LOCATION VIBORAS TX

Established Series
Rev. WJG-RM
11/2010

VIBORAS SERIES

The Viboras series consists of moderately deep, well drained, very slowly permeable soils that formed in calcareous, sodic clayey residuum weathered from siltstone and shale. These nearly level to gently sloping soils are on valley floors and valley sides. Slope ranges from 0 to 5 percent. Mean annual temperature is about 22 degrees C (72 degrees F) and mean annual precipitation is about 533 mm (21 in).

TAXONOMIC CLASS: Fine, mixed, superactive, hyperthermic Torrertic Haplustepts

TYPICAL PEDON: Viboras clay in rangeland. (Colors are for dry soil unless otherwise stated.)

A--0 to 8 cm (0 to 3 in); brown (7.5YR 4/2) clay, dark brown (7.5YR 3/2) moist; moderate medium angular blocky structure; very hard, very firm, very sticky and very plastic; many fine roots; few fine pores; surface has 12mm (0.5 in) mulch of brown (7.5YR 5/2) clay loam; few rounded pebbles on the surface; noncalcareous matrix, but parts of some peds are calcareous; moderately alkaline; clear smooth boundary. (0 to 25 cm [0 to 10 in])

Bn--8 tp 23 cm (3 to 9 in); reddish brown (5YR 5/3) clay, reddish brown (5YR 4/3) moist; moderate coarse angular blocky structure; very hard, very firm, very sticky and very plastic; common fine roots; few fine pores; shiny pressure faces on ped surfaces; few waterworn pebbles and fragments of snail shells; few streaks of A material from above; 10 percent calcium carbonate equivalent; 3.0 dS/m; ESP is 18; stronlgly effervescent; slightly saline; moderately alkaline; clear wavy boundary. (0 to 61 cm [0 to 24 in])

Bnz--23 to 41 cm (9 to 16 in); reddish brown (5YR 5/4) clay, reddish brown (5YR 4/4) moist; moderate coarse angular blocky structure; very hard, very firm, very sticky and very plastic; few fine roots; shiny pressure faces on peds; few waterworn pebbles, few snail shells; 10 percent calcium carbonate equivalent; 8.5 dS/m; ESP is 20; strongly effervescent; strongly saline; moderately alkaline; clear wavy boundary. (20 to 51 cm [8 to 20 in])

Bknyz--41 to 71 cm (16 to 28 in)s; reddish brown (5YR 5/4) clay, reddish brown (5YR 4/4) moist; weak medium subangular blocky structure; very hard, very firm, very sticky and very plastic; few fine roots; 2 percent threads and films of calcium carbonate; few threads, films and crystals of gypsum and other salts; few weathered siltstone fragments in lower part; 10 percent calcium carbonate equivalent; 11.0 dS/m; ESP is 25; strongly effervescent; strongly saline, moderately alkaline; clear wavy boundary. (0 to 41 cm [0 to 16 in])

Cd/Bknyz--71 to 91 cm (28 to 36 in); reddish brown (5YR 5/4) and light greenish gray (10Y 7/1) fractured weathered siltstone bedrock (Cd); massive; very hard, firm, very sticky and very plastic; reddish brown (5YR 5/4) clay, reddish brown (5YR 5/4) moist (Bkny2) in cracks and crevices; weak fine subangular blocky structure; hard, firm, very sticky and very plastic; few fine roots in cracks; siltstone fragments are partially weathered and slake in water: 2 percent threads, films, and concretions of calcium carbonate; few threads and crystals of gypsum and other salts; 17 percent calcium carbonate equivalent; 11 dS/m; ESP is 25; strongly effervescent; strongly saline; moderately alkaline, gradual wavy boundary.

Cd--91 to 152 cm (36 to 60 in); reddish brown (5YR 5/4) and light gray (10YR 7/1) fractured weathered siltstone bedrock that slakes in water; massive; very sticky and very plastic; can be dug with a spade when moist; 22 percent calcium carbonate equivalent; violently effervescent; 11 dS/m; ESP is 20; moderately alkaline.

TYPE LOCATION: Webb County, Texas; from intersection of Callaghan County Road and access road on east side of Interstate 35, 12.6 miles east on Callaghan Road to a windmill next to a gas plant; 0.45 mile east on Callaghan Road, 50 feet south of road in rangeland. Pato Creek, TX USGS topographic quadrangle. Latitude: 27 degrees, 51 minutes, 50.997 seconds, N; Longitude: 99 degrees 13, minutes, 6.043 seconds, W; NAD 83.

RANGE IN CHARACTERISTICS:

Soil Moisture: An aridic ustic moisture regime. The soil moisture control section is moist in some or all parts for less than 90 consecutive days in normal years. June to August and December to February are the driest months, while September to November and March to May are the wettest months.
Mean annual soil temperature: 22 to 24 degrees (72 to 76 degrees F).
Depth to densic contact: 51 to 102 cm (20 to 40 in)
Depth to cambic horizon: 8 to 71 cm (3 to 28 in)
Particle-size control section (weighted average)
Clay content: 40 to 60 percent
Coarse Fragments: 0 to 2 percent
CEC/clay ratio: 0.60 to 0.90

A horizon
Hue: 5YR or 7.5YR
Value: 4 or 5
Chroma: 2 to 4
Texture: clay loam or clay
Clay content: 35 to 60 percent
Coarse fragments: 0 to 5 percent
Base saturation: 100
Calcium carbonate equivalent: 0 to 20 percent
EC (dS/m): 1 to 8 dS/m
Gypsum: 0 to 2 percent
SAR: 0 to 12 percent
Effervescence: none to strong
Reaction: slightly or moderately alkaline

Bn, Bnz or Bknyz horizons
Hue: 5YR or 7.5YR
Value: 4 to 6
Chroma: 2 to 4
Texture: clay loam or clay
Clay content: 40 to 60 percent
Coarse fragments: 0 to 5 percent
Base saturation: 100 percent
Calcium carbonate equivalent: 5 to 30 percent
Identifiable secondary carbonate: 0 to 5 percent, fine and medium, films, threads, and masses
EC (dS/m): 4 to 35
Gypsum: 0 to 5 percent
SAR: 10 to 35. Averages 15 percent or more in the upper 20 inches and increases with depth
Effervescence: strong or violent
Reaction: moderately alkaline

Cd horizon
Hue: 2.5YR to 7.5YR
Value: 4 to 6
Chroma: 2 to 4
Texture: clay, clay loam or silty clay loam
Clay content: 40 to 60 percent
Coarse fragments: 0 to 10 percent
Base saturation: 100 percent
EC (dS/m): 4 to 35
Gypsum: 0 to 5 percent
SAR: 15 to 35
Effervescence: strong or violent
Reaction: moderately alkaline

COMPETING SERIES: The Runn (TX) series is in the same family. Similar soils are the Bayfield (CO), Catarina (TX), Lasalle (TX), and Maverick (TX) series.
Bayfield soils: are in a mesic soil temperature regime.
Catarina and Lasalle soils: have slickensides and are very deep.
Maverick soils: have hue of 10YR and yellower and do not have vertic properties.

GEOGRAPHIC SETTING:
Parent material: calcareous, sodic, clayey residuum weathered from shale and siltstone
Landform: valley floor and sides
Slope: 0 to 5 percent
Mean annual air temperature: 21 to 23 degrees C (70 to 74 degrees F).
Mean annual precipitation: 406 to 610 mm (16 to 24 in)
Frost-free period: 280 to 360 days
Elevation: 76 to 274 m (250 to 900 ft)
Thornthwaite annual P-E indices: 20 to 32

GEOGRAPHICALLY ASSOCIATED SOILS: These include Catarina, Jimenez, Maverick, Moglia, Montell, and Quemado soils.
Catarina soils: are in broad nearly level valleys at lower positions
Jimenez and Quemado: soils are gravelly and are on ridges and hilltops of higher positions
Maverick soils: are on higher positions on the more erosive and sloping surfaces
Montell soils: have intersecting slickensides and are on broad valleys at lower positions

DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is very slow. Runoff is high on slopes less than 1 percent and very high on 1 to 5 percent slopes.

USE AND VEGETATION: This soil is used primarily for rangeland and wildlife habitat. The native vegetation in excellent condition is composed of 90 percent grasses, 5 percent woody plants, and 5 percent forbs. In excellent
condition, mid grasses such as twoflower trichloris, Arizona cottontop, plains bristlegrass, pink pappusgrass, and alkali sacaton dominate; mesquite, guayacan, fourwing saltbush, and lotebush are dominant woody plants; the major forb is velvet bundleflower. As retrogression occurs, woody plants increase in density and curlymesquite increases or invades. Other plants that increase or invade the site are Texas varilla, cacti, and screwbean mesquite. The ecological site is Saline Clay 18-25 PZ (R083BY432TX).

DISTRIBUTION AND EXTENT: Western Rio Grande Plain, Texas. LRR I, MLRA 83B. The series is of moderate extent.

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

SERIES ESTABLISHED: Starr County, Texas; 1972.

REMARKS: These soils were included in Catarina series, or saline phases of Monteola and Maverick series in earlier published reports.

Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 23 cm (0 to 9 in)
Vertic features: Filled cracks and shiny pressure surfaces on faces of peds.
Densic contact: 91 cm (36 in)

ADDITIONAL DATA: none.
TAXONOMIC VERSION: Keys to Soil Taxonomy, Eleventh Edition, 2010.

National Cooperative Soil Survey
U.S.A.