LOCATION ELWOP WYEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Aridic Haplustalfs
TYPICAL PEDON: Elwop fine sandy loam -- on a northeast facing slope of 5 percent, utilized as rangeland. (Colors are for dry soil unless otherwise stated)
A--0 to 4 inches; yellowish brown (10YR 5/4) fine sandy loam, brown (10YR 4/3) moist; moderate fine granular structure; soft, friable, nonsticky and nonplastic; noneffervescent; neutral; clear smooth boundary. (2 to 7 inches thick)
Bt1--4 to 14 inches; yellowish brown (10YR 5/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, firm, moderately sticky and moderately plastic; few distinct discontinuous dark brown (10YR 3/3) clay films on faces of peds and in pores; noneffervescent; neutral; clear smooth boundary.
Bt2--14 to 24 inches; brown (10YR 5/3) sandy clay loam, brown (10YR 4/3) moist; weak fine and medium prismatic structure parting to moderate fine and medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; few distinct discontinuous dark brown (10YR 3/3) clay films on faces of peds and in pores; noneffervescent; slightly alkaline; clear wavy boundary. (Combined Bt horizons 10 to 27 inches thick)
Bk--24 to 35 inches; pale brown (10YR 6/3) fine sandy loam, brown (10YR 5/3) moist; weak fine and medium subangular blocky structure; soft, friable, nonsticky and nonplastic; carbonates are disseminated throughout; strongly effervescent; moderately alkaline; clear wavy boundary. (5 to 21 inches thick)
Cr--35 to 60 inches; soft calcareous sandstone.
TYPE LOCATION: Campbell County, Wyoming; about 500 feet west and 2300 feet north of the southeast corner of Sec. 7, T 48 N, R 71 W.; USGS The Gap, WY topographic quadrangle; lat. 44 degrees 9 minutes 6 seconds N. and long. 105 degrees 25 minutes 31 seconds W.
RANGE IN CHARACTERISTICS: Depth to bedrock ranges from 20 to 40 inches. Depth to the base of the Bt horizon ranges from 12 to 31 inches. Depth to carbonates ranges from 12 to 34 inches. Percent rock fragments ranges from 0 to 10 percent soft sandstone that generally break down with pretreatment. Average annual soil temperature is 47 to 50 degrees F.
The A horizon has hue of 10YR, value of 4 to 6 dry and 3 or 4 moist, and chroma of 2 to 4. It has textures of fine sandy loam, sandy loam, loam, or sandy clay loam. It is neutral or slightly alkaline.
The Bt horizon has hue of 7.5YR or 10YR and may have subhorizons with hue of 5YR. It has value of 5 or 6 dry and 3 or 4 moist, and chroma of 3 to 6. It is sandy clay loam. It has 20 to 35 percent clay and 45 to 65 percent sand, with 35 to 50 percent being fine and coarser sand. It is neutral or slightly alkaline. Some pedons have a Btk horizon.
The Bk horizon has hue of 10YR or 2.5Y, value of 5 to 7 dry and 4 or 5 moist, and chroma of 2 to 4. Texture is sandy loam, sandy clay loam, loamy sand or fine sandy loam. It is slightly alkaline or moderately alkaline.
A C horizon occurs in some pedons. It is typically slightly effervescent with less than 5 percent calcium carbonate equivalent, but may be noneffervescent in some pedons. It has properties similar to the Bk horizon except that it does not have secondary accumulations of calcium carbonate.
The Cr horizon consists of soft, effervescent sandstone or interbedded sandstone and shale. The bedrock is commonly inconsistently effervescent or noneffervescent below the upper 10 to 15 inches of this horizon.
COMPETING SERIES: These are the
Arwite,
Augustine,
Bosonoak,
Celacy,
Celavar,
Dalhart,
Deekay,
Dermala,
Evpark,
Flugle,
Fort Collins,
Gateson,
Goesling,
Iwela,
Lykorly,
Maia,
Nyjack,
Oldwolf,
Olnest,
Orlie,
Parkelei,
Pinitos,
Rauzi,
Ribera,
Rockybutte,
Stoneham,
Toluca and
Wagonhound series. Augustine, Celacy, Dermala, Goesling, Lykorly, Maia, Pinitos and Ribera soils are presumed to be competing pending an update of the classification. Arwite, Augustine, Dalhart, Deekay, Dermala, Flugle, Fort Collins, Goesling, Iwela, Lykorly, Maia, Olnest, Orlie, Parkelei, Pinitos, Rauzi, Stoneham and Wagonhound soils are very deep. Bosonoak soils occur above elevations of 6500 feet and receive most of their precipitation between July and October. Celavar, Evpark, Nyjack and Ribera soils have a lithic contact at 20 to 40 inches. Celacy soils are moist in some parts of the moisture control section during the 120 days following the winter solstice. Gateson soils have an E&B horizon. Oldwolf soils have 15 to 35 percent fine and coarser sand in the particle size control section. Toluca
soils have secondary calcium carbonate accumulations at 10 inches or less. Rockybutte soils are moderately deep to porcellanite.
GEOGRAPHIC SETTING: Elwop soils are on fan remnants, plateaus, and crests, shoulders, backslopes, footslopes, and toeslopes of hills and ridges. They formed in alluvium or eolian deposits over residuum derived from mixed sedimentary sources. Slopes are 0 to 15 percent. Elevations are 3,500 to 5,000 feet. The mean annual precipitation ranges from 15 to 19 inches, half of which falls as rain or snow from March through 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 Arwite, Deekay and Oldwolf soils and the Mittenbutte, Vonalf and Xema soils. Mittenbutte soils are shallow and calcareous throughout. Vonalf and Xema soils are coarse-loamy. Arwite, Deekay and Vonalf soils are on alluvial fans, fan remnants, and backslopes and footslopes of hills and ridges. Mittenbutte, Oldwolf and Xema soils are on shoulders and summits of hills and ridges.
DRAINAGE AND PERMEABILITY: Well drained; low or medium runoff depending on slope; moderate permeability.
USE AND VEGETATION: These soils are utilized as rangeland, hayland and pasture, and wildlife habitat. The native vegetation is mainly Indian ricegrass, little bluestem, needleandthread and prairie sandreed.
DISTRIBUTION AND EXTENT: Elwop soils occur in the Powder River basin of north-central and northeastern Wyoming. The series is of limited extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Campbell County, Wyoming, Southern Part; 1993
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 4 inches (A horizon)
Argillic horizon - 4 to 24 inches (Bt1 and Bt2 horizons)
Paralithic contact - 35 inches (Cr)
SIR- WY1365
LRR- G