LOCATION LAUBY IDEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Pachic Ultic Argixerolls
TYPICAL PEDON: Lauby silt loam--cropland--on a southwest-facing slope of 15 percent at 3,030 feet elevation. When described on October 15, 1987, the soil was moist between 4 and 10 inches. (Colors are for dry soil unless otherwise stated).
Ap--0 to 6 inches; grayish brown (10YR 5/2) silt loam, very dark brown (10YR 2/2) moist; weak fine granular structure; slightly hard, friable, slightly sticky and plastic; few fine and very fine roots; few very fine tubular pores; moderately acid (pH 6.0); clear smooth boundary. (6 to 9 inches thick).
A--6 to 12 inches; grayish brown (10YR 5/2) silt loam, very dark brown (10YR 2/2) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; few very fine and fine roots; many very fine tubular pores; many organic stains on faces of peds; moderately acid (pH 6.0); clear wavy boundary. (4 to 13 inches thick)
AB--12 to 17 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; moderate fine prismatic structure parting to moderate fine and medium subangular blocky; hard, friable, sticky and plastic; few very fine and fine roots; many very fine tubular pores; many distinct clay films on faces of peds and in pores; few faint silt coatings on faces of peds; 5 percent pebbles; neutral (pH 7.0); clear wavy boundary. (5 to 13 inches thick)
Bt--17 to 24 inches; brown (10YR 5/3) silty clay loam, dark brown (10YR 3/3) moist; moderate fine prismatic structure parting to moderate fine and medium subangular blocky; hard, friable, sticky and plastic; few very fine and fine roots; common very fine tubular pores; many distinct clay films on faces of peds and in pores; few patchy silt coatings on faces of peds; 7 percent fine gravel; neutral (pH 7.0); clear wavy boundary. (0 to 12 inches thick)
2Btb1--24 to 32 inches; light yellowish brown (10YR 6/4) clay loam, brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; hard, friable, sticky and plastic; few very fine roots; common very fine tubular pores; many prominent clay films on faces of peds and in pores; 7 percent fine pebbles; neutral (pH 7.0); clear wavy boundary.
2Btb2--32 to 50 inches; light brown (7.5YR 6/4) clay loam, dark brown (7.5YR 4/4) moist; moderate medium prismatic structure; very hard, very firm, sticky and plastic; few very fine roots; common very fine tubular pores; many prominent brown (7.5YR 5/4) clay films on faces of peds and in pores; slightly acid (pH 6.5); clear irregular boundary. (Combined thickness of the 2Btb horizons is 6 to 31 inches)
2C--50 to 60 inches; very pale brown (10YR 7/4) loam, mixed yellow (10YR 7/6) and brownish yellow (10YR 6/6) moist; massive; very hard, very firm, slightly sticky and slightly plastic; common very fine tubular pores; prominent clay accumulations on weathered rock faces; many very fine mica flakes; 5 percent fine pebbles; slightly acid (pH 6.5).
TYPE LOCATION: Lewis County, Idaho; about 9 miles north of Nezperce, about 2400 feet south and 700 feet east of the northwest corner of section 18, T. 35 N., R. 2 E..
RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon - 20 to 30 inches
Depth to soft weathered bedrock -- 40 to 60 inches or more
Moisture control section - dry 45 to 60 consecutive days following the summer solstice
Average annual soil temperature - 48 to 51 degrees F
Base saturation - 50 to 75 percent in some part between 10 and 30 inches
Particle-size control section
Clay content - averages 28 to 35 percent
A BE horizon is present in some pedons.
A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Reaction - moderately acid to slightly acid
Bt horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 through 4 dry or moist
Reaction - slightly acid to neutral
Textures - SICL or SIL
Clay content - 20 to 30 percent
Pebble content - 0 to 10 percent (fine)
2Btb horizons
Hue - 10YR or 7.5YR
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 4 through 6 dry, 3 or 4 moist
Texture - SICL or CL
Pebble content - 0 to 10 percent
Clay content - 28 to 37 percent
Reaction - slightly acid to neutral
2C horizon
Texture - L or GR-L
Pebble content - 0 to 25 percent
COMPETING SERIES: These are the Aptos, Buckeye (T), Campfour, Elmore, Hyprairie, Kiakus, Nisene, Paragone, Roseburg (T), Swalecreek (T), and Yaxing (T) series. Aptos and Paragon soils are moderately deep to a paralithic contact. Buckeye and Kiakus soils are moderately deep. Campfour soils are dry 60 to 80 days in summer and lack buried Bt horizons. Elmore and Swalecreek soils lack buried Bt horizons. Hyprairie soils are dry 75 to 90 days in summer and do not have mollic colors in any part of the argillic horizon. Nisene soils are dry for more than 90 consecutive days in summer and have average annual soil temperatures of 56 to 58 degrees F. Roseburg soils have average annual soil temperatures of 52 to 56 degrees F. and lack buried Bt horizons. Yaxing soils are dry for 75 to 90 days in summer and are mildly alkaline.
GEOGRAPHIC SETTING: Lauby soils are on south, southeast, and southwest-facing convex slopes on loess mantled granitic hills. Slopes range from 15 to 35 percent. These soils formed in material weathered from granitic residuum overlain by a thick mantle of loess at elevations of 2,700 to 3,400 feet. Average annual temperature is 47 to 50 degrees F. and the average annual precipitation is 22 to 25 inches. The frost-free period is from 110 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Driscoll, Johnson, Southwick and Wilkins soils. Driscoll soils are on loess uplands, and are fine in the particle-size control section. Johnson soils are on mountains and canyon breaks, have a mollic epipedon that is less than 20 inches thick, and are frigid. Southwick soils are on loess uplands, are fine-silty in the particle-size control section, and have a fragipan. Wilkins soils are in bottomlands and drainageways, are fine in the particle-size control section, and are frigid.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used for nonirrigated cropland in most areas. Some areas are also used for timber production, livestock grazing, and wildlife habitat. Potential natural vegetation is mainly ponderosa pine with an understory of common snowberry, bluebunch wheatgrass, Idaho fescue, and eriogonum.
DISTRIBUTION AND EXTENT: Northcentral Idaho. This soil is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Lewis County, Idaho 1989.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the surface to 24 inches (Ap, A, AB, and Bt horizons).
Argillic horizon - The zone from 17 to 50 inches (Bt, 2Btb1, and 2Btb2 horizons).
Particle-size control section - The zone from 17 to 37 inches (the Bt, 2Btb1 and part of 2Btb2 horizons).