LOCATION WINFALL MTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Lamellic Eutrudepts
TYPICAL PEDON: Winfall gravelly loam, in coniferous forest. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 2 inches; undecomposed and slightly decomposed forest litter. (1 to 3 inches thick)
E--2 to 20 inches; pinkish gray (7.5YR 7/2) gravelly loam, brown (7.5YR 5/2) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, fine, and medium roots and few coarse roots; many very fine and fine pores; 25 percent gravel; strongly acid (pH 5.5); gradual smooth boundary. (8 to 27 inches thick)
E and Bt--20 to 60 inches; E part (80 percent) is pinkish gray (7.5YR 7/2) very gravelly loam, brown (7.5YR 5/2) moist; B part (20 percent) is brown (7.5YR 5/2) very fine sandy loam lamellae 1/8- to 3/8-inch thick, brown (7.5YR 4/4) moist; texture mixed is very gravelly loam, moderate medium subangular blocky structure; hard, friable, nonsticky and nonplastic; few fine and medium roots; few fine pores; 35 percent gravel and 10 percent cobbles; moderately acid (pH 6.0).
TYPE LOCATION: Missoula County, Montana; 1,000 feet north and 1,000 feet west of the SE corner of sec. 21, T. 19 N., R. 16 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 46 degrees F.
Moisture control section - between 8 and 24 inches
A thin A horizon is allowed.
E horizon
Hue: 5YR, 7.5YR, or 10YR
Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Clay content: 10 to 20 percent
Rock fragments: 15 to 60 percent--0 to 10 percent cobbles and stones; 15 to 50 percent gravel
Reaction: pH 5.1 to 6.5
E and Bt horizon
Hue: E part 5YR, 7.5YR, or 10YR, B part 5YR, 7.5YR, or 10YR
Value: E part 6 or 7, B part 5 or 6 dry; E part 5 or 6, B part 4 or 5 moist
Chroma: E part 2 or 3; B part 3 or 4
Texture: loam, fine sandy loam, or sandy loam
Clay content: 10 to 20 percent, lamellae has less than 3 percent increase in clay
Rock fragments: 35 to 60 percent--0 to 15 percent cobbles; 30 to 45 percent gravel
Reaction: pH 5.1 to 6.5
This horizon is hard or very hard when dry
COMPETING SERIES:
Drexel (MT) - have greater than 35 percent shale fragments below 20 inches.
Lantern (MT) - 15 to 40 percent mica in the fine earth fraction.
Selway (MT) - has more than 50 percent coarse or very coarse sand in the particle-size control section.
GEOGRAPHIC SETTING:
Landform- mountains and moraines.
Elevation - 3,500 to 5,500 feet.
Slope - 2 to 60 percent.
Parent material - till and drift.
Climate - long, cold winters; moist springs.
Mean annual precipitation - 20 to 35 inches, much of which falls as snow or as spring rain.
Mean annual temperature - 38 to 45 degrees F.
Frost-free period - 70 to 95 days.
GEOGRAPHICALLY ASSOCIATED SOILS: none listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Winfall soils are used for timber production, watersheds, and recreation, and as wildlife habitat. The native vegetation is coniferous forest consisting of western larch, Douglas fir, ponderosa pine, and lodgepole pine with an understory of common snowberry, dwarf huckleberry, blue huckleberry, common beargrass, and pinegrass.
DISTRIBUTION AND EXTENT: Winfall soils are moderately extensive in western Montana. MLRA 43A and 44A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Missoula County, Montana, 1985
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 7 inches (Oi and E horizons);
Albic horizon - 2 to 20 inches (E horizon);
Cambic horizon - 20 to 60 inches (E and Bt horizon); and a
Particle-size control section - 10 to 40 inches (E and Bt horizon).
Winfall soils have a frigid temperature regime and a udic moisture regime.
ADDITIONAL DATA: Soil interpretation record MT0431.