LOCATION MARANA AZEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, hyperthermic Typic Haplocambids
TYPICAL PEDON: Marana silty clay loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; yellowish brown (10YR 5/4) silty clay loam, dark yellowish brown (10YR 3/4) moist; weak very thin platy structure; soft, very friable, sticky and plastic; few fine roots; common very fine tubular pores; strongly effervescent; slightly alkaline (pH 7.4); abrupt smooth boundary. (1 to 3 inches thick)
Bw1--2 to 8 inches; brown (10YR 5/3) silty clay loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common fine vesicular pores; strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (6 to 15 inches thick)
Bw2--8 to 23 inches; brown (10YR 5/3) silty clay loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, friable, sticky and slightly plastic; few fine roots; common fine tubular pores; secondary lime accumulations in root channels and on root hairs in lower part; thin discontinuous very dark brown (10YR 2/2) organic staining on some faces of peds; strongly effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (3 to 22 inches thick)
C--23 to 60 inches; brown (10YR 5/3) silty clay loam, brown (10YR 4/3) moist; massive; slightly hard, friable, slightly sticky, plastic; few fine tubular pores; strongly effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Pinal County, Arizona; 27 feet north and 107 feet west of the southeast corner of sec. 1, T. 10 S., R 8 E.
RANGE IN CHARACTERISTICS:
Soil moisture - Intermittently moist in some parts of the soil moisture control section during July-September and December-February. Typic aridic moisture regime.
Solum thickness - 10 to 40 inches.
Rock fragments - Less than 10 percent pebbles in the control section. Texture - Averages 18 to 34 percent clay in the control section. Organic matter - Less than 1 percent.
A horizon -
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 3, 4 or 5 moist
Chroma: 4 or 6 dry, 3, 4 or 6 moist
Texture: silty clay loam
B horizon -
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 3, 4 or 5 moist
Chroma: 3, 4 or 6 dry and moist
Texture: Silty clay loam, silt loam
C horizon -
Hue: 7.5YR or 10YR
Value: 5, 6 or 7 dry, 4, 5 or 6 moist
Chroma: 3, 4 or 6 dry and moist
Texture: Silty clay loam
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Marana soils are on stream terraces. Slopes are 0 to 2 percent. The soils formed in silty textured stream alluvium of Holocene Age. The alluvium is derived from acid and basic igneous rock such as granite, schist, rhyolite, andesite, quartzite and basalt rocks. Elevations are 1100 to 2000 feet. The climate is hot arid continental. The average annual precipitation is 4 to 10 inches. The mean annual temperature is 67 to 75 degrees F. The frost-free period is about 250 to 350 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These soils are the Gadsden, Gilman, Glenbar, Saminiego and Sasco soils. Gadsden, Gilman, and Glenbar soils lack cambic horizons and are on floodplains. Gadsden soils are fine. Saminiego soils are clayey over fine-silty. Sasco soils are coarse- silty. Saminiego and Sasco soils are on adjacent stream terraces.
DRAINAGE AND PERMEABILITY: Well drained, slow runoff. Moderately slow permeability.
USE AND VEGETATION: Used for limited grazing following seasonal rains and when irrigated, for growing cultivated crops such as alfalfa, cotton and small grains. Native vegetation is mesquite, creosotebush, desertbroom, annual weeds and grasses.
DISTRIBUTION AND EXTENT: South Central Arizona. This series is moderately extensive. MLRA 40.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Pinal County Area, Western Part, Arizona; 1984.
REMARKS: Diagnostic horizons and features recognized are:
Ochric epipedon - The zone from 0 to 2 inches (A horizon).
Cambic horizon - The zone from 2 inches to about 23 inches (Bw1 and Bw2 horizons).
In October 2000, taxonomic classification was converted to the closest match found in Soil Taxonomy, Second Edition 1999. No update was made to horizon nomenclature, competing series section, etc. Other placements may be more appropriate after a complete update.
Classified according to Soil Taxonomy Second Edition, 1999