LOCATION WHIPP CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Natric Duraquolls
TYPICAL PEDON: Whipp silt loam--on a North facing slope of 1 percent under a cover of salt grass, one-spike oatgrass and bluegrass at an elevation of 3300 feet. (Colors are for moist soil unless stated otherwise. When described on 7/22/82 the soil was moist throughout below 2 inches).
E--0 to 1 inch; dark grayish brown (10YR 4/2) silt loam, light gray (10YR 7/1) dry; common fine prominent very dark grayish brown (10YR 3/2) moist, dark yellowish brown (10YR 4/4) dry redox concentrations; moderate thin platy structure; hard, friable, nonsticky and nonplastic; many very fine roots; many very fine tubular and common fine vesicular pores; neutral (pH 7.0); abrupt smooth boundary. (1 to 4 inches thick)
Bw--1 to 3 inches; very dark grayish brown (2.5Y 3/2) silty clay loam grayish brown (2.5Y 5/2) dry; common fine prominent very dark grayish brown (10YR 3/2) redox concentrations, dark yellowish brown (10YR 4/4) dry; moderate medium angular blocky structure; very hard, firm, slightly sticky and plastic; many very fine roots; many very fine and few fine and medium tubular pores; moderately alkaline (pH 8.0); abrupt smooth boundary. (2 to 5 inches thick)
Btn--3 to 11 inches; very grayish brown (2.5Y 3/2) silty clay, grayish brown (2.5Y 5/2) dry; moderate medium prismatic structure parting to strong fine subangular blocky; hard, friable, sticky and plastic; many very fine and few fine and medium roots; many very fine and few fine and medium tubular pores; few thin clay films in pores; slightly effervescent; strongly alkaline (pH 8.9); clear wavy boundary. (8 to 12 inches thick)
Btnk1--11 to 16 inches; dark grayish brown (2.5Y 4/2) silty clay, grayish brown (2.5Y 5/2) dry; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, friable, sticky and plastic; few very fine and fine roots; many very fine and fine tubular pores; many fine slickensides; many thin clay films on peds and few thin clay films in pores; very slightly effervescent; lime segregated in common fine irregular soft masses; very strongly alkaline (pH 9.8); clear wavy boundary.
Btkn2--16 to 22 inches; dark grayish brown (2.5Y 4/2) silty clay loam, grayish brown (2.5Y 5/2) dry; common fine prominent dark brown (10YR 3/3) redox concentrations, brown (10YR 5/3) dry; weak thin platy parting to weak fine subangular blocky structure; hard, friable, sticky and plastic; few very fine and fine roots; many very fine and fine tubular pores; many thin clay films on peds and common thin clay films in pores; slightly effervescent lime segregated in common fine irregular soft masses; very strongly alkaline (pH 9.8); abrupt smooth boundary. (Combined thickness of the Btk horizons are 11 to 15 inches)
Bqkm--22 to 25 inches; dark grayish brown (10YR 4/2) indurated duripan with 2mm thick indurated silica cap on the surface; thin platy structure; very hard, very firm; slightly effervescent; strongly alkaline (pH 8.5); clear wavy boundary. (2 to 5 inches thick)
Bqm--25 to 42 inches; dark yellowish brown (10YR 4/4) weakly cemented fine sandy loam, light yellowish brown (10YR 6/4) dry; common fine prominent olive brown (2.5Y 4/4) redox concentrations, light olive brown (2.5Y 5/6) dry; massive; slightly hard, friable, nonsticky and nonplastic; many very fine and medium tubular pores; neutral (pH 7.0); clear wavy boundary. (15 to 18 inches thick)
C--42 to 60 inches; dark yellowish brown (10YR 4/4) fine sandy loam, yellowish brown (10YR 5/4) dry; common fine prominent light olive brown (2.5Y 5/6) redox concentrations, olive brown (2.5Y 4/4) moist; massive; soft, very friable, nonsticky and nonplastic; many very fine and medium tubular pores; neutral (pH 7.0).
TYPE LOCATION: Shasta County, California; about 2 miles NW of McArthur in McArthur Swamp 300 feet N and 600 feet E of the SW corner of section 6, T.37 N., R.5 E. Fall River Mills SW (Fall River) Quadrangle (7.5 minute series)
RANGE IN CHARACTERISTICS: The mollic epipedon is 7 to 14 inches thick and includes the upper part of the natric horizon. Depth to the duripan is 20 to 40 inches. The mean annual soil temperature is 50 to 52 degrees F. The soil temperature exceeds 41 degrees F.from mid February to mid December (300 days) and exceeds 47 degrees F. from mid April to mid November. The soil moisture control section (6 to 19 inches) unless drained, is moist in some or all parts the whole year. Unless drained, these soils are saturated from September to April due to a perched water table.
The E horizon color is 10YR 6/1, 6/2 or 7/1. Moist color is 10YR 3/2, 4/2 or 5/3. Clay content is 20 to 25 percent. Organic matter is 0.5 to 1 percent and when mixed with the underlying horizon to at least 7 inches, organic matter is greater than 1 percent. Reaction is neutral to moderately alkaline. The electrical conductivity is 0 to 1 mmhos/cm and sodium absorption ratio is 5 to 15.
The Bw horizon color is 2.5Y 5/1 or 5/2. Moist color is 2.5Y 3/1 or 3/2. It is silt loam or silty clay loam with 25 to 30 percent clay. Organic matter is 2 to 4 percent. Reaction is moderately alkaline or strongly alkaline. The electrical conductivity is 0.5 to 1 mmhos/cm and sodium absorption ration is 10 to 15.
The Btn horizon color is 2.5Y or 5Y 5/1 or 5/2. Moist color is 2.5Y or 5Y 3/1, 3/2, or 4/2. Clay content is 40 to 60 percent. Organic matter is 1 to 2 percent. Reaction is strongly alkaline or very strongly alkaline. The electrical conductivity is 0.8 to 2 mmhos/cm and sodium absorption ration is 15 to 25.
The Btk horizon color is 2.5Y or 5Y 5/2 or 6/1. Moist color is 2.5Y or 5Y 3/2 or 4/2 moist. Clay content is 35 to 40 percent. Calcium carbonate equivalent ranges from 2 to 15 percent. Reaction is strongly alkaline to very strongly alkaline.
The Bqkm horizon has a indurated silica capping 1/8 to 1 inch thick with a calcium carbonate equivalent ranging from 30 to 50 percent. The underlying material of the horizon has a calcium carbonate equivalent of 0.5 to 2 percent. Reaction is strongly alkaline to very strongly alkaline. The electrical conductivity is 1 to 2 mmhos/cm and sodium absorption ratio is 15 to 20.
The Bqm and C horizons reaction is neutral to moderately alkaline.
COMPETING SERIES: This is the Scherrard (CA) soil. The Scherrard soil has mollic epipedons that do not include part of the natric horizon.
GEOGRAPHIC SETTING: Whipp soils are in basins. Slopes are 0 to 2 percent. These soils formed in mixed alluvium. Elevation is 3300 to 4200 feet. The climate is subhumid with warm dry summers and cold moist winters. Mean annual precipitation is 14 to 20 inches. Snowfall is 24 to 36 inches. The mean annual temperature varies from 48 to 52 degrees F. Frost-free season is 100 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dudgen (T), Graven (T) and Cupvar (T) soils. Dudgen soils are on intermounds on terraces, 10 to 20 inches deep, and moderately well drained. Graven soils are on mounds on terraces, well drained, and noncalcareous. Cupvar soils are on similar landscape positions and have a petrocalcic horizon.
DRAINAGE AND PERMEABILITY: Poorly drained; ponded to slow runoff; slow permeability. A water table occurs at a depth of 20 to 40 inches from June through September and is perched above the duripan to the surface from November to April.
USE AND VEGETATION: These soils are mainly used for livestock grazing. Soils are cropped to pasture and grain. The natural vegetation is salt grass, one-spike oatgrass and bluegrass.
DISTRIBUTION AND EXTENT: Modoc Plateau basin area, Northeastern California. The soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Shasta County, Intermountain Soil Survey Area California, 1994. Source of name is from
Whipple Springs.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
A. Mollic epipedon: 0 to 11 inches ( E, Bw, Btn).
1. Organic matter by Walkley-Black ranges from 0.5 to 4 percent. 2. Base saturation by Hach Kit ranges from 95 to 100 percent.
B. Natric horizon: 3 to 22 inches (Btn, Btkn1, Btk2).
1. SAR by Lincoln Lab is 19 to 25. 2. EC is less than 2 mmhos/cm. 3. Clay content averages 40 to 60 percent.
C. Duripan: 22 to 24 inches (Bqkm) ranges from 2 to 5 inches thick.
1. Indurated duripan with continuous 2 mm thick silica capping. 2. Slightly effervescent. 3. Strongly alkaline.
ADDITIONAL DATA: Grab samples (Btk1, Btk2) were ran by the Lincoln Lab sample numbers 837106 and 837107.