LOCATION REDO AZEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed, thermic Typic Haplocalcids
TYPICAL PEDON: Redo very gravelly sand - rangeland. (Colors are for dry soil unless otherwise noted.
A--0 to 2 inches; brown (7.5YR 4/4) very gravelly sand, dark brown (7.5YR 3/4) moist; moderate fine granular structure; loose, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial pores; 30 percent gravel and 20 percent cobble; slightly effervescent; slightly alkaline (pH 7.6); abrupt smooth boundary. (1 to 3 inches thick)
Bk1--2 to 14 inches; brown (7.5YR 4/4) very gravelly sand, dark brown (7.5YR 3/4) moist; single grain; loose, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial pores; 30 percent gravel and 10 percent cobble; many distinct continuous calcium carbonate coatings on rock fragments; 6 percent calcium carbonate equivalent; strongly effervescent; slightly alkaline (pH 7.8); abrupt smooth boundary. (9 to 16 inches thick)
Bk2--14 to 60 inches; light brown (7.5YR 6/4) extremely gravelly sand, brown (7.5YR 5/4) moist; single grain; loose, very friable, nonsticky and nonplastic; many very fine and fine and few coarse roots; many very fine and fine interstitial pores; 40 percent gravel and 20 percent cobble; many distinct continuous calcium carbonate coatings on rock fragments; 6 percent calcium carbonate equivalent; violently effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Pima County, Arizona: Latitude of 32 degrees, 24 minutes, 10 seconds North and a longitude of 110 degrees, 28 minutes, 50 seconds West. Northwest corner of section 11, T.12.S., R.18.E.
RANGE IN CHARACTERISTICS:
Soil moisture: Intermittently moist in some part of the soil moisture control section during December - February and for more than 20 days cumulative during July - September. Driest during May and June. Typic aridic soil moisture regime.
Soil temperature: 64 to 72 degrees F.
Reaction: slightly to moderately alkaline
Organic matter: 0.3 to 1 percent
Depth to calcic horizon: 0 to 18 inches
Rock fragments: 25 to 60 percent gravel and cobble
A horizon
Hue: 7.5YR, 10YR
Value: 3 to 6 dry, 3 to 5 moist
Chroma: 3 to 4 dry or moist
B horizon
Hue: 7.5YR, 10YR
Value: 4 through 7 dry, 3 through 5 moist
Chroma: 3 to 5 dry or moist
Texture: sand, loamy sand (averages less than 8 percent clay), coarse sand, loamy coarse sand, sandy loam
Calcium carbonate equivalent: greater than 5 percent
COMPETING SERIES: These are the Caliza (NM), Eastland (NV), Niavi (NV), Shelley (AZ), and Tonopah (NV) series. Eastland, Niavi, Shelly, and Tonapah soils are moist in the soil moisture control section for less than 20 days cumulative between July and September and occur in the Mohave Desert.
Eastland and Tonapah have calcic horizons deeper than 18 inches.
Caliza soils are from the Desert Project and are dry in the soil moisture control section for longer periods due to a lower rainfall component.
GEOGRAPHIC SETTING: Redo soils are on hills and fan terraces at elevations of 2,600 to 4,100 feet. Slopes range from 5 to 50 percent. These soils formed in mixed stream alluvium and fan alluvium. The mean annual precipitation is 10 to 12 inches. The mean annual air temperature is 62 to 70 degrees F. The frost-free period is 190 to 280.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Redington and Queencreek soils. Redington soils are sandy and Queencreek soils do not have calcic horizons.
DRAINAGE AND PERMEABILITY: Excessively drained; moderate runoff; rapid permeability.
USE AND VEGETATION: Redo soils are used for livestock grazing and wildlife habitat. Vegetation includes creosotebush, mesquite, whitethorn acacia, black grama, sideoats grama, threeawn, slim tridens, bush muhly, annual grasses and forbs.
DISTRIBUTION AND EXTENT: Southern Arizona. This series is of moderate extent. MLRA is 40 and 41.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Pima County, Arizona; Soil survey of Pima County, Arizona, Eastern Part; 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 2 inches (A horizon)
Calcic horizon - The zone from 2 to 60 inches (Bk1, Bk2 horizons). It is assumed the percentage of carbonates decreases with depth.
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.