LOCATION OSHOTO WYEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aridic Haplustalfs
TYPICAL PEDON: Oshoto silt loam -- on a northwest facing slope of 5 percent, utilized as rangeland. (Colors are for dry soil unless otherwise stated)
A--0 to 7 inches; brown (10YR 5/3) silt loam, brown (10YR 4/3) moist; weak fine and medium subangular blocky structure; loose, friable, nonsticky and nonplastic; noneffervescent; neutral; abrupt smooth boundary. (2 to 9 inches thick)
Bt1--7 to 14 inches; brown (10YR 5/3) silty clay loam, brown (10YR 4/3) moist; moderate medium prismatic structure parting to moderate fine and medium subangular blocky; slightly hard, friable, 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 wavy boundary.
Bt2--14 to 22 inches; brown (10YR 5/3) silty clay loam, brown (10YR 4/3) moist; moderate medium prismatic structure parting to moderate fine and medium subangular blocky; slightly hard, friable, moderately sticky and moderately plastic; few distinct discontinuous dark brown (10YR 3/3) clay films on faces of peds and in pores; noneffervescent; slightly alkaline; gradual wavy boundary. (Combined Bt horizons 7 to 20 inches thick)
Btk--22 to 32 inches; light yellowish brown (2.5Y 6/3) silty clay loam, light olive brown (2.5Y 5/3) moist; moderate medium and coarse subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few distinct discontinuous olive brown (2.5Y 4/3) clay films on faces of peds and in pores; common fine irregular light gray (10YR 7/2) carbonate threads throughout; strongly effervescent; moderately alkaline; gradual wavy boundary. (0 to 14 inches thick)
Bk1--32 to 43 inches; light yellowish brown (2.5Y 6/3) silty clay loam, light olive brown (2.5Y 5/3) moist; moderate medium and coarse subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common fine irregular light gray (10YR 7/2) carbonate threads throughout; violently effervescent; strongly alkaline; gradual wavy boundary.
Bk2--43 to 60 inches; light yellowish brown (2.5Y 6/3) silt loam, light olive brown (2.5Y 5/3) moist; moderate medium and coarse angular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common fine irregular light gray (10YR 7/2) carbonate threads throughout; violently effervescent; strongly alkaline.
TYPE LOCATION: Campbell County, Wyoming; about 1300 feet west and 600 feet south of the northeast corner Section 34 T 56 N, R 75 W.; USGS Reservoir Creek, WY topographic quadrangle; lat. 44 degrees 47 minutes 37 seconds N. and long. 105 degrees 52 minutes 5 seconds W.
RANGE IN CHARACTERISTICS: Depth to the base of the argillic horizon ranges from 10 to 35 inches. Depth to continuous accumulations of calcium carbonate ranges from 10 to 27 inches, although some pedons may be slightly effervescent to within 5 inches of the surface where intermittent recharge has occurred. Rock fragments range from 0 to 10 percent. The moisture control section is usually moist in some or all parts in March through June. The average annual soil temperature is 47 to 50 degrees F.
The A horizon has hue of 10YR or 2.5Y, value of 4 or 5 dry and 3 or 4 moist, and chroma of 2 to 4. It is silt loam, loam or silty clay loam. It is slightly acid to slightly alkaline. Some pedons have an E horizon.
The Bt horizon has hue of 10YR or 2.5Y, value of 4 to 6 dry and 3 to 5 moist, and chroma of 2 to 4. Texture is commonly clay loam or silty clay loam and less commonly loam or silt loam. It is slightly acid to slightly alkaline.
The Btk horizon has hue of 10YR or 2.5Y, value of 4 to 6 dry and 3 to 5 moist, and chroma of 2 to 4. Texture is clay loam, silty clay loam, loam or silt loam. It has 3 to 12 percent calcium carbonate equivalent. It is slightly alkaline or moderately alkaline.
The Bk horizon has hue of 10YR, 2.5Y or 5Y, value of 5 to 7 dry and 4 to 6 moist, and chroma of 2 to 4. Textures include loam, silt loam, silty clay loam, clay loam and fine sandy loam. It has 4 to 15 percent calcium carbonate equivalent. It is slightly alkaline to strongly alkaline.
COMPETING SERIES: These are the Amal, Buick, Chita, Elpedro, Keiser, Klinedraw, Moncha, Pulpit, Roubideau, Sharps, Verde, Wetherill and Wiley series. It is assumed the Amal, Chita, Elpedro and Muncha soils are competing pending an update of the classification. Amal, Elpedro, Moncha and Wetherill soils have a Bt horizon with hues 7.5YR or redder. Buick soils have buried subhorizons. Chita soils have a calcic horizon. Keiser soils have carbonates shalloer than 10 inches. Klinedraw, Pulpit, Roubideau, Sharps and Verde soils have a paralithic or lithic contact within depths of 40 inches. Wiley soils have mean annual soil temperatures of 53 degrees F. or warmer.
GEOGRAPHIC SETTING: Oshoto soils are on fan remnants, alluvial fans, terraces, plateaus, ridges and hills. They formed in alluvium derived primarily from silty shale and very fine grained sandstone. Slopes are 0 to 15 percent. Elevations are 3,500 to 5,200 feet. The mean annual precipitation ranges from 15 to 17 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 Klinedraw and the Deekay, Leiter, Moorhead, Oldwolf and Ziggy soils. Deekay and Oldwolf are fine-loamy. Leiter and Moorhead soils are fine. Ziggy soils have a cambic horizon and are calcareous throughout. Deekay, Moorhead and Ziggy soils are on similar positions. Klinedraw, Lieter and Oldwolf soils are on shoulders and summits of hills and ridges.
DRAINAGE AND PERMEABILITY: Well drained; low or medium runoff; moderate permeability.
USE AND VEGETATION: These soils are utilized as rangeland, hayland and pasture, nonirrigated cropland and wildlife habitat. The native vegetation is mainly western wheatgrass, blue grama, needleandthread and green needlegrass. Winter wheat, oats, barley and alfalfa are the principle cultivated crops.
DISTRIBUTION AND EXTENT: Oshoto 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; 1995
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 7 inches (A horizon)
Argillic horizon - 7 to 32 inches (Bt1, Bt2 and Btk horizons)
SIR- WY1377
LRR- G