LOCATION BROWN WYEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic, shallow Aridic Argiustolls
TYPICAL PEDON: Brown very cobbly sandy loam in a map unit of Brown-Featherlegs-Recluse complex, 5 to 40 percent slopes, utilized as rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; brown (10YR 4/3) very cobbly sandy loam, dark brown (10YR 3/3) moist; weak very fine subangular blocky structure parting to weak fine granular; soft, very friable, slightly sticky and slightly plastic; common fine and coarse roots; few fine continuous random irregular pores; neutral (pH 7.0); 30 percent gravel and 25 percent cobbles; clear smooth boundary. (3 to 7 inches thick)
Bt--4 to 10 inches; brown (10YR 4/3) very gravelly sandy clay loam, dark brown (10YR 3/3) moist; weak subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few coarse and common very fine and fine roots; common distinct oriented clay occurs as bridges holding mineral grains together; 50 percent gravel; neutral (pH 7.2); gradual smooth boundary. (4 to 6 inches thick)
C--10 to 19 inches; yellowish brown (10YR 5/4) very gravelly sandy clay loam, dark yellowish brown (10YR 4/4) moist; weak very fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; 50 percent gravel; slightly alkaline (pH 7.4).
Cr--19 to 29 inches; soft granite and noncalcareous sandstone.
TYPE LOCATION: Platte County, Wyoming; 1,400 feet west and 1,800 feet south of the northeast corner of section 14, T28N, R70W.
RANGE IN CHARACTERISTICS: The mollic epipedon is 7 to 10 inches thick. The depth to a paralithic contact is 10 to 20 inches. Depth to the base of the Bt horizon is 7 to 10 inches. The particle size control section averages 20 to 30 percent clay, with greater than 35 percent fine sand or coarser. Reaction is neutral or slightly alkaline throughout the soil.
The A horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3. Total rock fragments range from 40 to 60 percent, with 20 to 30 percent gravel and 20 to 30 percent cobbles.
The Bt horizon has value of 4 or 5 dry, 3 or 4 moist, and chroma of 3 or 4. Total rock fragments range from 45 to 60 percent with 35 to 50 percent gravel and 0 to 10 percent cobbles.
The C horizon has value of 5 or 6 day, 3 through 5 moist, and chroma of 2 through 4. Total rock fragments range from 45 to 60 percent with 35 to 50 percent gravel and 0 to 10 percent cobbles.
COMPETING SERIES: This is the Brownrigg series. The Brownrigg soil has 4 to 15 percent calcium carbonate equivalent in the Bk horizon.
GEOGRAPHIC SETTING: The Brown soils are on hills. Slopes are 5 to 40 percent. The soil formed in alluvium and residuum from sandstone and granite. Elevation is 5,000 to 5,800 feet. The mean annual precipitation is 12 to 15 inches. The mean annual temperature is 46 to 48 degrees F. The frost-free season is 110 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Albinas, Featherlegs, Recluse, Snilloc (T), and Wolf soils. All of these soils are very deep to bedrock.
DRAINAGE AND PERMEABILITY: Well-drained; low to rapid runoff; moderate permeability.
USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. Native vegetation is little bluestem, needleandthread, western wheatgrass, Indian ricegrass, threadleaf sedge, and yucca.
DISTRIBUTION AND EXTENT: Southeastern Wyoming; MLRA 67 and 58-B; The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES PROPOSED: Platte County, Wyoming, 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 10 inches (A, Bt)
Argillic horizon - 4 to 10 inches (Bt)
Paralithic contact - 19 to 29 inches (Cr)
SIR- WY9793
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