LOCATION ROCHESTER MT
Established Series
Rev. JB-BDD-RJS
04/2013
ROCHESTER SERIES
The Rochester series consists of very deep, excessively drained soils that formed in colluvium derived mainly from gneiss, schist and granite. These soils are on mountain slopes, hillslopes and escarpments. Slopes are 4 to 80 percent. Mean annual precipitation is about 560 mm, and mean annual air temperature is about 4.5 degrees C.
TAXONOMIC CLASS: Sandy-skeletal, mixed, frigid Typic Ustorthents
TYPICAL PEDON: Rochester very stony loamy sand, in woodland (colors are for dry soil unless otherwise noted).
Oi--0 to 5 cm; slightly decomposed forest litter.
A--5 to 13 cm; dark grayish brown (10YR 4/2) very stony loamy sand, very dark grayish brown (10YR 3/2) moist; moderate very fine granular structure; soft, very friable, slightly sticky and nonplastic; common fine, medium and coarse roots; many fine pores; 30 percent gravel, 15 percent cobbles, 10 percent stones; neutral (pH 7.2); abrupt smooth boundary. (8 to 12 cm thick)
C1--13 to 41 cm; pale brown (10YR 6/3) very stony loamy sand, brown (10YR 4/3) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; common fine and medium roots, and few coarse roots; many fine pores; 30 percent gravel, 15 percent cobbles, 15 percent stones; neutral (pH 6.9); clear smooth boundary. (20 to 65 cm thick)
C2--41 to 152 cm; light brownish gray (2.5Y 6/2) very stony loamy sand, dark grayish brown (2.5Y 4/2) moist; single grain; loose, nonsticky and nonplastic; few fine, medium and coarse roots; 30 percent gravel, 15 percent cobbles, 15 percent stones; neutral (pH 7.1).
TYPE LOCATION: Madison County, Montana; 700 meters north and 30 meters east of the SW corner of sec. 35, T. 5 S., R. 1 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 3.5 to 8.0 degrees C.
A horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 1 to 3; dry or moist
Texture: loamy sand, sandy loam or coarse sandy loam
Clay content: 0 to 10 percent
Rock fragments: 10 to 65 percent--10 to 35 percent gravel, 0 to 40 percent cobbles, stones and boulders
Reaction: pH 6.6 to 7.3
C1 horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 1 to 3; dry or moist
Texture: loamy sand, loamy coarse sand, sandy loam, coarse sandy loam, or coarse sand (50 percent or more of the sand fraction is medium sand and coarser)
Clay content: 0 to 10 percent
Rock fragments: 15 to 80 percent--15 to 30 percent gravel, 0 to 40 percent cobbles, stones, and boulders
Reaction: pH 5.6 to 7.3
C2 horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 1 to 3; dry or moist
Texture: loamy sand, loamy coarse sand, sand, or coarse sand (50 percent or more of the sand fraction is medium sand and coarser)
Clay content: 0 to 10 percent
Rock fragments: 35 to 80 percent--15 to 60 percent gravel, 0 to 40 percent cobbles, stones, and boulders
Reaction: pH 5.6 to 7.8
COMPETING SERIES:
Clark Fork (MT) - have a Bw horizon
Hopdraw (SD) - are deep to a lithic contact
Nemote (MT) - have lamella
Oraid (MT) - are moderately deep to a lithic contact
Quamon (CO) - have C horizons that are calcareous
GEOGRAPHIC SETTING:
Landform - mountain slopes, hillslopes and escarpments
Elevation - 1,075 to 2,325 meters
Slope - 4 to 80 percent
Parent material - colluvium derived mainly from gneiss, schist and granite
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 380 to 650 mm
Mean annual air temperature - 2.5 to 7.5 degrees C.
Frost-free period - 70 to 110 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Excessively drained; rapid permeability.
USE AND VEGETATION: Rochester soils are used as woodland and for woodland understory grazing. The native vegetation is Douglas fir with an understory of bluebunch wheatgrass, Idaho fescue, and elk sedge.
DISTRIBUTION AND EXTENT: Rochester soils are of moderate extent in mountain areas in southwestern and west-central Montana. MLRAs - 43B, 44A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Madison County, Montana, March 1983.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to 13 cm (Oi, A horizons);
Particle-size control section - from 25 to 100 cm (part of C1, part of C2 horizon).
Rochester sols have a frigid temperature regime and an ustic moisture regime.
ADDITIONAL DATA: Soil interpretation records - MT0606, MT0849.
National Cooperative Soil Survey
U.S.A.