LOCATION PETESCREEK CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Pachic Ultic Haploxerolls
TYPICAL PEDON: Petescreek gravelly loam - on a convex north facing slope of 15 percent under mountain big sagebrush, Idaho fescue and bluebunch wheatgrass at 5,740 feet elevation. (When described on 8-17-81 the soil was dry. Colors are for dry soil unless otherwise stated.)
A1--0 to 5 inches; reddish gray (5YR 5/2) gravelly loam, dark reddish brown (5YR 3/2) moist; moderate coarse platy structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine interstitial and common fine interstitial and tubular pores; 25 percent pebbles; slightly acid (pH 6.5); clear wavy boundary. (5 to 10 inches thick)
A2--5 to 10 inches thick; reddish gray (5YR 5/2) gravelly loam, dark reddish brown (5YR 3/2) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, common fine and few medium roots; many very fine interstitial and tubular pores; 25 percent pebbles; neutral (pH 7.0); clear wavy boundary. (5 to 10 inches thick)
Bt--10 to 17 inches; reddish gray (5YR 5/2) gravelly loam, dark reddish brown (5YR 3/2) moist; moderate fine and medium subangular blocky structure; hard, friable, slightly sticky and plastic; common very fine, common fine and medium and few coarse roots; many very fine interstitial and tubular pores; many thin clay films bridge between mineral grains and on peds; 25 percent pebbles; neutral (pH 7.0); clear wavy boundary. (5 to 10 inches thick)
Bc--17 to 27 inches; reddish gray (5YR 5/2) cobbly loam, dark reddish brown (5YR 3/2) moist; moderate medium and coarse subangular blocky structure; hard, friable, slightly sticky and plastic; common very fine, few fine, medium and coarse roots; many very fine interstitial and tubular, and common fine tubular pores; 15 percent cobbles and 15 percent pebbles; neutral (pH 7.0); abrupt wavy boundary. (5 to 14 inches thick)
Cr1--27 to 39 inches; slightly weathered andesite; upper 7 inches breaks into coarse subangular blocks and below this it separates into cobble-size fragments; fractures about 3 inches apart, some filled the fine roots and soil; can be dug with a spade or auger, broken in hands and scratched with a fingernail; some fragments do not slake in water.
Cr2--39 to 60 inches; slightly weathered andesite.
TYPE LOCATION: Lassen County, California; 5.1 miles S.W. of Ravendale; 2 miles south of Ravendale on U.S. Highway 395 to Horse Lake Road, 2.8 miles west on Horse Lake Road, then 1.2 miles west on trail and 200 feet south of trail; 1,400 feet west and 200 feet south of northeast corner of section 9, T.33N., R.14E., MDBM.
RANGE IN CHARACTERISTICS: The thickness of the solum and depth to a paralithic contact ranges from 20 to 40 inches. The mean annual soil temperature is 43 to 47 degrees F. The soil moisture control section is moist, in all parts, from about December 1st to May 15th. It is dry, in all parts, from August 1st to November 1st. The soil temperature exceeds 41 degrees F. from May 1st to December 1st and exceeds 47 degrees F. from May 15 to October 15th. The mollic epipedon is 22 to 36 inches thick and includes part or all of the B horizon. Organic matter is 1 to 3 percent. Clay content of the control section ranges from 20 to 25 percent and total sand ranges from 35 to 45 percent. Some areas have about 10 to 20 percent cobbles or stones on the surface.
The A horizon is 5YR 5/2; 10YR 4/2, 4/3, 5/3; 7.5YR 4/2, 4/3, or 5/2. Moist color is 10YR 2/2, 3/2; 7.5YR 3/2; or 5YR 3/2. It is gravelly loam, stony loam, very gravelly loam or cobbly sandy loam. Rock fragments range from 15 to 45 percent. Structure of the upper part of the A horizon is strong or moderate coarse or very coarse platy or is strong medium granular.
The B horizon is 7.5YR 4/4, 5/4; 5YR 4/2, 5/2, 5/3, or 5/4. Moist color is 7.5YR 3/2; 5YR 3/2, 3/3, or 3/4. Chromas of 4 occur at a depth of over 25 inches. Rock fragments, mostly gravel and cobbles, range from 20 to 30 percent.
COMPETING SERIES: These are the Izee, Congle (T), Minam (T), Utley, Wallowa (T) and Wrightman series. Congle series are greater than 40 inches deep. Izee, Wallowa and Wrightman soils are 20 to 40 inches deep to hard bedrock. In addition, Izee soils have B horizons with hue of 10YR, Wallowa soils have B horizons with hue of 10YR and texture of silt loam in the fine earth fraction of the control section, and Wrightman soils have 0 to 10 percent pebbles in the control section. Minam soils are greater than 60 inches deep. Utley soils are greater than 40 inches deep.
GEOGRAPHIC SETTING: Petescreek soils are on hillslopes of mountains and hills, mostly on northerly aspects. Slopes are 5 to 50 percent. The soils formed in material weathered from andesitic tuff or basalt. Elevation is 5,400 to 7,800 feet. The climate is semi-arid with warm, dry summers and cold, moist winters. The mean annual precipitation varies from 12 to 16 inches including about 25 to 50 inches of snow. The mean annual temperature varies from 40 to 44 degrees F. Mean July temperature varies from 58 to 63 degrees F., and mean January temperature varies from 22 to 28 degrees F. Frost-free season is 60 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dunnlake (T), Fredonyer (T), McQuarrie, Rucklick and Searles soils. Dunnlake and McQuarrie soils have mollic epipedons less than 20 inches thick and argillic horizons and are 12 to 20 inches deep to hard bedrock. Fredonyer soils are loamy-skeletal. Rucklick soils are clayey-skeletal. Searles soils have an argillic horizon and is loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: Petescreek series are used for rangeland and to a minor extent, for recreation. Vegetation is mountain big sagebrush, Idaho fescue, bluebunch wheatgrass and bitterbrush.
DISTRIBUTION AND EXTENT: Northeastern California. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Susanville Area, Lassen County, California 1981.
SOURCE OF NAME: The name is from nearby Pete's Creek.
OSED scanned by SSQA. Last revised by state on 3/82.