LOCATION STEPHOUSE               CO

Established Series
Rev. JWH/CSW/JWB
04/2011

STEPHOUSE SERIES

The Stephouse series consists of shallow and very shallow, well drained soils that formed in residuum, eolian sands and/or slope alluvium derived from interbedded sandstone, shale and conglomerate. Stephouse soils are on ridges, mesas and structural benches. Slopes range from 3 to 15 percent. Mean annual precipitation is about 17 inches and the mean annual temperature is about 48 degrees F.

TAXONOMIC CLASS: Loamy, mixed, superactive, mesic Lithic Calciustepts

TYPICAL PEDON: Stephouse gravelly fine sandy loam, on an east facing, 4 percent slope in pinyon-juniper woodland at an elevation of 6,880 feet. (Colors are for dry soil unless otherwise noted. When described on July 2 the soil was dry throughout.) The surface is covered by 50 percent gravel and 3 percent cobbles.

A--0 to 1 inch; yellowish brown (10YR 5/4) gravelly fine sandy loam, brown (10YR 4/3) moist; single grain; loose, loose, nonsticky and nonplastic; few very fine roots throughout; common fine rounded soft masses of carbonate, 14 percent calcium carbonate; 30 percent gravel; strongly effervescent; moderately alkaline (pH 8.3); abrupt smooth boundary. (0 to 6 inches thick)

Bk1--1 to 3 inches; yellowish brown (10YR 5/4) gravelly fine sandy loam, brown (10YR 4/3) moist; weak very fine granular; soft, very friable, slightly sticky and nonplastic; common very fine, fine, and medium roots throughout; common fine rounded soft masses of carbonate, 18 percent calcium carbonate; 20 percent gravel; violently effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (1 to 8 inches thick)

Bk2--3 to 8 inches; pale brown (10YR 6/3) gravelly fine sandy loam, brown (10YR 5/3) moist; massive; soft, very friable, slightly sticky and nonplastic; common very fine, fine, and medium roots throughout; many medium rounded soft masses of carbonate, 21 percent calcium carbonate; 30 percent gravel; violently effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (0 to 8 inches thick)

Bk3--8 to 12 inches; pale brown (10YR 6/3) very gravelly fine sandy loam, brown (10YR 5/3) moist; massive; soft, very friable, slightly sticky and nonplastic; common very fine, fine, and medium roots throughout; many medium rounded soft masses of carbonate, 26 percent calcium carbonate; 40 percent gravel; violently effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (0 to 8 inches thick)

R--12 to 16 inches; hard fractured sandstone.

TYPE LOCATION: Montezuma County, Colorado; located in an unsectionized area; Wetherill Mesa, CO USGS quad; lat. 37 degrees 08 minutes 56 seconds N. and long. 108 degrees 30 minutes 57 seconds W., NAD27

RANGE IN CHARACTERISTICS:

Soil moisture regime: ustic bordering on aridic

Soil temperature regime: mesic

Mean annual soil temperature: 47 to 52 degrees F

Surface rock fragments: 0 to 60 percent, mainly gravel with many petrocalcic fragments; up to 15 percent cobbles and/or stones

Particle-size control section: 8 to 18 percent clay

Depth to lithic contact: 6 to 20 inches to hard sandstone or conglomerate

Depth to calcic horizon: 0 to 10 inches

A horizon:
Hue: 7.5YR or 10YR
Value: 5 to 7 (4 or 5 moist)
Chroma: 2 to 6
Texture: fine sandy loam or sandy loam
Rock fragments: 5 to 50 percent
Calcium carbonate equivalent: 0 to 40 percent
Reaction: slightly or moderately alkaline

Bk horizon:
Hue: 7.5YR or 10YR
Value: 5 to 7 (4 or 5 moist)
Chroma: 3 to 6
Texture: loam, fine sandy loam, or sandy loam
Rock fragments: 0 to 60 percent
Calcium carbonate equivalent: 5 to 40 percent
Reaction: moderately alkaline

COMPETING SERIES: This is the Peney series. The Peney series has 18 to 35 percent clay in the control section.

GEOGRAPHIC SETTING:

Parent material: residuum derived from sandstone and shale and/or eolian sands and slope alluvium derived from sedimentary rocks over residuum weathered from conglomerate

Landform: ridges, mesas and structural benches

Slopes: 3 to 15 percent

Elevation: 6,800 to 7,800 feet

Mean annual air temperature: 45 to 50 degrees F

Mean annual precipitation: 12 to 18 inches

Precipitation is fairly evenly distributed throughout the year with July and August being slightly wetter and June being slightly drier.

Frost-free period: 110 to 150 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arabrab and Longburn series. Arabrab and Longburn soils have argillic horizons.

DRAINAGE AND PERMEABILITY: well drained, low to very high runoff, moderate permeability

USE AND VEGETATION: potential native vegetation is twoneedle pinyon, Utah juniper, muttongrass, Indian Ricegrass, Utah serviceberry, true mountain mahagany, bottlebrush squireltail, and antelope bitterbrush.

DISTRIBUTION AND EXTENT: Southwest Colorado and central Utah. LRR D, MLRA 34B and 36. This series is of small extent.

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

SERIES ESTABLISHED: Cortez Area, Colorado, Parts of Dolores and Montezuma Counties 1997.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon: The zone from 0 to 1 inch. (A)

Calcic horizon: The zone from 1 to 12 inches. (Bk1, Bk2, and Bk3)

Lithic contact: The zone at 12 inches. (R)

This soil is thought to have lost most of the original surface material leaving mainly the calcic horizon.

Particle-size control section: The zone from 0 to 12 inches. (A, Bk1, Bk2, Bk3)

Soil Taxonomy Eleventh Edition, 2010

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National Cooperative Soil Survey
U.S.A.