LOCATION LANDUSKY                MT

Established Series
IRD: NRS-CNG-KLS
05/2023

LANDUSKY SERIES

The Landusky series consists of very deep, excessively drained soils that formed in colluvium and residuum from igneous rocks. These soils are on mountains. Slopes are 25 to 60 percent. Mean annual precipitation is about 510 mm, and mean annual air temperature is about 6 degrees C.

TAXONOMIC CLASS: Fragmental, mixed, frigid Typic Ustorthents

TYPICAL PEDON: Landusky extremely cobbly loam, forested (colors are for dry soil unless otherwise noted).

Oe--0 to 3 cm; forest litter of partially decomposed needles, twigs, and mosses.

A--3 to 8 cm; dark grayish brown (10YR 4/2) extremely cobbly loam, very dark brown (10YR 2/2) moist; strong fine and medium granular structure; soft, very friable, slightly sticky and slightly plastic; many fine and very fine and common medium and coarse roots; 30 percent pebbles, 60 percent cobbles; slightly acid (pH 6.4); clear smooth boundary. (0 to 10 cm thick)

Bw--8 to 26 cm; pale brown (10YR 6/3) extremely cobbly loam, brown (10YR 5/3) moist; weak fine subangular blocky structure parting to moderate fine granular; slightly hard, very friable, slightly sticky and slightly plastic; many fine and very fine and common medium and coarse roots; 25 percent pebbles, 35 percent cobbles; strongly acid (pH 5.4) clear wavy boundary. (15 to 25 cm thick)

2C--26 to 156 cm; fractured hard igneous rock with large voids; distinct faint clay films and other soil material on upper surface of some rock fragments; few fine and very fine roots; soil material is moderately acid (pH 5.6).

TYPE LOCATION: Phillips County, Montana; about 640 meters south and 135 meters east of the NW corner of sec. 24, T. 25 N., R. 24 E.

RANGE IN CHARACTERISTICS:
Soil temperature--4 to 7 degrees C
Soil moisture control section--10 to 25 cm

A horizon
Value--4 or 5 dry, 2 or 3 moist
Chroma--2 or 3
Clay content--20 to 27 percent
Rock fragment content--60 to 90 percent; 25 to 35 percent gravel, 35 to 60 percent cobbles
Reaction--pH 6.1 to 6.5

Bw horizon
Value--6 or 7 dry, 4 or 5 moist
Chroma--2 or 3
Clay content--15 to 27 percent
Rock fragment content--60 to 90 percent; 25 to 35 percent gravel, 35 to 60 percent cobbles
Reaction--pH 5.1 to 6.5

2C horizon
Fragmental material consisting of angular igneous gravel and cobbles.

COMPETING SERIES:
Brandenburg (ND) - neutral to slightly alkaline in the surface horizon above the fragmental material; formed in materials derived from porcelanite, argillites, or clinkers containing free carbonates.

GEOGRAPHIC SETTING:
Landform--mountains
Elevation--1400 to 1700 meters
Slope--25 to 60 percent
Parent material--colluvium or residuum from igneous rocks
Climate--long, cold winters; moist springs; and warm summers
Mean annual precipitation--460 to 610 mm
Mean annual air temperature--3 to 6 degrees C
Frost-free period--70 to 100 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed.

DRAINAGE AND PERMEABILITY: Excessively drained; rapid permeability.

USE AND VEGETATION: Landusky soils are used mainly for woodland and understory grazing. The potential native vegetation is Douglas-fir, lodgepole pine, bluebunch wheatgrass, Idaho fescue, common juniper, kinnikinnick, common snowberry, and common chokecherry. Most areas of Landusky soils in the Little Rocky Mountains have been recently burned and have grassland vegetation or dense stands of lodgepole pine.

DISTRIBUTION AND EXTENT: Landusky soils are of small extent in the Little Rocky Mountains in north-central Montana; MLRA 43B.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana

SERIES PROPOSED: Phillips County, Montana, 1994. Landusky is the name of a small town in southwestern Phillips County.

REMARKS: Soil interpretation record: MT1475.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon--3 to 26 cm (A, Bw horizons)
Particle-size control section--25 to 100 cm (small part of the Bw and all of the 2C horizon)

Landusky soils have a frigid temperature regime and an ustic soil moisture regime.

Converted to metric and O horizons were updated to start at zero. Competing series section was not updated. 05/2023

---

National Cooperative Soil Survey
U.S.A.