LOCATION ANDRADA                 AZ

Established Series
Rev. MLR/SJL/PDC/CEM
10/2013

ANDRADA SERIES

The Andrada series consists of very shallow to shallow, well drained soils formed in alluvium and residuum from sandstone, shale, diorite, and conglomerate. Andrada soils are on hills and pediments and have slopes of 3 to 45 percent. The mean annual precipitation is about 14 inches (355 mm) and the mean annual air temperature is about 63 degrees F (17.2 degrees C).

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic, shallow Ustic Haplocalcids

TYPICAL PEDON: Andrada extremely gravelly loam - rangeland. (Colors are for dry soil unless otherwise noted).

A--0 to 8 inches (0 to 20 cm); dark grayish brown (10YR 4/2) extremely gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate very fine, and fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine and few medium roots; many fine interstitial and few fine and medium tubular pores; 60 percent angular gravel that is intermittently calcium carbonate coated white (10YR 8/1); strongly effervescent; moderately alkaline (pH 8.2); abrupt broken to wavy boundary. (5 to 14 inches and 13 to 36 cm thick)

Bk--8 to 11 inches (20 to 51 cm); light brownish gray (10YR 6/2) extremely gravelly loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, slightly sticky and nonplastic; many very fine and a few fine roots; many interstitial pores; 75 percent gravel; violently effervescent, many very pale brown (10YR 8/2) and light gray (10YR 7/2) calcium carbonate coatings on rock fragments; moderately alkaline (pH 8.2); abrupt irregular boundary. (1 to 6 inches and 3 to 15 cm thick)

2Crk--11 to 60 inches (28 to 152 cm); fragmental; highly fractured and partially weathered sandstone; common very fine roots in fractures; many thin calcium carbonate coatings and common black stains in fractures.

TYPE LOCATION: Pima County, Arizona; 2,100 feet north and 2,400 feet east of the southwest corner of section 27, T. 17 S., R. 16 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. Ustic aridic soil moisture regime.

Soil temperature - 61 to 69 degrees F (16 to 20.6 degrees C).

Rock fragments (in control section) - 35 to 85 percent angular gravel and cobble, some stones

Depth to weathered bedrock - 6 to 20 inches (15 to 51 cm)

Calcium carbonate equivalent - 10 to 35 percent; includes part of the A horizon in some pedons

Reaction - slightly or moderately alkaline

A horizon
Hue: 10YR, 7.5YR
Value: 3 to 5 dry, 2 to 4 moist
Chroma: 2 to 4, dry or moist
Organic matter: greater than 1 percent
Calcium carbonate: strongly or violently effervescent
Rock fragments: 35 to 85 percent fine and medium angular gravel or channers

Bk horizon
Hue: 7.5YR, 10YR, 2.5Y
Value: 3 to 8 dry, 3 to 7 moist
Chroma: 1 to 4 dry, 1 to 6 moist
Texture: sandy loam, loam, fine sandy loam, sandy clay loam
Rock fragments: 60 to 80 percent fine and medium angular gravel or channers

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Andrada soils are on mountains, hills, and pediments. Slopes range from 3 to 45 percent. The soil formed in alluvium and residuum from sedimentary rock including sandstone, shale, chert, conglomerate, diorite, and quartzite. Elevations are 3,500 to 5,400 feet (1067 to 1646 meters). The mean annual precipitation is 12 to 16 inches (304 to 406 mm). The mean annual air temperature is 59 to 67 degrees F (15 to 19.4 degrees C). The frost-free period is 180 to 240 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Deloro, Oracle, Romero, Caralampi and Nolam series. Deloro soils have argillic horizons and are noncalcareous. Oracle and Romero soils do not have calcic horizons. Caralampi and Nolam soils are very deep and have argillic horizons.

DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability.

USE AND VEGETATION: Used mainly for livestock grazing and wildlife habitat. The vegetation consists of shrubby buckwheat, range ratany, mariola, sotol, mesquite, javelina bush, whitethorn, catclaw, sideoats, black, slender and hairy gramas, threeawn, bush muhly, wolftail, false- mesquite, ocotillo, curly mesquite and cane bluestem.

DISTRIBUTION AND EXTENT: Southern Arizona. The Andrada series is moderately extensive. It is usually in complex with other soils on cretaceous sediments. LRR-D, MLRA 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 8 inches (0 to 20 cm) (A horizon)

Calcic horizon - The zone from 0 to 11 inches (0 to 28 cm) (A, Bk horizons)

Paralithic contact - contact at 11 inches (28 cm) (2Crk horizon)

Classified according to Soil Taxonomy, Second Edition, 1999; Soil Taxonomy, Eleventh Edition, 2010.

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National Cooperative Soil Survey
U.S.A.