LOCATION LODICO CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Xeric Paleargids
TYPICAL PEDON: Lodico very cobbly silt loam--on a 5 percent slope under low sagebrush at 4,840 feet elevation--rangeland. (Colors are for dry soil unless otherwise noted. When described August 17, 1978, the soil was dry throughout.) The surface is covered with 30 percent cobbles and 2 percent stones.
A--0 to 3 inches; light brownish gray (10YR 6/2) very cobbly silt loam, very dark grayish brown (10YR 3/2) moist; moderate thick and very thick platy structure; hard, very friable, moderately sticky and moderately plastic; common very fine roots; many very fine interstitial pores; 2 percent stones, 30 percent cobbles, and 20 percent gravel; neutral (pH 7.0); abrupt wavy boundary. (3 to 6 inches thick).
Bt1--3 to 5 inches; brown (10YR 5/3) gravelly silty clay, dark brown (7.5YR 3/2) moist; moderate very fine and fine angular blocky structure; hard, very friable, very sticky and very plastic; common very fine and few fine and medium roots; few very fine tubular pores; many faint clay films on faces of peds and lining pores; 10 percent cobbles and 15 percent gravel; neutral (pH 7.0); clear wavy boundary. (0 to 2 inches thick)
Bt2--5 to 11 inches; brown (10YR 5/3) clay, dark brown (7.5YR 3/4) moist; moderate medium and coarse prismatic structure parting to moderate medium and coarse angular blocky; very hard, friable, very sticky and very plastic; few very fine and fine roots; few very fine tubular pores; few faint and distinct clay films on faces of peds and lining pores; 5 percent gravel; neutral (pH 7.0); clear wavy boundary.
Bt3--11 to 17 inches; brown (7.5YR 5/4) clay, brown (10YR 4/3) moist; weak medium and coarse prismatic structure parting to moderate medium and coarse angular blocky; very hard, very friable, very sticky and very plastic; few very fine roots; common very fine tubular pores; many distinct clay films on faces of peds and lining pores; 10 percent gravel; slightly alkaline (pH 7.5); clear wavy boundary.
Btk--17 to 23 inches; brown (7.5YR 5/4) clay, brown (7.5YR 4/4) moist; weak medium and coarse angular blocky structure; hard, very friable, moderately sticky and moderately plastic; few very fine roots; few very fine tubular pores; common faint clay films on faces of peds and lining pores; 10 percent cobbles; secondary carbonates segregated as common masses on bottoms of rock fragments; slightly alkaline (pH 7.8); abrupt irregular boundary. (Combined thickness of the Bt2, Bt3, and Btk horizons is 17 to 27 inches).
R--23 inches; hard basalt; pockets of weathered rock in the upper part soft enough to cut with a knife; many carbonate coats in some fractures and in weathered areas; discontinuous silica coats near the upper boundary and in fractures.
TYPE LOCATION: Lassen County, California; about 25 miles northeast of Susanville near Secret Valley; found by going east on the Shinn Ranch Road about 3.7 miles from its intersection with U.S. Highway 395 and the Karlo Road and 30 feet south of the road; about 350 feet west and 2,500 feet south of the northeast corner of section 32, T. 32 N., R. 16 E.; USGS Five Springs 7.5 minute topographic quadrangle; 40 degrees 35 minutes 33 seconds north latitude and 120 degrees 10 minutes 52 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - The soil moisture control section is moist in all parts from December 1 to May 1. It is dry in all parts from June 1 to November 15 (168 days). The soil temperature exceeds 41 degrees F from April to December 1 (244 days) and exceeds 47 degrees from April 15 to November 15; Aridic moisture regime that borders on xeric.
Mean annual soil temperature - 48 to 52 degrees F.
Depth to base of argillic horizon - 20 to 30 inches.
Depth to bedrock - 20 to 30 inches to a lithic contact.
Particle-size control section - Clay content: 40 to 50 percent; Rock fragments: Averages 5 to 15 percent, mainly gravel and cobbles. Lithology of fragments is volcanic rocks such as basalt or andesite.
Other features - An abrupt horizon boundary is normally present between the A horizon and the Bt1 horizon accompanied by an abrupt increase in clay content of 20 to 25 percent; Rock fragments on the surface range from 50 to 60 percent and are mainly cobbles and gravel.
A horizon - Dry color: 10YR 6/2 or 6/3.
Moist color: 10YR 3/2 or 3/3.
Clay content: 18 to 25 percent.
Rock fragments: 50 to 60 percent, mostly cobbles and gravel.
Bt horizons - Dry color: 10YR 5/2, 5/3, 5/4, 6/2 or 7.5YR 5/4.
Moist color: 10YR 3/2, 3/3, 4/3; 7.5YR 3/2, 3/4 or 4/4.
Texture: Clay or silty clay; some pedons have thin subhorizons that are gravelly.
Clay content: 40 to 50 percent.
Rock fragments: 5 to 25 percent.
Reaction: Neutral or slightly alkaline.
Other features: Some pedons do not have identifiable secondary carbonates in the lower subhorizon.
COMPETING SERIES: These are the Acoma, Berdugo, Borda, Bowns, Brent, Chardoton, Hagata, Jowec, Locey (T), Poall, Reba, and Spangenburg series.
Acoma, Berdugo, Brent, Chardoton, Jowec, Poall, Reba, and Spangenburg soils are very deep. Borda soils are deep to lithic contacts. Bowns soils have E horizons and mean annual soil temperature of 54 or 55 degrees F. Hagata soils are moderately deep to paralithic contacts over noncemented material below. Locey soils have ochric epipedons that are 8 to 12 inches thick, have rock fragments that are shale, and do not have rock fragments larger than 3 inches in diameter in the particle-size control section.
GEOGRAPHIC SETTING: Lodico soils are on plateaus. These soils formed in residuum weathered from volcanic rock such as basalt or andesite. Slopes are 2 to 9 percent. Elevation ranges from 4,800 to 5,200 feet. The climate is semiarid with cold, moist winters and warm, dry summers. The mean annual precipitation is 9 to 12 inches including 20 to 30 inches of snow. The mean annual temperature is 46 to 48 degrees F. The mean July temperature is about 64 degrees F. and the mean January temperature is about 26 degrees F. The frost-free period is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brubeck and Diaz soils on lower plateaus and the Devada and Longcreek soils on upper plateaus. Brubeck soils are clayey throughout, do not have argillic horizons, and have cracks that open and close once each year. Diaz soils lack an abrupt textural change. Devada and Longcreek soils are shallow to lithic contacts and have mollic epipedons.
DRAINAGE AND PERMEABILITY: Well drained; high surface runoff; very slow permeability.
USE AND VEGETATION: Lodico soils are used for rangeland. The vegetation is low sagebrush, Thurber's needlegrass, bottlebrush squirreltail, and Sandberg's bluegrass.
DISTRIBUTION AND EXTENT: Northeastern California. These soils are not extensive with about 1,600 acres of the series mapped to date. MLRA 23.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Lassen County (Susanville Area Soil Survey), California, 2000.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 3 inches (A horizon).
Argillic horizon - The zone from 3 to 23 inches (Bt1, Bt2, Bt3, Btk horizons).
Paleargid great group feature - There is an abrupt textural change at 3 inches with a clay increase of 20 percent or more (absolute) within one inch at the upper boundary of the argillic horizon (between the A and Bt1 horizons).
Identifiable secondary carbonates - The zone from 17 to 23 inches (Btk horizon).
Lithic contact - The boundary at 23 inches to underlying hard bedrock (R layer).
Particle-size control section - The zone from 3 to 23 inches (Bt1, Bt2, Bt3, Btk horizons).