LOCATION DELTHORNY AZEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Calcic Lithic Petrocalcids
TYPICAL PEDON: Delthorny very gravelly sandy loam - rangeland. (colors are for dry soil unless otherwise noted).
A--0 to 2 inches; brown (7.5YR 5/4) very gravelly sandy loam, brown (7.5YR 4/4) moist; weak thin platy structure; soft, very friable, slightly sticky and slightly plastic; common fine roots; common fine tubular pores; common distinct very pale brown (10YR 8/2) continuous calcium carbonate coatings on rock fragments; 55 percent gravel; strongly effervescent; slightly alkaline (pH 7.8); abrupt smooth boundary (1 to 5 inches thick).
Bk--2 to 9 inches; light brown (7.5YR 6/4) very gravelly sandy loam, brown (7.5YR 5/4) moist; massive; soft, very friable, slightly sticky and slightly plastic; common very fine roots; common fine tubular pores; many distinct very pale brown (10YR 8/2) continuous calcium carbonate coatings on rock fragments; 55 percent gravel; violently effervescent; moderately alkaline (pH 8.0); abrupt wavy boundary (3 to 15 inches thick),
2Bkm--9 to 16 inches; very pale brown (10YR 8/2); indurated hardpan; extremely hard (4 to 15 inches thick).
3R--16 inches; conglomerate.
TYPE LOCATION: Pima County, Arizona; latitude of 32 degrees 12 minutes and 30 seconds North and a longitude of 112 degrees 11 minutes and 30 seconds West. Three miles west and north of the Quijotoa Trading Post, 2,270 feet east and 2,420 feet south of the NW corner of section 17, T. 14 S., R. 2 E.
RANGE IN CHARACTERISTICS:
Soil moisture: Intermittently moist in some part of the soil moisture control section during December through February and July through September. Driest during May and June. Typic aridic soil moisture regime.
Soil temperature: 64 to 72 degrees F.
Rock fragments: 35 to 70 percent gravel, cobble and /or stones
Reaction: slightly to moderately alkaline
Clay content: averages less than 18 percent in the control section
Depth to petrocalcic: 6 to 20 inches
Depth to bedrock: 10 to 20 inches
A horizon
Hue: 7.5YR, 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 through 4, dry or moist
Calcium carbonate equivalent: 0 to 10 percent
Organic matter: less than 0.5 percent
Bk horizon
Hue: 7.5YR, 10YR
Value: 5 through 8 dry, 4 through 7 moist
Chroma: 2 through 4, dry or moist
Texture: fine sandy loam, sandy loam, loam
Calcium carbonate equivalent: 5 to 20 percent
Bkm horizon
Cementation: Indurated or strongly cemented with calcium carbonate
COMPETING SERIES: This is the Boludo (TX) series. Boludo soils have 20 to 35 percent clay and are in the ustic aridic soil moisture regime.
GEOGRAPHIC SETTING: Delthorny soils are on relict fan terraces, hills and mountains. Slopes range from 3 to 45 percent. They formed in slope alluvium and colluvium from dominantly conglomerate, basalt and other igneous rock. Elevation ranges from 2,000 to 4,000 feet. The mean annual precipitation is 10 to 13 inches. The mean annual air temperature ranges from 62 to 70 degrees F. The frost-free period is about 220 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Akela, Stagecoach, Topawa, Vado and Queencreek series. Stagecoach, Topawa, Vado and Queencrteek soils are very deep. Akela soils do not have petrocalcic horizons.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderately rapid permeability.
USE AND VEGETATION: Delthorny soils are used for livestock grazing and wildlife habitat. Vegetation includes creosotebush, paloverde, cacti, fluffgrass, bush muhly, ocotillo and jojoba.
DISTRIBUTION AND EXTENT: Southern Arizona. This series is of moderate extent. MLRA is 40.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Pima, County, Arizona; Soil survey of the Tohono O'odham Indian Reservation, AZ, Parts of Maricopa, Pima and Pinal Counties; 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 2 inches (A horizon)
Petrocalcic horizon - the zone from 9 to 16 inches (2Bkm horizon)
Lithic contact - the boundary at 16 inches (3R horizon)
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.
Updates to support changes in Soil Taxonomy, 11/07, CEM
Revised for the correlation of AZ661, 12/2008, WWJ
Note: The same typical pedon is used in AZ669 and AZ703. The PLSS location referenced in AZ669 is contradictory to the geographic (latitude/longitude) location referenced in AZ703. AZ669 location latitude of 32 degrees, 12 minutes, 28 seconds N., longitude of 112 degrees, 10 minutes, 56 seconds W., 2,640 feet north and 100 feet west of the SE corner section 17, T. 14 S., R 2 E.