LOCATION CHAPPUIS CA+NVEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Xeric Natrargids
TYPICAL PEDON: Chappuis silt loam--on a nearly level lake terrace under black greasewood, basin big sagebrush, and inland saltgrass at 4,060 feet elevation--rangeland. (Colors are for dry soil unless otherwise noted. When described on August 24, 1983, the soil was dry to a depth of 30 inches and slightly moist below).
A1--0 to 4 inches; pale brown (10YR 6/3) silt loam, dark brown (10YR 3/3) moist; moderate coarse prismatic structure parting to moderate thin platy; slightly hard, very friable, slightly sticky and slightly plastic; few very fine and common medium roots; many very fine tubular pores; violently effervescent; slightly alkaline (pH 7.8); abrupt smooth boundary.
A2--4 to 10 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; moderate thick platy structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine, many medium roots; many very fine tubular pores; moderately alkaline (pH 8.0); abrupt smooth boundary. (Combined thickness of the A horizons is 3 to 11 inches)
Btnk1--10 to 13 inches; brown (10YR 5/3) silty clay, dark brown (10YR 3/3) moist; strong medium columnar structure parting to strong fine angular blocky; very hard, friable, moderately sticky and moderately plastic; common very fine roots; many very fine tubular pores; common faint clay films on faces of peds; noneffervescent within peds and strongly effervescent on masses; secondary carbonates segregated in masses on faces of peds; SAR is 28; EC is 1 mmhos/cm; moderately alkaline (pH 8.2); clear smooth boundary.
Btnk2--13 to 19 inches; brown (10YR 5/3) silty clay, dark yellowish brown (10YR 3/4) moist; strong fine angular blocky structure; very hard, friable, moderately sticky and moderately plastic; common very fine roots; many very fine tubular pores; common faint clay films on faces of peds; noneffervescent within peds and strongly effervescent on masses; secondary carbonates segregated in masses on faces of peds; SAR is 46; EC is 3 mmhos/cm; moderately alkaline (pH 8.2); clear smooth boundary. (Combined thickness of the Btnk horizons is 8 to 18 inches)
Bkqnz--19 to 25 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine tubular pores; few faint clay films on faces of peds and lining pores; 15 percent hard firm durinodes; violently effervescent; secondary carbonates segregated in common medium irregular seams; SAR is 45; EC is 30 mmhos/cm; moderately alkaline (pH 8.2); clear smooth boundary. (6 to 10 inches thick)
Cnz1--25 to 38 inches; light yellowish brown (2.5Y 6/4) silt loam, brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine and very fine roots; many very fine tubular pores; strongly effervescent; SAR is 45; EC is 30 mmhos/cm; moderately alkaline (pH 8.2); clear wavy boundary.
Cnz2--38 to 49 inches; light brownish gray (2.5Y 6/2) silt loam, brown (10YR 4/3) moist; massive; hard, firm, slightly sticky and slightly plastic; few very fine roots; many very fine tubular pores; texture has a gritty feeling; common fine faint dark yellowish brown (10YR 3/4) moist masses of iron accumulation; strongly effervescent; SAR is 40; EC is 31 mmhos/cm; moderately alkaline (pH 8.0); clear wavy boundary.
Cnz3--49 to 60 inches; light gray (2.5Y 7/2) silt loam, brown (10YR 4/3) moist; massive; hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine tubular pores; common fine faint dark yellowish brown (10YR 4/4) and common fine distinct dark yellowish brown (10YR 4/6) moist masses of iron accumulation; strongly effervescent; SAR is 70; EC is 30 mmhos/cm; moderately alkaline (pH 8.0).
TYPE LOCATION: Lassen County, California; in Honey Lake Valley about 3 miles northwest of Standish; 40 feet south and 40 west of the southwest fence corner at the intersection of Chappuis Lane and Center Road; 2,600 feet north and 50 feet west of the southeast corner of section 1, T. 29 N., R. 13 E.; USGS Litchfield 7.5 minute topographic quadrangle; 40 degrees 24 minutes 03 seconds north latitude and 120 degrees 27 minutes 15 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - The moisture control section (6 to 18 inches) is dry throughout from mid June to mid November for about 150 to 160 days and moist throughout from December 1 through April 15. The soil temperature exceeds 47 degrees F. from April 15 to November 15; Typic aridic moisture regime.
Mean annual soil temperature - 53 to 56 degrees F.
Ochric epipedon thickness - 3 to 11 inches.
Depth to base of natric horizon - 13 to 20 inches.
Depth to identifiable secondary carbonates - 3 to 15 inches.
Particle-size control section - Clay content: 35 to 50 percent; Sand content: 2 to 10 percent.
A horizons - Dry color: 2.5YR 6/2; 10YR 6/2, 5/3, or 6/3.
Moist color: 2.5Y 4/2; 10YR 3/3, 4/2, or 4/3.
Texture: Silt loam, silty clay loam, sandy loam, or coarse sandy loam.
Reaction: Slightly alkaline or moderately alkaline.
Btnk horizons - Dry color: 10YR 5/3 or 6/3.
Moist color: 10YR 3/2, 3/3, 3/4, or 4/3.
Texture: Silty clay or silty clay loam.
Clay content: 35 to 50 percent.
Sand content: 2 to 10 percent.
Salinity (EC): 2 to 8 mmhos/cm.
Sodicity (SAR): 20 to 50.
Reaction: Moderately alkaline or strongly alkaline.
Calcium carbonate equivalent: 1 to 3 percent.
Bkqnz horizon - Dry color: 10YR 6/3, 2.5Y 7/2 or 2.5Y 6/4.
Moist color: 10YR 4/3, 4/4; 2.5Y 5/2, 4/2, or 4/4.
Texture: Loam, silt loam, or silty clay loam.
Clay content: 20 to 30 percent.
Durinodes: 5 to 20 percent.
Salinity (EC): 2 to 32 mmhos/cm.
Sodicity (SAR): 30 to 60.
Reaction: Moderately alkaline or strongly alkaline.
Calcium carbonate equivalent: 3 to 6 percent.
Other features: Some pedons have segregated gypsum below 30 inches or a Bk horizon below the Bkqnz horizon.
Cnz horizons - Dry color: 2.5Y 6/2, 6/4, 7/2; 10YR 6/2, 6/3, or 6/4.
Moist color: 2.5Y 4/2, 4/4, 5/4; 10YR 4/3 or 4/4.
Texture: Silt loam, very fine sandy loam, loam, or silty clay loam.
Clay content: 15 to 30 percent.
Rock fragments: 0 to 15 percent gravel.
Salinity (EC): 16 to 35 mmhos/cm.
Sodicity (SAR): 30 to 100.
Reaction: Moderately alkaline or strongly alkaline.
Redoximorphic features: Redox concentrations occur as few or common, faint or distinct masses of iron accumulation.
COMPETING SERIES: These are the Couch, Kiesel, Longdis, Owinza, Standish, and Tomera series.
Couch soils have lithologic discontinuities to 2C horizon within 22 inches of the soil surface, very strongly alkaline Btn horizons, mean annual soil temperature of 47 to 52 degrees F., and do not have durinodes. Kiesel soils do not have durinodes, are very strongly alkaline, do not have identifiable secondary carbonates in the natric horizon, and have endosaturation at depths of 3 to 4 feet from April through June. Longdis soils have mean annual soil temperature of 47 to 51 degrees F. Owinza soils have calcic horizons, do not have durinodes, and do not have redoximorphic features or endosaturation within 60 inches of the soil surface. Standish soils average 30 to 50 percent total sand in the particle-size control section with texture of clay or sandy clay. Tomera soils have gravelly natric horizons, are noneffervescent to depths of 15 to 30 inches, and have depth to base of the natric horizon of 30 to 42 inches.
GEOGRAPHIC SETTING: Chappuis soils are on lake terraces. These soils formed in lacustrine deposits derived from mixed igneous rocks such as basalt and granodiorite. Slopes are 0 to 2 percent. Elevation ranges from 3,980 to 4,100 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 7 to 12 inches including 20 to 40 inches of snow. The mean annual temperature is 49 to 52 degrees F. The frost-free period is 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Humboldt, Smocreek, Susanville, and Wespac soils. Humboldt, Smocreek and Susanville soils have mollic epipedons and are on flood plains and stream terraces. Wespac soils are fine-loamy.
DRAINAGE AND PERMEABILITY: Moderately well drained; high surface runoff; slow permeability. Endosaturation is present with an apparent seasonal high water table between 4.0 and 5.0 feet (deep free water occurrence class) from January through April. Cumulative annual duration class is Common.
USE AND VEGETATION: Chappuis soils are used as rangeland. The vegetation is basin big sagebrush, black greasewood, basin wildrye, and inland saltgrass.
DISTRIBUTION AND EXTENT: Northeastern California and northwestern Nevada. These soils are not extensive with about 3,900 acres of the series mapped to date. The series concept and main acreage is in MLRA 23, while other acreage occurs in MLRA 26.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Washoe County (Central Part), Nevada, 1990. The series was proposed from the Susanville Area Soil Survey, California in 1985. The type location is currently in this survey area.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 10 inches (A1 and A2 horizons).
Natric horizon - The zone from 10 to 19 inches (Btnk1 and Btnk2 horizons).
Identifiable secondary carbonates - The zone from 10 to 25 inches (Btnk1, Btnk2, and Bkqnz horizons).
Durinodes - The zone from 19 to 25 inches (Bkqnz horizon).
Endosaturation feature - The condition of ground water with an upper boundary between 50 and 60 inches at certain times during normal years (part of the Cnz3 horizon).
Particle-size control section - The zone from 10 to 19 inches (Btnk1 and Btnk2 horizons).