LOCATION JENKINS            CO+WY
Established Series
Rev. RHM
03/1999

JENKINS SERIES


The Jenkins series consists of moderately deep, well drained soils that formed in material weathered from sedimentary rock. Jenkins soils are on mountain sides and ridges at relatively high elevations and have slopes of 4 to 40 percent. The mean annual precipitation is about 20 inches and the mean annual air temperature is about 34 degrees F.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Spodic Dystrocryepts

TYPICAL PEDON: Jenkins gravelly loam, forested. (Colors are for dry soil unless otherwise noted.)

01--2 to inch; undecomposed organic material, mainly bark, twigs, and needles.

02--1 to 0 inches; decomposed and partly decomposed organic material.

A1--0 to 3 inches; pinkish gray (7.5YR 6/2) gravelly loam; brown (7.5YR 4/2) moist; weak thin platy structure that parts to moderate fine crumbs; soft, very friable; 15 percent sandstone pebbles and sandstone fragments; very strongly acid; clear smooth boundary. (1 to 4 inches thick)

B2--3 to 9 inches; brownish yellow (10YR 6/6) gravelly loam, dark yellowish brown (10YR 4/5) moist; moderate very fine subangular blocky structure; slightly hard, very friable; 15 percent sandstone pebbles; very strongly acid; gradual wavy boundary. (5 to 10 inches thick)

B3--9 to 18 inches; light olive brown (2.5Y 5/4) channery loam, olive brown (2.5Y 4/4) moist; weak very fine subangular blocky structure; slightly hard, very friable; 20 percent sandstone and hard shale fragments; medium acid; gradual irregular boundary. (6 to 12 inches thick)

C--18 to 28 inches; light brownish gray (2.5Y 6/2) channery sandy loam, dark grayish brown (2.5Y 4/2) moist; massive; slightly hard, very friable; 20 percent sandstone and dark shale fragments; medium acid; gradual wavy boundary. (6 to 16 inches thick)

R--28 to 35 inches; interbedded sandstone and hard shale.

TYPE LOCATION: Gunnison County, Colorado; S1/2 Sec. 23, T. 14 S., R. 84 W.

RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 12 to 24 inches, and depth to bedrock ranges from 20 to 40 inches. The fine earth portion of the control section is typically sandy loam or loam and has 7 to 18 percent clay, 15 to 50 percent silt, and 30 to 70 percent sand. Rock fragments range from 5 to 35 percent by volume and are mostly gravel and thin, flat fragments less than 10 inches in length.

The A2 horizon has hue of 2.5Y through 7.5YR, value of 6 or 7 dry, 5 or 6 moist, and chroma of 2 through 4. This horizon typically has weak platy structure that parts to fine granules and crumbs. Dry consistence is soft or slightly hard. Reaction ranges from pH 4.5 to 5.5.

The B2 horizon has hue of 10YR through 5YR, value of 5 or 6 dry, 4 or 5 moist, and chroma of 4 through 6. Typically the horizon has subangular blocky structure. Dry consistence is hard or slightly hard. Reaction ranges from pH 4.5 to 5.5.

The C horizon has hue of 2.5Y or 10YR. Reaction ranges from 5.0 to 6.5.

COMPETING SERIES: These are the Azwell, Bobtail, Hanks, Jughandle, Lake Janee, Liggett, Ryorp, Sambrito, and Walters series. Azwell soils have chroma of 2 to 4 in the B2 horizon, are dry in the summer, and formed in material weathered from mixed igneous rocks. Hanks, Jughandle, Lake Janee, Liggett, Sambrito, and Walters soils are deeper than 40 inches to a lithic contact. Bobtail soils have 15 to 75 percent of the sand fraction as medium, coarse, and very coarse sand and formed in material weathered from mixed igneous rocks. Ryorp soils are slightly or medium acid; the mean annual soil temperature is above 38 degrees F. and the frost-free season is longer than 50 days.

GEOGRAPHIC SETTING: The Jenkins soils are on mountain sides and ridges at relatively high elevations. Slopes range from 4 to about 40 percent. The soils formed in moderately coarse textured, medium acid parent materials weathered from sandstone and shale. At the type location, the average annual precipitation is 20 inches with generally uniform distribution occurring throughout the year. The mean annual temperature is about 32 to 35 degrees F. and the frost-free season is about 20 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Leal, Matcher, and Rarick soils. Leal and Rarick soils have no bedrock above a depth of 40 inches. Matcher soils have more than 35 percent rock fragments in the control section.

DRAINAGE AND PERMEABILITY: Well drained; medium to slow runoff; moderate to rapid permeability.

USE AND VEGETATION: These soils are used for forestry, for rangeland, and for recreational purposes. Native vegetation is mainly spruce, subalpine fir, lupine, and vaccinium.

DISTRIBUTION AND EXTENT: High mountainous areas of central Colorado. The series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Gunnison County, Colorado, 1975.

REMARKS: Differentiation from the Bobtail series needs further study. Last updated by the state 6/75.


National Cooperative Soil Survey
U.S.A.