LOCATION IRION TX

Established Series
WCC-RD-RM
01/2018

IRION SERIES

The Irion series consists of very deep, well drained, very slowly permeable soils formed in clayey alluvium derived from limestone over fractured limestone bedrock of the Buda Formation of Cretaceous age. These nearly level soils occur in shallow depressions. Slope ranges from 0 to 1 percent. Mean annual precipitation is about 559 mm (22 in) and the mean annual air temperature is about 18 degrees C (64 degrees F).

TAXONOMIC CLASS: Fine, smectitic, thermic Typic Haplusterts

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

A1--0 to 10 cm (0 to 4 in); very dark grayish brown (10YR 3/2) clay, very dark grayish brown (10YR 3/2) moist: moderate fine subangular blocky structure; slightly hard, friable, very sticky, very plastic: common fine roots; few fine limestone gravel; strongly effervescent; moderately alkaline; clear smooth boundary.

A2--10 to 36 cm (4 to 14 in); dark grayish brown (10YR 4/2) clay, very dark grayish brown (10YR 3/2) moist; moderate fine and medium angular blocky structure; very hard, very firm, very sticky, very plastic; few fine roots, few shiny ped surfaces; few fine and medium limestone gravel; strongly effervescent; moderately alkaline; gradual smooth boundary. (Combined thickness of the A horizon is 25 to 76 cm [10 to 30 in])

Bss1--36 to 102 cm (14 to 40 in); dark grayish brown (10YR 4/2) clay, very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure parting to moderate fine and medium angular blocky; very hard, very firm, very sticky, very plastic; few fine roots on surface of peds; many prominent slickensides; few shiny ped surfaces; few fine and coarse limestone gravel; strongly effervescent; moderately alkaline; gradual smooth boundary.

Bss2--102 to 137 cm (40 to 54 in); dark grayish brown (10YR 4/2) clay, very dark grayish brown (10YR 3/2) moist: weak medium prismatic structure parting to weak medium angular blocky; very hard, very firm, very sticky, very plastic; few fine roots on surface of peds; common prominent slickensides; few brown (10YR 4/3) stains on ped surfaces; few black concretions; common fine limestone gravel; strongly effervescent; moderately alkaline; gradual smooth boundary. (Combined thickness of Bss horizon is 46 to 150 cm [18 to 59 in])

Bk--137 to 183 cm (54 to 72 in); grayish brown (10YR 5/2) clay, dark grayish brown (10YR 4/2) moist; weak medium prismatic structure parting to weak coarse angular blocky; very hard, very firm; common shiny ped surfaces; common brown (10YR 4/3) stains on ped surfaces; few fine limestone gravel; few masses of calcium carbonate in lower part; strongly effervescent; moderately alkaline; abrupt smooth boundary. (Thickness is 0 to 63 cm [0 to 25 in])

R--183 to 191 cm (72 to 75 in); indurated platy limestone interbedded with thin layers of marl.

TYPE LOCATION: Crockett County, Texas; from the intersection of Texas Highway 137 and Texas Highway 163 about 1 mile north of Ozona; 5.4 miles north on Texas Highway 163; 3.7 miles east on Crockett County road 109; 1.7 miles east and 0.4 mile south on private ranch road; 510 ft southwest in rangeland.

USGS topographic quadrangle: Square Top Mountain, TX;
Latitude: 30 degrees, 49 minutes, 26 seconds N;
Longitude: 101 degrees, 05 minutes, 18 seconds W;
Datum: WGS84.

RANGE IN CHARACTERISTICS:
Soil Moisture: Typic-ustic soil moisture regime; these soils receive extra moisture due to position and are generally associated with soils in a drier soil moisture regime.
Depth to lithic contact: 137 to 203 cm (54 to 80 in)
Rock fragments throughout the solum: 0 to 15 percent total; 0 to 15 percent gravel, 0 to 2 percent cobbles, 0 to 1 percent stones; indurated limestone
Depth to slickensides: 25 to 76 cm (10 to 30 in)
Gilgai microrelief: native rangeland has microlows that are 5 to 30 cm (2 to 12 in) lower than the microhighs. Distance between microhighs and microlows ranges from 2 to 5 m (6.6 to 16.4 ft).

Particle-size control section (weighted average):
Total clay content: 40 to 55 percent
Carbonate clay content: 1 to 10 percent

A horizon
Hue: 7.5YR, 10YR, or 2.5Y
Value: 2 to 5, 2 to 3 moist
Chroma: 1 to 3 dry and moist
Texture: clay, silty clay
Total clay content: 40 to 55 percent
Carbonate clay content: 1 to 10 percent
Calcium carbonate equivalent: 1 to 10 percent
Electrical conductivity (decisiemens per meter): 0 to 2
Effervescence: strongly
Reaction: neutral to moderately alkaline

Bss horizon
Hue: 7.5YR or 10YR
Value: 3 to 5, 2 to 4 moist
Chroma: 1 to 3 dry and moist
Texture: clay, silty clay
Total clay content: 40 to 55 percent
Carbonate clay content: 1 to 10 percent
Calcium carbonate equivalent: 1 to 10 percent
Electrical conductivity (decisiemens per meter): 0 to 2
Effervescence: strongly
Reaction: slightly alkaline or moderately alkaline

Bk horizon
Hue: 5YR, 7.5YR, or 10YR
Value: 4 to 6, 3 to 5 moist
Chroma: 2 to 4, dry and moist
Texture: clay, silty clay
Total clay content: 40 to 55 percent
Carbonate clay content: 1 to 12 percent
Calcium carbonate equivalent: 2 to 15 percent
Electrical conductivity (decisiemens per meter): 0 to 2
Effervescence: strongly
Reaction: slightly alkaline or moderately alkaline

Bw horizon (where present)
Hue: 7.5YR, 10YR, or 2.5Y
Value: 4 to 6, 3 to 5 moist
Chroma: 1 to 3, dry or moist
Texture: clay, silty clay
Total clay content: 40 to 55 percent
Carbonate clay content: 1 to 12 percent
Calcium carbonate equivalent: 2 to 15 percent
Electrical conductivity (decisiemens per meter): 0 to 2
Effervescence: strongly
Reaction: slightly alkaline or moderately alkaline

R horizon
Texture: indurated limestone bedrock

COMPETING SERIES: These are the Campwood, Hollister, Indiahoma, Leeray, Lockney, Roscoe, and Teagard series in the same family.
All of these soils do not have limestone bedrock within 203 cm (80 in) of the surface.
Campwood soils: formed in alluvium on terraces.
Hollister soils: formed in alluvial sediments on broad terraces and have cooler mean annual temperature.
Indianhoma soils: formed in Permian age sediments, have linear shaped gilgai microrelief and have cooler mean annual temperature.
Leeray soils: formed in alluvial sediments and have Sodium Adsorption Ration of 8 to more than 15 within 102 cm (40 in) of the surface.
Lockney soils: are moderately well drained, formed in eolian sediments of the High Plains, and have cooler mean annual temperature.
Roscoe soils: are on flats and are moderately well drained.
Teagard soils: have sola less than 102 cm (40 in) thick over claystone.

GEOGRAPHIC SETTING:
Parent Material: clayey alluvium derived from limestone over fractured limestone bedrock of the Buda Formation of Cretaceous age
Landscape: dissected plateaus
Landform: shallow concave depressions
Slope: 0 to 1 percent
Mean annual precipitation: 432 to 711 mm (17 to 28 in)
Thornthwaite P.E. Index: 24 to 36
Mean annual air temperature: 17.2 to 18.9 degrees C (63 to 66 degrees F)
Frost-free period: 210 to 240 days
Elevation: 533.4 to 876.3 m (1750 to 2875 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are Ector, Noelke, Ozona, Texon, and Tobosa series.
Ector and Noelke soils: are shallow or very shallow to bedrock and occur on higher positions
Ozona soils: are shallow or very shallow to a petrocalcic horizon and occur on higher positions
Texon soils: have a calcic horizon and occur on higher positions
Tobosa soils: occur on slightly higher broad flat positions

DRAINAGE AND PERMEABILITY:
Drainage class: Well.
Permeability class: Very slow.
Runoff is negligible.
Wetness: this soil may be occasionally ponded for a month or more in about 1 out of 10 years.

USE AND VEGETATION: Used mostly for rangeland but a few areas are cropped to cotton, grain sorghum, and wheat. Native vegetation is buffalograss, curly mesquite, threeawn, buffalo bur, prickly pear, and mesquite trees.

DISTRIBUTION AND EXTENT: Texas in the Edwards Plateau, Western Part (MLRA 81A) and the Edwards Plateau, Central Part (MLRA 81B). The series is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Temple, Texas.

SERIES ESTABLISHED: Crockett County, Texas: 2002. The series was proposed and established for a special survey of the Texas Range Station in 1938. The series was later deactivated and combined with the Lipan and Roscoe series. The series is reactivated to interpret soils originally proposed for the Irion series.

REMARKS: This soil was formerly included with the Roscoe and Lipan series.

Edited 11/2013 (RFG-THW): Converted to tabular format and added metric measurements. Updated the competing series, geographic setting, and associated soils sections.

Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 0 to 36 cm (0 to 14 in) (Al and A2 horizons)
Vertisol feature: Slickensides: 36 to 137 cm (14 to 54 in) (Bssl and Bss2 horizons) and cracks that open and close periodically.
Cambic horizon: 137 to 183 cm (54 to 72 in) (Bk horizon)
Lithic contact: at 183 cm (72 in) (R horizon)

ADDITIONAL DATA: None

Taxonomic Version: Keys to Soil Taxonomy, Twelfth Edition, 2014

National Cooperative Soil Survey
U.S.A.