LOCATION ELCAPITAN               CA

Established Series
Rev: AJT/JJJ/BRY/KDA/KP
01/2023

ELCAPITAN SERIES

The Elcapitan series consists of very deep, somewhat poorly drained soils formed in stream alluvium weathered from granitoid rock and reworked lake sediments. Elcapitan soils are on relict point bars, well defined bars and channels, scour channels, abandoned channels with year-round pools, intermediate flood plains, in mountain valleys. Slope is 0 to 2 percent. The mean annual precipitation is about 37 inches (940 millimeters) and the mean annual temperature is about 53 degrees F (11.7 degrees C).

TAXONOMIC CLASS: Coarse-loamy, isotic, mesic Vitrandic Dystroxerepts

TYPICAL PEDON: Elcapitan fine sandy loam, on a 0 to 2 percent slope under meadow grasses and forbs at an elevation of 3,963 feet (1,207.9 meters). (Colors are for dry soil unless otherwise stated. When described on May 14, 1991, the soil was moist throughout.)

Oi--0 to 1 inch (0 to 3 centimeters); slightly decomposed organic material.

A--1 to 7 inches; (3 to 18 centimeters); stratified grayish brown (10YR 5/2), light brownish gray (10YR 6/2), and brown (10YR 5/3) fine sandy loam, very dark grayish brown (10YR 3/2), brown (10YR 4/3), and dark brown (10YR 3/3) moist; weak fine granular structure; soft, very friable, non-sticky, non-plastic; many very fine roots; moderately acid (pH 5.8); abrupt smooth boundary. (4 to 8 inches [10 to 20 centimeters] thick)

2Ab1--7 to 12 inches (18 to 31 centimeters); dark grayish brown (10YR 4/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; moderate medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky, non-plastic; weakly smeary; many very fine roots; moderately acid (pH 5.8); clear smooth boundary. (4 to 6 inches [10 to 15 centimeters] thick)

2Ab2--12 to 20 inches (31 to 51 centimeters); dark grayish brown (10YR 4/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; very dark brown (10YR 2/2) coatings on faces of peds; moderate coarse subangular blocky structure; slightly hard, friable, slightly sticky, non-plastic weakly smeary; common very fine roots; moderately acid (pH 5.8); clear smooth boundary. (6 to 10 inches [15 to 25 centimeters] thick)

2Ab3--20 to 31 inches (51 to 79 centimeters); brown (10YR 5/3) fine sandy loam, dark brown (10YR 3/3) moist; massive; slightly hard, friable, slightly sticky, non-plastic; weakly smeary; few very fine roots; moderately acid (pH 5.8); clear smooth boundary. (8 to 12 inches [20 to 30 centimeters] thick)

2Ab4--31 to 38 inches (79 to 97 centimeters); grayish brown (10YR 5/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; massive; soft, very friable, non-sticky, non-plastic; few very fine roots; charcoal; moderately acid (pH 5.8); abrupt smooth boundary. (5 to 10 inches [13 to 25 centimeters] thick)

3C--38 to 44 inches (97 to 112 centimeters) stratified light brownish gray (10YR 6/2) loamy sand and white (10YR 8/1) sand, very dark grayish brown (10YR 3/2) and light brownish gray (10YR 6/2) moist; common medium distinct strong brown (7.5YR 4/6) moist; masses of iron accumulation; massive; soft, very friable, non-sticky, non-plastic and loose, non-sticky, non-plastic; moderately acid (pH 5.8); abrupt smooth boundary. (4 to 6 inches [10 to 15 centimeters] thick)

3Ab--44 to 47 inches (112 to 120 centimeters) brown (10YR 5/3) loamy sand, dark brown (10YR 3/3) moist; massive; loose, non-sticky, non-plastic; moderately acid (pH 5.8); abrupt smooth boundary. (2 to 6 inches [5 to 15 centimeters] thick)

3C'--47 to 53 inches (120 to 135 centimeters) white (10YR 8/1), light gray (10YR 7/2) and black (10YR 2/1) coarse sand, 45 percent light brownish gray (10YR 6/2), 45 percent grayish brown (10YR 5/2) and 10 percent black (10YR 2/1) moist; massive; loose, non-sticky, non-plastic; moderately acid (pH 5.8); abrupt smooth boundary. (4 to 8 inches [10 to 20 centimeters] thick)

3Ab1--53 to 58 inches (135 to 148 centimeters) grayish brown (10YR 5/2) loamy coarse sand, very dark grayish brown (10YR 3/2) moist; massive; soft, very friable, non-sticky, non-plastic; moderately acid (pH 5.8); abrupt smooth boundary. (4 to 7 inches [10 to 18 centimeters] thick)

3Ab2--58 to 60 inches (148 to 152 centimeters) very pale brown (10YR 8/2) and very pale brown (10YR 7/3) loamy sand, 85 percent light gray (10YR 7/2) and 15 percent grayish brown (10YR 5/2) moist; massive; soft, very friable, non-sticky, non-plastic; moderately acid (pH 5.8).

TYPE LOCATION: Mariposa County, California; 900 feet (274.3 meters) northwest of Sentinel Chapel, Sentinel Meadow, Yosemite National Park, Yosemite Valley; Latitude 37 degrees 44 minutes 29 seconds north and Longitude 119 degrees 35 minutes 37 seconds west; UTM Zone 11, easting 271479.64 and northing 4180284.21; USGS Half Dome, California Quadrangle, NAD 83.

RANGE IN CHARACTERISTICS: Depth of the solum is more than 60 inches (152 centimeters). The mean annual soil temperature is 52 to 56 degrees F (11.1 to 13.3 degrees C). The soil temperature exceeds 41 degrees F (5.0 degrees C) from March through November and exceeds 47 degrees F (8.3 degrees C) from mid April through October. The difference between mean winter and mean summer soil temperature is about 28 degrees F (15.0 degrees C) The soil moisture control section is dry in all parts from early July to early November (140-160 days) and is moist in all parts from December to mid May. Base saturation is less than 50 percent. Rock fragment content is 0 to 3 percent.

A Horizon
Hue: 10YR (dry and moist)
Value: 5 or 6 (dry) and 3 or 4 (moist)
Chroma: 2 or 3 (dry and moist)
Texture: stratified sandy loam to mucky loam
Clay content: 2 to 18 percent
Organic matter content: 1 to 5 percent
Reaction: moderately acid

2Ab Horizon
Hue: 10YR (dry and moist)
Value: 4 to 8 (dry) and 2 to 7 (moist)
Chroma: 2 to 3 (dry) and 2 (moist)
Texture: stratified sandy loam to mucky loam
Clay content: 2 to 18 percent
Organic matter content: 1.5 to 5 percent
Reaction: moderately acid

3C Horizon
Hue: 10YR or 7.5YR (dry and moist)
Value: 2 to 8 (dry) and 2 to 6 (moist)
Chroma: 1 or 2 (dry) and 1 to 6 (moist)
Texture: stratified sand to loam
Clay content: 2 to 18 percent
Organic matter content: 1 to 5 percent
Reaction: moderately acid

COMPETING SERIES: These are the Leidig and Sentinel soils. Leidig are on high floodplains and do not have well defined stratification. Sentinel soils are on lake terraces and are well drained.

GEOGRAPHIC SETTING: Elcapitan soils are on relict point bars, well defined bars and channels, scour channels, abandoned channels with year-round pools, and intermediate flood plains in mountain valleys. Slope is 0 to 2 percent. These soils formed in stream alluvium from granitoid rock and reworked lake deposits. Elevation is 3,873 to 4,027 feet (1,180.4 to 1,227.5 meters). The climate is subhumid with warm, dry summer and cool, moist winters. Mean annual precipitation is 35 to 40 inches (889 to 1,016 millimeters), some of which falls as snow. The mean annual temperature is 50 to 55 degrees F (10.0 to 12.8 degrees C). The mean January temperature is about 36 degrees F (2.2 degrees C). The mean July temperature is about 72 degrees F (22.2 degrees C). The frost-free period is 100 to 150 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Leidig and Sentinel soils.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained; very low runoff; saturated hydraulic conductivity is high or very high. Occasional flooding occurs for long periods from November through June.

USE AND VEGETATION: This soil is used for recreation, wildlife, and watershed. This soil is capable of supporting both meadow and woodland plant communities. Encroachment of woodland species, particularly, Ponderosa pine and incense cedar, increases the rate of summer drawdown so that an anaerobic hydrology is supplanted by an aerobic hydrology culminating in the development of an open canopy woodland plant community with an understory of grasses and forbs. The degree to which soil water is aerated is also influenced by the lateral, subsoil flow of aerated water into the floodplain soil from both up-valley and side-valley sources.

DISTRIBUTION AND EXTENT: West side of the central Sierra Nevada Range, California. The soils are not extensive. MLRA is 22A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Yosemite Valley Part, California 1991. Source of name is El Capitan glacial escarpment.

REMARKS: All lab data from similar soils in the Yosemite Valley Part Soil Survey indicates isotic mineralogy. Elcapitan soils have an umbric epipedon, a cambic horizon and vitrandic properties.

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National Cooperative Soil Survey
U.S.A.