LOCATION MENDENHALL              CO

Established Series
Rev. AJC-LF-KLS
01/2023

MENDENHALL SERIES

The Mendenhall series consists of very deep, poorly drained soils with moderately rapid permeability. These soils formed in thick calcareous moderately coarse textured alluvial materials derived from sedimentary, metamorphic, and igneous rocks and are found on terraces, stream bottoms, and alluvial fans. Slopes are 0 to 6 percent. Mean annual precipitation is about 310 mm, and mean annual air temperature is about 3 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, calcareous Cumulic Cryaquolls

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

Oi--0 to 8 cm; undecomposed organic material mostly the remains of grasses.

A--8 to 33 cm; dark gray (10YR 4/1) loam, black (10YR 2/1) moist; moderate medium and fine granular and crumb structure; soft, very friable, slightly sticky, slightly plastic; 10 percent gravel; calcareous; moderately alkaline (pH 8.0); clear smooth boundary. (10 to 30 cm)

Ag--33 to 74 cm; gray (10YR 5/1) sandy loam, very dark gray (10YR 3/1) moist; common medium prominent mottles of reddish brown (5YR 5/3) moist and dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure that parts to fine granules; slightly hard, very friable, nonsticky, nonplastic; 10 percent gravel; calcareous; moderately alkaline (pH 8.2); clear smooth boundary. (20 to 100 cm thick)

Bg--74 to 135 cm; light brownish gray (10YR 6/2) sandy loam, dark grayish brown (10YR 4/2) moist; many large prominent mottles of reddish brown (5YR 5/3) moist, dark yellowish brown (10YR 4/4) moist, and dark gray (2.5Y 4/1) moist; massive; slightly hard, very friable, nonsticky, nonplastic; 10 percent gravel; calcareous; moderately alkaline (pH 8.2).

TYPE LOCATION: Jackson County, Colorado; about 470 meters west and 525 meters south of NE corner of sec. 3, T. 8 N., R. 79 W.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--4 degrees C
Mean summer soil temperature--11 degrees C
Thickness of mollic epipedon--50 to 125 cm
Electrical conductivity--0 to 16 mmhos/cm, with no subhorizon more than 10 cm thick above 50 cm depth that exceeds 15 percent

Particle-size control section:
Texture--sandy loam or gravelly sandy loam
Clay content--5 to 18 percent
Sand content--45 to 82 percent sand, with more than 35 percent fine or coarser sand
Rock fragment content--0 to 35 percent and are mainly 5 to 250 mm in diameter

A horizon
Hue--2.5Y through 7.5YR
Value--4 or 5 dry, 2 or 3 moist
Chroma--neutral through 3
Reaction--pH 7.4 to 9.0

Bg horizon
Hue--5Y through 7.5YR
Value--5 through 7 moist, and 4 through 6 dry
Chroma--neutral through 2
Reaction--pH 7.9 to 9.0

COMPETING SERIES: These are the Dobrow, Fleer, and Tepee soils. Dobrow soils are noncalcareous. Fleer soils have sandy-sketetal material in the lower part of the control section. Tepee soils have more that 18 percent clay and are noncalcareous.

GEOGRAPHIC SETTING:
Landform--nearly level to moderately sloping terraces, stream bottoms, and alluvial fans
Elevation--2375 to 2625 meters
Slope--0 to about 6 percent
Parent material--thick calcareous, moderately coarse textured alluvial materials derived from sedimentary, metamorphic, and igneous rocks
Mean annual precipitation--260 to 380 mm with peak periods of precipitation in the spring and early summer
Mean annual air temperature--2 to 3 degrees C
Mean summer air temperature--14 degrees C
Frost-free period--30 to 40 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed

DRAINAGE AND PERMEABILITY: Poorly drained; slow to very slow runoff; moderately rapid permeability

USE AND VEGETATION: These soils are used for grazing or as native hay meadow. Native vegetation is timothy, redtop, Junegrass, willows, sedges, and rushes.

DISTRIBUTION AND EXTENT: Mendenhall soils are of small extent in the high mountain valleys of Colorado; MLRA 48B.

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

SERIES ESTABLISHED: Jackson County, Colorado. 1973

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

Converted to metric and O horizons were updated to start at zero. Competing series section was not updated. 01/2023

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National Cooperative Soil Survey
U.S.A.