LOCATION YOAKRAN            TX

Established Series
Rev. TCB-WMR-FBP
07/1999

YOAKRAN SERIES

The Yoakran series consists of very deep, well drained, moderately rapidly permeable soils. The soils formed in sandy, eolian sediments of the Blackwater Draw Formation of Pleistocene age. These soils occur on nearly level to gently sloping plains. Slope ranges from 0 to 5 percent. The mean annual precipitation is 18 inches and the mean annual temperature is 60 degrees F.

TAXONOMIC CLASS: Loamy, siliceous, active, thermic Arenic Aridic Haplustalfs

TYPICAL PEDON: Yoakran fine sand, on east-facing, nearly level plain, 1 percent slope in rangeland at an elevation of about 3,545 feet. (Colors are for dry soil unless otherwise stated.)

A--0 to 5 inches; brown (7.5YR 5/4) fine sand, brown (7.5YR 4/4) moist; single grain; loose; common very fine and fine roots; neutral; clear smooth boundary. (4 to 15 inches thick)

E--5 to 25 inches; pink (7.5YR 7/4) fine sand, light brown (7.5YR 6/4) moist; single grain; loose; few very fine and fine roots; neutral; clear wavy boundary. (10 to 30 inches thick)

Bt/E--25 to 36 inches; 80 percent strong brown (7.5YR 5/8) sandy clay loam, strong brown (7.5YR 4/6) moist; and 20 percent very pale brown (10YR 7/4) loamy fine sand, very pale brown (10YR 6/3) moist; weak coarse prismatic structure parting to weak fine and medium subangular blocky; hard, firm; few fine roots; few fine pores; neutral; gradual irregular boundary. (8 to 25 inches thick)

E/B1--36 to 48 inches; 60 percent very pale brown (10YR 7/4) loamy fine sand, pale brown (10YR 6/3) moist; and 40 percent light yellowish brown (10YR 6/4) fine sandy loam, brown (10YR 5/3) moist; few fine distinct brownish yellow (10YR 6/8) mottles; weak coarse prismatic structure parting to weak fine and medium subangular blocky; soft, very friable; few very fine roots; few very fine and fine pores; neutral; gradual smooth boundary.

E/B2--48 to 66 inches; 60 percent very pale brown (10YR 8/4) loamy fine sand, very pale brown (10YR 7/3) moist; and 40 percent light yellowish brown (10YR 6/4) fine sandy loam, brown (10YR 5/3) moist; few fine distinct brownish yellow (10YR 6/8) mottles; weak coarse prismatic structure parting to weak fine and medium subangular blocky; soft, very friable; few very fine roots; few very fine pores; neutral; diffuse wavy boundary. (combined E/B horizons are 20 to 40 inches thick)

2C--66 to 80 inches; very pale brown (10YR 8/2) fine sand, light gray (10YR 7/2) moist; single grain; loose; few very fine roots; neutral.

TYPE LOCATION: Terry County, Texas; From the intersection of Farm Road 1780 and Farm Road 2196 23 miles south of Whiteface; 2 miles east on Farm Road 2196; 1 mile north on county road; 3 miles north on ranch road; 300 feet west in rangeland; Latitude: 33 degrees, 19 minutes, 06 seconds N; Longitude: 102 degrees, 34 minutes, 19 seconds W; North of Tokio, Texas USGS quad; NAD 27.

RANGE IN CHARACTERISTICS:
Soil moisture: An ustic moisture regime bordering on aridic. The soil moisture control section is dry in some or all parts for more than 180 but less than 205 days, cumulative, in normal years. July through August and December through February are the driest months. These soils are intermittently moist in September through November and March through June.
Mean annual soil temperature: 60 to 65 degrees F.
Depth to argillic: 20 to 40 inches.
Solum thickness: 60 to 80 inches.
Particle-size control section: 10 to 25 percent silicate clay.

A horizon:
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 4 to 6
Texture: fine sand
Effervescence: none
Reaction: neutral to slightly alkaline

E horizon:
Hue: 7.5YR or 10YR
Value: 6 or 7 dry, 6 or 7 moist
Chroma: 3 or 4
Texture: fine sand, loamy fine sand
Effervescence: none
Reaction: neutral or slightly alkaline

Bt/E horizons:
Hue: 7.5YR or 10YR
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 4 to 8
Texture: fine sandy loam, sandy clay loam
Mottles: none to common in shades of reddish yellow or brownish yellow
Effervescence: none
Reaction: slightly acid or neutral

E/B horizons: (where present)
Hue: 7.5YR or 10YR
Value: 7 or 8 dry, 6 or 7 moist
Chroma: 2 to 4
Texture: loamy fine sand, fine sandy loam
Mottles: none to common in shades of reddish yellow or brownish yellow
Effervescence: none
Reaction: slightly acid or neutral

2C horizon:
Hue: 10YR or 2.5YR
Value: 7 or 8 dry, 6 or 7 moist
Chroma: 2 or 3
Texture: fine sand, loamy fine sand
Mottles: none to common in shades of reddish yellow or brownish yellow
Effervescence: none
Reaction: slightly acid or neutral

COMPETING SERIES: This is the Dutek series. Similar soils include the Brownfield, Circleback, Patricia, Plains, and Spantara series.
Dutek series: is moist for longer periods in the moisture control section.
Brownfield and Patricia series: do not have a clay decrease of 20 percent of the maximum clay content and have hues of 5YR or redder in subsoil horizons.
Circleback series: have lamellae in subsoil horizons.
Plains series: has sandy particle-size class extending from the mineral soil surface to the top of the argillic that is 40 or more inches thick.
Spantara series: do not have sandy particle-size class extending from the mineral soil surface to the top of the argillic that is 20 or more inches thick.

GEOGRAPHIC SETTING:
Parent material: sandy, eolian sediments of the Blackwater Draw Formation of Pleistocene Age.
Landform: nearly level to gently sloping plains.
Slopes: 0 to 5 percent.
Mean annual temperature: 58 to 63 degrees F.
Mean annual precipitation: 15 to 20 inches.
Frost-free period: 180 to 220 days.
Elevation: 2,700 to 3,900 feet.
Thornthwaite annual P-E Index Values: 24 to 32.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the similar Brownfield, Patricia, Plains, Spantara series and the Circleback, Nutivoli, and Yikes series.
Brownfield and Patricia soils are on similar landscapes and have fine-loamy control sections.
Plains soils are on similar landscape positions and have an argillic horizon between 40 and 60 inches.
Circleback soils are on higher landscape positions and have lamellae.
Nutivoli and Yikes soils are on eolian dunes and do not have an argillic horizon.
Spantara soils are on similar landscapes and have an argillic horizon within 20 inches of the soil surface.

DRAINAGE AND PERMEABILITY: Well drained. Moderately rapid permeability. Surface runoff is negligible on slopes less than 3 percent, and very low on 3 to 5 percent slopes.

USE AND VEGETATION: Mainly used for rangeland. Climax vegetation is tall and mid grasses, with sand bluestem, little bluestem, giant sandreed, and switchgrass dominating. Sand paspalum, sideoats grama, hairy grama and perennial threeawn are the main mid and short grasses. Sand sagebrush, shinoak, and skunkbush are the main shrubs. This is a fragile site and is subject to severe wind erosion if not protected by cover. This soil has been correlated to the Sand Hills (077CY034TX) range site in MLRA-77.

DISTRIBUTION AND EXTENT: Southern High Plains of western Texas and eastern New Mexico (sub-MLRA-77C). The series is of moderate extent.

MLRA OFFICE RESPONSIBLE: Temple, Texas

SERIES PROPOSED: MLRA-77 Soil Survey; Terry County, Texas; 1995.

REMARKS: These soils were formerly included in the Brownfield and Tivoli series.

Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon: 0 to 25 inches. (A, E horizons)
Albic horizon: 4 to 24 inches. (E, Bt/E, E/B horizons)
Argillic horizon: 25 to 36 inches. (Bt/E horizon)
Arenic feature: 0 to 25 inches of loamy fine sand. (A, E horizons)

Soil interpretations record: TX1300

Taxonomic version: Keys to Soil Taxonomy, Eighth Edition, 1998.

National Cooperative Soil Survey
U.S.A.