LOCATION DOUBLEADOBE AZEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, thermic Petronodic Natrargids
TYPICAL PEDON: Doubleadobe sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 1 inch; brown (7.5YR 5/4) sandy loam, dark brown (7.5YR 3/3) moist; weak, thin platy structure; soft, very friable, nonsticky and nonplastic; many very fine and common fine roots; few very fine vesicular pores; strongly effervescent, 8 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); abrupt smooth boundary. (2 to 5 inches thick)
Btknzy1--1 to 4 inches; brown (7.5YR 5/3) clay loam, brown (7.5YR 5/3) moist; strong fine angular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine and fine roots; common very fine irregular pores; many distinct clay films on faces of peds; few calcium carbonate coatings on faces of peds; few fine soft gypsum and calcium carbonate masses; EC of 21 dS/m; violently effervescent, 17 percent calcium carbonate equivalent; very strongly alkaline (pH 9.4); abrupt wavy boundary.
Btknzy2--4 to 13 inches; brown (7.5YR 5/4) clay, brown (7.5YR 5/3) moist; weak fine subangular blocky structure; soft, very friable, very sticky and very plastic; few very fine roots; common very fine tubular pores; few distinct clay films on faces of peds; many fine soft gypsum and salt masses in clusters and seams; EC of 24 dS/m; violently effervescent, 15 percent calcium carbonate equivalent; strongly alkaline (pH 8.8); abrupt wavy boundary.
Btknzy3--13 to 31 inches; pinkish gray (7.5YR 7/2) and light brown (7.5YR 6/3) clay, pinkish gray (7.5YR 7/2) moist; moderate fine subangular blocky structure; hard, friable, very sticky and very plastic; many very fine and fine tubular pores; few patchy clay films in root channels and on faces of peds; many fine gypsum and salt crystals; many fine and medium soft calcium carbonate and gypsum masses; common manganese coatings on faces of peds; 3 percent fine and medium petronodes; EC of 17 dS/m; violently effervescent, 50 percent calcium carbonate equivalent; strongly alkaline (pH 8.8); clear smooth boundary. (Combined thickness of the Btknzy horizons 5 to 35 inches)
Bknzyc--31 to 60 inches; white (7.5YR 8/1) and light brown (7.5YR 6/3) gravelly clay loam, pinkish gray (7.5YR 6/2) moist; moderate fine angular blocky structure; slightly hard, firm, moderately sticky and moderately plastic; many very fine and fine tubular pores; many manganese coatings on faces of peds; many fine gypsum and salt crystals; many fine and medium soft calcium carbonate and gypsum masses; common areas of iron depletions; few fine yellow iron masses; 25 percent fine and medium petronodes; EC of 16 dS/m; violently effervescent, 15 percent calcium carbonate equivalent; very strongly alkaline (pH 9.6).
TYPE LOCATION: Cochise County, Arizona; about 1,200 feet west and 500 feet north of the southeast corner of section 19, Township 21 S., Range 26 E.; Elfrida topographic map; latitude 31 degrees, 34 minutes, 39 seconds North and longitude 109 degrees, 43 minutes, 55 seconds West.
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 soils moisture regime.
Soil Temperature: 62 to 67 degrees F.
Rock fragments: generally less than 35 percent gravel and/or petronodes
Reaction: slightly alkaline to very strongly alkaline
Clay content: averages more than 35 percent in control section
Organic matter: 0.5 to 2 percent
Depth to natric horizon: 1 to 15 inches
Depth to calcic horizon: 10 to 20 inches
A horizon
Hue: 10YR, 7.5YR
Value: 3 through 6, dry or moist
Chroma: 2 through 4, dry or moist
Texture: silty clay loam, silt loam, clay loam, sandy loam
Btknzy horizon
Hue: 7.5YR, 5YR
Value: 3 through 5, dry or moist
Chroma: 2 through 4, dry or moist
Texture: clay, silty clay, clay loam
Calcium carbonate equivalent: 5 to 20 percent
Gypsum content: 2 to 5 percent
Salinity: slightly to strongly (EC of 4 to 32 dS/m)
Sodicity: moderate to strong (SAR of 13 to 50)
Bknzyc horizon
Hue: 10YR, 7.5YR
Value: 5 through 8 dry, 4 through 7 moist
Chroma: 1 through 4, dry or moist
Texture: clay loam, loam, clay, silty clay
Petronodic feature: 1 to 35 percent petronodes
Calcium carbonate equivalent: 15 to 60 percent, but averages less than 40 percent
Gypsum content: 1 to 5 percent
Salinity: slightly to strongly (EC of 4 to 32 dS/m)
Sodicity: moderate to strong (SAR: 13 to 60)
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: The Doubleadobe soils are in the Chihuahuan desert on flood plains and basin floors at elevations of 3,600 to 4,100 feet. Slope ranges from 0 to 5 percent. These soils formed from mixed alluvium. The mean annual precipitation is 12 to 16 inches and occurs as thunderstorms during July to September and as gentle rains during December and January. 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 Libby, Gulch, Guest, Riveroad, Forrest, Bonita, Chorro, and Gothard soils. The Libby and Forrest soils have argillic horizons that also have more than 35 percent clay but do not have salts or gypsum. Guest, Riveroad, and Bonita soils do not have any salts or gypsum. Chorro and Gothard soils have less than 35 percent clay.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow runoff; slow permeability.
USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation includes alkali sacaton, giant sacaton, inland saltgrass, tobosa, vine mesquite, fourwing saltbush, mesquite.
DISTRIBUTION AND EXTENT: Southeastern Arizona portion of the Chihuahuan desert. MLRA is 41. Doubleadobe soils are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Cochise County, Arizona; Soil Survey of Cochise County, Arizona, Douglas-Tombstone Part; 2000.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 1 inches (A horizon)
Natric horizon - The zone from 1 to 13 inches (Btknzy1 and Btknzy2 horizons)
Calcic horizon - The zone from 13 to 60 inches (Btknzy3 and Bknzyc horizons)
Petronodic feature - 25 percent petronodes (Bknzyc horizon)