LOCATION TAHOE CA NVEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, acid, frigid Cumulic Humaquepts
TYPICAL PEDON: Tahoe mucky silt loam on a 0 percent slope at an elevation of 2158 meters. When described on 07/10/2003 the soil was moist throughout. Colors are for moist soils unless otherwise noted.
Oe--0 to 8 cm; moderately decomposed plant material; abrupt smooth boundary. (0 to 13 cm thick)
A1--8 to 28 cm; mucky silt loam, black (10YR 2/1) rubbed moist; 13 percent clay; weak fine subangular blocky and moderate fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine through medium roots throughout; 2 percent strong brown (7.5YR 5/6), moist, masses of oxidized iron; slightly acid, pH 6.2 by Bromthymol blue; abrupt smooth boundary.
A2--28 to 38 cm; mucky silt loam, very dark grayish brown (10YR 3/2) rubbed moist; 13 percent clay; moderate medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine and many medium roots throughout; common very fine tubular pores; 5 percent dark red (2.5YR 3/6), moist, masses of oxidized iron; slightly acid, pH 6.4 by Bromthymol blue; abrupt smooth boundary.
A3--38 to 51 cm; gravelly coarse sand, very dark grayish brown (10YR 3/2) rubbed moist; 95 percent sand; structureless single grain; loose, loose, nonsticky and nonplastic; common fine and medium roots throughout; many fine interstitial pores; 3 percent gravel 5 to 75 millimeter and 30 percent gravel 2 to 5 millimeter; neutral, pH 7.2 by Bromthymol blue; abrupt smooth boundary.
A4--51 to 76 cm; mucky silt loam, black (10YR 2/1) rubbed moist; 13 percent clay; moderate medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common fine and very fine roots throughout; neutral, pH 7.0 by Bromthymol blue; abrupt smooth boundary. (the combined thickness of the A horizons is 60 to 100 cm thick)
Cg1--76 to 125 cm; loam, dark grayish brown (10YR 4/2) rubbed moist; 44 percent sand; 10 percent clay; massive; slightly hard, nonsticky, nonplastic; 2 percent olive gray (5Y 5/2), moist, masses of reduced iron and 15 percent yellowish red (5YR 5/6), moist, masses of oxidized iron; 2 percent gravel 2 to 5 millimeter; neutral, pH 7.0 by Bromthymol blue.
Cg2--125 to 150 cm; loamy sand, dark grayish brown (10YR 4/2) rubbed moist; massive; nonsticky and nonplastic; 2 percent yellowish red (5YR 5/6), moist, masses of oxidized iron; 3 percent gravel 2 to 5 millimeter; neutral, pH 7.0 by Bromthymol blue.
TYPE LOCATION: El Dorado County, California, Inside the bend of highway 89 in the meadow on Big Meadow Creek., 480 meters west and 92 meters south of the northeast corner of Section 20, Township 11N, Range 18E, 38 degrees, 47 minutes, 29 seconds North latitude and 120 degrees, 0 minutes, 32 seconds West longitude, NAD83 - U.S.G.S Quad: Echo Lake, California.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil is usually moist throughout. The surface horizons occasionally dry out in late summer and early fall as the water table drops to between 76 to 203 cm. The soils have an aquic moisture regime.
Water features:
Seasonal high water table: 0 to 25 cm.
Flooding: Frequent
Ponding: Frequent
Reaction: strongly acid to neutral
Base saturation: Is very low (less than 10) when the influence of the andesitic lahar is strong and as high as 60 in the lower horizons when the influence of the granodiorite is stronger. The A horizons have a base saturation of less than 50 percent. (base saturation by ammonium acetate)
Depth to redoximorphic features: 0 to 50 cm, typically in the first mineral horizon.
Control section: 25 to 100 cm
Rock fragments: 0 to 35 percent, with 0 to 35 percent gravel, predominantly 2 to 5 millimeters.
Clay content: averages 8 to 18 percent clay
Mineralogy: mixed
A horizons:
Hue: 10YR
Value: 2 or 3 moist
Chroma: 1 through 3 moist
Organic matter: 5 to 20 percent
Redoximorphic features: Masses of oxidized iron
Hue: 2.5YR, 5YR, 7.5YR or 10YR
Value: 3 through 6
Chroma: 4 through 8
Texture of the fine earth fraction: Sandy loam, loam, or silt loam, thin horizons of higher energy material such as the A3 horizon can have textures of coarse sand or sand with small gravels.
Clay content: 0 to 25 percent (typically less than 5 in the higher energy horizons such as the A3)
Cg horizons:
Hue: 10YR
Value: 4 through 6 moist
Chroma: 2 through 4 moist
Organic matter: 0.25 to 5 percent
Redoximorphic features: Masses of oxidized iron, masses of reduced iron
Texture of the fine earth fraction: Coarse sand, loamy sand, loamy fine sand, fine sand or loam
Clay content: 0 to 15 percent
Rock fragments: 0 to 35 percent
0 to 35 percent gravel
COMPETING SERIES: There are no other series in this family at this time.
GEOGRAPHIC SETTING: The Tahoe soils are on flood plains. Slopes range from 0 to 5 percent. These soils formed in alluvium derived from mixed sources. The headwaters of these areas are predominantly granodiorite and andesitic lahar. Elevation is 1888 to 2431 meters. The climate is subhumid with warm dry summers and cold wet winters. The mean annual precipitation is 483 to 1700 millimeters and the mean annual air temperature is 5 to 8 degrees C. The frost free season is 20 to 60 days. Snotel data has shown that some of these areas are subject to cold air drainage.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Marla and Watah soils. Marla soils are poorly drained and are slightly higher on the landscape typically with lodgepole pine vegetation. Watah soils have a histic epipedon.
DRAINAGE AND PERMEABILITY: Very poorly drained, moderately slow to rapid permeability, very high runoff in concave areas and very high in non-concave areas. Frequent flooding for long duration during spring snow melt, frequent ponding for long duration during spring snow melt.
USE AND VEGETATION: This soil is used for wildlife and grazing. Vegetation is willows, sedges and rushes.
DISTRIBUTION AND EXTENT: Tahoe soils are of moderate extent in California and Nevada in MLRA 22A -- Sierra Nevada Mountains
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: El Dorado County, (Tahoe Basin area), California. Source of name from Lake Tahoe.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle Size Control Section for this pedon: 33 to 108 cm (the A1 through A4 horizons and part of the Cg1)
Aquic Conditions 0 to 150 cm (all the horizons)
Redox Concentrations 8 to 150 cm (all horizons but the Oe)
Umbric Epipedon 8 to 76 cm (the A1 through A4 horizons)