LOCATION SPLITRO                 WY+CO MT

Established Series
Rev. AJC/CRP/JCK
04/2018

SPLITRO SERIES

The Splitro series consists of shallow, well drained soils that formed in slope alluvium or colluvium over residuum derived from sandstone. These soils are on mountain slopes, dipslopes and hillslopes. Slopes are 0 to 65 percent. Mean annual precipitation is 559 mm, and mean annual air temperature is 3.9 degrees C.

TAXONOMIC CLASS: Loamy, mixed, superactive Lithic Haplocryolls

TYPICAL PEDON: Splitro sandy loam, on a west facing 7 percent slope in grassland. (Colors are for dry soil unless otherwise stated.)

A--0 to 20 cm; brown (7.5YR 5/3) sandy loam, dark brown (7.5YR 3/3) moist; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; many fine and very fine roots; many fine and very fine pores; 5 percent gravel and 2 percent cobbles; neutral (pH 6.8); clear smooth boundary. (18 to 35 cm thick)

Bw--20 to 41 cm; brown (7.5YR 5/4) fine sandy loam, brown (7.5YR 4/4) moist; moderate coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; 5 percent gravel and 3 percent cobbles; neutral (pH 6.8); abrupt smooth boundary. (15 to 25 cm thick)

R--41 cm; hard quartzitic sandstone.

TYPE LOCATION: Johnson County, Wyoming; NE1/4, NE1/4, Sec. 30, T45N, R85W. Tabletop Quadrangle. 43 degrees 50 minutes 38 seconds north latitude and 107 degrees 6 minutes 34 seconds west longitude.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 2.7 to 5.4
Mollic epipedon - 18 to 35 cm
Depth to lithic contact - 33 to 50 cm
Particle-size control section (weighted average):
Clay content - 8 to 18 percent

A horizon
Hue: 10YR or 7.5YR
Value: 3, 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3
Texture: sandy loam or fine sandy loam
Clay content: 8 to 18 percent
Rock fragments: 0 to 35 percent
Reaction: pH 6.4 to 7.4

Bw horizon
Hue: 10YR, 7.5YR or 5YR
Value: 4, 5 or 6 dry; 3, 4 or 5 moist
Chroma: 2, 3 or 4
Texture: sandy loam or very fine sandy loam
Clay content: 8 to 18 percent
Rock fragments: 0 to 30 percent
Reaction: pH 6.4 to 7.4

COMPETING SERIES:
Dickle (OR) - have more than 18 percent clay in the particle-size control section
Hanagita (AK) - have less than 15 percent fine sand or coarser in the particle-size control section
Hazton (WY) - do not have a cambic horizon
Heisspitz (CO) - do not have a cambic horizon
Jenkinson (WY) - have more than 18 percent clay in the particle-size control section; are calcareous throughout
Lotex (UT) - have hue redder than 7.5YR throughout
Paddy (MT) - have more than 18 percent clay in the particle-size control section
Skisams (CO) - have more than 18 percent clay in the particle-size control section
Spliten (ID) - have a xeric soil moisture regime
Tuggle (MT) - have a paralithic contact above the lithic contact; formed in granite
Udelope (NV) - have a xeric soil moisture regime
Vorsid (CO) - do not have a cambic horizon

GEOGRAPHIC SETTING:
Landform - mountain slopes, dip slopes and hillslopes
Elevation - 1,981 to 3,048 meters
Slope - 0 to 60 percent
Parent material - slope alluvium or colluvium over residuum
Mean annual precipitation - 457 to 635 mm
Mean annual air temperature - 1.7 to 4.4 C
Frost-free period - 40 to 75 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Passcreek and Sawcreek soils. Both of these soils are moderately deep and occur on lower landscape positions.

DRAINAGE AND PERMEABILITY: Well drained; moderately rapid permeability.

USE AND VEGETATION: These soils are used principally as native pastureland or for recreational purposes. Native vegetation is green needlegrass, Idaho fescue, and yarrow. May have scattered ponderosa pine and quaking aspen.

DISTRIBUTION AND EXTENT: Splitro soils are of moderate extent in the Bighorn Mountain areas of Wyoming and Montana, and the western slope of Colorado. MLRA 43B, 46 and 48A.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Lower Colorado Area, Colorado 1970.

REMARKS: Diagnostic horizons and features recognized in this pedon.
Mollic epipedon - from 0 to 20 cm (A horizon)
Cambic horizon - from 20 to 41 cm (Bw horizon)
Lithic contact - at 41 cm (R horizon)
Particle-size control section - from 25 to 41 cm (part of the Bw horizon)

Note: These soils were originally classified as Lithic Cryoborolls with an MAP of 508 cm (20 inches). In 1994 an MAP range of 457 to 635 mm (18-25 inches) was added to the OSD. Currently (04/2018), Splitro soils are mapped along the Rocky Mountains from southern Montana to central Colorado and encompass what appear to be both udic and ustic soil moisture regimes, as well as, both cryic and frigid temperature regimes. An investigation to determine correct moisture and temperature regimes for the extent of these soils is warranted.

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National Cooperative Soil Survey
U.S.A.