LOCATION STANFORD                AZ

Established Series
Rev. WAS/CEM
04/2011

STANFORD SERIES

The Stanford series consists of very deep, stratified, well drained soils that formed in mixed alluvium. Stanford soils are on alluvial fans and flood plains. Slope ranges from 0 to 10 percent. The mean annual precipitation is about 18 inches and the mean annual air temperature is about 60 degrees F.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Cumulic Haplustolls

TYPICAL PEDON: Stanford fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.) 10 to 20 percent of the surface is covered with gravel

A1--0 to 2 inches; brown (7.5YR 4/3) fine sandy loam, very dark brown (7.5YR 2.5/2) moist; moderate very thick and moderately thick platy structure parting to weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial pores; 2 percent gravel; noneffervescent; slightly acid (pH 6.2); abrupt smooth boundary.

A2--2 to 10 inches; dark brown (7.5YR 3/2) sandy loam, very dark brown (7.5YR 2.5/2) moist; moderate fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine tubular pores; 5 percent gravel; noneffervescent; slightly acid (pH 6.2); abrupt smooth boundary.

A3--10 to 16 inches; dark brown (7.5YR 3/2) sandy loam, very dark gray (7.5YR 3/1) moist; massive; soft, very friable, slightly sticky and nonplastic; many very fine and fine roots; many very fine and fine tubular pores; 5 percent gravel; noneffervescent; slightly acid (pH 6.4); clear smooth boundary. (Combined thickness of the A horizons is 10 to 18 inches.)

C1--16 to 30 inches; dark gray (7.5YR 4/1) loam, black (7.5YR 2.5/1) moist; moderate very fine and fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine and few medium roots; many very fine and fine and common medium tubular pores; 3 percent gravel; noneffervescent; slightly acid (pH 6.2); clear smooth boundary.

C2--30 to 60 inches; dark gray (7.5YR 4/1) clay loam, black (7.5YR 2.5/1) moist; moderate very fine and fine subangular blocky structure; slightly hard, friable, very sticky and very plastic; common very fine and fine and few medium roots; many very fine and fine and common medium tubular pores; 3 percent gravel; noneffervescent; neutral (pH 6.6). (Combined thickness of the C horizons is 30 to 45 inches.)

TYPE LOCATION: Cochise County, Arizona; located about 2,400 feet north and 1,400 feet west of the southeast corner section 10, Township 20 S., Range 28 E.; Bruno Peak topography map; latitude 31 degrees, 42 minutes, 20 seconds North and longitude 109 degrees, 28 minutes, 10 seconds West.

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. Aridic Ustic soil moisture regime.

Soil Temperature: 59 to 64 degrees F.

Rock fragments: less than 20 percent gravel

Clay content: 18 to 35 percent in the control section

Organic matter: 1 to 3 percent

Reaction: slightly acid to neutral

A horizon
Hue: 7.5YR, 10YR
Value: 2 through 5 dry, 2 to 4 moist
Chroma: 1 through 3, dry or moist
Texture: fine sandy loam, sandy loam, sandy clay loam, loam, clay loam, silt loam

C horizon
Hue: 7.5YR, 10YR
Value: 2 through 5 dry, 2 to 4 moist
Chroma: 1 through 3, dry or moist
Texture: loam, clay loam, sandy clay loam, silty clay loam

COMPETING SERIES: These are the Bippus (TX), Bosque (TX), Gageby (TX), Gowen (TX), and Whitesboro (TX) series. Bippus soils have visible accumulations of calcium carbonate in the subsoil. Bosque, Gageby, and Gowen soils have a typic ustic moisture regime. Whitesboro soils have a udic ustic moisture regime. In addition, these soils occur in the Central Great Plains and Southwestern Prairies Land Resource Regions and are moist in May and June.

GEOGRAPHIC SETTING: The Stanford soils are in the Chihuahuan desert on alluvial fans and flood plains at elevations of 4,200 to 6,200 feet. Slope ranges from 0 to 10 percent. These soils formed from mixed alluvium. The mean annual precipitation is 16 to 20 inches and occurs as thunderstorms during July to September and as gentle rains during December and January. The mean annual air temperature is 57 to 62 degrees F. The frost-free period is 160 to 210 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blacktail, Cherrycow, Ashcreek, and Terrarossa soils. These all have clay content greater than 35 percent.

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

USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation includes blue grama, sideoats grama, vine mesquite, creeping muhly, and cane beardgrass.

DISTRIBUTION AND EXTENT: Southeastern Arizona portion of the Chihuahuan Desert. MLRAs are 38 and 41. Stanford soils are of moderate extent.

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

SERIES ESTABLISHED: Cochise County, Arizona; Soil Survey of Cochise County, Arizona, Douglas-Tombstone Part; 2000.

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

Mollic epipedon - the zone from 0 to 30 inches (A1, A2, and A3 horizons)

Cumulic feature - irregular decrease of organic matter is inferred by color changes and stratification.

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

Revised for the correlation of AZ661, 2/2009, WWJ

Revised for the correlation of AZ675, 5/2009, WWJ

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

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National Cooperative Soil Survey
U.S.A.