LOCATION EPIKOM                  AZ

Established Series
Rev. DRT/RLB
10/2011

EPIKOM SERIES

The Epikom series consists of shallow, well drained soils that formed in alluvium from sandstone, mudstone and shale. Epikom soils are on plateaus and mesas and have slopes of 0 to 25 percent. The mean annual precipitation is about 8 inches and the mean annual air temperature is about 51 degrees F.

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

TYPICAL PEDON: Epikom fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 3 inches; reddish brown (5YR 5/4) fine sandy loam, reddish brown (5YR 4/4) moist; weak thin platy structure; slightly hard, very friable, slightly sticky and slightly plastic; few fine roots; common fine vesicular and many irregular pores; violently effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (3 to 5 inches thick)

Bw--3 to 15 inches; reddish yellow (5YR 6/6) gravelly loam, yellowish red (5YR 5/6) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and plastic; common fine and medium roots; few irregular and tubular pores; 20 percent gravel; violently effervescent; moderately alkaline (pH 8.2); abrupt wavy boundary. (7 to 15 inches thick)

2R--15 inches; interbedded sandstone and shale; common calcium carbonate coatings in joints.

TYPE LOCATION: Coconino County, Arizona; about 48 miles east and 18 miles south of Flagstaff; 600 feet west of the center of section 32, T. 18 N., R. 14 E.

RANGE IN CHARACTERISTICS:

Soil Moisture: Intermittently moist in some part of the soil moisture control section during July-September and December-February. Driest during May and June. Typic aridic soil moisture regime.

Soil Temperature: 51 to 59 degrees F.

Depth to bedrock: 10 to 20 inches

Clay content: Averages less than 18 percent in the control section

Rock Fragments: Averages less than 35 percent in the control section; can range to 60 percent in any one horizon.

A horizon
Hue: 2.5YR, 5YR, 7.5YR
Value: 4 to 7 dry, 3 to 5 moist
Chroma: 2 to 6, dry or moist
Reaction: Slightly to strongly alkaline

B horizon
Hue: 2.5YR, 5YR, 7.5YR
Value: 4 to 7 dry, 3 to 6 moist
Chroma: 2 to 6, dry or moist
Texture: Sandy loam, loam, fine sandy loam
Reaction: Slightly to strongly alkaline
Calcium carbonate: Less than 15 percent calcium carbonate equivalent as disseminated or coatings on rock fragments.

COMPETING SERIES: These are the Leanto (UT) and Lyeflat (OR) series. Leanto soils have hue yellower than 5YR and are moist in the moisture control section for longer periods due to a higher rainfall component. Lyeflat soils have 10YR or 2.5Y hues and SAR that range from 13 to 30 percent.

GEOGRAPHIC SETTING: Epikom soils are on plateaus and mesas and have slopes of 0 to 25 percent. These soils formed in alluvium from sandstone, mudstone and shale. Elevations range from 4,220 to 7,000 feet. The mean annual precipitation ranges from 6 to 10 inches. The mean annual air temperature is 49 to 57 degrees F. The frost-free period is 130 to 180 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Boysag, Navajo, Purgatory, and Tours soils. Boysag soils have argillic horizons. Navajo and Tours soils are very deep. Tours soils are also fine-silty. Purgatory soils have bedrock at depths of 20 to 40 inches.

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

USE AND VEGETATION: Epikom soils are used for livestock grazing and wildlife habitat. The present vegetation is black grama, blue grama, galleta, alkali sacaton and fourwing saltbush.

DISTRIBUTION AND EXTENT: Northern Arizona. This series is extensive. MLRA 35.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Coconino County Area, Arizona, Central Part; 1980.

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

Ochric epipedon - The zone from 0 to 3 inches (A horizon)

Cambic horizon - The zone from 3 to 15 inches (Bw horizon)

Lithic contact - The boundary at 15 inches (2R horizon)

Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy, Eleventh Edition, 2010

Update and revisions for the correlation of Little Colorado River Area (AZ707), Sept. 2011, CEM

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National Cooperative Soil Survey
U.S.A.