LOCATION LASVAR CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aquic Durixererts
TYPICAL PEDON: Lasvar clay on a west facing 1 percent slope under a cover of grasses and sedges at an elevation of 4238 feet. (Colors are for dry soil unless, otherwise stated. When described August 19, 1987, the soil was slightly moist from 3 to 50 inches.)
Ass--0 to 3 inches; grayish brown (10YR 5/2) clay, brown (10YR 4/3) moist; moderate fine subangular blocky structure; very hard, very firm, sticky and plastic; common fine roots; few very fine tubular pores; 5 percent manganese nodules; common intersecting slickensides; common very fine distinct dark gray (N 4/0) redox depletions; neutral (pH 7.0); abrupt smooth boundary, (2 to 8 inches thick).
Bss--3 to 28 inches; brown (10YR 5/3) clay, brown (10YR 4/3) moist; strong coarse prismatic structure parting moderate coarse to angular blocky; extremely hard, extremely firm, sticky and plastic; few very fine and fine roots; few very fine tubular pores; 5 percent manganese nodules; common intersecting slickensides; common very fine distinct dark gray (7.5YR 4/0) redox depletions; moderately alkaline (pH 8.0); abrupt smooth boundary. (18 to 28 inches thick)
2Bq--28 to 31 inches; very pale brown (10YR 7/4) weakly cemented silt loam, dark yellowish brown (10YR 4/4) moist; moderate very thin platy structure parting to moderate fine angular blocky; very firm, slightly sticky and slightly plastic; common very fine roots; few very fine tubular pores; 5 percent manganese nodules; common very fine distinct dark gray (N 4/0) redox depletions; moderately alkaline (pH 8.0); abrupt smooth boundary. (0 to 6 inches thick)
2Bqm--31 to 60 inches; very pale brown (10YR 7/4) continuously indurated duripan; dark yellowish brown (10YR 4/4) moist.
TYPE LOCATION: Modoc County, California; about 9.4 miles northwest of Lookout, 1600 feet east and 500 feet south from the northwest corner of Sec 15, T.40N, R.6E Whitehorse SE (Egg Lake) quadrangle, (7.5 minute series).
RANGE IN CHARACTERISTICS: Depth to duripan is 20 to 40 inches. The mean annual soil temperature is 47 to 50 degrees F. The soil temperature exceeds 41 degrees F.
from mid March to late December (270 to 285 days) and exceeds 47 degrees F. from early May to early December. The soil moisture control section (7 to 21 inches) is dry in all parts from mid August to mid September (25 to 35 days) and is moist in all parts from late September to early July. Surface cracks are 0.5 to 2 inches wide, and extend to a depth of 20 to 25 inches and even though the soil is moist in some part the racks are open for at least 60 days.
The Ass horizon color is 10YR 4/2, 5/2; 7.5 4/2 or 5/2. Moist color is 10YR 3/2, 4/3; 7.5YR 3/2, or 4/2. Clay content ranges from 45 to 55 percent. Organic matter ranges from 1 to 2 percent.
The Bss horizon color is 10YR 4/2, 5/2, 5/3 or 7.5YR 4/2. Moist color is 10YR 3/2, 4/3 or 7.5YR 3/2. Clay content ranges from 45 to 55 percent. Reaction ranges from neutral to mildly alkaline.
The 2Bq horizon color is 10YR 5/3, 6/3, or 7/4. Moist color is 10YR 4/4; 7.5YR 3/4, 4/4 or 5/4. Texture is silt loam or silty clay loam. Clay content ranges from 25 to 35 percent.
COMPETING SERIES: These are the Dosa (T CA) and Pitvar (T CA) soil. Piline soils are very deep and lack a duripan. Pitvar soils are deep to a hardpan. Dosa soils are ?????
GEOGRAPHIC SETTING: Lasvar soils are in basins and drainageways. Slopes are 0 to 2 percent. These soils formed in alluvium from extrusive igneous rock. Elevation is 3100 to 4800 feet. The climate is subhumid with warm dry summers and cold moist winters. Mean annual precipitation is 16 to 35 inches. Snowfall is 48 to 60 inches. The mean annual temperature is 45 to 48 degrees F. The mean January temperature is about 32 degrees F. The mean July temperature is about 65 degrees F. Frost-free season is 50 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Burman, Fleener, Gasper, Loveness, Patburn, Scarface and Swanberger soils and the competing Pitvar series. Burman soils lack vertic properties. Fleener soils are on lava plateaus, are very deep and are medial-skeletal over loamy-skeletal. Gasper soils are on lava plateaus and hills, have ochric epipedon, are very deep and are medial-skeletal over loamy-skeletal. Loveness soils are on lava plateaus, are very deep and are medial over loamy. Patburn soils are in basins and drainageways, are very deep, and are fine. Scarface soils are on lava plateaus and hills, are very deep, have ochric epipedon and are fine-loamy,. Swanberger soils are in basins are very deep, and are poorly drained.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow to ponded runoff; slow permeability. A perched water table occurs at depths of 2 to 6 inches above the surface from December through April. A perched water table occurs at depths of 0 to 3 feet from April through July.
USE AND VEGETATION: This soil is used for livestock grazing. The natural vegetation is yampah, danthonia bluegrass, and sedges.
DISTRIBUTION AND EXTENT: Northeastern California. The soils are not extensive. MLRA is 22.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Modoc County, Intermountain Soil Survey Area, California 1994. Source of name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the soil surface to about 28 inches. (Ass and Bss horizons)
Duripan - the zone from 31 to 60 inches (2Bqm).