LOCATION PLINCO CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Cumulic Haploxerolls
TYPICAL PEDON: Plinco loam, native hayland, on a slope of 6 percent under meadow grasses. (When described, September 15, 1983, the soil was nearly dry from the surface to a depth of 30 inches and moist from a depth of 30 to 64 inches. Colors are for dry soil unless otherwise noted.)
A1--0 to 5 inches; dark grayish brown (10YR 4/2) loam, black (10YR 2/1) moist; moderate medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine interstitial pores; neutral (pH 7.0); clear wavy boundary.
A2--5 to 11 inches; dark grayish brown (10YR 4/2) sandy loam, black (10YR 5/1) moist; moderate fine and medium angular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and many fine roots; many very fine interstitial pores; 10 percent 2 to 5 mm pebbles; neutral (pH 7.0); gradual wavy boundary.
A3--11 to 30 inches; dark grayish brown (10YR 4/2) gravelly sandy loam, very dark gray (10YR 3/1) moist; moderate medium angular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, many fine and few medium roots; many very fine interstitial pores; 20 percent 2 to 5 mm pebbles; neutral (pH 7.0); clear wavy boundary.
Ab1--30 to 47 inches; dark gray (10YR 4/1) gravelly sandy loam,
black (N 2/0) moist; massive; slightly hard, very friable, sticky and plastic; few very fine, common fine and few medium roots; many very fine interstitial pores; 20 percent 2 to 5 mm pebbles; neutral (pH 7.0); clear wavy boundary.
Ab2--47 to 58 inches; grayish brown (10YR 5/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; massive; slightly hard, very friable, sticky and plastic; few very fine and fine roots; many very fine interstitial pores; 25 percent 2 to 5 mm pebbles; neutral (pH 7.0); clear wavy boundary. (The combined thickness of the A horizons is 40 to 60 inches.)
C1--58 to 64 inches; light brownish gray (2.5Y 6/2) gravelly loam, dark grayish brown (2.5Y 4/2) moist; common fine distinct light yellowish brown (10YR 6/4) mottles, dark yellowish brown (10YR 4/4) moist; massive slightly hard, very friable, sticky and plastic; few very fine roots; many very fine interstitial pores; 25 percent 2 to 5 mm pebbles; neutral (pH 7.0); clear wavy boundary.
TYPE LOCATION: Lassen County, California; 1.05 miles east of the town of Milford on U.S. Highway 395 and 0.15 mile south of U.S. Highway 395; 800 feet north and 1,200 feet east of the SW corner of sec. 25, T. 27., R. 14. E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature varies from 47 to 50 degrees F. The thickness of the A horizon and depth to mottles is 40 to 60 inches. The control section has a weighted average of 15 to 20 percent gravel and 12 to 18 percent clay. These soils are dry in all parts of the moisture control section (7 to 21 inches) from July 15 to November 1 (105 days) and moist in all parts from November 15 to June 1. The soil temperature exceeds 41 degrees F from April 1 to December 15 (255 days) and exceeds 47 degrees F from May 1 to December 1.
The A horizon is 10YR 3/2, 4/1, 4/2, 5/2 or 5/3. Moist color is 10YR 2/1, 3/1, 3/2, 3/3 or N2/0.
The C horizon is 10YR 7/3, 6/3, 2.5Y 6/2 or 5Y 7/2. Moist color is 10YR 5/3, 4/3; 2.5Y 4/2 or 5Y 5/2. Texture is gravelly loam or gravelly sandy loam with 15 to 35 percent gravel.
COMPETING SERIES: These are the Endersby, Evans Leavenworth, Narcisse, Patit Creek, Pleasant View and Redola series. Endersby soils have a mean annual soil temperature of 51 to 55 degrees F and are mildly or moderately alkaline in the C horizon. Evans soils are dry only 60 consecutive days and have no rock fragments in the control section. Leavenworth soils contain lenses of loamy fine sand throughout and contain less than 10 percent rock fragments in the control section. Narcisse soils are dry 60 to 80 days, have a B horizon with prismatic structure are mottled between a depth of 25 to 48 inches and contain no gravel. Patit Creek soils have an average texture of silt loam in the control section and contain 35 to 80 percent gravel in the C horizon. Pleasant View soils are mildly to moderately alkaline throughout and have a Cca horizon with a calcium carbonate equivalent of 12 to 25 percent. Redola soils have an epipedon less than 35 inches thick, are mildly to moderately alkaline throughout, are calcareous throughout and have no gravel in the control section.
GEOGRAPHIC SETTING: Plinco soils are on fans. Slopes are 2 to 9 percent. These soils formed in granitic alluvium. Elevation is 4,200 to 4,400 feet. The climate is semi-arid with warm dry summers and cold moist winters. The mean annual precipitation is 10 to 14 inches with 15 to 30 inches of snow. The mean annual temperature is 49 to 52 degrees F. The frost-free season is 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Calpine, Mottsville and Springmeyer soils. Calpine soils have epipedons less than 40 inches thick and are on upper fans. Mottsville soils have epipedons less than 20 inches thick and are in the sandy family, and they are on remnant lake terraces. Springmeyer soils have a fine-loamy argillic horizon and are on alluvial fans.
DRAINAGE AND PERMEABILITY: Moderately well drained, runoff is medium; moderately rapid permeability. A seasonal high water table is at a depth of 40 to 60 inches from April to May.
USE AND VEGETATION: Used for native hay and pasture, and strawberries. The vegetation is sedges, basin wildrye and other grasses.
DISTRIBUTION AND EXTENT: Northeastern California, southern Lassen County in the Honey Lake Valley. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Lassen County, California. Susanville Area Soil Survey Area, 1984. Plinco is the name of a nearby mine.
REMARKS: Diagnostic horizons and features recognized in the pedon are:
Mollic epipedon: Zone from the surface to a depth of 58 inches (A1, A2, A3, Ab1, Ab2).