LOCATION WEPO AZ

Established Series
Rev. RJA/DJP/CLG/WWJ
10/2014

WEPO SERIES

The Wepo series consists of deep, well drained, slowly permeable soils that formed in mixed alluvium derived dominantly from shale and sandstone. Wepo soils are on stream terraces and have slopes ranging from 0 to 3 percent. The average annual precipitation is about 8 inches (203 mm) and the mean annual air temperature is about 53 degrees F (12 degrees C).

TAXONOMIC CLASS: Fine, mixed, superactive, mesic Vertic Haplocambids

TYPICAL PEDON: Wepo clay loam - rangeland (Colors are for dry soil unless otherwise noted.)
A--0 to 3 inches (0 to 8 cm); pale brown (10YR 6/3) clay loam, yellowish brown (10YR 5/4) moist; strong thick platy structure over strong fine granular; soft, friable, moderately sticky and slightly plastic; few very fine roots; many very fine vesicular pores; strongly effervescent; moderately alkaline; abrupt smooth boundary. (1 to 4 inches or 3 to 10 cm thick)

Bw1--3 to 11 inches (8 to 28 cm); pale brown (10YR 6/3) clay loam, yellowish brown (10YR 5/4) moist; moderate fine subangular blocky structure; slightly hard, firm, very sticky and moderately plastic; few very fine roots; many very fine pores; cracks 1 to 3 cm wide every 4 to 6 inches; strongly effervescent; moderately alkaline; clear smooth boundary. (5 to 12 inches or 13 to 30 cm thick)

Bw2--11 to 18 inches (28 to 46 cm); pale brown (10YR 6/3) clay, yellowish brown (10YR 5/4) moist; weak medium subangular blocky structure; hard, very firm, very sticky and very plastic; many very fine roots; common very fine tubular pores; cracks 1 to 2 cm wide every 5 to 7 inches; strongly effervescent; slightly alkaline; clear smooth boundary. (6 to 10 inches or 15 to 25 cm thick)

Bk1--18 to 26 inches (46 to 66 cm); brown (10YR 5/3) clay loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; hard, firm, moderately sticky and very plastic; common very fine roots; common fine tubular pores; cracks 1 or 2 cm wide every 6 to 8 inches; few fine lime accumulations in root channels and pores; strongly effervescent; slightly alkaline; abrupt smooth boundary. (6 to 15 inches thick)

Bk2--26 to 32 inches (66 to 81 cm); pale brown (10YR 6/3) clay with few thin strata of sandy loam and silt loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; very hard, very firm, very sticky and very plastic; few very fine roots; common very fine interstitial pores; few fine lime accumulations in root channels and pores; strongly effervescent; slightly alkaline; abrupt smooth boundary. (4 to 11 inches thick or 10 to 28 cm)

2C1--32 to 36 inches (81 to 91 cm); light yellowish brown (10YR 6/4) very fine sandy loam with strata of clay and silt loam, yellowish brown (10YR 5/4) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; common very fine vesicular pores; strongly effervescent; slightly alkaline; abrupt smooth boundary. (1 to 5 inches thick 3 to 13 cm)

3C2--36 to 43 inches(91 to 109 cm); pale brown (10YR 6/3) clay with strata of very fine sandy loam, silt loam and loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; very hard, very firm, very sticky and very plastic; few fine roots; few fine vesicular pores; strongly effervescent; slightly alkaline; abrupt smooth boundary. (4 to 15 inches or 10 to 38 cm thick)

4C3--43 to 60 inches (109 to 152 cm); light yellowish brown (10YR 6/4) stratified very fine sandy loam, clay, silt loam and sand, brown (10YR 5/3) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky and slightly plastic; few fine roots; few very fine tubular pores; strongly effervescent; slightly alkaline.

TYPE LOCATION: Navajo County, Arizona, about 1.5 miles west of Elbow Point; about 1,200 feet east and 1,600 feet north of the southwest corner of section 8, T. 25 N., R. 16 E.

RANGE IN CHARACTERISTICS:
Soil Moisture: Intermittently moist in some part of the SMCS during July-August and December-February. Driest during May and June. Typic aridic soil moisture regime.

Soil Temperature: 52 to 56 degrees F (11 to 13 degrees C).

Carbonates: Slightly to strongly effervescent throughout; secondary lime as masses and fillings in the lower part. Calcium carbonate equivalent is less than 15 percent.
Cole: more than 0.05 in the A and B horizons

A horizon
Hue: 10YR, 7.5 YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 to 4, dry or moist
Texture: clay loam, clay

B horizon
Hue: 10YR, 7.5YR
Value: 5 or 6 dry, 3 to 5 moist
Chroma: 3 or 4, dry or moist
Texture: clay loam, clay with some thin strata of coarser material
Reaction: slightly to moderately alkaline

C horizon
Hue: 10YR, 7.5YR
Value: 5 to 7 dry, 4 or 5 moist
Chroma: 2 to 4, dry or moist
Texture: stratified clay and sand
Reaction: slightly or moderately alkaline, strongly alkaline in the lower part of some pedons

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Wepo soils are on stream terraces. Flooding is very rare and very brief. Elevations range from 5,100 to 6,200 feet (1,555 to1890 meters) . Slope ranges from 0 to 3 percent. The soils formed in stream alluvium derived dominantly from shale and sandstone. The average annual precipitation ranges from 6 to 10 inches (152 to 254 mm). The average annual temperature ranges from 51 to 54 degrees F (11 to 12 degrees C). The average frost free period is 130 to 160 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Jocity, Polacca (P) and Tewa (P) soils. Jocity soils are on alluvial fans and flood plains and are stratified throughout. Polacca and Tewa soils are on stream terraces. Polacca soils have contrasting particle size and Tewa soils are fine-loamy.

DRAINAGE AND PERMEABILITY: Well drained; slow runoff; slow permeability.

USE AND VEGETATION: Used primarily for livestock grazing. Vegetation includes alkali sacaton, galleta, bottlebrush squirreltail, blue grama and fourwing saltbush.

DISTRIBUTION AND EXTENT: Northeast Arizona. The series is moderately extensive. MLRA 35; LRR-D.

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

SERIES ESTABLISHED: Navajo County, Arizona 1985. Hopi Area, Parts of Coconino and Navajo Counties. Name is from a village on First Mesa.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
COLE greater than 0.05 in the A and B horizons
Cambic horizon - the zone from 3 to 18 inches (8 to 46 cm) (Bw1 and Bw2 horizons)
Secondary carbonates - the zone from 18 to 32 inches (46 to 81 cm) (Bk1 and Bk2 horizons)

Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, 11th Edition, 2010.
Updated and revised for the correlation of Ft. Defiance Area AZ715 2/08 DWD

National Cooperative Soil Survey
U.S.A.