LOCATION GRAHAM                  AZ+NM

Established Series
Rev. YHH/CCC/PDC/CEM
04/2011

GRAHAM SERIES

The Graham series consists of shallow and very shallow, well drained soils formed in slope alluvium from basic igneous rock. Graham soils are on hills and mountains and have slopes of 2 to 60 percent. Mean annual precipitation is about 14 inches and the mean annual air temperature is about 61 degrees F.

TAXONOMIC CLASS: Clayey, smectitic, thermic Lithic Ustic Haplargids

TYPICAL PEDON: Graham cobbly clay loam - rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 1 inch; reddish brown (5YR 4/3) cobbly clay loam, dark reddish brown (5YR 3/3) moist; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; common fine irregular and few fine tubular pores; neutral (pH 7.0); clear smooth boundary. (1 to 4 inches thick)

Bt1--1 to 6 inches; dark reddish brown (5YR 3/3) gravelly clay loam, dark reddish brown (5YR 3/3) moist; weak fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common fine roots; few fine tubular pores; common faint clay films on faces of peds; slightly alkaline (pH 7.5); clear smooth boundary. (3 to 6 inches thick)

Bt2--6 to 14 inches; dark reddish brown (5YR 3/3) gravelly clay, dark reddish brown (5YR 3/3) moist; weak coarse subangular blocky structure; very hard, firm, moderately sticky and very plastic; few fine roots; few fine and very fine tubular and common fine irregular pores; common faint clay films on faces of peds; slightly effervescent; moderately alkaline (pH 8.0); clear irregular boundary. (6 to 10 inches thick)

2R--14 inches; basalt; slightly effervescent in fractures.

TYPE LOCATION: Graham County, Arizona; 600 feet south and 200 feet east of northwest corner of section 22, T. 6 S., R. 27 E.

RANGE IN CHARACTERISTICS:

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

Soil temperature - 59 to 72 degrees F.

Rock fragments - Averages 1 to 35 percent. May have as much as 85 percent gravel, cobble, and stones on the surface

Depth to bedrock - 8 to 20 inches

Organic matter content - 1 to 5 percent

A horizon
Hue: 5YR, 7.5YR, 10YR
Value: 2 through 5 dry, 2 through 4 moist
Chroma: 2 through 4 dry, 1 through 4 moist
Reaction: slightly acid to moderately alkaline

B horizon
Hue: 5YR, 7.5YR
Value: 2 through 5 dry, 2 through 4 moist
Chroma: 1 through 4, dry or moist
Texture: clay, silty clay, clay loam
Reaction: neutral to moderately alkaline
Calcium carbonate: None to slightly effervescent

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Graham soils are on hills and mountains at elevations ranging from 3,000 to 5,600 feet. Slopes are dominantly 8 to 25 percent and range from 2 to 60 percent. The Graham soils formed in slope alluvium from basalt, andesite, tuff and other extrusive igneous rocks. The mean annual air temperature is 57 to 70 degrees F. Mean annual precipitation ranges from 12 to 16 inches. The frost-free period is 170 to 250 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Deloro, Lampshire and Romero soils. Deloro soils are clayey-skeletal. Lampshire and Romero soils are loamy-skeletal and do not have argillic horizons.

DRAINAGE AND PERMEABILITY: Well-drained; medium to high runoff; very slow or slow permeability.

USE AND VEGETATION: Used for livestock grazing. The vegetation is sideoats grama, curlymesquite, tobosa grass, threeawn, ocotillo, prickly pear and annual grasses and weeds.

DISTRIBUTION AND EXTENT: Southern and central Arizona and New Mexico. Graham soils are moderately extensive. MLRA is 38, 40, 41 and 42.

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

SERIES ESTABLISHED: Graham County (Gila River Project) Arizona; 1936.

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

Ochric epipedon - the zone from 0 to 1 inch (A horizon)

Argillic horizon - the zone from 1 to 14 inches (Bt1, Bt2 horizons)

Lithic contact - the boundary at 14 inches (2R horizon)

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

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

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National Cooperative Soil Survey
U.S.A.