value: 6 to 8
Chroma: 1 to 8
Texture: loam, sandy clay loam, clay loam, or clay
Clay content: 20 to 48 percent
Redox concentrations: amount-5 to 20 percent, location-lining pores and in matrix, shades-brown, red or yellow
Redox depletions: amount-0 to 20 percent, location-lining pores and in matrix, shades-blue, gray or green
Reaction: extremely acid to moderately acid

COMPETING SERIES: These are the Chickasaw (TN), Colbert (AL), Etoile (TX), Iota (LA), Kellison (TX), Oakhurst (TX), Oula (LA), Rayburn (TX), Telogia (FL), and Woodtell (TX) series. Similar soils are the Spurger (TX), Woodville (TX) and the tentative Buna (TX) series.
Chickasaw soils: weakly cemented fractured claystone at 45 in
Colbert soils: limestone bedrock at 140 cm (55 in)
Etoile soils: shale at 135 cm (53 in)
Iota soils: well drained; less acidic in the lower part of the solum
Kellison soils: shale at 119 cm (47 in)
Oakhurst soils: volcanic tuff at 117 cm (46 in)
Oula soils: well drained; solum ranges from 64 cm (25 in)
Rayburn soils: weakly consolidated tuffaceous sandstone at 140 cm (55 in)
Telogia soils: somewhat poorly drained; limestone at 122 cm (48 in)
Woodtell soils: shale at 114 cm (45 in)
Buna soils: less than 35 percent base saturation in the lower part of the argillic horizon
Spurger soils: have aquic conditions
Woodville soils: do not have a decrease in clay percentage in the lower part of the solum

GEOGRAPHIC SETTING:
Parent material: loamy fluvial deposits of Pleistocene age.
Landscape: river valleys
Landform: terraces
Slope: 0 to 1 percent
Mean annual air temperature: 19.5 to 20.6 degrees C (67 to 69 degrees F).
Mean annual precipitation: 1219 to 1473 mm (48 to 56 in)
Precipitation pattern: uniform throughout the year with slight peaks in the spring and summer
Frost-free period: 240 to 300 days
Elevation: 3 to 61 m (10 to 200 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hatliff (TX), Kian (TX), Pluck (TX), Segno (TX), and Splendora (TX) series.
Hatliff, Kian, and Pluck soils: are loamy throughout; on flooded areas
Segno and Splendora soils: are loamy throughout; on an interfluve

DRAINAGE AND PERMEABILITY: moderately well drained. Runoff is very high.

USE AND VEGETATION: Most areas are in pine and hardwood forest and used mainly for woodland grazing and pasture, with some areas having urban encroachment. Principal vegetation consists of loblolly pine, red oak, water oak, hackberry, sweetgum, winged elm, hawthorne, yaupon, American beautyberry, berry vines, and longleaf uniola.

DISTRIBUTION AND EXTENT: Southeast Texas mainly west of the Trinity River; Land Resource Region T; MLRA 152B; the series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Harris County, Texas; 1973.

REMARKS: The Atasco series was formerly included in the Acadia, Woodville and Spurger series. The classification was changed during the update of MLRA 152Bs. Prior classifications included a glossic horizon and mixed mineralogy. Areas of these soils do not show evidence of clay stripping.

Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 36 to 86 cm (14 to 34 in). (Bt1, Bt2, and Bt3 horizons)

Ochric epipedon: 0 to 36 cm (0 to 14 in). (A and E horizons)
Argillic horizon: 36 to 203 cm (14 to 80 in). (Bt1, Bt2, Bt3, Btg1, Btg2 horizons)

Vertic features: The presence of pressure faces and slickensides and clayey texture from 36 to 123 cm (14 to 49 in) (Bt1, Bt2, and Bt3 horizons)

Additional Comments: Gray, brown and yellow colors in the variegated matrix are due to wetness, which formed during wetter than normal conditions.

ADDITIONAL DATA: KSSL data available on pedon S12TX3391032.

Taxonomic Version: Keys to Soil Taxonomy, Eleventh Edition, 2010

National Cooperative Soil Survey
U.S.A.