LOCATION ALTAR                   AZ+TX

Established Series
Rev. CCC
10/2012

ALTAR SERIES

The Altar series consists of very deep, well drained soils formed in fan alluvium dominantly from granite and schist. Altar soils are on fan terraces and have slopes of 0 to 8 percent. The mean annual precipitation is about 14 inches and the mean annual air temperature is about 65 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Ustic Haplocambids

TYPICAL PEDON: Altar gravelly sandy loam - rangeland (colors are for dry soil unless otherwise noted)

A--0 to 2 inches; yellowish brown (10YR 5/4) gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; weak moderately thick platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; common very fine tubular pores; 25 to 35 percent gravel and cobble on the surface and 20 percent gravel within the horizon; neutral (pH 6.6); abrupt smooth boundary (2 to 6 inches thick).

Bw--2 to 17 inches; brown (7.5YR 4/4) very gravelly sandy clay loam, dark brown (7.5YR 3/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine and common very fine roots; common fine tubular pores; 40 percent gravel; neutral (pH 6.9); gradual wavy boundary (9 to 24 inches thick).

BC--17 to 39 inches; brown (7.5YR 5/4) very cobbly sandy loam, dark brown (7.5YR 3/4) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; common fine and very fine roots; common fine tubular pores; 25 percent gravel and 35 percent cobble; neutral (pH 7.0); gradual wavy boundary (0 to 30 inches thick).

C--39 to 60 inches; light brown (7.5YR 6/4) extremely gravelly loamy sand, brown (7.5YR 4/4) moist; single grain; loose, nonsticky and nonplastic; common very fine roots; 70 percent gravel and 10 percent cobble; neutral (pH 7.0).

TYPE LOCATION: Pima County, Arizona; 1750 feet west and 870 feet north of the southeast corner of section 12, T. 20 S., R. 8 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. Ustic aridic soil moisture regime.

Soil temperature - 62 to 69 degrees F.

Rock fragments - 35 to 80 percent gravel and cobble

A horizon
Hue: 10YR, 7.5YR
Value: 3 to 6 dry, 2 to 5 moist
Chroma: 2 to 6, dry or moist
Rock fragments: 15 to 80 percent gravel and cobble
Organic matter: less than 1 percent
Reaction: moderately acid to neutral
Texture: sandy loam, loam, fine sandy loam, sandy clay loam

Bw, Bk and BC horizons
Hue: 5YR, 7.5YR, 10YR
Value: 2 to 7 dry, 2 to 6 moist
Chroma: 2 to 6, dry or moist
Texture: sandy loam, loam, sandy clay loam, clay loam, loam (10 to 30 percent clay)
Rock fragments: 35 to 80 percent gravel and cobble
Reaction: slightly acid to moderately alkaline

C horizon
Hue: 7.5YR, 10YR
Value: 2 through 6 dry, 2 through 4 moist
Chroma: 2 to 8, dry or moist
Texture: loam, sandy loam, loamy sand, coarse sand, sand, coarse sandy loam
Rock fragments: 35 to 90 percent gravel and cobble
Reaction: neutral or slightly alkaline

In some pedons the C horizon is not present.

In some pedons a buried Btb horizon is present at depths of 30 inches or more. These horizons have hue of 2.5YR or 5YR and contain more clay than is typical of the C horizon.

COMPETING SERIES: These are the Ohtwo (TX) and Pilabo (NM) series. Ohtwo soils have bedrock at 60 to 80 inches. Pilabo are effervescent throughout with 7 to 14 percent calcium carbonate.

GEOGRAPHIC SETTING: Altar soils are on fan terraces and alluvial fans. Slopes range from 0 to 8 percent. The soils formed in gravelly mixed fan alluvium dominantly from granite and schist. Elevation ranges from 2,680 to 5,500 feet. The mean annual precipitation is 12 to 16 inches occurring as summer thunderstorms and winter rain. Mean annual air temperature is 60 to 67 degrees F. The frost-free period is 180 to 250 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Caralampi, Courtland, Diaspar, and Sasabe soils. These soils have argillic horizons.

DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately rapid permeability.

USE AND VEGETATION: Used mainly for livestock grazing. Vegetation is Arizona cottontop, cholla spp., sideoats grama, Rothrock grama, black grama, desert hackberry, and burroweed.

DISTRIBUTION AND EXTENT: Central and Southern Arizona and west Texas. Altar soils are of minor extent. MLRA is 41 & 42.

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

SERIES ESTABLISHED: Pima County, Arizona; Soil survey of Pima County, Arizona, Eastern Part; 1986.

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

Ochric epipedon - the zone from 0 to 2 inches (A horizon)

Cambic horizon - the zone from 2 to 17 inches (Bw horizon)

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

Updated competing series section 4/10/08, CEM

Revised for the correlation of Big Bend National Park, TX, Oct. 2010, CEM

Revised for the correlation of Graham County, AZ, Southwestern Part; March, 2011, WWJ

Revised for the correlation of Hudspeth County, Texas (Main Part) and Culberson County, Texas (Main Part); July, 2012, NMS

Revised for the correlation of Black Hills-Sedona, AZ, August 2012, CEM

Revised for the correlation of Presidio County, Texas ; Oct, 2012, WWJ

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National Cooperative Soil Survey
U.S.A.