LOCATION ROUNDBARN CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Vitrandic Argixerolls
TYPICAL PEDON: Roundbarn gravelly sandy loam on an east facing convex slope of 15 percent under a cover of incense cedar, white fir and jeffrey pine at an elevation of 5150 feet. (Colors are for dry soil unless otherwise stated. When described on August 27, 1980, the soil was dry throughout.)
A1--0 to 2 inches; dark grayish brown (10YR 4/2) gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak coarse platy structure parting to weak thick subangular blocky; slightly hard, very friable, slightly sticky and nonplastic; many very fine and common fine roots; many very fine interstitial pores; 15 percent gravel; neutral (pH 6.6); abrupt smooth boundary. (2 to 6 inches thick)
A2--2 to 10 inches; dark grayish brown (10YR 4/2) gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak coarse and medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; many very fine, common fine, medium, and coarse roots; many very fine interstitial pores; 10 percent gravel and 5 percent cobbles; neutral (pH 6.6); gradual wavy boundary. (2 to 8 inches thick)
2Bt1--10 to 24 inches; brown (7.5YR 4/2) very cobbly sandy loam, dark brown (7.5YR 3/2) moist; weak coarse and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and common fine, medium and coarse roots; common very fine tubular pores; common thin clay films in bridges between mineral grains and in pores; 20 percent cobbles, 10 percent stones and 10 percent gravel; neutral (pH 6.6); gradual wavy boundary. (6 to 14 inches thick)
2Bt2--24 to 41 inches; brown (7.5YR 4/2) very cobbly sandy clay loam, dark brown (7.5YR 3/2) moist; weak coarse and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine and medium roots; common very fine tubular pores; many thin clay films in bridges between mineral grains and in pores, few thin clay films on peds; 30 percent cobbles and 15 percent gravel; neutral (pH 6.8); clear wavy boundary. (5 to 20 inches thick)
2Bt3--41 to 50 inches; brown (7.5YR 4/2) very cobbly sandy loam, dark brown (7.5YR 3/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, few fine and medium roots; common very fine tubular pores; many thin clay films in bridges between mineral grains and in pores; 30 percent cobbles and 15 percent gravel; neutral (pH 6.8); clear wavy boundary. (9 to 25 inches thick)
3Crt--50 inches; highly weathered basalt. Clay films line cracks and fractures.
TYPE LOCATION: Lassen County, California; about 2.7 miles west of Nubieber, on Big Valley Mtn. 1.6 miles north of Highway 299 on dirt logging road, 50 feet east of road; 900 feet east and 2,400 feet north of the southwest corner of sec. 36, T. 38 N., R. 6 E., Bieber SW (Bieber) quadrangle (7.5 minute series).
RANGE IN CHARACTERISTICS: The mollic epipedon is 30 to 50 inches thick. Thickness of solum and depth to paralithic contact ranges from 40 to 60 inches. The mean annual soil temperature is about 41 to 47 degrees F. The soil moisture control section is dry in all parts from mid August until early November (90 to 100 days) and is moist in all parts from mid January until mid May. The soil temperature exceeds 41 degrees F.from mid May until mid November (185 days) and exceeds 47 degrees F. from early July until early October. Base saturation ranges from 59 to 73 throughout. Organic matter ranges from 1 to 5 percent to a depth of 30 to 50 inches.
The A horizon color is 10YR 5/3, 5/2, 4/3, 4/2; or 7.5YR 5/4, 4/4, 4/2. Moist color is 10YR 3/2, 2/2; 7.5YR 3/2; or 5YR 3/3, 3/2. Clay content ranges from 10 to 15 percent. Rock fragments range from 15 to 35 percent. Aluminum and 1/2 iron (by ammonium oxalate) range from 0.4 to 1.0. Volcanic glass content ranges from 5 to 15 percent.
The 2Bt horizon color is 10YR 4/4, 4/3; or 7.5YR 5/4, 5/2, 4/4, 4/2. Moist color is 10YR 3/2, 2/2; 7.5YR 3/4, 3/2; or 5YR 3/4, 3/3. Clay content ranges from 15 to 27 percent and averages 18 to 25 in the particle-size control section. Rock fragments range from 35 to 60 percent
The 2Bt3 horizon has 5 to 7 percent less clay than 2Bt2 horizon.
Andic property data (see remarks for explanation):
Depth P-ret B.D. pH NaF Glass Alo Feo 15 barH20
0-2 61 0.83 10.5 10 0.81 0.56 20.3
2-10 62 0.90 10.0 12 0.67 0.53 18.8
10-24 56 1.1 9.0 4 0.59 0.69 18.8
24-41 49 1.2 9.0 1 0.45 0.65 19.7
41-50 40 1.2 8.5 ND 0.33 0.63 23.2
COMPETING SERIES: These are the Larabee (T ID), Millerflat (OR), Saturday (T ID), Stemilt (WA) and Wilt (OR) soils. These soils are?????
GEOGRAPHIC SETTING: Roundbarn soils are on mountain foot slopes and ridge tops. Slopes range from 5 to 50 percent. The soils formed in slope alluvium from tephra of dominantly basalt origin and in various stages of weathering. The paralithic contact ranges from moderately to strongly weathered basalt that has clay films and some manganese stains in cracks. In some pedons soft tuff is in pockets over weathered basalt. Elevations are 4,800 to 6,300 feet. The lower elevations are found mainly on northeast slopes. The climate is subhumid with warm dry summers and cold moist winters. Mean annual precipitation is about 20 to 30 inches. Snowfall is 48 to 60 inches. Mean annual temperature is 39 to 45 degrees F. Frost-free period is about 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chirpchatter (T), Hunsinger (T) and Rivalier (T) soils. Chirpchatter and Hunsinger soils have a mean annual soil temperature greater than 48 degrees F. Also, Chirpchatter soils have a fine-loamy control section. Rivalier soils are 20 to 40 inches deep.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: These soils are used for timber production and livestock grazing. Vegetation includes white fir, sugar pine, incense cedar, Jeffrey pine, California black oak, western chokecherry, greenleaf manzanita, birchleaf mountain mahogany, and perennial grasses.
DISTRIBUTION AND EXTENT: Northeastern California. The series is not extensive. MLRA is 21.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Lassen County, Intermountain Soil Survey Area, California 1994. Source of name is from Little Valley, Little Valley Quadrangle.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from 0 to 30 inches (A1, A2, Bt1, Bt2)
Argillic horizon - the zone from 10 to 50 inches (Bt1, Bt2, Bt3)
Paralithic contact - the boundary at 50 inches (3Crt)
ADDITIONAL DATA: Grab samples (Bt1, Bt2 horizons) were sent to Lincoln. Pedon number is S83CA-35-5 and sample number is 837725 and 837726, unpublished. UCD lab pedon 88 CA-089006; lab no. 1692.