LOCATION EPOT CAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Typic Natrargids
TYPICAL PEDON: Epot very fine sandy loam--on a 1 percent slope under shadscale, bud sagebrush, and annual forbs at 4,010 feet elevation--rangeland. (Colors are for dry soil unless otherwise noted. When described on August 2, 1983, the soil was dry throughout.) The soil surface is composed of polygonal cracks 6 inches by 8 inches with a microbiotic crust of lichens growing on it.
An--0 to 6 inches; light gray (2.5Y 7/2) very fine sandy loam, dark grayish brown (2.5Y 4/2) moist; moderate thin and medium platy structure; hard, very friable, slightly sticky and slightly plastic; few very fine roots; many very fine interstitial pores; strongly effervescent; SAR is 18; E.C. is 4 mmhos/cm; moderately alkaline (pH 8.0); clear wavy boundary. (3 to 6 inches thick)
En--6 to 13 inches; very pale brown (10YR 7/3) loam, yellowish brown (10YR 5/4) moist; weak medium prismatic structure parting to moderate very fine subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; common very fine tubular pores; violently effervescent; SAR is 13; E.C. is 3 mmhos/cm; strongly alkaline (pH 8.5); clear wavy boundary. (2 to 7 inches thick)
Btkn--13 to 21 inches; light gray (2.5Y 7/2) clay loam, yellowish brown (10YR 5/4) moist; moderate medium angular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine and few fine and medium roots; few very fine tubular pores; common faint clay films on faces of peds; secondary carbonates segregated in common fine masses; violently effervescent; SAR is 44; E.C. is 5 mmhos/cm; strongly alkaline (pH 8.5); abrupt wavy boundary.
Btknz--21 to 26 inches; light gray (2.5Y 7/2) clay loam, brown (10YR 5/3) moist; moderate medium prismatic structure parting to moderate fine angular blocky; hard, friable, moderately sticky and moderately plastic; few fine and medium roots; common very fine tubular pores; many faint clay films on faces of peds and few distinct clay films lining pores; secondary carbonates segregated in common fine and medium masses; violently effervescent; SAR is 88; E.C. is 10 mmhos/cm; strongly alkaline (pH 8.5); clear wavy boundary. (The combined thickness of the Bt horizons is 8 to 18 inches)
BCnz--26 to 35 inches; light gray (2.5Y 7/2) clay loam, olive (5Y 5/3) moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and moderately plastic; few very fine roots; few very fine tubular pores; many fine distinct brownish yellow (10YR 6/6) masses of iron accumulation which are relict redoximorphic features, dark yellowish brown (10YR 4/4) moist; violently effervescent; SAR is 61; E.C. is 25 mmhos/cm; strongly alkaline (pH 8.5); clear wavy boundary. (5 to 10 inches thick)
Cynz1--35 to 42 inches; light gray (2.5Y 7/2) loam, olive (5Y 5/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; common very fine tubular pores; few fine filaments of secondary gypsum and soluble sodium salts; SAR is 66; E.C. is 29 mmhos/cm; violently effervescent; strongly alkaline (pH 8.5); abrupt smooth boundary.
Cynz2--42 to 48 inches; light gray (2.5Y 7/2) clay loam, olive brown (2.5Y 4/3) moist; massive; slightly hard, very friable, slightly sticky and moderately plastic; few very fine roots; common very fine tubular pores; common 0.5 mm ostracod shells; few fine filaments of secondary gypsum and soluble sodium salts; violently effervescent; SAR is 73; E.C. is 32 mmhos/cm; strongly alkaline (pH 8.5); abrupt smooth boundary. (The combined thickness of the Cynz horizons is 12 to 24 inches)
2Cnz--48 to 63 inches; pale yellow (5Y 8/2) stratified fine sand and very fine sand, olive (5Y 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; many very fine interstitial pores; many 0.5 mm ostracod shells; slightly effervescent; SAR is 38; E.C. is 16 mmhos/cm; strongly alkaline (pH 8.5).
TYPE LOCATION: Lassen County, California; in the Honey Lake Valley about 2.3 miles east of the Sierra Army Depot and 1.8 miles west of the California-Nevada state line; 0.5 miles west of Calneva Lake and 0.5 miles southeast along trail from its intersection with east-west trail; 2,000 feet east and 2,100 feet south of the projected northwest corner of section 26, T. 27 N., R. 17 E.; USGS Calneva Lake 7.5 minute topographic quadrangle; 40 degrees 09 minutes 59 seconds north latitude and 120 degrees 01 minute 49 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - These soils are moist in all parts of the moisture control section from December 15 to March 15 and dry in all parts from April 15 to November 15 (215 days); typic aridic moisture regime.
Mean annual soil temperature - 53 to 56 degrees F.; The soil temperature exceeds 41 degrees F. from March 1 to December 1 (275 days) and exceeds 47 degrees F. from April 15 to November 15.
Ochric epipedon thickness - 5 to 13 inches.
Depth to base of natric horizon - 13 to 27 inches.
Particle-size control section - Clay content: 27 to 35 percent; Fine sand or coarser content: 10 to 15 percent sand coarser than very fine sand.
An and En horizons - Hue: 10YR or 2.5Y.
Value: 6 through 8 dry, 4 or 5 moist.
Chroma: 2 or 3 dry, 2 through 4 moist.
Reaction: Moderately alkaline or strongly alkaline.
Salinity (EC): 2 to 4 mmhos/cm.
Sodicity (SAR): 8 to 20.
Btn horizons - Hue: 10YR or 2.5Y.
Value: 6 through 8 dry, 4 or 5 moist.
Chroma: 2 through 4 dry, 3 or 4 moist.
Texture: Clay loam or silty clay loam.
Salinity (EC): 4 to 32 mmhos/cm.
Sodicity (SAR): 40 to 120.
Calcium carbonate equivalent: 10 to 15 percent.
BC, Cy, and 2C horizons - Hue: 2.5Y or 5Y.
Value: 7 or 8 dry, 4 through 6 moist.
Chroma: 2 or 3, dry or moist.
Texture: Stratified sand, very fine sand, fine sandy loam, and clay loam.
Effervescence: Slightly effervescent through violently effervescent.
Salinity (EC): 16 to 32 mmhos/cm.
Sodicity (SAR): 20 to 80.
Gypsum content: 0 to 1 percent.
COMPETING SERIES: There are currently no other series in this family.
GEOGRAPHIC SETTING: Epot soils are on lakebeds. They formed in lacustrine deposits derived from mixed sources and influenced with small amounts of loess. Slopes are 0 to 2 percent. Elevation ranges from 3,995 to 4,015 feet. The climate is arid with cool, moist winters and warm, dry summers. The mean annual precipitation is 6 to 8 inches, mean annual temperature is 49 to 52 degrees F., and the frost-free period is 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ardep and Ragtown soils. Ardep soils are coarse-loamy, have calcic horizons, and have B horizons with 20 to 50 percent durinodes. Ragtown soils are fine, have ochric epipedons, and do not have diagnostic subsurface horizons.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; slow permeability.
USE AND VEGETATION: Epot soils are used for rangeland. The vegetation is mainly shadscale, bud sagebrush, and bottlebrush squirreltail.
DISTRIBUTION AND EXTENT: Northeastern California. These soils are moderately extensive. MLRA 27.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Lassen County (Susanville Area Soil Survey), California, 2000.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 13 inches (An and En horizons).
Natric horizon - The zone from 13 to 26 inches (Btkn and Btknz horizons).
Identifiable secondary carbonates - The zone from 13 to 26 inches (Btkn and Btknz horizons).
Particle-size control section - The zone from 13 to 26 inches (Btkn and Btknz horizons).
ADDITIONAL DATA: The typical pedon at the series type location has full characterization by the Soil Survey Laboratory (SSL), Lincoln, NE, as soil survey sample number S84CA-035-006 (pedon # 84P0753). Another pedon is reference sampled as soil survey sample number S86CA-035-004 (pedon # 86P0487).