LOCATION WOODS              OK

WOODS SERIES

TAXONOMIC CLASS: Fine, smectitic, thermic Typic Calciusterts

TYPICAL PEDON: Woods silty clay loam, on a 5 percent slope in rangeland. (Colors are for dry soil unless otherwise stated.)

A--0 to 10 inches; dark grayish brown (10YR 4/2) silty clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure parting to moderate fine granular; very hard, firm; many fine roots; few fine concretions of calcium carbonate; slightly effervescent; moderately alkaline; clear smooth boundary. (9 to 13 inches thick)

Btss--10 to 26 inches; brown (10YR 5/3) silty clay, brown (10YR 4/3) moist; strong medium prismatic structure parting to strong medium angular blocky; extremely hard, very firm; few fine and common very fine roots; few fine threads and concretions of calcium carbonate; common distinct pressure faces and slickensides at approximately 45 degree angles; cracks filled with very dark grayish brown (10YR 3/2) silty clay loam material; prominent clay films on faces of peds; strongly effervescent; moderately alkaline; clear smooth boundary. (9 to 26 inches thick)

Bk--26 to 30 inches; light brown (7.5YR 6/4) clay loam, brown (7.5YR 5/4) moist; weak coarse prismatic structure parting to weak medium subangular blocky; very hard, very firm; few fine and very fine roots; common medium soft masses and filmsof calcium carbonate which make up about 25 percent by volume; violently effervescent; moderately alkaline; clear smooth boundary. (0 to 18 inches thick)

Ck--30 to 80 inches; pink (7.5YR 7/4) stratified layers of silt loam, clay loam, and silty clay; light brown (7.5YR 6/4) moist; massive; hard, firm; common fine and few medium soft masses and filmsof calcium carbonate which make up about 10 percent by volume; a 2 inch strata contains many fine gypsum crystals and is noncalcareous; violently effervescent; moderately alkaline.

TYPE LOCATION: Woods County, Oklahoma; about 11 miles north and 2 miles west of Freedom, Oklahoma; 1550 feet west and 2600 feet south of the northeast corner of Sec. 4, T. 28N., R. 18W.

RANGE IN CHARACTERISTICS: Solum thickness ranges from 20 to 40 inches. Cracks up to 1 inch wide at the surface extend to 20 inches or more when the soil is dry and are 1cm or more wide at 20 inches. Thickness of the mollic epipedon ranges from 9 to 13 inches. Average clay content of the Bt horizon ranges from 35 to 60 percent.

The A horizon has hue of 10YR, value of 4 (3 moist), and chroma of 1 or 2. Texture is silty clay loam or clay loam. Reaction is moderately alkaline and it is typically calcareous, but some pedons may be noncalcareous in the upper 10 inches. Calcium carbonate equivalent ranges from 0 to 5 percent.

The Btss horizon has hue of 7.5YR or 10YR, value of 5 or 6 (4 or 5 moist), and chroma of 3, 4, or 6. Texture is clay loam, clay, silty clay or silty clay loam. Reaction is moderately alkaline and calcareous. This layer has pressure faces and slickensides at 45 to 60 degree angles and cracks are filled with darker material from above. Calcium carbonate equivalent ranges from 5 to 15 percent.

The Bk horizon has hue of 7.5YR or 10YR, value of 5 or 6 (4 or 5 moist), and chroma of 4 or 6. Reaction is moderately alkaline and it is calcareous. Texture is silty clay, silty clay loam, clay, or clay loam. Common faint stratification is evident in some pedons. Visible calcium carbonates in the form of coatings and soft masses range from 5 to 30 percent by volume. Some pedons have slickensides or pressure faces in this layer. Calcium carbonate equivalent ranges from 15 to 40 percent.

The Ck horizon has hue of 7.5YR, 10YR, and 2.5Y, value of 5 to 7 (4 to 6 moist), and chroma of 4 to 6. This layer is usually stratified sediments of clay, silty clay, silty clay loam, silt loam, and clay loam. Some thin strata of sand are also common. The densely compacted layers of clay sometimes have the appearance of rock structure of shale. Visible carbonates in the form of seams, threads, films, and soft masses range from 0 to 10 percent by volume. Calcium carbonate equivalent ranges from 5 to 20 percent.

COMPETING SERIES: There are no other series in the same family. Culp and Lofton soils are in similar families. The Culp and Lofton soils have mixed mineralogy and solum thickness of more than 40 inches.

GEOGRAPHIC SETTING: Woods soils are on nearly level to moderately steep lower ridgetops and side slopes of the uplands in the Southern High Plains Breaks (MLRA 77E). Slopes range from 0 to 15 percent. These soils formed in calcareous clayey alluvium of the Ogallala formation of Pliocene Period. Climate is subhumid dry. Mean annual precipitation ranges from 20 to 24 inches. Mean annual temperature ranges from 57 to 64 degrees F. Thornthwaite annual P-E indices ranges from 30 to 38. Frost free days range from 185 to 230. Elevation ranges from 1400 to 2500 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Abbie, Case, Farry, Fortyone, Irene, Mansic and Oklark series.

Farry and Fortyone soils are typically on back slopes, shoulder slopes, and summits at higher elevations, and occur in sandy and gravelly sediments. Fortyone soils have coarse-loamy textural control section and Farry soils have fine-loamy textural control section. Mansic and Oklark soils are on slightly higher side slopes. Mansic soils have fine-loamy textural control sections and Oklark soils have coarse-loamy textural control sections. Irene and Abbie soils are on broad smooth ridgetops and have less than 35 percent clay in the textural control. Case soils have fine-loamy textural control section and occur on higher sideslopes.

DRAINAGE AND PERMEABILITY: Woods soils are well drained, runoff is very high; and permeability is very slow.

USE AND VEGETATION: Used mainly for rangeland. Native vegetation is mainly buffalograss, bluegrama, and sideoats grama.
DISTRIBUTION AND EXTENT: Southern High Plains Breaks (MLRA-77E) of Northwestern of Oklahoma and possibly south central Kansas. The Woods series is of minor extent.

MLRA OFFICE RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Woods County, Oklahoma; 1995. Name is from the County.

REMARKS: Soil Interpretation Record: Series OK0355

Diagnostic horizons and features recognized in this pedon are:

Mollic epipedon - the zone from the surface of the soil to a depth of approximately 10 inches (A horizon).
Argillic horizon - the zone from approximately 10 to 26 inches (Btss horizon).
Calcic horizon - the zone from approximately 26 to 40 inches (Bk, Ck horizons).
Vertic feature - more than 35 percent clay in horizons that total more than 20 inches in thickness, cracks at some period in most years and has a (COLE) of 0.07 or more.
Moisture Regime: Aridic-Ustic.