LOCATION FURSHUR IDEstablished Series
The Furshur series consists of shallow to a duripan well drained soils
formed in residuum and slope alluvium from rhyolite. Furshur soils are
on mountain sides and have slopes to 2 to 60 percent. Permeability is
very slow. The average annual precipitation is about 12 inches, and
average annual air temperature is about 43 degrees F.
TAXONOMIC CLASS: Clayey, smectitic, frigid, shallow Abruptic Durixeralfs
Durixeralfs.
TYPICAL PEDON: Furshur very channery loam on a 5 percent slope at an
elevation of 5,440 feet in rangeland. When described on May 23, 1983,
the soil was dry to 1 inch and moist below this depth. (Colors are for
dry soil unless otherwise noted.)
A--0 to 2 inches; dark grayish brown (10YR 4/2) very channery loam,
very dark grayish brown (10YR 3/2) moist; moderate medium, coarse and
very coarse platy structure; hard, friable, slightly sticky and
slightly plastic; many very fine, fine and medium roots; many very
fine, fine and medium tubular pores; about 40 percent channers; neutral
(pH 6.8); clear smooth boundary. (1 to 4 inches thick)
BA--2 to 5 inches; brown (10YR 5/3) clay loam, dark brown (10YR
3/3) moist; moderate medium subangular blocky structure; hard, friable,
sticky and plastic; many very fine, fine and medium roots; common fine
tubular pores; few thin clay films lining pores and on faces of peds;
about 5 percent pebbles and 5 percent cobbles; neutral (pH 7.0); abrupt
wavy boundary. (2 to 5 inches thick)
Bt--5 to 13 inches; yellowish brown (10YR 5/4) clay, dark yellowish
brown (10YR 4/4) moist; strong medium prismatic structure; very hard,
firm, very sticky and very plastic; common very fine and fine and few
medium and coarse roots; few fine tubular pores; continuous thick clay
films lining pores and on faces of peds; 5 percent pebbles and 5
percent cobbles; neutral (pH 7.0); clear wavy boundary. (4 to 12
inches thick)
Btq--13 to 15 inches; brownish yellow (10YR 6/6) gravelly clay,
yellowish brown (10YR 5/6) moist; moderate medium angular blocky
structure; very hard, very firm, very sticky and very plastic; common
very fine, fine and few medium roots; few fine tubular pores; many
moderately thick clay films lining pores and on faces of peds; 15
percent pebble size pan fragments, 5 percent pebbles and 10 percent
cobbles; neutral (pH 7.2); abrupt smooth boundary. (0 to 5 inches
thick)
Bqkm--15 to 20 inches; very pale brown (10YR 8/3) silica and
calcium carbonate cemented hardpan with strong medium plates;
indurated; few very fine and fine roots as mats on top of this horizon;
slight effervescence (5 to 15 percent calcium carbonate); a continuous
laminar cap 1 to 3 mm thick is at 15 inches; mildly alkaline (pH 7.8).
(3 to 7 inches thick)
R--20 inches; fractured layered rhyolitic bedrock with calcium
carbonate and silica in the fractures.
TYPE LOCATION: Blaine County, Idaho about 2 miles southeast of the
junction of highways 93 and 20; 1,700 feet west and 1,500 feet north of
the southeast corner of section 25, T. 1 S., R. 18 E.
RANGE IN CHARACTERISTICS:
Depth to a duripan - 14 to 20 inches
Depth to bedrock - 18 to 24 inches
Average annual soil temperature - 42 to 47 degrees F
A horizon
Value- 4 or 5 dry
Chroma- 2 or 3 dry or moist
BA horizon
Chroma- 3 or 4 dry
Textures of the fine earth fraction - L, CL
Bt horizon
Hue- 7.5YR or 10YR
Value- 5 or 6 dry and 4 or 5 moist
Chroma- 4 through 6 moist
Textures - C and GR-C
Rock fragments - 5 to 20 percent
Clay content - 50 to 60 percent
Bqkm horizon
Hue- 7.5YR or 10YR
Value- 7 or 8 dry and 5 through 8 moist
Chroma- 1 through 4 dry and 2 through 4 moist
Reaction - mildly to moderately alkaline
COMPETING SERIES: These are the Bigspring(T), Nicholflat(T), and the
Ponina series. Bigspring soils have slow permeability and less than 5
percent rock fragments above the pan. Nicholflat and Ponina soils do
not have bedrock under the duripan above 40 inches. Ponina soils have
a frost-free period of less than 50 days.
GEOGRAPHIC SETTING: Furshur soils are on mountain sides. Slopes range
from 2 to 60 percent. Elevation ranges from 4,700 to 5,600 feet. The
soil formed in residuum from rhyolite. The annual precipitation is 12
to 14 inches, most of which falls as snow and early spring rain. The
annual air temperature is about 40 to 45 degrees F. The frost free
season is 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Elksel, Hamtah,
Peeveywell, Starhope, and Winridge soils. These soils all have mollic
epipedons. Elksel, Hamtah, Starhope and Winridge soils are on mountain
sides. Peeveywell soils are on alluvial fans and fan terraces.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff;
very slow permeability.
USE AND VEGETATION: Mainly used for rangeland. Vegetation is alkali
sagebrush, low sagebrush, Idaho fescue, and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Furshur soils are inextensive in south
central Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Blaine County, Idaho, 1985.
REMARKS: Diagnostic horizons and features recognized in this series
are:
Ochric epipedon - occurs from the soil surface to approximately 5
inches (A and BA horizons)
Argillic horizon - the zone from approximately 5 to 15 inches (Bt and
Btq horizons)
Duripan - the zone from 15 to 20 inches (Bqkm horizon)
National Cooperative Soil Survey