LOCATION SILVERSTRIKE AZ
Established Series
Rev. CRP/DWD/PDC
05/2011
SILVERSTRIKE SERIES
The Silverstrike series consists of moderately deep, well drained soils that formed in residuum and colluvium from sandstone and siltstone. Silverstrike soils are on hills and mountains. Slopes range from 5 to 60 percent. The mean annual precipitation is about 18 inches and the mean annual air temperature is about 60 degrees F.
TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive, thermic Aridic Haplustalfs
TYPICAL PEDON: Silverstrike very cobbly sandy loam - wildlife habitat. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; brown (10YR 5/3) very cobbly sandy loam, dark brown (10YR 3/3) moist; moderate thick platy structure; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; common very fine and few fine and medium irregular and few medium tubular pores; 25 percent gravel, 20 percent cobble, 5 percent stone; noneffervescent; slightly acid (pH 6.4); abrupt wavy boundary.
A2--2 to 6 inches; brown (10YR 5/3) very cobbly sandy clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky and moderate medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; common very fine and few fine irregular and few medium tubular pores; 30 percent gravel, 20 percent cobble, 5 percent stone; noneffervescent; slightly acid (pH 6.2); clear wavy boundary. (Combined thickness of the A horizons is 2 to 10 inches)
Bt1--6 to 11 inches; brown (10YR 5/3) extremely cobbly clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and few fine roots; few very fine irregular and common very fine and few fine tubular pores; common faint and few distinct clay films on faces of peds and common distinct clay films in pores; 20 percent gravel, 50 percent cobble, 5 percent stones; noneffervescent, neutral (pH 6.6); clear wavy boundary.
Bt2--11 to 22 inches; brown (7.5YR 4/4) and yellowish red (5YR 4/6) very cobbly clay loam, dark brown (7.5YR 3/4) and dark reddish brown (5YR 3/4) moist; moderate and strong fine and medium subangular blocky structure; hard, friable, very sticky and very plastic; common very fine roots; common very fine tubular pores; many distinct clay films on faces of peds and in pores; 30 percent gravel, 20 percent cobble; noneffervescent; neutral (pH 6.6); abrupt smooth boundary. (Combined thickness of the Bt horizons is 8 to 20 inches)
2C--22 to 25 inches; dark yellowish brown (10YR 4/4) extremely gravelly clay loam, brown (7.5YR 4/4) moist; strong medium platy; hard, friable, very sticky and very plastic; few very fine roots; few very fine irregular and tubular pores; continuous faint clay films on coarse fragments and very few prominent clay films on rock fragments; 75 percent gravel; noneffervescent; neutral (pH 7.0); abrupt irregular boundary. (3 to 8 inches thick)
2Cr--25 inches; weathered siltstone.
TYPE LOCATION: Fort Bowie National Historic Site; located at a latitude of 32 degrees, 8 minutes, 57 seconds North and longitude of 109 degrees, 26 minutes, 2 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: 10 to 50 percent gravel, 10 to 45 percent cobble, 0 to 5 percent stones
Clay content: 35 to 60 percent
Organic matter: less than 1 percent
Lithochromic colors. The organic carbon content does not decrease by more than 0.6 percent with increasing depth
Depth to weathered bedrock: 20 to 40 inches
A horizon
Hue: 7.5YR, 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 to 4 dry, 2 or 3 moist
Bt horizon
Hue: 5YR, 7.5YR, 10YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 3 through 6, dry or moist
Texture: clay, clay loam
C horizon
Hue: 7.5YR, 10YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 2 through 4, dry or moist
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Silverstrike soils are on hills and mountains at elevations of 4,160 to 6,000 feet. Slopes range from 5 to 60 percent. These soils formed in residuum and colluvium from siltstone and sandstone. The mean annual precipitation is 16 to 20 inches and occurs as thunderstorms during July to September and as gentle rains during December to February. 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
Budlamp,
Siphoncan and
Yarbam soils. Budlamp, Siphoncan and Yarbam soils do not have argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; moderate to rapid runoff; moderately slow permeability.
USE AND VEGETATION: Used for wildlife habitat. Vegetation includes mesquite, one-seed juniper, ocotillo, agave, yucca, snakeweed, turpentine bush, mariola, sotol, bullgrass, sideoats grama, black grama, purple grama, crinkleawn, cholla, and prickly pear.
DISTRIBUTION AND EXTENT: Southern Arizona. Silverstrike soils are of limited extent. MLRA is 38 & 41. The name is coined from the nearby Silverstrike Mine.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Cochise County, Arizona; Soil survey of Fort Bowie National Historic Site; 1996.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 6 inches (A1, A2 horizons)
Argillic horizon - the zone from 6 to 22 inches (Bt1, Bt2 horizons)
Paralithic contact - the boundary at 25 inches (2Cr horizon)
Classified according 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
National Cooperative Soil Survey
U.S.A.