LOCATION NUGGET                  AZ

Established Series
Rev. WAS/CEM
04/2011

NUGGET SERIES

The Nugget series consists of shallow, well drained soils that formed in slope alluvium and residuum derived from granite, granodiorite, and quartzite. Nugget soils are on hills and mountains. Slope ranges from 3 to 45 percent. The mean annual precipitation is about 18 inches and the mean annual air temperature is about 60 degrees F.

TAXONOMIC CLASS: Loamy, mixed, superactive, thermic, shallow Aridic Argiustolls

TYPICAL PEDON: Nugget sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.) 80 to 100 percent of the surface is covered with gravel and cobble.

A--0 to 1 inch; brown (7.5YR 4/3) sandy loam, dark brown (7.5YR 3/3) moist; weak thin platy structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; few fine irregular pores; 10 percent gravel; noneffervescent; slightly acid (pH 6.2); abrupt smooth boundary. (1 to 3 inches thick)

Bt1--1 to 5 inches; dark brown (7.5YR 3/3) gravelly sandy loam, dark brown (7.5YR 3/2) moist; weak fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine and fine roots; few fine tubular pores; few distinct clay films on ped faces and rock fragments; few distinct organic coatings on ped faces and rock fragments; 20 percent gravel; noneffervescent; slightly acid (pH 6.4); clear wavy boundary.

Bt2--5 to 12 inches; dark reddish brown (5YR 3/3) gravelly sandy clay, dark reddish brown (5YR 3/2) moist; moderate fine and medium angular blocky rock structure; hard, firm, very sticky and very plastic; many very fine and fine roots; few fine tubular pores; many distinct clay films on ped faces and rock fragments; few distinct organic coatings on ped faces and rock fragments; 25 percent gravel; noneffervescent; neutral (pH 6.6); abrupt wavy boundary. (Combined thickness of the Bt horizons is 10 to 20 inches.)

Crt--12 to 17 inches; highly fractured decomposed granodiorite; extremely hard; many distinct clay films and distinct organic coatings on rock fragments; common very fine roots along fractures; abrupt wavy boundary.

Cr--17 to 24 inches; highly fractured decomposed granodiorite; extremely hard; few very fine roots along fractures; clear wavy boundary.

R--24 inches; unweathered granodiorite.

TYPE LOCATION: Cochise County, Arizona; located about 2,500 feet south and 2,700 feet east of the northwest corner of section 19, Township 19 S., Range 25 E.; Turquoise Mountain topographic map; latitude 31 degrees, 46 minutes, 17 seconds North and longitude 109 degrees, 50 minutes, 49 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 35 percent

Reaction: slightly acid to neutral

Clay content: averages 18 to 35 percent in the control section, but can range up to 40 percent in any one horizon

Organic matter: 0.6 to 3 percent. Averages 1 to 3 percent in the upper part of the profile, but ranges to 0.6 percent in the lower part.

Depth to weathered bedrock: 10 to 30 inches

Depth to unweathered bedrock: 20 to 40 inches

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

Bt horizon
Hue: 5YR, 7.5YR, 2.5YR
Value: 3 through 5 dry, 2.5 to 4 moist
Chroma: 1 to 4, dry or moist
Texture: sandy clay loam, sandy clay, sandy loam, clay loam

COMPETING SERIES: There are no competing series

GEOGRAPHIC SETTING: The Nugget soils are in the Chihuahuan desert on hills and mountains at elevations of 4,000 to 6,200 feet. Slope ranges from 3 to 60 percent. These soils formed from slope alluvium and residuum derived from granite, granodiorite, and quartzite. 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 65 degrees F. The frost-free period is 150 to 210 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Turquoise, Gardencan and Lanque soils. Turquoise soils have less than 18 percent clay. The Gardencan and Lanque soils are very deep.

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

USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation includes Texas bluestem, plains lovegrass, sideoats grama, beggartick threeawn, hairy grama, manzanita, bullgrass and Emory oak.

DISTRIBUTION AND EXTENT: Southeastern Arizona portion of the Chihuahuan desert. MLRAs are 38 and 41. Nugget 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 5 inches (A and Bt horizons)

Argillic horizon - the zone from 1 to 12 inches (Bt1 and Bt2 horizons)

Paralithic contact - the boundary at 12 inches (Crt and Cr horizons)

Lithic contact - the boundary at 24 inches (R horizon)

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.