LOCATION MIDELIGHT WYEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Ustic Haplocryolls
TYPICAL PEDON: Midelight very channery loam-rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 8 inches; brown (10YR 4/3) very channery loam, dark brown (10YR 3/3) moist; weak very fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; 50 percent schist channers and 10 percent pebbles; slightly alkaline (pH 7.4); abrupt smooth boundary. (5 to 14 inches thick)
Bk--8 to 41 inches; pale brown (10YR 6/3) extremely channery loam, dark grayish brown (10YR 4/2) moist; massive; slightly hard, very friable, slightly sticky and nonplastic; strongly effervescent, lime as common soft masses and as crusts on underside of rock fragments; 65 percent channers and 5 percent semirounded cobble; moderately alkaline (pH 8.4). (Combined thickness of the Bk and C horizon is 30 to 48 inches.)
R--41 to 60 inches; hard schist bedrock fractured in upper few inches.
TYPE LOCATION: Fremont County, Wyoming; NW1/4 SW1/4 of sec. 33, T. 30 N., R. 99 W.
RANGE IN CHARACTERISTICS: Depth to hard metamorphic rock ranges from 40 to 60 inches. Thickness of the mollic epipedon, after mixing, ranges from 7 to 14 inches. The mean annual soil temperature ranges from 39 to 44 degrees F., and the mean summer soil temperature ranges from 5 to 58 degrees F. Matrix texture of the particle size control section is loam or clay loam with 18 to 35 percent clay modified with 35 to 70 percent channers and 0 to 5 percent semirounded cobbles. EC of the entire soil is less than 2 mmhos.
The A horizon has hue of 2.5Y or 10YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 through 4 dry and 2 or 3 moist. This horizon is typically free of carbonates but may be slightly effervescent due to recharge from upslope. Reaction is typically neutral or slightly alkaline but may be moderately alkaline due to upslope recharge.
The Bk horizon has hue of 2.5Y through 7.5YR, value of 4 through 6 dry, 3 through 5 moist, and chroma of 3 through 6. Carbonates occur as few to common soft masses and as crusts on undersides of rock fragments. Some discontinuous strata may appear engulfed by carbonates. Calcium carbonate equivalent ranges from 4 to 14 percent. Reaction is moderately or strongly alkaline.
The C horizon, absent in some pedons, has hue of 2.5Y through 7.5Y, value of 4 or 5 dry, 3 through 5 moist, and chroma of 3 through 6. This horizon may be slightly effervescent with carbonates disseminated. Reaction is moderately or strongly alkaline.
The lithic contact is hard schist or gneiss. Other metamorphic bedrock could also form the contact.
COMPETING SERIES: These are the Antrobus, Grafen, Greyback, Handran, Maurice, Parachute, Sebud, Supervisor, Surdal, Teemat, Thornburgh, Tiban, Tineman, and Vanwirt series. The Antrobus, Sebud, Tineman, and Vanwirt soils are very deep and do not have horizons of secondary carbonate accumulation. The Grafen soils are moderately deep to a paralithic contact and do not have horizons of secondary carbonate accumulation. The Greyback and Teemat soils are very deep and have less than 18 percent clay in the particle-size control section. The Handran and Maurice soils are very deep, do not have horizons of secondary carbonate accumulation and have less than 18 percent clay in the particle-size control section. The Parachute, Supervisor, and Surdal soils are moderately deep to a lithic contact and do not have horizons of secondary carbonate accumulation. The Thornburgh soils do not have horizons of secondary carbonate accumulation. The Tiban soils are very deep.
GEOGRAPHIC SETTING: Midelight soils are on alluvial fan aprons, fan piedmonts, and strath terraces. These soils formed in alluvium derived locally from schist or gneiss. Slopes range from 0 to 15 percent. Elevation ranges from 7,000 to 8,500 feet. The mean annual precipitation ranges from 11 to 16 inches. The mean annual temperature ranges from about 33 to 44 degrees F. Estimated frost-free season is variable but ranges from 45 to 80 days depending upon elevation, aspect, and air drainage.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Irigul and the competing Handran soils. Irigul soils have a lithic contact at 10 to 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium or rapid runoff depending upon slope; moderate permeability.
USE AND VEGETATION: Rangeland. Native vegetation is bluebunch wheatgrass, Idaho fescue, prairie junegrass, and western wheatgrass.
DISTRIBUTION AND EXTENT: Mountains of western Wyoming. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Fremont County, Lander Area, Wyoming; 1975.