LOCATION EBON AZEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive, hyperthermic Typic Haplargids
TYPICAL PEDON: Ebon gravelly loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; brown (7.5YR 5/4) gravelly loam, reddish brown (5YR 4/4) moist; weak thin platy structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine roots; few fine tubular pores; few very fine interstitial pores; 20 percent pebbles; noneffervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (1 to 4 inches thick)
BA--2 to 13 inches; reddish brown (5YR 4/4) very cobbly clay loam, yellowish red (5YR 4/6) moist; moderate fine subangular blocky structure; hard, friable, sticky and plastic; common fine roots; few fine tubular pores; 60 percent pebbles and cobblestones; many pressure faces on peds; noneffervescent; moderately alkaline (pH 8.0); clear irregular boundary. (2 to 12 inches thick)
Bt--13 to 23 inches; yellowish red (5YR 4/6) very cobbly clay, yellowish red (5YR 4/6) moist; moderate medium subangular blocky structure; very hard, firm, sticky and plastic; common very fine roots; few fine tubular pores; few thin clay films on faces of peds; 60 percent rounded pebbles and cobblestones; many pressure faces of peds; noneffervescent; moderately alkaline (pH 8.0); clear wavy boundary. (8 to 12 inches thick)
Btk--23 to 38 inches; reddish brown (5YR 5/4) very cobbly clay, yellowish red (5YR 4/6) moist; weak fine subangular blocky structure; hard, friable, sticky and plastic; few fine roots; few fine tubular pores; few thin clay films on faces of peds; 60 percent coarse pebbles and cobbles stones with thin lime coatings; common black (10YR 2/1) stains on faces of peds; few fine soft lime masses; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (9 to 24 inches thick)
BCk--38 to 60 inches; light reddish brown (5YR 6/4) extremely cobbly sandy clay loam, yellowish red (5YR 4/6) moist; massive; hard, friable, sticky and plastic; common fine tubular and many fine interstitial pores 60 percent coarse pebbles and cobblestones; few fine lime accumulations and soft lime masses; strongly effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Maricopa County, Arizona 2,300 feet south and 1,450 feet west of the NE corner of section 31, T. 3 N., R. 2 W. Latitude of 33 degrees, 33 minutes, 34 seconds N., Longitude of 112 degrees, 30 minutes, 3 seconds W., NAD 83.
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. Typic aridic moisture regime.
Rock fragments: Greater than 35 percent pebbles and cobbles.
Solum thickness: 40 to 60 inches or more.
Carbonates: Noneffervescent in upper part; slightly to strongly effervescent in lower part.
A horizon
Hue: 10YR, 7.5YR, 5YR
Value: 4 to 7 dry; 3 to 5 moist
Chroma: 2 to 6, dry or moist
Texture: sandy loam, loam, sandy clay loam, clay loam
Rock fragments: 5 to 45 percent by volume
Organic matter: less than 1 percent
Reaction: neutral to slightly alkaline
BA and Bt horizons
Hue: 7.5YR, 5YR, 2.5YR
Value: 4 to 7 dry; 3 to 5 moist
Chroma: 4 to 8 dry; 2 to 6 moist
Texture: loam, sandy clay loam, clay loam, sandy clay
Reaction: slightly or moderately alkaline
Btk and BCk horizons
Hue: 7.5YR, 5YR, 2.5YR
Value: 4 to 7 dry; 3 to 5 moist
Chroma: 4 to 8 dry or moist
Texture: clay, sandy clay, clay loam in the upper part; and sandy clay, clay loam, sandy clay loam, sandy loam in the lower part
Carbonates: 1 to 15 percent, as accumulations and soft masses. Weakly cemented in some pedons
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Ebon soils are on fan terraces and have slopes of 0 to 40 percent. They formed in mixed alluvium from volcanic, granitic and metamorphic rock. The climate is hot arid continental. Elevation is 850 to 2,290 feet. Mean annual air temperature is 70 to 75 degrees F. Precipitation is 2 to 10 inches, falling mainly as thunderstorms in July, August and September and as gentle rains in December and January. The frost-free season is 240 to 325 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Antho, Beardsley, Carefree, Carrizo, Cavelt, Contine, Pinamt and Tremant soils. Antho, Carefree, Carrizo and Cavelt soils lack argillic horizons. Beardsley soils have duripans. Contine soils lack 35 percent gravel in the control section. Pinamt soils are loamy-skeletal. Tremant soils are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: These soils are used as rangeland and for homesites. Native vegetation is creosotebush, triangle bursage, mesquite, littleleaf paloverde, Mormon-tea, ocotillo, saguaro, cholla cactus, tobosa, bush muhly, staghorn cholla, ironwood, barrel cactus, range ratany, rabbitbush, brickellia, pricklypear cactus, jojoba and brittlebush.
DISTRIBUTION AND EXTENT: Central and southern Arizona. Ebon soils are moderately extensive. MLRA 40.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Maricopa County (Central Maricopa County Area), Arizona, 1972.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon the zone from 0 to 2 inches (A horizon)
Argillic horizon the zone from 13 to 38 inches (Bt and Btk horizons)
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.
Revised for the correlation of AZ661, 12/2008, WWJ