LOCATION REKOP WY+SDEstablished Series
TAXONOMIC CLASS: Loamy, gypsic, mesic, shallow Ustic Torriorthents
TYPICAL PEDON: Rekop loam-rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; brown (7.5YR 5/3) loam, brown (7.5YR 4/3) moist; moderate fine granular structure; soft, very friable, slightly sticky and nonplastic; common fine roots; strongly effervescent, calcium carbonate disseminated; 10 percent cherty alabaster fragments, most of which are on the surface; strongly alkaline (pH 8.5); gradual smooth boundary. (2 to 6 inches thick)
C--4 to 16 inches; pink (7.5YR 8/4) gravelly loam, pink (7.5YR 7/4) moist; massive; hard, very friable, slightly sticky and nonplastic; few fine roots; strongly effervescent, calcium carbonate disseminated and as few soft masses and filaments; gypsum occurs as few nests of crystals and disseminated throughout the matrix as small to medium crystals; 20 percent alabaster and chert fragments; moderately alkaline (pH 8.4); abrupt wavy boundary. (4 to 17 inches thick)
Cr--16 to 60 inches; gypsum bedrock and alabaster. Hardness less than 3.
TYPE LOCATION: Johnson County, Wyoming; SW1/4, NW1/4 of sec. 11, T. 42 N., R. 84 W. Poker Butte Quadrangle. 43 degrees 37 minutes 28 seconds north latitude and 106 degrees 54 minutes 44 seconds west longitude.
RANGE IN CHARACTERISTICS: Depth to bedrock and the paralithic contact ranges from 6 to 20 inches. The organic matter content of the surface horizon ranges from 1 to 2 percent. The mean annual soil temperature ranges from 47 to 53 degrees F. The particle size control section has a matrix texture of loam or silt loam modified with 0 to 35 percent angular chert and alabaster fragments. The amount of hard rock fragments is dependent upon the amount of cherty material in the parent beds. Clay percent averages from 18 to 27 percent in the control section. Gypsum plus calcium carbonate ranges from 40 to over 65 percent with gypsum dominating. EC ranges from 2 to 4 mmhos throughout.
The A horizon has hue of 10YR through 2.5YR, value of 5 or 6 dry, 4 or 5 moist, and chroma of 2 through 4. This horizon appears soft and fluffy in many pedons due to frost heave because of the high gypsum content. Others may appear compacted. Reaction is slightly alkaline through strongly alkaline.
The C horizon has hue of 7.5YR through 2.5YR, value of 6 through 8 dry, 5 through 7 moist, and chroma of 2 through 6. The majority of the gypsum and carbonate is disseminated with only minor secondary accumulations. Reaction ranges from slightly alkaline to strongly alkaline.
COMPETING SERIES: This is the Ovmesa, Retsabal, and Tanbark series. Ovmesa and Retsabal soils have less than 20 percent clay in the particle-size control section. Tanbark soils have a mean annual soil temperature greater than 53 degrees F. and occurs in areas with frost-free seasons greater than 170 days.
GEOGRAPHIC SETTING: Rekop soils are on bedrock controlled hills, ridges, and plateaus. Rekop soils are formed in residuum and colluvial slopewash derived from gypsiferous siltstone, gypsum bedrock and alabaster. The hardness is less than 3 for the gypsum bedrock and alabaster. Slopes are 3 to 60 percent. Elevations are 2950 to 6,300 feet. The mean annual precipitation is about 10 to 16 inches of which about half falls as snow and later rain in April, May, and early June. The mean annual air temperature is about 43 to 48 degrees F. The frost-free season is estimated to range from 100 to 135 days depending upon elevation, aspect, and air drainage.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gystrum and Pokeman soils. Gystrum soils are moderately deep. Pokeman soils have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well to somewhat excessively drained; low to very high runoff depending upon slope and surface compaction; moderate permeability.
USE AND VEGETATION: Rangeland and wildlife habitat. Native vegetation consists of bluebunch wheatgrass, needleandthread, western wheatgrass, Indian ricegrass, and scattered big sagebrush.
DISTRIBUTION AND EXTENT: Northern and central Wyoming and extreme western South Dakota. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Johnson County, Wyoming, South Part; 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 4 inches (A)
Paralithic contact - 17 inches (Cr)
Gypsic family - Gypsum plus calcium carbonate greater
than 40 percent being mostly gypsum in (C)
MLRR- G
SIR's- WY0034, WY9020, WY1205