LOCATION BOSS AZEstablished Series
TAXONOMIC CLASS: Clayey, mixed, superactive, thermic Lithic Ustic Haplargids
TYPICAL PEDON: Boss clay loam - rangeland. (Colors are for dry soil unless otherwise noted.) 75 to 85 percent of the surface is covered with cinders, and basalt gravel, cobbles, and stones
A--0 to 2 inches; brown (7.5YR 4/2) clay loam, dark brown (7.5YR 3/2) moist; weak fine granular structure; soft, very friable, moderately sticky and moderately plastic; many very fine and fine roots; common fine irregular pores; 10 percent gravel; noneffervescent; neutral (pH 6.8); abrupt smooth boundary. (2 to 4 inches thick)
Bt--2 to 14 inches; dark brown (7.5YR 3/2) clay, dark brown (7.5YR 3/2) moist; strong fine and medium subangular blocky structure; slightly hard, friable, very sticky and very plastic; many very fine and fine roots; common fine tubular pores; common distinct clay films on ped faces, in pores, and on rock fragments; common pressure faces; 10 percent gravel; noneffervescent; neutral (pH 7.0); clear wavy boundary. (12 to 16 inches thick)
R--14 inches; unweathered basalt and welded tuff.
TYPE LOCATION: Cochise County, Arizona; located at a latitude of 31 degrees, 29 minutes, 44 seconds North and longitude of 109 degrees, 14 minutes, 55 seconds West; 2,400 feet north and 900 feet east from the southwest corner of section 24, Township 22 S., Range 30 E.
RANGE IN CHARACTERISTICS:
Soil moisture - Intermittently moist in some part of soil moisture control section during July - September and December - February. Driest during May and June. Ustic aridic soil moisture regime.
Soil temperature: 62 to 69 degrees F.
Reaction: neutral to slightly alkaline
Clay content: more than 35 percent
Organic matter content: 1 to 3 percent
Depth to unweathered bedrock: 5 to 20 inches
A horizon
Hue: 5YR, 7.5YR
Value: 2.5 through 4, dry or moist
Chroma: 1 through 3, dry or moist
Texture: clay loam, silty clay loam, loam
B horizon
Hue: 5YR, 7.5YR
Value: 2.5 through 4, dry or moist
Chroma: 1 through 4, dry or moist
Texture: clay, clay loam, silty clay
COMPETING SERIES: This is the Leyte (AZ) series. Leyte soils are on hills and mountains and formed from slope alluvium and residuum derived from granodiorite, quartzite, and rhyolite.
GEOGRAPHIC SETTING: Boss soils are on cinder cones at elevations of 3,800 to 5,200 feet. Slopes range from 15 to 55 percent. These soils formed in slope alluvium and residuum from basalt, cinders, bombs, and volcanic rocks. The mean annual precipitation is 12 to 16 inches and occurs as thunderstorms during July to September and as gentle rains during December to February. The mean annual air temperature is 60 to 67 degrees F. The frost-free period is 180 to 230 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Paramore, Krentz, Epitaph, and Outlaw soils. Krentz and Outlaw soils are very deep. Epitaph soils have a petrocalcic horizon. Paramore soils are moderately deep.
DRAINAGE AND PERMEABILITY: Well drained; very rapid runoff; slow permeability.
USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation includes tobosa, sideoats grama, and other annual grasses and forbs.
DISTRIBUTION AND EXTENT: Southern Arizona. Boss soils are of moderate extent. MLRA is 41.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Cochise County, Arizona. Soil survey of Cochise County, Arizona, Douglas - Tombstone Part; San Bernardino Valley Interim Report, 1998.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 2 inches (A horizon)
Argillic horizon - The zone from 2 to 14 inches (Bt horizon)
Lithic contact at 14 inches
Boss was first proposed in 1959 in the Whitewater Draw portion of the Sulphur Springs Valley area soil survey of Cochise County, Arizona. The original Official Series Description was updated to reflect current soil taxonomy, to clearly define the range of characteristics, and to improve interpretations. The central concept, definition, and historical importance of the series was preserved.
Soil Taxonomy Second Edition, 1999