LOCATION OVERSIGHT AZEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Aridic Haplustepts
TYPICAL PEDON: Oversight fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.) 35 to 70 percent of the surface is covered with gravel and/or cobble
A1--0 to 1 inch; brown (7.5YR 4/4) fine sandy loam, dark brown (7.5YR 3/4) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; few fine irregular pores; noneffervescent; neutral (pH 7.2); abrupt smooth boundary.
A2--1 to 4 inches; brown (7.5YR 4/4) sandy loam, dark brown (7.5YR 3/4) moist; moderate thick platy structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; common fine irregular pores; noneffervescent; neutral (pH 6.8); abrupt wavy boundary. (Combined thickness of the A horizons is 3 to 6 inches)
Bw1--4 to 12 inches; brown (7.5YR 4/3) sandy loam, dark brown (7.5YR 3/4) moist; moderate medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few fine roots; few fine irregular pores; noneffervescent; neutral (pH 7.0); abrupt wavy boundary.
Bw2--12 to 25 inches; reddish brown (5YR 4/4) very cobbly sandy loam, dark reddish brown (5YR 3/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; few fine roots; few fine irregular pores; 20 percent cobble and 30 percent gravel; noneffervescent; neutral (pH 7.0); abrupt wavy boundary. (Combined thickness of the Bw horizons is 10 to 25 inches)
Btb1--25 to 45 inches; reddish brown (5YR 5/4) very cobbly sandy loam, yellowish red (5YR 5/6) moist; moderate fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few very fine roots; few fine irregular and tubular pores; common distinct clay films on ped faces, in pores and on rock fragments; few faint manganese coatings on ped faces; 30 percent cobble and 20 percent gravel; noneffervescent; neutral (pH 7.2); clear smooth boundary.
Btb2--45 to 60 inches; yellowish red (5YR 5/6) very cobbly sandy clay loam, yellowish red (5YR 4/6) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few fine irregular and tubular pores; many distinct clay films on ped faces, in pores and on rock fragments; 20 percent cobble and 30 percent gravel; noneffervescent; neutral (pH 7.2). (Combined thickness of the Btb horizons is 25 to 35 inches)
TYPE LOCATION: Cochise County, Arizona; located at a latitude of 31 degrees, 17 minutes, 20 seconds North and longitude of 110 degrees, 27 minutes, 15 seconds West; about 1,900 feet south and 1,100 feet east from the northwest corner of Section 2, T. 23 S., R. 20 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. Aridic ustic soil moisture regime.
Soil Temperature: 59 to 64 degrees F.
Rock fragments: averages more than 35 percent gravel and/or
cobble
Reaction: slightly acid or neutral
A horizon
Hue: 7.5YR, 5YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 2 through 4, dry or moist
Texture: sandy loam, fine sandy loam
Bw horizon
Hue: 7.5YR, 5YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 3 or 4, dry or moist
Texture: sandy loam, fine sandy loam, loam, sandy clay loam
Btb horizon
Hue: 7.5YR, 5YR
Value: 4 through 6 dry, 3 through 6 moist
Chroma: 3, 4 or 6, dry or moist
Texture: sandy loam, sandy clay loam (10 to 35 percent clay)
Some pedons do not have a buried argillic horizon.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Oversight soils are on alluvial fans and fan terraces at elevations of 4,500 to 6,200 feet. Slopes range from 1 to 35 percent. These soils formed in mixed fan alluvium. 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 62 degrees F. The frost-free period is 160 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gardencan, Lanque and Terrarossa soils. Terrarossa and Gardencan soils have argillic horizons. Lanque soils are coarse-loamy.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately rapid permeability in the upper part and moderately slow in the buried argillic horizons.
USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation includes plains lovegrass, sideoats grama, blue grama, cane beardgrass, hairy grama and shrubby buckwheat.
DISTRIBUTION AND EXTENT: Southern Arizona. Oversight soils are of moderate extent. MLRA is 41. Named derived from a canyon in the Huachuca Mountains.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Cochise County, Arizona. Soil survey of Cochise County, Arizona, Douglas - Tombstone Part; 1996. San Pedro Valley Interim Report.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 4 inches (A1, A2 horizons)
Cambic horizon - The zone from 4 to 25 inches (Bw1, Bw2 horizons)
Buried paleosol - The zone from 25 to 60 inches (Btb1, Btb2 horizons)
Soil Taxonomy second Edition, 1999