LOCATION POWERLINE AZEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Ustic Haplocalcids
TYPICAL PEDON: Powerline very gravelly sandy loam - rangeland (Colors are for dry soil unless otherwise noted).
A--0 to 3 inches; pale brown (10YR 6/3) very gravelly sandy loam, brown (10YR 4/3) moist; weak moderately thick platy structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots; common fine tubular pores; 40 percent gravel; strongly effervescent; moderately alkaline (pH 8.2); clear smooth boundary (2 to 6 inches thick).
Bk1--3 to 17 inches; very pale brown (10YR 7/3) gravelly loam, light yellowish brown (10YR 6/4) moist; weak medium subangular blocky structure; slightly hard, friable, sticky and plastic; many fine roots; common very fine tubular pores; few distinct calcium carbonate coatings on gravel and lining pores; 25 percent gravel and 5 percent cobble; violently effervescent; moderately alkaline (pH 8.2); gradual wavy boundary (12 to 16 inches thick).
Bk2--17 to 29 inches; very pale brown (10YR 7/3) very gravelly sandy loam, light yellowish brown (10YR 6/4) moist; massive; hard, firm, slightly sticky and slightly plastic; common fine roots; common fine tubular pores; common distinct calcium carbonate coatings on gravel and lining pores; 50 percent gravel and 5 percent cobble; violently effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary (6 to 18 inches thick).
2Crkq--29 to 60 inches; sandy fanglomerate; thin discontinuous lime-silica cemented cap on bedrock; common fine roots in fractures; many distinct calcium carbonate coatings in fractures; strongly effervescent.
TYPE LOCATION: Pima County, Arizona; 300 feet east and 1,800 feet north of the southwest corner of sec. 12, T. 17 S., R. 17 E.
RANGE IN CHARACTERISTICS:
Soil moisture - Intermittently moist in some part of the soil moisture control section during July-September and December-March. Driest during May and June. Ustic aridic soil moisture regime.
Soil temperature - 61 to 68 degrees F.
Rock fragments - averages 35 to 65 percent gravel and cobble in the control section
Depth to bedrock - 20 to 40 inches
Calcium carbonate equivalent - 15 to 35 percent
Organic matter - greater than 1 percent
A horizon
Hue: 10YR, 7.5YR
Value: 5, 6, or 7 dry, 3, 4, 5, or 6 moist
Chroma: 2, 3, or 4, dry or moist
Bk horizon
Hue: 10YR, 7.5YR
Value: 5, 6, or 7 dry, 4, 5, 6, or 7 moist
Chroma: 2, 3, or 4 dry, 3 or 4 moist
Texture: sandy loam, loam, fine sandy loam (10 to 20 percent clay)
COMPETING SERIES: These are the Chilicotal (TX), Gallen (NM), Gilland (NM), Polar (TX), and Tombstone (AZ) series. Chilicotal, Gallen, Polar, and Tombstone soils are very deep. Gilland soils formed in alluvium and colluvium derived from red sandstone and calcareous shale and have hues of 2.5YR and 5YR. In addition, Gallen soils are in the Pecos-Canadian Plains and Valleys; Polar soils are in the Central Rolling Red Plains; both soils are moist in May and June.
GEOGRAPHIC SETTING: Powerline soils are on hills. Slopes are commonly 5 to 30 percent but range from 2 to 40 percent. They formed in slope alluvium from calcareous sandy fanglomerate. Elevations range from 3300 to 5000 feet. Mean annual precipitation is 12 to 16 inches occurring as summer thunderstorms and winter rain. Mean annual air temperature is 59 to 67 degrees F. The frost-free period is about 180 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Andrada, Bodecker, and Kimrose soils. Bodecker soils are sandy-skeletal and very deep. Kimrose soils are shallow to a petrocalcic horizon. Andrada soils are shallow to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; moderately rapid runoff; moderate permeability.
USE AND VEGETATION: Used mainly for livestock grazing. Vegetation is ocotillo, range ratany, sotol, black grama, banana yucca, creosotebush, sideoats grama, slim tridens, wolftail, threeawn, fluffgrass, bush muhly, whitethorn, and Mormon-tea.
DISTRIBUTION AND EXTENT: Southern Arizona. The Powerline soils are of minor extent. MLRA is 41.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Pima County, Arizona; Soil survey of Pima County, Arizona, Eastern Part; 1986.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 3 inches (A horizon)
Calcic horizon - the zone from 3 to 29 inches (Bk1, Bk2 horizons)
Paralithic contact - the boundary at 29 inches (2Crkq horizon)
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.
Revised for the correlation of AZ661, 2/2009, WWJ