LOCATION BISCHOFF ID
Established Series
Rev. SM/FRK/CBR
10/2026
BISCHOFF SERIES
The Bischoff series consists of very deep, well drained soils that formed in loess influenced colluvium and slope alluvium derived from sedimentary rock. These soils are on mountain slopes, hillslopes, swales on mountain slopes, interfluves, and valley floors. Slopes are 5 to 60 percent. Mean annual precipitation is about 680 mm and mean annual air temperature is about 3 degrees C.
TAXONOMIC CLASS: Fine, smectitic Pachic Argicryolls
TYPICAL PEDON: Bischoff silt loam, in rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 3 cm; brown (7.5YR 4/2) silt loam, very dark gray (7.5YR 3/1) moist; moderate medium and coarse granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and common fine roots; common very fine and few fine tubular and irregular pores; 5 percent gravel; slightly alkaline (pH 7.4); abrupt smooth boundary.
A2--3 to 10 cm; brown (7.5YR 4/2) silt loam, dark brown (7.5YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and common fine roots; common very fine and few fine tubular and irregular pores; 5 percent gravel; neutral (pH 7.3); clear wavy boundary.
AB--10 to 41 cm; brown (7.5YR 4/3) silt loam, dark brown (7.5YR 3/2) moist; weak medium and coarse subangular blocky structure parting to moderate fine angular blocky; moderately hard, friable, slightly sticky and slightly plastic; common very fine and few fine and medium roots; common very fine and few fine tubular and irregular pores; few discontinuous faint clay films on faces of peds and in pores; 5 percent gravel; neutral (pH 7.1); clear wavy boundary.
Bt1--41 to 74 cm; reddish brown (5YR 5/3) silty clay loam, dark reddish brown (5YR 3/3) moist; weak fine and medium prismatic structure parting to moderate fine and medium angular blocky; hard, firm, moderately sticky and moderately plastic; few very fine, fine, and medium roots; few very fine and fine tubular pores; many continuous distinct clay films on faces of peds and in pores; common uncoated silt grains; 5 percent gravel; neutral (pH 7.1); clear wavy boundary.
Bt2--74 to 119 cm; reddish brown (5YR 5/3) silty clay loam, reddish brown (5YR 4/3) moist; moderate medium prismatic structure parting to moderate fine and medium subangular blocky; very hard, extremely firm, very sticky and very plastic; few very fine roots; few very fine tubular pores; many continuous prominent clay films on faces of peds and in pores; 5 percent gravel, 2 percent cobbles; slightly alkaline (pH 7.4); clear wavy boundary.
Bt3--119 to 152 cm; reddish brown (5YR 5/4) silty clay, reddish brown (5YR 4/3) moist; moderate medium and coarse subangular blocky structure; extremely hard, extremely firm, very sticky and very plastic; few very fine roots; few very fine tubular pores; many discontinuous prominent clay films on faces of peds and in pores; 5 percent gravel, 2 percent cobbles; slightly alkaline (pH 7.6).
TYPE LOCATION: Bear Lake County, Idaho; USGS Geneva topographic quadrangle; latitude 42.3288611 degrees north, longitude 111.1078333 degrees west, datum WGS84.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature-1.7 to 5.0 degrees C
Thickness of mollic epipedon--40 to 100 cm
Depth to argillic--13 to 66 cm
Particle-size control section (weighted averages):
Clay content--35 to 50 percent
Total rock fragments--0 to 10 percent
A horizons
Value--3 or 4 dry, 2 or 3 moist
Chroma--1 or 2 moist
Texture (less than 2 mm fraction)--clay loam, silt loam
Clay content--15 to 32 percent
Rock fragments--0 to 10 percent- 0 to 8 percent gravel, 0 to 2 percent cobbles
Reaction--pH 6.6 to 7.5
Thickness--8 to 20 cm
AB horizon
Hue--7.5YR or 5YR
Value--4 or 5 dry
Chroma--2 to 4 dry or moist
Clay content--15 to 20 percent
Rock fragments--0 to 10 percent- 0 to 8 percent gravel, 0 to 2 percent cobbles
Reaction--pH 7.0 to 7.5
Thickness--23 to 36 cm
Bt1 horizon
Hue--7.5YR or 5YR
Value--4 or 5 dry
Texture (less than 2 mm fraction)--clay loam, silty clay, silty clay loam
Clay content--29 to 42 percent
Rock fragments--0 to 10 percent- 0 to 7 percent gravel, 0 to 3 percent cobbles
Reaction--pH 6.6 to 7.6
Thickness--10 to 39 cm
Bt2 and Bt3 horizons
Chroma--3 or 4 dry or moist
Texture (less than 2 mm fraction)--clay, clay loam, silty clay, silty clay loam
Clay content--35 to 55 percent
Rock fragments--0 to 30 percent-0 to 20 percent gravel, 0 to 10 percent cobbles
Reaction--pH 6.6 to 7.6
Thickness--25 to 50 cm
C horizon (when present)
Hue--10Y or 10YR moist or dry
Chroma--1 to 3 moist or dry
Texture (less than 2 mm fraction)--clay loam, clay
Clay content--31 to 50 percent
Rock fragments--0 to 10 percent- 0 to 10 percent gravel
Reaction--pH 6.6 to 7.3
Thickness--0 to 59 cm
COMPETING SERIES:
Burnette (MT)--soils have an ustic moisture regime
Cochetopa (CO)--soils have an ustic moisture regime
Currycreek (MT)--soils have an udic moisture regime
Faim (UT)--soils have an udic moisture regime
Fulcher (CO)--soils have calcium carbonate accumulations
Grouseville (ID)--soils have calcium carbonate accumulations
Guero (T)(CO)--soils have a presumed[RC-NIFI1.1] udic moisture regime
Leemorris (OR)--soils are moderately deep to lithic contact
Lintim (CO)--soils have an ustic moisture regime
Mancos (CO)--soils have an udic moisture regime
Mayflower (MT)--soils are moderately deep to paralithic contact
Paulson (WY)--soils have an ustic moisture regime
Perinos (T)(UT)--soils have colors more yellow than 7.5YR in the A horizons
Richens (UT)--soils are deep to lithic contact
Runlett (CO)--soils are moderately deep to lithic contact
Skutum (UT)--soils are deep to paralithic contact
Windridge (ID)--soils are moderately deep to lithic contact
GEOGRAPHIC SETTING:
Landform--mountain slopes, hillslopes, swales on mountain slopes, interfluves, and valley floors
Elevation--1,770 to 2,750 meters
Slope--5 to 60 percent
Parent material--loess influenced colluvium and slope alluvium weathered from sedimentary rock
Climate--long, cold winters; cool, moist springs; short, cool summers
Mean annual precipitation--350 mm to 850[RC-NIFI2.1] mm
Mean annual air temperature-0.6 to 5 degrees C
Frost-free period--30 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; 0.5 to 5.0 um/sec
USE AND VEGETATION: Bischoff soils are primarily used for grazing and wildlife habitat. The potential natural vegetation is mountain big sagebrush and Idaho fescue.
DISTRIBUTION AND EXTENT: Bischoff soils are of moderate extent in southeastern Idaho; MLRA 43B.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Bear Lake County, Idaho 2008.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon--0 to 74 cm (A1, A2, AB, and Bt1 horizons)
Argillic horizon--40 to greater than 152 cm (Bt1, Bt2, and Bt3 horizons)
Particle-size control section--41 to 91 cm (Bt1 and part of the Bt2 horizon)
Taxonomic version: Twelfth Edition, 2014
National Cooperative Soil Survey
U.S.A.