LOCATION GRINDER                 CA

Established Series
Rev: PBF/CAH/ET
04/2015

GRINDER SERIES

The Grinder series consists of very shallow and shallow, well drained soils that formed in residuum from granitoid rocks. Grinder soils are on pediments. Slopes range from 2 to 30 percent. The mean annual precipitation is 138 millimeters (5.5 inches) and the mean annual air temperature is about 18.5 degrees C (65 degrees F).

TAXONOMIC CLASS: Loamy, mixed, superactive, thermic Lithic Haplargids

TYPICAL PEDON: Grinder gravelly fine sandy loam, on a west-facing, convex, 5 percent slope under desert shrubs at an elevation of 967 meters (3,172 feet). (Colors are for dry soil unless otherwise noted.) The surface is covered by approximately 30 percent fine gravel, 17 percent medium and coarse gravel and 3 percent cobbles.

A -- 0 to 1 centimeter (0 to 0.5 inch); yellowish brown (10YR 5/4) gravelly fine sandy loam, dark yellowish brown (10YR 4/4) moist; weak thin platy structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; few very fine and fine vesicular pores; 19 percent fine gravel and 1 percent medium and coarse gravel; neutral (pH 7.3); abrupt smooth boundary. (1 to 3 centimeters thick)

Bt1 -- 1 to 8 centimeters (0.5 to 3 inches); yellowish brown (10YR 5/6) gravelly fine sandy loam, yellowish brown (10YR 5/4) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine and fine and very few medium roots; 2 percent faint, yellowish brown (10YR 5/6) clay films on ped faces and 5 percent faint, yellowish brown (10YR 5/6) clay films on rock fragments; 24 percent fine gravel and 1 percent medium and coarse gravel; slightly alkaline (pH 7.5); clear wavy boundary.

Bt2 -- 8 to 20 centimeters (3 to 8 inches); dark yellowish brown (10YR 4/6) gravelly sandy loam, strong brown (7.5YR 4/6) moist; moderate medium subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; very few fine and medium roots; 6 percent faint, dark yellowish brown (10YR 4/6) clay films on ped faces; 22 percent fine gravel and 3 percent medium and coarse gravel; slightly alkaline (pH 7.5); abrupt irregular boundary. (Combined thickness of Bt horizon is 12 to 20 centimeters thick)

R -- 20 centimeters (8 inches); unweathered, slightly fractured granitoid bedrock.

TYPE LOCATION: Riverside County, California; approximately 3.8 kilometers (2.4 miles) north northeast of Cottonwood Visitors Center on Pintobasin Road and 650 meters (2,132 feet) east of Pintobasin Road; 785 meters (2,574 feet) south and 435 meters (1,427 feet) east of the NW corner of section 36, T. 4 S., R. 16 E., San Bernardino Base and Meridian; 33 degrees, 46 minutes and 49.0 seconds north latitude, and 115 degrees, 47 minutes and 30.3 seconds west longitude; USGS Porcupine Wash 7.5 minute topographic quadrangle; UTM 11S 0611868e 3738449n (DTM: NAD83).

RANGE IN CHARACTERISTICS:

Soil moisture control section: usually dry, moist in some parts for short
periods during winter and early spring and for 10 to 20 days cumulative
between July and September following summer convection storms. The soils have a typic-aridic soil moisture regime.

Soil temperature: 19 to 22 degrees C (66 to 72 F).
Surface rock fragments: 50 to 98 percent, with 15 to 40 percent fine gravel,
15 to 75 percent medium and coarse gravel, 0 to 10 percent cobbles and 0
to 2 percent stones.

Control section
Rock fragments: 10 to 35 percent gravel.
Clay content: averages 12 to 18 percent.
Organic matter: 0 to 0.25 percent.
Depth to an argillic horizon: 1 to 8 centimeters (0.5 to 3 inches).
Depth to a lithic contact: 20 to 36 centimeters (6 to 14 inches).

Some pedons have a rock layer C horizon above the A horizon with 85 to 98 percent rock fragments, dominantly fine gravel.

A horizon
Value: 5 or 6 dry, 3 to 5 moist.
Chroma: 3 or 4, dry or moist.
Texture of the fine earth: loamy fine sand, fine sandy loam or loam.
Clay content: 3 to 15 percent.
Rock fragments: 10 to 30 percent gravel.
Calcium carbonate equivalent: 0 to 5 percent.
Effervescence: noneffervescent to slightly effervescent.
Reaction: neutral or slightly alkaline.

Bt horizon
Hue: 10YR or 7.5YR.
Value: 3 to 5 dry, 4 or 5 moist.
Chroma: 4 to 6 dry, 3 to 6 moist.
Texture of the fine earth: sandy loam, fine sandy loam, loam
or sandy clay loam.
Clay content: 12 to 23 percent.
Rock fragments: 10 to 35 percent gravel.
Calcium carbonate equivalent: 0 to 5 percent.
Effervescence: noneffervescent to strongly effervescent.
Reaction: slightly or moderately alkaline.

C horizon (when present)
Hue: 10YR or 7.5YR.
Clay content: 2 to 8 percent.
Texture of the fine earth: sand or loamy sand.
Rock fragments: 35 to 70 percent, with 30 to 65 fine gravel and 0 to 5 percent medium and coarse gravel.
Effervescence: noneffervescent or very slightly effervescent.

COMPETING SERIES: These are the Aftaden (NM), Copperworld (CA), Sparkhule (CA), Stonegold (CA) and Zyplar (NV) series. Aftaden soils are formed in eolian sediments and material from basaltic sources, have mean annual precipitation of about 203 millimeters and are characterized by 5YR hues throughout the profile. Copperworld soils are formed from metamorphic rocks. Sparkhule soils average more than 25 percent clay in the particle-size control section. Stonegold soils are formed in volcanic residuum. Zyplar soils are formed in volcanic ash and rhyolitic tuff, average 20 to 30 percent clay in the particle size control section and have a mean annual soil temperature of 15 to 19 degrees C.

GEOGRAPHIC SETTING: Grinder soils are on pediments. Slopes range from 2 to 30 percent. These soils formed in residuum from granitoid rocks. Elevations range from 700 to 1,230 meters (2,295 to 4,035 feet). The climate is arid, with hot, dry summers and warm, moist winters. The mean annual precipitation is 100 to 175 millimeters (4 to 7 inches) and the mean annual air temperature is 17 to 20 degrees C (62.5 to 68 degrees F). The frost-free season is 270 to 320 days.

GEOGRAPHICALLY ASSOCIATED SOILS: This is the Pinkcan (CA) soil on adjacent fan remnants. Pinkcan soils are very deep and have a duripan between 100 and 150 centimeters.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well-drained; medium runoff; high saturated hydraulic conductivity above the bedrock and moderately low saturated hydraulic conductivity within the bedrock.

USE AND VEGETATION: Grinder soils are used for recreation and wildlife habitat. The present vegetation is mainly burrobush, blackbrush, Hall's shrubby spurge, creosote bush, and range ratany.

DISTRIBUTION AND EXTENT: Southern Mojave Desert of southeastern California. MLRA 30. These soils are of small extent.

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

SERIES ESTABLISHED: Riverside County, California; Soil Survey of Joshua Tree National Park, California, 2012. The name is coined.

REMARKS: Diagnostic horizons and features in this pedon include:

Ochric epipedon - from a depth of 0 to 1 centimeter (A horizon).
Argillic horizon - from a depth of 1 to 20 centimeters (Bt horizon).
Lithic contact - the zone beginning at 20 centimeters (R horizon).
Particle-size control section - from a depth of 0 to 20 centimeters (A and Bt
horizons).

ADDITIONAL DATA: NASIS Pedon User ID: POWA107.

Responsibility for this series was transferred from Davis to Phoenix 4/2015. The last revision to the series was 9/2012. ET

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National Cooperative Soil Survey
U.S.A.