LOCATION STRONGHOLD AZ

Established Series
Rev. DJB
12/2014

STRONGHOLD SERIES

The Stronghold series consists of very deep, well drained soils that formed in fan alluvium from mixed sources. Stronghold soils are on fan remnants. Slope is 1 to 60 percent. Mean annual precipitation is about 14 inches and the mean annual air temperature is about 63 degrees F.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, thermic Ustic Haplocalcids

TYPICAL PEDON: Stronghold very gravelly loamy sand - rangeland. (Colors are for dry soil unless otherwise noted.) Surface gravel - 35 to 55 percent of the surface is covered with gravel

A--0 to 1 inch; brown (7.5YR 4/2) very gravelly loamy sand, dark brown (7.5YR 3/2) moist; weak thick platy structure; loose, nonsticky and nonplastic; few very fine roots; common fine irregular pores; 37 percent gravel; strongly effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary.

A/Bk1--1 to 8 inches; brown (7.5YR 4/2) gravelly sandy loam, dark brown (7.5YR 3/2) moist; weak fine subangular blocky structure; soft, very friable, moderately sticky and moderately plastic; common very fine and fine roots; few fine tubular pores; few patchy calcium carbonate coatings on rock fragments; common distinct organic coatings on rock fragments; 34 percent gravel; violently effervescent, 14 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); clear smooth boundary.

Bk2--8 to 25 inches; light brown (7.5YR 6/3) gravelly sandy loam; brown (7.5YR 5/4) moist; massive; slightly hard, very friable, slightly sticky and moderately plastic; common very fine and fine roots; few fine tubular pores; many distinct calcium carbonate coatings on rock fragments; common fine and medium calcium carbonate filaments; 23 percent gravel; violently effervescent, 20 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); clear smooth boundary.

Bk3--25 to 60 inches; light brown (7.5YR 6/3) and pink (7.5YR 7/3) gravelly sandy loam, brown (7.5YR 4/4) moist; massive; slightly hard, friable, nonsticky and nonplastic; few very fine and fine roots; few fine tubular pores; many distinct calcium carbonate coatings on rock fragments; common fine calcium carbonate filaments; horizontal seams of calcium carbonate .5 to 1 inch thick and 12 to 18 inches long; 18 percent gravel; violently effervescent, 18 percent calcium carbonate equivalent; moderately alkaline (pH 8.2).

TYPE LOCATION: Cochise County, Arizona located at a latitude of 31 degrees, 44 minutes, 36 seconds North and a longitude of 110 degrees, 01 minutes, 00 seconds West; about 2,230 feet west and 390 feet south of the northeast corner of section 32, Township 19 S., Range 23 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.

Depth to calcic horizon: 1 to 20 inches; calcium carbonate equivalent averages 15 to 35 percent, but ranges from 2 to 45 percent in any one subhorizon

Rock fragments: averages less than 35 percent in the control section; can range to 50 percent in any one subhorizon

Reaction: slightly to strongly alkaline

Organic matter: greater than 1 percent

A horizon
Hue: 10YR, 7.5YR
Value: 3 to 7 dry, 2 to 6 moist
Chroma: 1 to 4, dry or moist
Calcium carbonate equivalent: 1 to 15 percent

Bk horizon
Hue: 10YR, 7.5YR
Value: 4 to 8 dry, 3 to 7 moist
Chroma: 2, 3 or 4, dry or moist
Texture: fine sandy loam, sandy loam, loam, coarse sandy loam, loamy sand (7 to 20 percent clay)
Effervescence: strong or violent
Calcium carbonate equivalent: 5 to 40 percent

Buried soil: Some pedons have a buried soil at depths of 40 to 60 inches

COMPETING SERIES: These are the Bilgray (AZ), Geta (NV), Kinco (TX), Luckyhills (AZ), and Potrillo (I)(TX) series. Bilgray soils contain compacted Cd layers. Geta soils are in the Mohave Desert and are moist in the soil moisture control section for less than 20 days cumulative between July and September. Kinco soils have calcic horizons at depths greater than 20 inches. Luckyhills soils have thin surface layers that contain less than 1 percent organic matter. Potrillo soils are inactive.

GEOGRAPHIC SETTING: Stronghold soils are in the Upper Sonoran and Chihuahuan deserts on upper parts of fan remnants. Slopes range from 1 to 60 percent. They formed in fan alluvium from limestone, schist, granite, andesite and rhyolite. Elevations range from 2,990 to 5,200 feet. The mean annual precipitation is 12 to 16 inches. The mean annual air temperature is 59 to 69 degrees F. The frost-free period is 180 to 260 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Bernardino, Elgin, McAllister and Tombstone series. Bernardino, Elgin, and McAllister soils all have argillic horizons. Tombstone soils are loamy-skeletal.

DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate or moderately rapid permeability.

USE AND VEGETATION: Stronghold soils are used for livestock grazing and wildlife habitat. Vegetation includes bush muhly, sideoats grama, black grama, blue grama, cane beardgrass, false mesquite, and yucca.

DISTRIBUTION AND EXTENT: Central Arizona and Southeastern Arizona. The Stronghold soils are of moderate extent. MLRAs 38 and 41.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Yavapai County, Arizona; Soil survey of Black Hills-Sedona Area, Arizona, Parts of Coconino and Yavapai Counties; 1996.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - the zone from 0 to 8 inch (A and A/Bk horizon)

Calcic horizon - the zone from 1 to 60 inches (A/Bk1, Bk2, Bk3 horizons)

Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy, Twelfth Edition, 2014.

The type location was moved to the Douglas-Tombstone Area in April 2000.

Revised for the correlation of AZ661, 2/2009, WWJ

Revised for the correlation of White Sands Missile Range, New Mexico; October, 2014, NMS

National Cooperative Soil Survey
U.S.A.