LOCATION CHILDERS AZEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic, shallow Calcic Petrocalcids
TYPICAL PEDON: Childers very cobbly fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; brown (7.5YR 5/4) very cobbly fine sandy loam, brown (7.5YR 4/4) moist; weak thin platy and weak fine granular structure; soft, very friable, nonsticky and nonplastic; many fine and very fine roots; common very fine vesicular and irregular pores; 20 percent gravel and 20 percent cobble; strongly effervescent with disseminated calcium carbonate, 8.5 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); abrupt smooth boundary. (1 to 3 inches thick)
Bk--2 to 18 inches; light brown (7.5YR 6/4) very cobbly loam, brown (7.5YR 5/4) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many fine and very fine roots; common fine tubular pores; 30 percent gravel and 25 percent cobble; violently effervescent with disseminated and segregated calcium carbonate as pendants and coatings on rock fragments, 37 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); abrupt wavy boundary. (10 to 19 inches thick)
Bkm1--18 to 21 inches; indurated, calcium carbonate cemented hardpan with laminar cap; abrupt wavy boundary. (0.5 to 6 inches thick)
Bkm2--21 to 30 inches; white (N/8) and pink (7.5YR 8/4) strongly calcium carbonate cemented hardpan, pink (7.5YR 8/4) moist; massive; extremely hard, extremely firm; abrupt irregular boundary. (4 to 30 inches thick)
2R--30 inches; basalt.
TYPE LOCATION: Mohave County, Arizona; on West Mesa about 18 miles southeast of St. George, Utah; about 1500 feet south and 1900 feet east of the northwest corner of section 13, T. 40 N., R. 11 W.; about 36 degrees, 52 minutes, 26 seconds north latitude and 113 degrees, 25 minutes, 48 seconds west longitude.
RANGE IN CHARACTERISTICS:
Soil moisture; Intermittently moist in some part of the soil moisture control section during July through September and December through February. Driest during May and June. Ustic Aridic soil moisture regime.
Soil temperature: 54 to 57 degrees F.
Organic matter: 0.5 to 1 percent in the upper 1 to 4 inches
Depth to calcic horizon: 1 to 3 inches
Depth to petrocalcic horizon: 10 to 20 inches
Depth to bedrock: 20 to 40 inches
Clay content: Average 5 to 18 percent in the particle size control section
Rock fragments: Averages 35 to 60 percent in the control section; ranges from 15 to 40 percent gravel, 0 to 35 percent cobble and 0 to 5 percent stones
A horizon
Hue: 7.5YR, 5YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 to 4, dry or moist
Reaction: slightly to moderately alkaline
Effervescence: slightly to violently effervescent, 5 to 30 percent calcium carbonate equivalent
Bk horizon
Hue: 7.5YR, 5YR
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 2 to 4, dry or moist
Texture: sandy loam, loam (5 to 18 percent clay)
Reaction: moderately to strongly alkaline
Effervescence: strongly to violently, 15 to 40 percent calcium carbonate equivalent
COMPETING SERIES: The competing Curhollow (AZ), Havauspai (AZ), Pibler (UT) and Pinetown (UT) series.
Curhollow soils contain 18 to 27 percent clay in the particle size control section.
Havasupai soils do not have bedrock below petrocalcic horizon.
Pibler soils have a soil moisture regime that is aridic bordering xeric.
Pinetown soils derived from sedimentary and metamorphic rocks and bedrock is below the petrocalcic horizon.
GEOGRAPHIC SETTING: Childers soils are on mesas and plateaus and have slopes of 2 to 15 percent. These soils formed in mixed alluvium colluvium and residuum derived dominantly from volcanic and sedimentary formations. Elevations range from 4000 to 6000 feet. The mean annual air temperature is 52 to 55 degrees F. Mean annual precipitation is 10 to 14 inches. The frost-free period is 135 to 165 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Pocum and Ubank soils. Pocum soils contain less than 35 percent rock fragments. Ubank soils are very deep and have carbonatic mineralogy.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.
USE AND VEGETATION: Childers soils are used for livestock grazing and wildlife habitat. The present vegetation is blackbrush, green Mormon-tea, banana yucca, Wyoming big sagebrush, Indian ricegrass, bush muhly, black grama, galleta, and bottlebrush squirreltail.
DISTRIBUTION AND EXTENT: Northwestern Arizona. This soil is of limited extent. MLRA is 35. Name derived from Childers Well on the Russel Springs Quad.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Mohave County, Arizona; Soil survey of the Shivwits Area, Arizona, Part of Mohave County; 1994.
REMARKS: Formerly classified as Ustochreptic Paleorthids.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 2 inches (A horizon)
Calcic horizon - The zone from 2 to 18 inches (Bk horizon)
Petrocalcic horizon - The zone from 18 to 30 inches (Bkm1, Bkm2 horizons)
Lithic contact - The boundary at 30 inches (2R horizon)