LOCATION LIGON TXEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, thermic Typic Rhodustalfs
TYPICAL PEDON: Ligon loam--in rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 10 cm (0 to 4 in); reddish brown (5YR 4/4) fine sandy loam, dark reddish brown (5YR 3/4) moist; weak fine subangular blocky structure parting to moderate very fine granular; hard, friable, many very fine and fine roots; many very fine and fine tubular pores; 10 percent, 76 to 250 mm, quartz, non-flat, subangular, indurated; slightly acid; abrupt smooth boundary. (Thickness of the A horizon is 8 to 23 cm [3 to 9 in])
Bt1--10 to 18 cm (4 to 7 in); reddish brown (2.5YR 4/4) clay; dark reddish brown (2.5YR 3/4) moist; moderate fine subangular blocky structure; very hard, firm; common fine and few medium roots; 20 percent dark reddish brown (2.5YR 3/4) clay films on faces of peds and on rock fragments; 15 percent, 76 to 250 mm, quartz, non-flat, subangular, indurated; slightly acid; clear smooth boundary.
Bt2--18 to 46 cm (7 to 18 in); red (2.5YR 4/6) clay; dark red (2.5YR 3/6) moist; weak medium prismatic structure parting to moderate medium subangular blocky; very hard, firm; few fine and very fine roots; 20 percent dark red (2.5YR 3/6) clay films on faces of peds; neutral; gradual smooth boundary. (Combined thickness of the Bt horizon is 15 to 58 cm [6 to 23 in])
Bt3--46 to 58 cm (18 to 23 in); red (2.5YR 4/6) paracobbly sandy clay loam, dark red (2.5YR 3/6) moist; weak medium prismatic structure parting to weak medium subangular blocky; hard, firm; few fine and medium roots; 10 percent clay films; 3 percent, 2 to 5 mm, quartz, non-flat, subrounded, indurated gravel, 20 percent, 2 to 250 mm, schist, non-flat, subangular, weakly cemented gravel and cobbles; neutral; gradual wavy boundary. (Thickness of the Bt3 horizon is 10 to 51 cm [4 to 20 in])
Cd--58 to 81 cm (23 to 32 in); reddish brown (5YR 4/4) noncemented weathered schist bedrock that slakes in water; few very fine and fine roots penetrating cleavage planes; neutral; gradual wavy boundary. (Thickness of the C horizon is 8 to 25 cm [3 to 10 in])
Cr--81 to 132 cm (32 to 52 in); tilted weakly cemented schist bedrock; few fine roots between plates and seams.
TYPE LOCATION: Llano County, Texas; From the intersection of Texas Highway 16 and Ranch Road 2323 in Llano, 11.6 miles southwest on Ranch Road 2323, 3.0 miles north on county road, 1.3 miles north on private road, 60 feet west in rangeland. (Scotts Crossing USGS topographic quadrangle; Latitude: 30 degrees, 40 minutes, 53.4 seconds, N; Longitude: 98 degrees, 51 minutes, 32.4 seconds, W.; NAD83.)
RANGE IN CHARACTERISTICS:
Depth to paralithic contact: 50 to 100 cm (20 to 40 in)
Solum thickness: 50 to 100 cm (20 to 40 in)
Particle-size control section (weighted average)
Clay content: 35 to 45 percent
Rock fragments: Amount-5 to 35 percent by volume, kind-schist and quartz gravel and cobbles
A horizon
Hue: 2.5YR to 7.5YR
Value: 3 to 5, 2 to 4 moist
Chroma: 3 to 6, dry and moist
Texture: Sandy loam, fine sandy loam, loam, or sandy clay loam, or clay loam and their gravelly, very gravelly, and cobbly counterparts
Rock fragments: amount-5 to 40 percent by volume; size-gravel and cobbles; kind-schist and quartz
Organic matter content: 0 to 1 percent
Reaction: moderately acid to slightly alkaline
Bt horizon
Hue: 10R or 2.5YR
Value: 2 to 4, 2 to 3 moist
Chroma: 4 to 6, dry and moist
Texture: Sandy clay loam, clay loam, sandy clay, or clay and their gravelly, very gravelly, and cobbly counterparts
Rock fragments: amount-5 to 40 percent by volume; size-gravel and cobbles; kind-schist and quartz
Reaction: moderately acid to slightly alkaline
Cd layer (where present)
Hue: 2.5YR or 5YR
Value: 3 to 5, 2 to 4 moist
Chroma: 3 to 6, dry and moist
Kind: Weathered schist berock that slakes in water
Cementation: Noncemented
Reaction: moderately acid to slightly alkaline
Cr layer
Kind: hornblende Schist or schistose-gneiss bedrock
Cementation: Weakly cemented or moderately cemented
Vertical fractures: Greater than 10 cm (4 in) apart horizontally
Tilt from horizontal: 30 to 60 degrees
COMPETING SERIES: There are no soils in the same family. Similar soils include
Cosh (TX),
Exray (TX),
Hensley (TX), and
Katemcy (TX) soils.
Cosh soils: are less than 50 cm (20 in) to sandstone bedrock and have loamy control sections.
Exray soils: are less than 50 cm (20 in) to sandstone .
Hensley soils are less than 50 cm (20 in) to limestone.
Katemcy soils: have 5YR to 10YR colors in the argillic horizon.
GEOGRAPHIC SETTING:
Parent material: Residuum weathered from schist and/or gneiss
Landscape: Dissected plain
Landform: Shoulders, backslopes and summits of ridges and hills
Slope: 1 to 15 percent, but are dominantly less than 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 air temperature: 18 to 19 degrees C (65 to 67 degrees F)
Mean annual precipitation: 610 to 762 mm (24 to 30 in)
Frost-free period: 215 to 235 days
Elevation: 305 to 686 m (1,000 to 2,250 ft)
Thornthwaite P-E Index: 38 to 44
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Castell,
Honeycreek, the similar
Katemcy, and
Keese soils.
Castell, Honeycreek, and Katemcy soils: occur lower on the landscape on undulating plains and footslopes of ridges and hills.
Castell soils: are 50 to 100 cm (20 to 40 in) to gneiss bedrock.
Honeycreek soils: have fine-loamy control sections
Keese soils: Are less than 50 cm (less than 20 in) to granite bedrock and occur on similar positions.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately slow. Runoff is medium on 1 to 5 percent slopes and high on 5 to 15 percent slopes.
USE AND VEGETATION: Used for mainly for rangeland. Originally, the prairie had scattered oak with climax dominants that were mainly little bluestem, plains lovegrass, sideoats grama, and Arizona cottontop. Many areas are invaded by brushy species, mainly whitebrush, mesquite, and black persimmon and shorter grasses, including threeawn, annuals, and numerous forbs.
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 with about 125,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: McCulloch County, Texas; 1970.
REMARKS:
Data are available in a thesis "A Study of Mineral Transformations and Weathering Process occurring during the Genesis of Two Soils developed from Gneiss and Schist in Llano County, Texas; May 1965" by Clyde Stahnke for a Masters Degree, Texas Technological College, Lubbock, Texas.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 10 cm (0 to 4 in) (A horizon)
Argillic horizon: 10 to 58 cm (4 to 23 in) (Bt horizons)
Densic material: 58 to 82 cm (23 to 32 in) (Cd layer)
Paralithic contact: at 81 cm (32 in) (at top of the Cr layer)
ADDITIONAL DATA: Lab data available from the National Soil Survey Laboratory on pedon number 86TX299004 (samples 8 6P01749-8 6P01754) from Llano County, TX.
TAXONOMIC VERSION: Keys to Soil Taxonomy, 11th Edition, 2010.