LOCATION EPIKOM AZEstablished Series
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 58 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 6 dry, 3 to 5 moist
Chroma: 3 to 6, dry or moist
Reaction: Slightly or moderately alkaline
B horizon
Hue: 2.5YR, 5YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 3 to 6, dry or moist
Texture: Sandy loam, 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 4,800 to 7,000 feet. The mean annual precipitation ranges from 6 to 10 inches. The mean annual air temperature is 49 to 56 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 OFFICE 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.