LOCATION ORPHA WY+NEEstablished Series
TAXONOMIC CLASS: Mixed, mesic Ustic Torripsamments
TYPICAL PEDON: Orpha loamy sand - on a west facing dune slope of 6 percent; utilized as rangeland. (Colors are for dry soil unless otherwise stated)
A--0 to 6 inches; grayish brown (10YR 5/2) loamy sand, dark grayish brown (10YR 4/2) moist; weak medium and coarse granular structure; loose, soft, nonsticky and nonplastic; slightly alkaline (pH 7.6); gradual wavy boundary. (2 to 6 inches thick)
C--6 to 60 inches; light brownish gray (10YR 6/2) sand, grayish brown (10YR 5/2) moist; single grain, loose, nonsticky and nonplastic; slightly alkaline (pH 7.8).
TYPE LOCATION: Converse County, Wyoming; 2,000 feet west, 1,250 feet south of the NE corner of sec. 31, T. 41 N., R. 67 W. Wagonhound Creek Quadrangle. 43 degrees 29 minutes 22 seconds north latitude and 104 degrees 56 minutes 50 seconds west longitude.
RANGE IN CHARACTERISTICS: Rock fragments are less than 15 percent in the particle-size control section. Depth to carbonates is typically greater than 40 inches but may be 30 inches in some pedons. The soil is dry in the moisture control section more than half the time cumulative that the soil temperature at a depth of 20 inches is 41 degrees F. It is never moist in all parts for as long as 60 consecutive days from July 15 to October 25 and for at least 90 cumulative days during this period. The mean annual soil temperature is 44 to 52 degrees F., and the soil temperature at a depth of 20 inches is 41 degrees F. or more for 175 to 192 days.
The A horizon has hue of 10YR or 2.5Y, value of 4 to 7 dry, 3 to 6 moist, and chroma of 2 to 4. Texture is sand, fine sand, loamy sand and loamy fine sand. Reaction is neutral or slightly alkaline.
The C horizon has hue of 10YR or 2.5Y, value of 5 to 8 dry, 4 to 7 moist, and chroma of 2 to 6. Texture is sand, fine sand, loamy sand or loamy fine sand. Some pedons may have thin strata of sandy loam or fine sandy loam where they are near the parent source. Reaction ranges from neutral to moderately alkaline. Some pedons have AC horizons.
COMPETING SERIES: These are the Calladito, Dwyer, Mido, Pensom, Pinavetes, Tullock, Valent and Wigton series. Calladito soils occur in areas with less than 10 inches of preciptation. Dwyer soils are calcareous above a depth of 30 inches. Mespun, Mido and Pensom soils have hue of 7.5YR or redder. Tullock soils have a paralithic contact between 20 and 40 inches. Pinavetes, Valent and Wigton soils are moist in some parts for at least 90 cumulative days when the soil temperature at a depth of 20 inches is 41 degrees F. or more, and also have soil temperatures warmer than 41 degrees F.for 195 to 210 days or more.
GEOGRAPHIC SETTING: Orpha soils occur primarily as rolling or hilly dunes. They are on hills, valley side slopes, footslopes, toeslopes, stream terraces, broad floodplains and uplands. They formed in alluvium or eolian deposits generally adjacent to and downwind of sandy parent sources. Slopes are usually 0 to 45 percent. In Nebraska slopes are as high as 60 percent. Elevations are 3,500 to 6,500 feet. Precipitation ranges from 10 to 18 inches with over half the annual precipitation falling in April, May, and June. The mean annual air temperature ranges from 44 to 50 degrees F. The frost-free season is about 105 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Dwyer and Tullock soils and the Clarkelen, Draknab, Embry and Haverdad soils. Clarkelen, Draknab and Haverdad soils are stratified and have an irregular decrease in organic carbon. Clarkelen and Embry soils have coarse-loamy control sections. Haverdad soils have fine-loamy control sections.
DRAINAGE AND PERMEABILITY: Well or excessively drained; low or very low runoff; rapid or very rapid permeability.
USE AND VEGETATION: These soils are dominantly used for livestock grazing. Potential native vegetation is needleandthread, prairie sandreed, Indian ricegrass, little bluestem, and sand bluestem.
DISTRIBUTION AND EXTENT: Powder River Basin, central and eastern Wyoming, and western Nebraska. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Converse County, Wyoming, North Part; 1983.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon--0 to 6 inches (A)
Ustic subgroup--The moisture control section of this soil is dry for less than three fourths of the time that the soil temperature is 41 degrees F.or greater.
MLRR- G
SIR- WY0497, WY0854, WY0946