LOCATION SIERRAVILLE CA
Established Series
Rev. JHR-GMK-LCL
12/2022
SIERRAVILLE SERIES
The Sierraville series is a member of the fine, montmorillonitic, frigid family of Ultic Haploxeralfs. Typically, Sierraville soils have reddish brown, slightly acid, stony sandy loam and stony loam A horizons that grade to weak red, slightly and medium acid, heavy clay loam and light clay B2t horizons underlain by volcanic rock at a depth of 75 inches.
TAXONOMIC CLASS: Fine, smectitic, frigid Ultic Haploxeralfs
TYPIFYING PEDON: Sierraville stony sandy loam - woodland (Colors are for dry soil unless otherwise noted.)
O1 and O2--2 to 0 inches; Fresh pine needles, twigs and litter, duff and humus.
A11--0 to 3 inches; reddish brown (5YR 5/3) stony sandy loam, dark reddish brown (5YR 3/3) moist; moderate fine granular structure; soft, very friable, nonsticky, nonplastic; many very fine and fine roots; many very fine and fine interstitial pores; slightly acid (pH 6.5); clear smooth boundary. (2 to 6 inches thick)
A3--3 to 9 inches; reddish brown (2.5YR 4/4) stony loam, dark reddish brown (2.5YR 3/4) moist; weak fine subangular blocky and moderate fine granular structure; slightly hard, friable, slightly sticky, slightly plastic; many fine and medium roots; many very fine and fine tubular and interstitial pores; slightly acid (pH 6.5); clear smooth boundary. (4 to 10 inches thick)
B1t--9 to 24 inches; reddish brown (2.5YR 4/4) stony clay loam, dusky red (10R 3/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, sticky, slightly plastic; common fine and many medium and coarse roots; many very fine and fine tubular and interstitial pores; common thin clay films line pores; slightly acid (pH 6.4); clear wavy boundary. (10 to 20 inches thick)
B21t--24 to 48 inches; weak red (10R 5/3) heavy clay loam, dusky red (10R 3/4) moist; moderate fine and medium subangular blocky structure; hard, firm, sticky, plastic; few fine and common medium and coarse roots; many very fine and fine tubular and interstitial pores; many thin clay films line pores and few clay films on faces of peds; slightly acid (pH 6.3); gradual smooth boundary. (15 to 25 inches thick)
B22t--48 to 75 inches; weak red (10R 4/3) light clay, dark red (10R 3/6) moist; moderate fine angular blocky structure; hard, firm, very sticky, plastic; few fine and coarse, common medium roots; common very fine and fine tubular, many very fine interstitial pores; many thin clay films line pores and on faces of peds; moderately acid (pH 6.0); abrupt irregular boundary. (10 to 30 inches thick)
R--75 to 80 inches; light gray, porous, and vesicular, slightly weathered andesite.
TYPE LOCATION: Plumas County, California; 5 miles south of Portola, along Forest Service road from Portola to Carmen Valley; 3/8 mile southeast of northwest corner sec. 21, T.22N., R.14E.
RANGE IN CHARACTERISTICS: Depth to a lithic contact of volcanic bedrock is 40 to 80 inches. The mean annual soil temperature is about 43 degrees to 47 degrees F. The soil temperature is above 41 degrees F. from about April 1 to November 1 and above 47 degrees F. from about April 15 to November 1. Mean summer soil temperatures are more than 59 degrees F. The soil between depths of about 8 to 14 inches is usually dry all of the time from July 15 until November 1 and is moist in some or all parts all the rest of the year. Rock fragments including stones, cobblestones and gravel range from 20 to 50 percent by volume in the A horizon. Fragments decrease with increasing depth and range from 5 to 20 percent by volume in the B horizon. The base saturation of all horizons is between 50 and 75 percent. The A horizon is dark reddish brown or reddish brown in hue of 2.5YR or 5YR. Moist chroma is 4 in some or all parts. It is sandy loam and loam. The B2t horizon is reddish brown and weak red in hue of 2.5YR or 10R, and the dry value is more than 1 unit higher than the moist value in some or all parts. It is heavy clay loam or clay and total clay content is 35 to 45 percent. This horizon has subangular blocky or angular blocky structure. It is slightly or medium acid. The upper boundary is gradual or there is a transitional horizon or both.
COMPETING SERIES: These are the
Boomer and
Trojan series. Boomer soils have a mean annual soil temperature of 54 degrees to 58 degrees F. and have 25 to 35 percent clay in the argillic horizon. Trojan soils have hue of 5YR or 7.5YR in the B2t horizon.
GEOGRAPHIC SETTING: The Sierraville soils are gently sloping to moderately steep and are in mountainous uplands at elevations of 5,200 to 6,500 feet. They formed in residuum weathered from basic volcanic rock. The climate is subhumid with warm dry summers and cold moist winters. Mean annual precipitation is 14 to 28 inches. Average January temperature is about 27 degrees F.; average July temperature is about 60 degrees F.; mean annual temperature is 43 degrees to 45 degrees F. The mean summer temperatures are about 60 degrees F. The freeze-free season is 50 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Portola and
Sattley soils and the competing
Trojan soils. Portola soils lack argillic horizons and formed in materials containing over 60 percent volcanic ash. Sattley soils have over 35 percent rock fragments by volume and less than 35 percent clay in the control section.
DRAINAGE AND PERMEABILITY: Well-drained; slow to rapid runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used for timber production and some grazing. The vegetation is open stands of ponderosa pine, Jeffrey pine, incense cedar, and white fir with an understory of manzanita, prostrate ceanothus, big sagebrush and some perennial grasses and forbs.
DISTRIBUTION AND EXTENT: Eastern slopes of the Sierra Nevada Mountains in northeastern California. The soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Plumas County, California, 1973.
OSED scanned by SSQA. Last revised by state on 11/73.
National Cooperative Soil Survey
U.S.A.