LOCATION GYSTRUM WY+SDEstablished Series
TAXONOMIC CLASS: Fine-silty, gypsic, mesic Ustic Haplocambids
TYPICAL PEDON: Gystrum silty clay loam, rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; reddish brown (5YR 5/3) silty clay loam, reddish brown (5YR 4/3) moist; moderate fine granular structure; soft, very friable, sticky and plastic; slightly effervescent; many fine roots; slightly alkaline (pH 7.8); clear smooth boundary. (3 to 6 inches thick)
Bw--4 to 12 inches; light reddish brown (5YR 6/3) silty clay loam, reddish brown (5YR 5/3) moist; moderate medium prismatic structure parting to moderate fine subangular blocky; very hard, very friable, sticky and plastic; many fine and medium roots; slightly effervescent; few faint clay films on faces of peds; moderately alkaline (pH 8.4); gradual wavy boundary. (5 to 15 inches thick)
Cy--12 to 27 inches; pinkish white (5YR 8/2) silty clay loam, pinkish gray (5YR 6/2) moist; hard, very friable, sticky and plastic; strongly effervescent; many prominent gypsum crystals; calcium carbonate disseminated and as soft masses; moderately alkaline (pH 8.4); clear wavy boundary. (12 to 19 inches thick)
Cr--27 to 34 inches; soft gypsum bedrock.
TYPE LOCATION: Johnson County, Wyoming; SW1/4 NW1/4 section 11, T.42N., R.84W. Poker Butte Quadrangle. 43 degrees 37 minutes 28 seconds north latitude and 106 degrees 54 minutes 39 seconds west longitude.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 degrees to 53 degrees F. The depth to the base of the cambic horizon is 10 to 15 inches. Depth to the paralithic contact is 20 to 40 inches. Rock fragments range from 0 to 5 percent and are mostly gravel. The particle size control section averages 18 to 35 percent clay and less than 15 percent fine sand or coarser.
The A horizon has hue of 7.5YR through 2.5YR, value of 5 or 6 dry, 3 through 5 moist, and chroma of 2 through 4. It is slightly or moderately alkaline.
The Bw horizon has hue of 7.5YR to 2.5YR, value of 6 or 7 dry, 5 or 6 moist, and chroma of 3 or 4. This horizon is moderately or strongly alkaline.
The Cy horizon has hue of 7.5YR through 2.5YR. It contains 40 to 60 percent gypsum. There is no decrease in gypsum content with increasing depth. This horizon is moderately or strongly alkaline.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Gystrum soils are on nearly level to very steep hills and ridges. Slopes are 0 to 60 percent. These soils formed in gypsiferous, reddish brown sediments weathered from gypsum bedrock and interbedded redbed shales and siltstones. Elevation is 2950 to 6,000 feet. The mean annual precipitation is 10 to 15 inches with peak periods of precipitation in the spring and early summer. Mean annual temperature is 43 degrees to 53 degrees F., summer temperature is 60 to 74 degrees F. Frost-free season is 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Connerton, Rekop, and La Fonda soils. Connerton soils have mollic epipedons and lack high gypsum content in the C horizons. Rekop soils have a paralithic contact at depths of 10 to 20 inches. La Fonda soils lack high gypsum content in the C horizon.
DRAINAGE AND PERMEABILITY: Well-drained; medium to high runoff; moderate permeability.
USE AND VEGETATION: These soils are used for native pastureland and wildlife habitat. Native vegetation is threadleaf sedge, western wheatgrass, cactus, blue grama, Sandberg bluegrass, and needleandthread grass.
DISTRIBUTION AND EXTENT: Northern Wyoming and west South Dakota. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Johnson County (Southern Johnson Area), Wyoming. 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 4 inches (A)
Cambic horizon - 4 to 12 inches (Bw)
Gypsic mineralogy - 12 to 27 inches (Cy)
Paralithic contact - 27 inches (Cr)
MLRR- G
SIR- WY0024