LOCATION PISHKUN MT+UT WYEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, calcareous Typic Cryorthents
TYPICAL PEDON: Pishkun gravelly loam - native grass. (Colors are for dry soil unless otherwise noted.)
A11--0 to 4 inches; very dark grayish brown (10YR 3/2) gravelly loam, very dark brown (10YR 2/2) moist; weak fine crumb structure; soft, very friable, nonsticky, nonplastic; many very fine roots holding soil en masse; many fine and medium interstitial pores; 20 percent coarse fragments; noneffervescent; mildly alkaline; clear irregular boundary. (2 to 4 inches thick)
A12--4 to 10 inches; pale brown (10YR 6/3) gravelly loam, dark brown (10YR 4/3) moist; weak medium subangular blocky structure and weak granular structure; slightly hard, very friable, slightly sticky, nonplastic; common very fine roots; common fine and medium interstitial pores, and few medium tubular pores; 20 percent coarse fragments; very thin lime casts on lower sides of pebbles; slight effervescence; moderately alkaline; clear wavy boundary. (5 to 15 inches thick)
C1--10 to 24 inches; light brownish gray (10YR 6/2) very gravelly loam, dark grayish brown (10YR 4/2) moist; single grained; loose, very friable, nonsticky, nonplastic; common very fine roots; 70 percent coarse fragments; slight effervescence; moderately alkaline; gradual boundary.
C2ca--24 to 48 inches; light brownish gray (10YR 6/2) very gravelly loam, dark grayish brown (10YR 4/2) moist; single grained; loose, very friable, nonsticky, nonplastic; few very fine roots; strong effervescence with light lime casts on all sand and gravel.
TYPE LOCATION: Glacier County, Montana; 50 feet from the top of the slope, 1,600 feet east and 50 feet north of center of section 6, T.36N., R.12W.;
RANGE IN CHARACTERISTICS: The amount of gravel and cobble in the soil ranges from 35 to as much as 80 percent of the volume. The fine earth is loam, sandy loam or clay loam with less than 35 percent clay. The thickness of the very gravelly soil ranges from 40 inches to several feet. This soil rests on sandstone or shale bedrock or on fine earth alluvium and glacial till. Hue ranges from 10YR through 5Y. The average summer soil temperature ranges from 55 to 59 degrees F. After mixing the surface 7 inches the dry soil color value is greater than 5.5. There usually is no free lime in the upper few inches of dark colored soil. Free lime lightly coats sand, gravel and cobbles in part of the C horizon but increase in amount of lime is estimated to be less than 5 percent.
COMPETING SERIES: These are the Brickel, Garlet, Merino, Mirabal, Stecum, Tropal, Utica and Whitore series. Brickel soils have a mollic epipedon. Garlet soils are noncalcareous and have translocated clay and silt coating gravel and cobble in thin bands in a cambic horizon. Merino and Tropal soils have hard bedrock at depths shallower than 20 inches, also Tropal soils have more than 40 percent CaC03 in the whole soil. Mirabal soils have summer soil temperatures warmer than 59 degrees F. Stecum soils have sand filling interstices between coarse fragments. Utica and Whitore soils have calcic horizons and more than 40 percent CaC03 in the whole soil ______________.
GEOGRAPHIC SETTING: Steep and very steep escarpments of gravelly benches in cold areas at elevations of 4,500 to 6,000 feet. At the type location the soil material is derived mainly from argillite, quartzite and limestone rocks in the Lewis Range. Mean annual temperature is 39 to 40 degrees F. Precipitation ranges from 15 to 20 inches annually.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Adel soils in swales and bottoms of valleys and Farnuf and Michelson soils on the upland benches. These are nonskeletal soils; also Farnuf and Michelson soils have B2t horizons.
DRAINAGE AND PERMEABILITY: Excessively drained; rapid runoff; moderate or rapid permeability.
USE AND VEGETATION: Used mainly for range. Vegetation is rough fescue and _____ fescue in the more moist, cool areas and bluebunch wheatgrass and prairie junegrass in the drier areas. Creeping juniper and shrubby cinquefoil are common.
DISTRIBUTION AND EXTENT: Pishkun soils are moderately extensive east of and adjacent to the northern Rocky Mountains in western Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Glacier County, (Blackfeet Reservation-Cut Bank Area), Montana, 1969.
REMARKS: Pishkun soils were formerly classified as _egosols.
OSED scanned by SSQA. Last revised by state on 8/82.