LOCATION AMOS AZ

Established Series
Rev. JEJ
09/2025

AMOS SERIES

The Amos series consists of deep, well drained soils that formed in material weathered from shale, siltstone and calcareous sandstone. These soils are on rolling uplands. The mean annual precipitation is about 19 inches (480 mm) and the mean annual air temperature is about 51 degrees F (11 degrees C).

TAXONOMIC CLASS: Fine, mixed, superactive, mesic Typic Haplustalfs

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

A--0 to 3 inches (0 to 8 cm); brown (10YR 5/3) clay loam, brown (10YR 4/3) moist; weak very fine granular structure; soft, friable, slightly sticky and slightly plastic; common fine roots; common very fine interstitial pores; neutral (pH 7.0); clear smooth boundary. (2 to 4 inches thick)

Bt1--3 to 10 inches (8 to 25 cm); brown (10YR 4/3) clay, brown (10YR 4/3) moist; moderate fine subangular blocky structure; hard, firm, sticky and plastic; common fine, very fine and few coarse roots; few fine interstitial and tubular pores; common moderately thick clay films on peds; neutral (pH 7.0); clear wavy boundary. (3 to 11 inches (8 to 28 cm) thick)

Bt2--10 to 25 inches (25 to 64 cm); yellowish brown (10YR 5/4) clay, dark yellowish brown (10YR 4/4) moist; few fine distinct reddish yellow (7.5YR 6/6) mottles, strong brown-(7.5YR 5/6) moist; strong medium subangular blocky structure; very hard, very firm, sticky and plastic; few very fine and common coarse roots; few fine interstitial and tubular pores; many moderately thick clay films on peds; slightly effervescent; slightly alkaline (pH 7.5); gradual wavy boundary. (15 to 24 inches (38 to 61 cm) thick)

BCt--25 to 41 inches (64 to 104 cm); yellowish brown (10YR 5/4) heavy clay loam, dark yellowish brown (10YR 4/4) moist; common medium distinct reddish yellow (7.5YR 6/6) mottles; weak medium subangular blocky parting to weak thin and medium platy structure; hard, firm, slightly sticky and plastic; few very fine and few coarse roots; few fine interstitial and tubular pores; few thin clay films line interstitial pores; common horizontal pressure faces; slightly effervescent; moderately alkaline (pH 8.0); diffuse wavy boundary. (10 to 17 inches (25 to 43 cm) thick)

Cr1--41 to 50 inches (104 to 127 cm); light yellowish brown (10YR 6/4) and reddish yellow (5YR 6/6) weathered stratified shale and siltstone, yellowish brown (10YR 5/4) and yellowish red (5YR 5/6) moist; moderate thin and medium platy structure; hard, firm, nonsticky and slightly plastic; few very fine roots; common horizontal pressure faces; strongly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (6 to 12 inches (15 to 30 cm) thick)

Cr2--50 to 56 inches (127 to 142 cm); stratified shale, siltstone and calcareous sandstone with broken colors of yellowish red (5YR 5/6), yellowish red (5YR 5/6) moist; moderate medium and thick platy structure; hard to extremely hard, extremely firm, strongly effervescent; moderately alkaline (pH 8.2).

TYPE LOCATION: Navajo County, Arizona; NW1/4 of section 3, T.8N., R.22E., Photo 3242, Fort Apache Indian Reservation. Note: County is unsurveyed. Approximate locations on a grid extended from nearby surveys.

RANGE IN CHARACTERISTICS: The solum ranges in thickness from 30 to 56 inches (75 to 142 cm). The depth to the Cr horizon is over 40 inches (100 cm). The mean annual soil temperature ranges from 47 to 55 degrees F (8 to 13 degrees C). Soil moisture is usually deficient from May 1 to late in June.

The A horizon has hue of 7.5YR or 10YR, value of 5 or 6 dry, 3 or 4 moist and chroma of 3 or 4. It is heavy loam or clay loam.

The Bt horizon has hue of 7.5YR or 10YR, value of 4 or 5 dry, and 3 or 4 moist, and chroma of 3 or 4, but are dominantly 4. It is heavy clay loam and clay.

The Cr horizon is finely stratified and includes shale, siltstone and calcareous sandstone.

COMPETING SERIES: These are the Arriba, Jacks, Lama, and Lemmon series. Arriba (MLRA 36) and Lemmon (MLRA 41) soils have a paralithic contact between 20 and 40 inches (50 to 100 cm). Jacks soils (MLRA 35 and 39) have a lithic contact between 20 and 50 inches (50 to 125 cm). Lama soils (MLRA 51) formed in mixed alluvium and are very deep.

GEOGRAPHIC SETTING: The Amos soils are on rolling uplands. Slopes range from 5 to 20 percent but are dominantly 9 to 15 percent. These soils formed in place on shale, siltstone and calcareous sandstone. Elevations range from 6,000 to 6,800 feet (1820 to 2060 m). The average annual precipitation ranges from 16 to 22 inches (405 to 560 mm). The mean annual temperature ranges from 48 degrees to 54 degrees F (9 to 12 degrees C) and the frost-free season ranges from 110 to 130 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Telephone soils and the competing Elledge, Overgaard and Showlow soils. Telephone soils are shallow and very shallow to bedrock and lack an argillic horizon.

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

USE AND VEGETATION: These soils are used for the production of timber and for grazing of livestock. Vegetation is mainly ponderosa pine, Gambel oak, alligator juniper with an understory of western wheat, junegrass, mountain and spike muhly and Arizona fescue.

DISTRIBUTION AND EXTENT: Along the breaks of the Mogollon Rim west of Lakeside, Arizona, MLRA 39. The series is of small extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California

SERIES PROPOSED: Fort Apache Indian Reservation, Navajo County, Arizona, 1971.

REMARKS:
Particle Size Control Section for this pedon: 8 to 58 cm
Diagnostic horizons and features recognized in this pedon are:
Ochric Epipedon 0 to 8 cm
Argillic Horizon 8 to 104 cm
Paralithic Contact 104 cm
Paralithic Materials 104 to 142 cm

OSED scanned by NSSQA. Last revised by state on 1/75.
09/2025--Competing series checked and updated. -JBB

National Cooperative Soil Survey
U.S.A.