LOCATION UPSON                   CO

Established Series
Rev. RLM/RHM/KLS
11/2022

UPSON SERIES

The Upson series consists of moderately deep, well drained soils that formed in highly weathered granite (gruss). Upson soils are on mountain sides and crests and have slopes of 3 to 65 percent. The mean annual precipitation is about 510 mm and the mean annual air temperature is about 4 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Ustic Haplocryepts

TYPICAL PEDON: Upson stony sandy loam, forested. (Colors are for dry soil unless otherwise noted.)

Oi--0 to 3 cm; undecomposed needles, bark, and twigs. (3 to 8 cm thick)

A--3 to 49 cm; pale brown (10YR 6/3) stony sandy loam, brown (10YR 4/3) moist; weak coarse granular structure; soft, very friable; 5 to 10 percent stones on surface, 10 percent fine gravel slightly acid; clear wavy boundary. (25 to 50 cm thick)

AC--49 to 87 cm; brown (10YR 5/3) sandy loam, brown (10YR 4/3) moist; weak medium and coarse subangular blocky structure; slightly hard, very friable; 10 percent fine gravel; slightly acid; gradual wavy boundary. (20 to 40 cm thick)

C--87 to 95 cm; grayish brown (10YR 5/2) loamy coarse sand, dark grayish brown (10YR 4/2) moist, massive; slightly hard, very friable; 10 percent fine gravel; slightly acid; gradual wavy boundary. (8 to 10 cm thick)

Cr--95 to 156 cm; highly weathered granite.

TYPE LOCATION: Grand County, Colorado; about 16 km southeast of Granby; about 805 meters west, 15 meters south of the northeast corner of sec. 34, T. 1 N., R. 76 W.

RANGE IN CHARACTERISTICS:
Depth to paralithic contact--50 to 100 cm
Surface fragments--stones ranging in size from 250 mm to larger than 600 mm cover 2 to 25 percent of the surface

Particle-size control section:
Texture--sandy loam
Clay content--10 to 18 percent
Silt content--5 to 40 percent
Sand content--45 to 85 percent, with more than 35 percent being fine or coarser sand
Rock fragment content--0 to 25 percent and are mainly 6 to 25 mm in diameter

A horizon
Hue--2.5Y through 7.5YR
Value--6 through 8 dry, 4 or 5 moist
Chroma--2 through 4

C horizon
Hue--2.5Y through 7.5YR
Reaction--pH 5.6 to 7.3

COMPETING SERIES: These are the Baldy and Mine series, both of which are deep soils.

GEOGRAPHIC SETTING:
Landform--mountain sides and crests
Elevation--2600 to 3050 meters
Slope--3 to 65 percent
Parent material--colluvium and/or residuum derived from highly weathered granite (gruss)
Mean annual precipitation--510 mm with peak periods of precipitation occurring during the winter and spring
Mean annual air temperature--4 degrees C
Mean annual summer air temperature--13 degrees C
Frost-free period--30 to 50 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed

DRAINAGE AND PERMEABILITY: Well drained; medium runoff: rapid permeability

USE AND VEGETATION: These soils are used principally for woodland production and recreation. Native vegetation is mainly lodgepole pine, aspen and a sparse understory of grasses and shrubs.

DISTRIBUTION AND EXTENT: Upson soils are moderately extensive in the mountains of northcentral Colorado; MLRA 48A.

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

SERIES ESTABLISHED: Grand County, Colorado, 1977

REMARKS: 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.