LOCATION LOU TX

Established Series
Rev. PRF-GLL-ACT-ALB
04/2011

LOU SERIES

The Lou series consists of very deep, well drained soils that formed in residuum from granite grus of pre-Cambrian age. These gently sloping soils are on shoulders and summits of ridges and hills. Slope ranges from 1 to 5 percent. Mean annual air temperature ranges from 19 degrees C (66 degrees F), and mean annual precipitation is about 686 mm (27 in).

TAXONOMIC CLASS: Fine-loamy, mixed, active, thermic Typic Haplustalfs

TYPICAL PEDON: Lou coarse sandy loam--in rangeland. (Colors are for dry soil unless otherwise stated.)

A1--0 to 18 cm (0 to 7 in); brown (7.5YR 5/3) coarse sandy loam, dark brown (7.5YR 3/3) moist; weak fine granular structure; very hard, friable; common fine roots; 13 percent, 2 to 75 mm, granite gravel, non-flat, subangular, indurated; neutral; clear smooth boundary.

A2--18 to 30 cm (7 to 12 in); brown (7.5YR 5/4) gravelly coarse sandy loam, brown (7.5YR 4/4) moist; weak very fine and fine subangular blocky structure; hard, friable; common fine roots; 20 percent, 2 to 75 mm, granite gravel, non-flat, subangular, indurated; neutral; clear smooth boundary. (Combined thickness of the A horizon is 8 to 56 cm [3 to 22 in])

Bt1--30 to 51 cm (12 to 20 in); reddish brown (5YR 5/4) gravelly coarse sandy loam, reddish brown (5YR 4/4) moist; moderate fine subangular blocky structure; hard, firm; common fine roots; 10 percent clay bridging of sand grains; 27 percent, 2 to 75 mm, granite gravel, non-flat, subangular, indurated; neutral; clear smooth boundary.

Bt2--51 to 76 cm (20 to 30 in); yellowish red (5YR 5/6) gravelly sandy clay loam; yellowish red (5YR 4/6) moist; moderate fine subangular blocky structure; hard, firm; few fine roots; 10 percent clay films on surface of peds and fragments and in pores; 27 percent, 2 to 75 mm, granite gravel, non-flat, subangular, indurated; neutral; gradual wavy boundary.

Bt3--76 to 97 cm (30 to 38 in); yellowish red (5YR 5/6) gravelly sandy clay loam; yellowish red (5YR 4/6) moist; few faint red and reddish brown mottles; moderate fine subangular blocky structure; very hard, firm; few fine roots; 10 percent clay films on surface of peds and fragments; 30 percent, 2 to 75 mm, granite gravel, non-flat, subangular, indurated; slightly acid; clear wavy boundary. (Combined thickness of the Bt horizon is 51 to 129 cm [20 to 51 in])

BCt--97 to 191 cm (38 to 75 in); red (2.5YR 5/8) extremely gravelly loam, red (2.5YR 4/8) moist; moderate very fine subangular blocky structure; very hard, firm, slightly sticky, slightly plastic; few very fine roots in cracks; common very fine and common fine pores; 90 percent clay films on rock fragments; 85 percent, 2 to 75 mm, granite gravel, non-flat, angular, indurated; noneffervescent; moderately acid. (Combined thickness of the BCt horizon is 18 to 120 cm [7 to 47 in])

TYPE LOCATION: Llano County, Texas; From the intersection of Texas Highway 16 and Texas Highway 29 in Llano, 15 miles east of Llano on Texas Highway 29, 1.6 miles north on Ranch Road 1431, 0.6 mile north on county road and private road, 100 feet east in rangeland. (Lake Buchanan USGS topographic quadrangle; Latitude: 30 degrees, 45 minutes, 54 seconds N; Longitude: 98 degrees, 28 minutes, 4.8 seconds W; NAD83.)

RANGE IN CHARACTERISTICS:
Solum thickness is more than 150 cm (60 in)

Particle-size control section (weighted average):
Clay content: 18 to 35 percent
Rock fragments: 5 to 35 percent total by volume, kind-granite and saprolite; 4 to 28 percent fine gravel; 1 to 7 percent medium and coarse gravel.

A horizon
Hue: 7.5YR or 10YR
Value: 4 to 5, 3 to 4 moist
Chroma: 2 to 4, dry and moist
Texture: coarse sandy loam, sandy loam, or fine sandy loam and gravelly phases
Clay content: 10 to 17 percent
Rock fragments: 2 to 20 percent by volume, kind-granite, size-2 to 75 mm
Other features: The A horizon is hard and massive when dry. A thin E horizon is present in some pedons.
Reaction: slightly acid or neutral

Bt horizon
Hue: 2.5YR to 10YR
Value: 4 to 6, 3 to 5 moist
Chroma: 3 or 6, dry and moist
Texture: coarse sandy loam, sandy loam, or sandy clay loam and gravelly phases
Clay content: 18 to 35 percent
Rock fragments: 5 to 35 percent by volume, kind-granite, size-2 to 75 mm
Clay films: amount-few to common, location-faces of peds, fragments, and pores
Base saturation: 75 to 100 percent
Reaction: moderately acid to neutral

BCt horizon
Hue: 10R to 7.5YR
Value: 4 to 6, 3 to 5 moist
Chroma: 4 to 8, dry and moist
Texture: extremely gravelly loam or extremely gravelly sandy clay loam
Clay content: 15 to 30 percent
Rock fragments: Amount-60 to 90 percent by volume, kind-granite and granite saprolite, size-2 to 75 mm
Reaction: Moderately acid or slightly acid

COMPETING SERIES: These include the Arnett (OK), Cobb (TX), Decobb (OK), Grandmore (OK), Mcknight (OK), and Menard (TX) soils. Similar soils are Click (TX), Grandfield (OK), Honeycreek (TX), Hye (TX), Rochelle (TX), and Seagraves (TX) soils.
Arnett soils: have identifiable secondary carbonates within 25 to 127 cm (10 to 50 in) and formed in loamy and gravelly alluvium.
Cobb soils: are 50 to 100 cm (20 to 40 in) to sandstone bedrock and receive less rainfall.
Decobb soils: are 150 to 200 cm (60 to 80 in) to sandstone bedrock.
Click soils: have more than 35 percent coarse fragments in the control section.
Granfield soils: have less than 5 percent coarse fragments
Grandmore soils: are 76 to 150 cm (30 to 60 in) to a lithologic discontinuity, have less than 15 percent coarse fragments in the argillic horizon.
Honeycreek soils: are 100 to 150 cm (40 to 60 in) to schist bedrock.
Hye soils: are 50 to 100 cm (20 to 40 in) to sandstone bedrock and have less than 15 percent gravel in the argillic horizon.
Mcknight, Menard, and Rochelle soils: contain identifiable secondary carbonates at depths less than 76 cm (30 in).
Seagraves soils: contain identifiable secondary carbonates at 127 to 200 cm (50 to 80 in) and formed in lacustrine sediments.

GEOGRAPHIC SETTING:
Parent material: Residuum from pre-Cambrian granite bedrock and grus
Landscape: Dissected plains
Landform: Backslopes, shoulders and summits of ridges and hills
Slope: 1 to 5 percent
Climate: Dry subhumid
Soil moisture: A typic ustic moisture regime.
Precipitation Pattern: The majority of the yearly amount occurs during the fall and spring months. The winter and summer months are normally drier.
Mean annual precipitation: 610 to 762 mm (24 to 30 in)
Mean annual air temperature: 18 to 20 degrees C (65 to 68 degrees F)
Frost-free period: 210 to 240 days
Elevation: 244 to 671 m (800 to 2,200 ft)
Thornthwaite P-E Index: 38 to 44

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Bauman, Castell, Click, Katemcy, Keese, Ligon, and Voca soils.
Bauman soils: are on lower concave positions and have natric horizons.
Castell and Katemcy soils: are 50 to 100 cm (20 to 40 in) to gneiss and schist bedrock, respectively, and occur on undulating plains and footslopes of ridges and hills
Keese soils: are less than 50 cm (20 in) to bedrock and occur on similar positions.
Ligon soils: have greater than 35 percent clay in the control section and are on similar positions.
Voca soils: have greater than 35 percent clay in the control section and are on undulating plains and footslopes of ridges and hills

DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate. Runoff is medium on 1 to 5 percent slopes.

USE AND VEGETATION: Used mainly for rangeland. Some areas are used for wildlife land and improved pastures. The potential plant community is an open savannah of post oak, blackjack oak, and live oak with mid and tall grasses in thin stands. The dominant grass is little bluestem. Other grasses include sideoats grama, yellow Indiangrass, sandhill lovegrass, Arizona cottontop, fringeleaf paspalum, pinhole bluestem, vine mesquite and purpletop tridens. The dominant forbs include orange zexmenia, sagewort, snoutbean, and heath aster. The woody plants include post oak, blackjack oak and live oak. Continued heavy use causes further deterioration and plants such as mesquite, whitebrush, yucca, Ashe juniper, gummy lovegrass, Texas grama, prairie coneflower, and basin sneezeweed, invade or increase on the ecological site.

DISTRIBUTION AND EXTENT: Central Texas; Southwest Plateaus and Plains Range and Cotton Region, LRR-I; MLRA 82A-Texas Central Basin. This series is of large extent.

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

SERIES ESTABLISHED: Llano County, Texas; 1984. Lou is a coined name.

REMARKS: This soil was formerly included with the Voca or Click series.

The Lou series was previously considered to have a paralithic contact within 102 cm (40 in). The series concept has been changed to very deep with no bedrock based on observations and descriptions.

Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 30 cm (0 to 12 in) (A1 and A2 horizons)
Argillic horizon: 30 to 191 cm (12 to 75 in) (Bt1, Bt2, Bt3, and BCt horizons)

ADDITIONAL DATA: NSSL-S82TX-299-002. (sampled as Voca-like)

TAXONOMIC VERSION: Keys to Soil Taxonomy, 11th Edition, 2010.

National Cooperative Soil Survey
U.S.A.