LOCATION LANARK ID

Established Series
Rev. RAS/JOH/GHL
06/2011

LANARK SERIES

The Lanark series consists of very deep, well drained soils that formed in loess. Lanark soils are on mountain slopes and fans and have slopes of 0 to 45 percent. The mean annual precipitation is about 16 inches.

TAXONOMIC CLASS: Fine-silty, mixed, superactive Pachic Argicryolls

TYPICAL PEDON: Lanark silt loam, grass. (Colors are for dry soil unless otherwise noted.)

A1--0 to 2 inches; grayish brown (10YR 5/2) silt loam, very dark brown (10YR 2/2) (very dark grayish brown 10YR 3/2, crushed) moist; moderate very fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; common very fine and fine tubular pores; neutral (pH 6.8); abrupt smooth boundary. (0 to 4 inches thick)

A2--2 to 7 inches; dark grayish brown (10YR 4/2) (dark brown 10YR 4/3, crushed) silt loam, very dark brown (10YR 2/2) (very dark grayish brown 10YR 3/2, crushed) moist; moderate fine and medium granular and weak fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine tubular pores; neutral (pH 7.0); gradual smooth boundary. (4 to 10 inches thick)

A3--7 to 14 inches; brown (10YR 5/3) silt loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine tubular pores; neutral (pH 7.2); gradual smooth boundary. (5 to 10 inches thick)

Bt1--14 to 28 inches; brown (10YR 5/3) heavy silt loam, dark brown (10YR 3/3) moist; weak medium and coarse subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine tubular pores; faint patchy clay films in some channels; few uncoated silt particles on peds; neutral (pH 7.2); abrupt wavy boundary. (6 to 16 inches thick)

Bt2--28 to 41 inches; brown (10YR 5/3) (pale brown 10YR 6/3, crushed) light silty clay loam, brown (10YR 4/3) moist; weak fine prismatic structure that parts to moderate medium and fine subangular blocky; hard, friable, sticky and plastic; few very fine tubular pores; faint patchy clay films on peds and thin and medium nearly continuous ones on many pores; few uncoated silt particles on peds; slightly alkaline (pH 7.8); gradual smooth boundary. (10 to 15 inches thick)

Bk1--41 to 54 inches; pale brown (10YR 6/3) heavy silt loam, brown (10YR 4/3) moist; weak medium and fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine and fine tubular pores; thin patchy clay films in few pores; moderately calcareous, few fine veins and spots of calcium carbonate; moderately alkaline (pH 8.1); clear wavy boundary. (5 to 15 inches thick)

Bk2--54 to 66 inches; very pale brown (10YR 7/3) silt loam, brown (10YR 5/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; many very fine and fine tubular pores; strongly calcareous, many fine veins and spots of calcium carbonate; moderately alkaline (pH 8.4).

TYPE LOCATION: Bingham County, Idaho; 2,300 feet south and 1,980 feet east of the NW corner sec. 12, T. 3 S., R. 41 E.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 35 to 43 degrees F., and the mean summer temperature is 55 to 59 degrees F. The soil moisture regime is xeric and the soils are dry for 45 to 60 consecutive days. The solum is 25 to 50 inches thick. The mollic epipedon is 16 to 30 inches thick. The profile is noncalcareous to a depth of 40 to 60 inches.

The A horizon when mixed to 7 inches has value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3. It has weak to moderate granular to weak subangular blocky structure. It has 3.5 to 5.5 percent organic matter having a C:N ratio of 10 to 13. It ranges in pH from 6.5 to 7.4

The Bt horizon has value of 5 or 6 dry, 3 or 4 moist, and chroma of 2 through 4. It is silt loam or silty clay loam and averages 24 to 30 percent clay and less than 15 percent particles coarser than very fine sand. It ranges in pH from 6.6 to 7.8.

COMPETING SERIES: These are the Bozeman an Robana series. Bozeman soils are calcareous below a depth of 20 to 40 inches. Robana soils have sola thicker than 50 inches and lack secondary carbonates.

GEOGRAPHIC SETTING: The soils formed in deep loess in mountain slopes and fans at elevations of 5,800 to 7,000 feet. Slopes are 0 to 45 percent. The subhumid continental climate has a mean annual precipitation of 14 to 18 inches including 3 to 6 feet of snowfall, and a frost-free season of 30 to 80 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Steelton and Enochville soils. Steelton soils are less than 20 inches deep over basalt. Enochville soils are noncalcareous and have redox features due to wetness in or immediately below the A horizon.

DRAINAGE AND PERMEABILITY: Well drained; medium or rapid runoff; moderate permeability.

USE AND VEGETATION: Used for nonirrigated small grains and range. The principal native plants are Idaho fescue, streambank wheatgrass, Columbia needlegrass, Nevada bluegrass, and geranium.

DISTRIBUTION AND EXTENT: The series is moderately extensive in southeastern Idaho; MLRA 13.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Star Valley Area, Wyoming, 1941. Although the series was established in 1941, the series is not in the published report or correaltion document (1971) for the Star Valley Area, Wyoming-Idaho soil survey. The series was first used in a correlation in the Bingham Area, Idaho soil survey in 1968.

REMARKS:

National Cooperative Soil Survey
U.S.A.