LOCATION SUNROCK                 AZ+CA NV

Established Series
Rev. WJ/PH/PDC/ET
12/2015

SUNROCK SERIES

The Sunrock series consists of very shallow and shallow, somewhat excessively drained soils formed in colluvium and residuum from volcanic rocks on mountains, hills, and mesas. Slopes range from 2 to 75 percent. The mean annual precipitation is about 6 inches. The mean annual air temperature is about 75 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, calcareous, hyperthermic Lithic Torriorthents

TYPICAL PEDON: Sunrock extremely gravelly sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 2 inches; brown (10YR 5/3) extremely gravelly sandy loam, brown (10YR 4/3) moist; weak fine granular structure; loose, nonsticky and nonplastic; many very fine roots; many very fine irregular pores; 65 percent gravel and 5 percent cobble; slightly alkaline (pH 7.8); abrupt smooth boundary. (1 to 4 inches thick)

Bk--2 to 5 inches; brown (10YR 5/3) very gravelly sandy loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many very fine roots; many very fine irregular pores; 50 percent gravel with few thin calcium carbonate coatings; strongly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (2 to 16 inches thick)

2R--5 inches; thin layer of weathered andesite over hard andesite; common calcium carbonate coatings on rock surfaces and in fractures.

TYPE LOCATION: Mohave County, Arizona: about 850 feet north and 1,800 feet west of the southeast corner of section 32, T. 28 N., R. 22 W. Gila and Salt River Base Meridian. 35 degrees, 45 minutes, 59 seconds north latitude and 114 degrees, 39 minutes, 10 seconds west longitude.

RANGE IN CHARACTERISTICS:

Soil moisture: Intermittently moist in some part of the soil moisture control section during December-February and for less than 20 days cumulative during July-September. Driest during May and June. Typic aridic soil moisture regime.

Soil Temperature: 72 to 80 degrees F.

Rock fragments: Averages 35 to 65 percent.

Clay content: Averages 5 to 18 percent.

Depth to bedrock: 4 to 20 inches

A horizon - Hue: 7.5YR, 10YR

Value: 5 or 6 dry, 4 or 5 moist

Chroma: 3 or 4, dry or moist

Texture of the fine earth: Loamy sand, sandy loam and fine sandy loam

Clay content: 5 to 20 percent.

Calcium carbonate equivalent: 1 to 15 percent

Reaction: Slightly alkaline or moderately alkaline

Bk, Bkq and Bw horizons - Hue: 7.5YR, 10YR

Value: 5 or 6 dry, 4 or 5 moist

Chroma: 3 or 4, dry or moist

Texture of the fine earth: Fine sandy loam, sandy loam and loam; dominantly fine and medium in the sand fraction

Calcium carbonate equivalent: 1 to 15 percent

Reaction: Slightly alkaline or moderately alkaline

Some pedons do not have secondary accumulations of calcium carbonate and silica.

COMPETING SERIES: These are the Appleseed (AZ)(T), Goldroad (AZ), Hyder (AZ), Quilotosa (AZ), and Redneedle (NV)(T) series. Appleseed soils have 15 to 35 percent calcium carbonate equivalence and limestone bedrock. Goldroad soils have control sections dominated by coarse and very coarse sand and formed on granite. Hyder and Quilotosa soils are intermittently moist in some part of the soil moisture control section for more than 20 days cumulative during July-September. Redneedle soils are dry in the soil moisture control section July to September.

GEOGRAPHIC SETTING: Sunrock soils are on hills, mountains and mesa tops and have slopes of 2 to 75 percent. They formed in residuum and colluvium from volcanic rocks. Elevations range from 600 to 3,000 feet. The mean annual precipitation is 2 to 8 inches. The mean annual air temperature is 70 to 78 degrees F. The frost-free period is 280 to 360 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Carrizo, Huevi, Riverbend, and Tyro soils. Carrizo, Huevi, and Riverbend soils are very deep. Tyro soils have a calcic horizon and a duripan at depths less than 20 inches.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; medium to very high runoff; moderate or moderately rapid permeability over impermeable bedrock.

USE AND VEGETATION: This soil is used for recreation, rangeland and wildlife habitat. The present vegetation is creosotebush, white bursage, white brittlebush, and annuals.

DISTRIBUTION AND EXTENT: Mojave Desert of Arizona, California and Nevada; MLRA 30. These soils are extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA

SERIES ESTABLISHED: Fort Irwin National Training Center, CA (CA697) 2000.

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

Ochric epipedon - 0 to 5 inches (A and Bk horizons).

Lithic contact - 5 inches (2R horizon)

Entisol feature - The absence of diagnostic subsurface horizons

Particle-size control section 0 to 5 inches (A and Bk horizons).

Soils with depths greater than 10 inches to bedrock do not have Bk or Bw horizons that qualify as Calcic or Cambic horizons.

Series originally proposed in Mohave County, Arizona; Soil survey of Mohave County, Arizona, Central Part; 1993.

Responsibility for this series was transferred from Davis to Phoenix 12/2015. The last revision to the series was 4/2006. ET

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National Cooperative Soil Survey
U.S.A.