LOCATION LEDMOUNT                CA

Established Series
FOS/CEJ/AGB/JTW
12/2018

LEDMOUNT SERIES

The Ledmount series consists of shallow, well to somewhat excessively drained soils formed in material weathered from andesitic tuff breccia. These soils are on mountains and have slopes of 2 to 75 percent. The mean annual precipitation is 1345 mm and the mean annual air temperature is 11 degrees C.

TAXONOMIC CLASS: Medial, amorphic, mesic Lithic Haploxerands

TYPICAL PEDON: Ledmount sandy loam--on a southwest-facing, linear, slope of about 5 percent. Vegetation at the site is whiteleaf manzanita, grasses and a few scattered California black oak, incense cedar and ponderosa pine. (Colors are for dry soil unless otherwise noted).

Oi--trace; litter and duff.

A1--0 to 18 cm; dark grayish brown (10YR 4/2) sandy loam, black (10YR 2/1) moist; moderate very fine and fine granular structure; soft, very friable, nonsticky and nonplastic; weakly smeary; many very fine roots; many very fine interstitial pores; 10 percent gravel; slightly acid; clear wavy boundary. (10 to 23 cm thick)

A2--18 to 46 cm; brown (10YR 5/3) gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak very fine subangular blocky structure parting to moderate very fine and fine granular; soft, very friable, nonsticky and nonplastic; weakly smeary; many very fine, few fine, medium and coarse roots; many very fine interstitial pores; 10 percent gravel, 5 percent cobbles; slightly acid, abrupt wavy boundary. (15 to 30 cm thick)

R--46 cm; fractured andesitic tuff breccia.

TYPE LOCATION: Nevada County, California. 400 meters (0.25 miles) east of the turnoff to the Diamond Creek Plantation; 100 meters (330 feet) north of the highway. NE 1/4, NE 1/4, sec. 27, T. 17 N., R. 11 E., MDBM; 3.2 km (2 miles) east of Alpha-Omega Overlook on CA Highway 20. WGS84 39.307436 latitude and -120.723769 longitude. UTM Zone 10 696257 meters E 4353367 meters N NAD83.

RANGE IN CHARACTERISTICS:
Soil temperature: The mean annual soil temperature above the lithic contact ranges from 12 to 15 degrees C. The soils have a mesic temperature regime.

Soil moisture: The soil moisture control section is dry in all parts from about June to October. The soils have a xeric moisture regime.

Diagnostic Feature(s)
Depth to lithic contact: 25 to 50 cm

Particle size control section weighted averages:
Clay content: 10 to 20 percent
Rock fragments: 10 to 25 percent


1500 kPa water to clay ratio: 1.2 to 2.0
Bulk density: 0.85 to 1.0 g/cc
Base saturation (by ammonium acetate): 10 to 50 percent

A horizon
Hue: 10YR
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 1 to 3 dry or moist
Textures: sandy loam, loam
Clay content: 10 to 20 percent
Rock fragments: 5 to 35 percent gravel and cobbles
Reaction: moderately acid to slightly acid
Organic matter: 2 to 6 percent

C horizon (when present)
Hue: 10YR
Value: 5 or 6 dry
Chroma: 2 to 4 moist
Texture: sandy loam, sandy clay loam
Clay content: 10 to 25 percent
Rock fragments: 5 to 35 percent gravel and cobbles
Reaction: strongly acid to moderately acid

The soil is assumed to be dominated by amorphous material based on similar surrounding soils.

COMPETING SERIES: There are no other series in this family at this time.

GEOGRAPHIC SETTING: Ledmount soils are on backslopes, shoulders and summits of lahars at elevations of 1190 to 1950 meters. They formed in material weathered from andesitic tuff breccia. Outcrops of breccia are common. The climate has cool, moist winters and warm, dry summers. Annual precipitation ranges from 1170 to 1930 mm, of which 8 to 30 percent falls as snow. Mean annual air temperature is 11 degrees C. Average January temperature is 1 degrees C, average July temperature is about 21 degrees C. Frost-free season is about 130 to 210 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aiken, Cohasset, Crozier, Devilsnose, Iron Mountain, Lilygap, McCarthy and Redapple soils. All except Iron Mountain are greater than 50 cm to a root-restrictive bedrock contact and occur on lahars. Aiken, Cohasset, Crozier, Devilsnose, Lilygap and Redapple have argillic horizons. Iron Mountain, Aiken, Cohasset, Crozier and Redapple lack andic soil properties in 60 percent or more of the upper 60 cm. McCarthy and Devilsnose are on higher and steeper portions of flanks of lahars (on shoulders and backslopes), often closely intermingled with Iron Mountain. McCarthy has more than 35 percent rock fragments throughout. Aiken, Lilygap and Redappple occur on backslopes, footslopes and summits of lahars.

DRAINAGE AND PERMEABILITY: Well to somewhat excessively drained; Saturated hydraulic conductivity of the soil is moderately high. Saturated hydraulic conductivity of the bedrock is very low.

USE AND VEGETATION: Used for livestock grazing. Vegetation is scattered California black oak, California foothill pine, whiteleaf manzanita, greenleaf manzanita, canyon live oak, buckbrush, grasses, and forbs with stunted conifers (ponderosa pine, incense cedar) in places.

DISTRIBUTION AND EXTENT: Sierra Nevada Mountains of California; MLRA 22A. The soils are moderately extensive.

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

SERIES ESTABLISHED: Nevada County, California, 1981.

REMARKS:

Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon: 0 to 46 cm (A1, A2 horizons)
Lithic contact: 46 cm

Some areas of Ledmount soils were formerly mapped as Iron Mountain series.

ADDITIONAL DATA:
NASIS User Pedon ID: 1982CA057002

No certified laboratory data exist for this soil. Laboratory data described in the range of characteristics are from an unknown source.


The soil was classified using the 12th edition of the Keys to Soil Taxonomy.

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National Cooperative Soil Survey
U.S.A.