LOCATION WILLOW OK+TX

Established Series
RFG-CDS-CLN
01/2017

WILLOW SERIES

The Willow series consists of deep, well drained, moderately to moderately slowly permeable soils that formed in loamy alluvium or pedisediments over sandstone bedrock of Permian age. These nearly level to very gently sloping soils are on plain terraces and footslopes and toeslopes of pediments. Slope ranges from 0 to 3 percent. Mean annual precipitation is about 635 mm (25 in), and mean annual temperature is about 16.1 degrees C (61 degrees F).

TAXONOMIC CLASS: Fine-silty, mixed, superactive, thermic Typic Argiustolls

TYPICAL PEDON: Willow loam--on a 1 percent slope in cropland.
(Colors are for dry soil unless otherwise stated.)

Ap--0 to 18 cm (0 to 7 in); brown (7.5YR 4/2) loam, dark brown (7.5YR 3/2), moist; moderate fine and medium granular structure; very friable, hard; common fine and very fine roots; 1 percent quartz gravels; noneffervescent; slightly acid, pH 6.5; abrupt smooth boundary. Thickness is 15 to 41 cm (6 to 16 in)

Bt1--18 to 43 cm (7 to 17 in); reddish brown (5YR 4/3) clay loam, dark reddish brown (5YR 3/3), moist; weak medium prismatic structure parting to moderate fine and medium subangular blocky; friable, very hard; few fine and very fine roots; common fine and very fine pores; many distinct clay films on all faces of peds; 1 percent quartz gravels; noneffervescent; slightly acid, pH 6.5; gradual smooth boundary.

Bt2--43 to 64 cm (17 to 25 in); reddish brown (5YR 5/4) clay loam, reddish brown (5YR 4/4), moist; weak medium prismatic structure parting to moderate fine and medium subangular blocky; friable, very hard; few fine and very fine roots; common fine and very fine pores; common distinct clay films on all faces of peds; 1 percent quartz gravels; noneffervescent; neutral, pH 7.0; gradual smooth boundary. Combined thickness of the Bt horizons is 46 to 97 cm (18 to 38 in)

Btk--64 to 79 cm (25 to 31 in); yellowish red (5YR 5/6) clay loam, yellowish red (5YR 4/6), moist; weak medium prismatic structure parting to moderate fine and medium subangular blocky; friable, hard; few fine and very fine roots; common fine and very fine pores; few faint clay films on vertical faces of peds; 3 percent fine and medium masses and threads of calcium carbonate; 1 percent quartz gravels and 1 percent paragravel of sandstone; strongly effervescent; moderately alkaline, pH 8.0; clear wavy boundary. Thickness of the Btk horizon is 0 to 25 cm (0 to 10 in)

2Bk--79 to 99 cm (31 to 39 in); reddish yellow (5YR 6/6) loam, yellowish red (5YR 5/6), moist; weak coarse prismatic structure parting to weak fine and medium subangular blocky; friable, very hard; few fine and very fine roots; many fine and very fine and few medium pores; 5 percent fine and medium masses of calcium carbonate; 4 percent paragravel of sandstone; strongly effervescent; moderately alkaline, pH 8.0; gradual wavy boundary. Thickness is 0 to 38 cm (0 to 15 in)

2BCk--99 to 137 cm (39 to 54 in); yellowish red (5YR 5/6) loam, yellowish red (5YR 4/6), moist; weak coarse prismatic structure parting to weak medium subangular blocky; friable, very hard; few fine and very fine roots; many fine and very fine and few medium pores; 1 percent fine masses of iron-manganese; 2 percent masses of calcium carbonate; 5 percent noncemented sandstone fragments and 5 percent paragravel of sandstone; strongly effervescent; moderately alkaline, pH 8.0; gradual wavy boundary. Thickness is 20 to 38 cm (8 to 15 in)

2Cd--137 to 203 cm (54 to 80 in); pale yellow (2.5Y 7/3) noncemented sandstone bedrock that slakes to loam, light yellowish brown (2.5Y 6/3), moist; slightly effervescent; moderately alkaline.

TYPE LOCATION:
Greer County, Oklahoma; from the intersection of U.S. Highway 283 and OK State Highway 34 in Mangum; about 7 miles north on U.S. Highway 283and 7.55 miles west on county road; 225 feet south in cultivated field.
Located about 225 feet south and 2400 feet east of the northwest corner of section 28, T. 6 N., R. 23 W.

USGS topographic quadrangle: Reed, Oklahoma;
Latitude: 34 degrees, 58 minutes, 21.20 seconds N;
Longitude: 99 degrees, 38 minutes, 7.07 seconds W.;
Datum: NAD 1927.

RANGE IN CHARACTERISTICS:
Soil Moisture: Typic Ustic soil moisture regime. The soil moisture control section is dry in some or all parts for more than four-tenths and less than six-tenths of the cumulative days in normal years.
Depth to densic bedrock: 102 to 152 cm (40 to 60 in)
Thickness of the mollic epipedon, 18 to 46 cm (7 to 18 in), 25 to 46 cm (10 to 18 in) in pedons that have identifiable secondary carbonate at a depth of more than 30 inches)
Depth to identifiable secondary carbonate: 15 to 36 inches
Depth to calcic horizon (where present): 28 to 52 inches
Depth to lithologic discontinuity: 25 to 52 inches

Particle-size control section (weighted average)
Clay content: 18 to 35 percent
Total sand content: 15 to 50 percent
Fine sand or coarser content: less than 15 percent
CEC/clay ratio: more than 0.6

A Horizon
Hue: 5YR, 7.5YR
Value: 4 (3 moist)
Chroma: 2 or 3
Texture: Loam, silt loam, or clay loam
Clay content: 18 to 30 percent
Coarse fragments: 0 to 2 percent rounded siliceous gravel
Effervescence: None to very slight
Reaction (pH): Slightly acid to slightly alkaline (6.1 - 7.8)

Bt Horizons (and Btk where present)
Hue: 5YR, 7.5YR
Value: 4 to 5 (3 to 4 moist)
Chroma: 3 to 6
Texture: Clay loam, silty clay loam, loam, or silt loam
Clay content: 25 to 38 percent
Coarse fragments: 0 to 2 percent rounded siliceous gravels
Calcium carbonate equivalent: 0 to 10 percent
Identifiable secondary carbonate: 0 to 5 percent, fine and medium, concretions, threads and/or masses
Effervescence: None to strong
Reaction (pH): Neutral to moderately alkaline (6.6 - 8.4)

Bk Horizon (where present)
Hue: 5YR, 7.5YR
Value: 5 to 6 (4 to 5 moist)
Chroma: 4 to 6
Texture: Loam, silt loam, or clay loam
Clay content: 18 to 30 percent
Pararock fragments: 0 to 5 percent paragravel of sandstone
Calcium carbonate equivalent: 10 to 40 percent
Identifiable secondary carbonate: 3 to 30 percent, fine to coarse, concretions, films, and/or masses
Electrical Conductivity (dS/m): 0 to 4
Gypsum: 0 to 2 percent
Sodium Adsorption Ratio: 0 to 4
Effervescence: Strong to violent
Reaction (pH): Moderately alkaline to strongly alkaline (7.9 to 9.0)

BCk Horizon
Hue: 5YR, 7.5YR, 10YR
Value: 5 to 7 (4 to 6 moist)
Chroma: 4 to 8
Texture: Loam, silt loam, or very fine sandy loam
Clay content: 10 to 20 percent
Pararock fragments: 0 to 15 percent paragravel of sandstone
Calcium carbonate equivalent: 10 to 25 percent
Identifiable secondary carbonate: 2 to 20 percent, fine and medium, concretions, films, and/or masses
Electrical Conductivity (dS/m): 0 to 8
Gypsum: 0 to 5 percent
Sodium Adsorption Ratio: 0 to 8
Effervescence: Slight to violent
Reaction (pH): Moderately alkaline to strongly alkaline (7.9 to 9.0)

Cd Horizon
Hue: 2.5YR to 5Y
Value: 5 to 8 (4 to 7 moist)
Chroma: 1 to 6
Texture: interbedded layers of red to white sandstone bedrock with a few layers of red siltstone
Cementation: Mostly noncemented with few thin layers of extremely to weakly cemented which increase with depth
Excavation difficulty: Moderate to high
Effervescence: None to slight
Reaction (pH): Moderately alkaline to strongly alkaline (7.9 to 9.0)

COMPETING SERIES:
These are the Carey and Selman series in the same family. Similar soils include the Farry, Madge, and Ozark series.
Carey and Selman soils: are more than 152 cm (60 in) deep to bedrock and do not have a calcic horizon.
Farry, Madge, and Ozark soils: are more than 152 cm (60 in) deep to bedrock, have a fine-loamy particle-size control section, and do not have a calcic horizon.

GEOGRAPHIC SETTING:
Parent material: Loamy alluvium and pedisediments over Permian age sandstones mainly of the Duncan/San Angelo, Brinkman, Hennessey, and Clear Fork Formations
Landscape: Dissected plain
Landform: Plain terraces and footslopes and toeslopes of pediments
Slope: 0 to 3 percent
Mean annual precipitation: 610 to 711 mm (24 to 28 in)
Thornthwaite annual P-E indices: 32 to 44
Mean annual air temperature: 15.6 to 17.8 degrees C (60 to 64 degrees F)
Frost-free period: 210 to 230 days
Elevation: 335.3 to 518.2 meters (1100 to 1700 feet)

GEOGRAPHICALLY ASSOCIATED SOILS:
These are the Burford, Gotebo, Roark, and Westill series.
Burford soils: occur on similar to slightly higher positions and do not have a mollic epipedon or an argillic horizon.
Gotebo soils: occur on similar to slightly higher positions, do not have a mollic epipedon, and are less than 102 cm (40 in) deep to bedrock.
Roark soils: occur on lower positions, have a mollic epipedon more than 51 cm (20 in) thick, and do not have bedrock within 152 cm (60 in) of the surface.
Westill soils: occur on similar to slightly lower positions and have a fine textured particle-size control section.

DRAINAGE AND PERMEABILITY:
Well drained.
Permeability is moderately slow.
Runoff is low on 0 to 1 percent slopes and medium on 1 to 3 percent slopes.

USE AND VEGETATION:
The major use of these soils is crop production with a lesser amount used for livestock grazing. The major crops are wheat and cotton. Native vegetation is a mixture of tall, mid, and short grasses, mainly little bluestem, sideoats grama, blue grama, sand bluestem, yellow Indiangrass, switchgrass, buffalograss, and other perennial grasses and forbs.

DISTRIBUTION AND EXTENT:
Southwestern Oklahoma and possibly northwestern Texas; LRR H; MLRA 78C - Central Rolling Red Plains, eastern part. Moderate extent.

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

SERIES ESTABLISHED: Greer County, Oklahoma; 2005. The name comes from a small town in the county.

REMARKS: These soils were formerly mapped as St. Paul silt loam, 1 to 3 percent slopes in the soil survey of Greer County, OK, issued 1967.

Edited 01/2017 (RFG): Added metric measurements. Updated competing series, geographic setting, and associated soils sections.

Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 18 TO 69 cm (7 to 27 in)
Mollic epipedon: 0 to 43 cm (0 to 17 in) (A and Bt1 horizons)
Argillic horizon: 18 to 79 cm (7 to 31 in) (Bt and Btk horizons)
Calcic horizon: 79 to 99 cm (31 to 39 in) (2Bk horizon)
Densic bedrock: The contact with sandstone at 137 cm (54 in) (2Cd horizon)
Lithologic discontinuity: 79 cm (31 in) At the upper boundary of the 2Bk horizon

Additional Comments: The assignment of the cation-exchange activity class is supported by laboratory data number (S2000OK-055-001) from Greer County, Oklahoma.

ADDITIONAL DATA: KSSL data from Greer County, Oklahoma (S2000OK-055-001) and similar soils sampled as Tillman variant: 82TX207002, 82TX207003, and 82TX207004 from Haskell County, Texas.

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

National Cooperative Soil Survey
U.S.A.