LOCATION WICHUP                  CO+MT

Established Series
Rev. AJC/GB/KLS
11/2022

WICHUP SERIES

The Wichup series consists of deep, poorly drained soils that formed in mixed alluvial fan sediments derived from sandstone, quartzite, shale and small amounts of limestone. These soils are on alluvial fans. Slopes range from 0 to 3 percent. The mean annual precipitation is about 460 mm and the mean annual air temperature is about 4 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Histic Cryaquolls

TYPICAL PEDON: Wichup loam - grassland. (Colors are for dry soil unless otherwise noted.)

Oe--0 to 13 cm; brown, calcareous fibrous sedge-rush peat; effervescence in upper 5 cm; slightly alkaline (pH 7.8); gradual smooth boundary. (13 to 30 cm thick)

Oa--13 to 26 cm; black, calcareous muck with some plant residue forms and some mineral matter; neutral (pH 6.8); gradual wavy boundary. (0 to 15 cm thick)

Ag--26 to 46 cm; gray (2.5Y 5/1) gravelly loam, black (2.5Y 2/1) moist; common medium distinct brown (7.5YR 4/4) moist mottles; moderate fine granular structure; soft, very friable; slightly alkaline (pH 7.4); gradual wavy boundary. (15 to 36 cm thick)

Bg1--46 to 61 cm; light brownish gray (2.5Y 6/2) very gravelly loam, dark grayish brown (2.5Y 4/2) moist; many large prominent brown (7.5YR 4/4) mottles; weak coarse subangular blocky structure; slightly hard, very friable; slightly alkaline (pH 7.4); gradual wavy boundary. (10 to 30 cm thick)

Bg2--61 to 178 cm; light brownish gray (10YR 6/2) fine sandy loam, dark grayish brown (10YR 4/2) moist; common medium distinct olive brown (2.5Y 4/3) and brown (10YR 4/3) mottles; massive; slightly hard, very friable; 10 percent gravel; slightly alkaline (pH 7.4).

TYPE LOCATION: Jackson County, Colorado; center of NE 1/4 Sec. 32, T. 9 N., R. 77 W.

RANGE IN CHARACTERISTICS:
Organic surface horizon thickness--20 to 30 cm; Muck horizons are not always present, but if present they range in thickness from 3 to 15 cm.
Mollic epipedon thickness--18 to 48 cm thick
Depth to calcareous soil--150 cm or more; however, the Oe horizon may be weakly calcareous in places.
Particle-size control section:
Texture--sandy loam or loam
Clay content--8 to 18 percent
Silt content--5 to 35 percent
Sand content--50 to 80 percent, with more than 35 percent being fine or coarser sand
Some stratification is common, particularly in the surface horizons but organic content decreases uniformly.
Rock fragment content--0 to 15 percent; however, thin horizons containing 15 to 35 percent pebbles and cobbles are present in some pedons
Depth to water table--less than 100 cm during most of the year

Ag horizon
Hue--10YR through 5Y
Value--5 or less dry, 3 or less moist
Chroma--2 or less
Typically, there are distinct or prominent mottles throughout or in some part.
Structure--granular or crumb structure
Consistence--soft or slightly hard
Reaction--pH 6.0 to 7.6

Bg horizons
Hue--10YR or 2.5Y
Value--more than 5.5 dry or more than 3.5 moist
Chroma--not more than 2
This horizon has distinct or prominent mottles of both bright and dull chroma.
Reaction--pH 7.0 to 7.8, usually nearly constant in reaction with increasing depth

C horizon, when present, has higher chroma in some pedons.

COMPETING SERIES: This is the Dutson series. Dutson soils lack histic epipedons and have argillic horizons.

GEOGRAPHIC SETTING:
Landform--alluvial fans
Elevation--1850 to 3050
Slope--0 to 3 percent
Parent material--mixed alluvial fan sediments derived from sandstone, quartzite, shale, and small amounts of limestone
Mean annual precipitation--460 mm with peak periods of precipitation occurring during the spring and summer
Mean annual air temperature--4 degrees C
Mean summer air temperature--9 degrees C

GEOGRAPHICALLY ASSOCIATED SOILS: None listed

DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff; moderate permeability

USE AND VEGETATION: These soils are used for wet meadow pastures. Hydrophytic plants dominate the community. The main plants are sedges, rushes, tufted hairgrass, willows, shrubby cinquefoil, Poa spp., and marsh marigold.

DISTRIBUTION AND EXTENT: The soils are moderately extensive in mountain meadows at moderately high and high elevations in central Colorado and southwest Montana; MLRAs 43B, 44B and 48A.

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

SERIES ESTABLISHED: Jackson County, Colorado, 1973

REMARKS:
The superactive cation exchange activity class was added to the taxonomic classification by the National Soil Survey Center on request of the Lakewood office, without review of the soil series property data. 03/2003

Converted to metric, updated formatting, and O horizons were updated to start at zero. Competing series section was not updated. 11/2022

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National Cooperative Soil Survey
U.S.A.