LOCATION SOTORAN CA

Established Series
Rev: LJL/ET
12/2015

SOTORAN SERIES

The Sotoran series consists of very deep, moderately well drained soils that formed in alluvium derived from mixed sources. Sotoran soils are on stream terraces. Slopes range from 0 to 2 percent. The mean annual precipitation is about 100 millimeters and the mean annual temperature is about 23 degrees C.

TAXONOMIC CLASS: Fine, smectitic, calcareous, hyperthermic Typic Torrifluvents

TYPICAL PEDON: Sotoran silty clay, irrigated cropland. (Colors are for dry soil unless otherwise noted.)

Ap--0 to 20 centimeters (0 to 8 inches); pale brown (10YR 6/3) silty clay, brown (10YR 4/3) moist; moderate coarse subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; common very fine through medium roots; few very fine and fine tubular pores; strongly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (15 to 25 centimeters thick)

BA--20 to 55 centimeters (8 to 22 inches); pale brown (10YR 6/3) silty clay, brown (10YR 4/3) moist; moderate coarse subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; common very fine through medium roots; few very fine and fine tubular pores; 5 percent, medium, distinct, yellowish brown (10YR 5/6) iron masses, irregular, in the matrix around depletions, noncemented, diffuse; strongly effervescent; moderately alkaline (pH 8.0); abrupt wavy boundary.

Bk--55 to 102 centimeters (22 to 40 inches); pale brown (10YR 6/3) stratified silty clay to silty clay loam, brown (10YR 4/3) moist; moderate coarse subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; few very fine through coarse roots; few very fine and fine tubular pores; 15 percent, coarse, distinct, yellowish brown (10YR 5/6) iron masses, irregular, in the matrix around depletions, noncemented, diffuse; 1 percent, prominent, black (10YR 2/1) manganese coats, on all faces of peds; 3 percent, prominent, white (10YR 8/1) carbonate coats, on all faces of peds; strongly effervescent; moderately alkaline (pH 8.3); abrupt wavy boundary. (The combined thickness of the B horizons is 75 to 125 centimeters.)

2C--102 to 162 centimeters (40 to 64 inches); very pale brown (10YR 7/4) fine sand, yellowish brown (10YR 5/4) moist; single grain; loose, nonsticky and nonplastic; common very fine interstitial pores; 15 percent, coarse, distinct, yellowish brown (10YR 5/6) iron masses, irregular, in the matrix around depletions, noncemented, diffuse; very slightly effervescent or noneffervescent; moderately alkaline (pH 8.2).

TYPE LOCATION: San Bernardino County, California; about 15 kilometers north and 4 kilometers west of Needles California at the north end of Fort Mojave Indian Reservation; approximately 160 meters west and 325 meters south of Soto Ranch; un-sectionalized area 340 meters south and 200 meters west of the southeast corner of section 36, T. 11 N., R. 21 E.; USGS Needles NW, CA-AZ 7.5 minute topographic quadrangle; 34 degrees, 58 minutes, 46.9 seconds north latitude and 114 degrees, 39 minutes, 9.2 seconds west longitude; UTM 11S 714282e 3873308n; (DATUM: NAD83).

RANGE IN CHARACTERISTICS:

Soil moisture control section - usually dry, moist in some part for short periods during winter and early spring. The soils have a Typic-aridic moisture regime.

Soil temperature: 22 to 26 degrees C. (72 to 79 degrees F.)

Control section -
Rock fragments: 0 to 5 percent.
Clay content: 35 to 50 percent.

Ap horizon
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 or 3 dry, 2 through 4 moist.
Texture: Silty clay or silty clay loam
Effervescence: Strongly or violently effervescent.

B horizons
Hue: 10YR or 7.5YR.
Value: 4 through 6 dry, 3 or 4 moist.
Chroma: 2 through 4 moist.
Texture: Silty clay loam, silty clay or clay.
Structure: Weak or moderate, fine though very coarse.
Consistence: Moderately hard through very hard dry, friable through very firm moist, moderately sticky or very sticky and moderately plastic or very plastic wet.
Rock fragments: 0 to 5 percent.
Effervescence: Strongly or violently effervescent.
Reaction: Moderately alkaline with some pedons strongly alkaline in the lower part.
Other features: Some pedons have 0 to 5 percent gypsum coats on ped faces.

2C horizon
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 3 or 4 dry, 3, 4 or 6 moist.
Texture: Fine sand, loamy fine sand, loamy sand or sand.
Structure: Single grained or massive.
Consistence: Soft or loose dry, very friable or loose moist.
Rock fragments: 0 to 5 percent.
Effervescence: Noneffervescent through violently effervescent.
Reaction: Moderately alkaline or strongly alkaline.

COMPETING SERIES: There are no competing series. Similar soils are the Gadsden and Imperial series. Gadsden and Imperial soils are in the vertic subgroup and do not have a contrasting particle size at 100 to 150 centimeters.

GEOGRAPHIC SETTING: Sotoran soils are on stream terraces. Slopes range from 0 to 2 percent. These soils formed in alluvium derived from mixed sources. Elevations are 135 to 160 meters (450 to 525 feet). The climate is arid with warm, moist winters and hot, dry summers. The mean annual precipitation is 75 to 125 millimeters; mean annual air temperature is 20 to 24 degrees C., and the frost-free season is 340 to 360 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Gadsden and Kofa soils. Gadsden soils are fine textured to below 150 centimeters. Kofa soils have sand at depth of 50 to 100 centimeters.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained; medium runoff; saturated hydraulic conductivity is moderately low or low in the upper part and high in the lower part.

USE AND VEGETATION: Soils are under cultivation with alfalfa the principle crop.

DISTRIBUTION AND EXTENT: Mojave Desert of southeastern California, U.S.A.; MLRA 30. These soils are not extensive.

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

SERIES ESTABLISHED: Colorado Desert Area, California, San Bernardino, California, 2010 (Mojave Indian Reservation). The name is coined from Soto Ranch located one quarter of a mile to the north.

REMARKS: Diagnostic horizons and features recognized in the profile are:
Ochric epipedon - 0 to 18 centimeters (0 to 7 inches) (Part of the A horizon).
Particle-size control section - 25 to 100 centimeters (10 to 40 inches) (Part of the BA and Bk horizons).

Responsibility for this series was transferred from Davis to Phoenix 12/2015. The last revision to the series was 10/2012. ET

National Cooperative Soil Survey
U.S.A.