LOCATION BEAVERDAM IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic Vertic Argicryolls
TYPICAL PEDON: Beaverdam silt loam - on a 30 percent west-facing slope under Douglas-fir at 6,600 feet elevation. (Colors are for air-dry soil unless otherwise stated. When described the soil was moist below 45 inches.)
Oi--0 to 1 inch; slightly decomposed needles, leaves, twigs, and grass. (0 to 4 inches thick)
Oe--1 to 2 inches; moderately decomposed needles, leaves, twigs, grass. (0 to 2 inches thick)
A--2 to 5 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine, and common medium and coarse roots; many very fine interstitial pores; about 5 percent pebbles and cobbles; slightly acid (pH 6.4); abrupt smooth boundary. (3 to 11 inches thick)
AB--5 to 14 inches; brown (10YR 5/3) silt loam, very dark grayish brown (10YR 3/2) moist; weak medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine, and common medium and coarse roots; many very fine and fine tubular pores; about 5 percent pebbles and cobbles; moderately acid (pH 6.0); clear smooth boundary. (5 to 9 inches thick)
Bt1--14 to 21 inches; light yellowish brown (10YR 6/4) silty clay loam, brown (10YR 4/3) moist; strong medium and coarse subangular blocky structure; hard, very firm, very sticky and very plastic; common very fine, fine and medium roots; common very fine and fine tubular pores and many very fine interstitial pores when dry; many distinct clay films on the faces of peds and in pores; about 5 percent pebbles and cobbles; slightly acid (pH 6.3); gradual smooth boundary. (7 to 16 inches thick)
Bt2--21 to 47 inches; light yellowish brown (10YR 6/4) silty clay, brown (10YR 4/3) moist; strong medium and coarse angular blocky structure; hard, very firm, very sticky and very plastic; common very fine, fine and medium roots; many very fine interstitial pores when dry; continuous distinct clay films on the faces of peds and in pores; about 5 percent pebbles and cobbles; slightly acid (pH 6.4); clear smooth boundary. (14 to 26 inches thick)
Bt3--47 to 67 inches; light yellowish brown (10YR 6/4) silty clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium and coarse subangular blocky structure; hard, friable, moderately sticky and moderately plastic; few very fine and fine roots; few very fine and fine tubular pores; common faint clay films on the faces of peds and in pores; slightly acid (pH 6.1).
TYPE LOCATION: Bannock County, Idaho; about 6 miles southwest of Lava Hot Springs; 1,000 feet south and 500 feet east of the center of sec. 30, T. 10 S., R. 38 E.
RANGE IN CHARACTERISTICS:
Moisture regime - udic
Average annual soil temperature - 37 to 43 degrees F
Thickness of the solum - 60 inches or more
Particle size control section - 35 to 45 percent clay
Rock fragments - 0 to 10 percent
Mollic epipedon thickness - 10 to 16 inches
A horizon
Color value, dry - 4 or 5
Value, moist - 2 or 3
Chroma, dry or moist - 1 through 3
Reaction - moderately acid to neutral
Bt horizon
Color hue - 7.5YR or 10YR
Color value, dry - 5 through 7
Value, moist - 3 through 5
Chroma, dry or moist - 3 through 6
Reaction - slightly acid or neutral
Texture - silty clay loam, silty clay
Clay - 35 to 45 percent
Rock fragments - 0 to 10 percent
COMPETING SERIES: These are the Cimarron, Cucharas, Gourley, Heathcoat, Sudduth, Toponce, Wetopa and Youman series. Cimarron soils lack an O horizon and formed in glacial till with rock fragments dominated by stones. Cucharas soils are moderately deep to paralithic contact. Gourley soils have calcareous material at depths of 20 to 40 inches. Heathcoat soils have a calcic horizon at 10 to 30 inches. Sudduth soils are pachic with a mollic epipedon beging 16 to 50 inches thick. Toponce soils are pachic with a mollic epipedon 18 to 25 inches thick. Wetopa soils have a mollic epipedon over 16 inches thick. Youman soils have hue of 5YR to 10R throughout the subsoil and substratum.
GEOGRAPHIC SETTING: Beaverdam soils are on mountain slopes on all aspects. Slopes range from 30 to 60 percent. Elevation is 5,500 to 7,500 feet. The soils formed in colluvium from a variety of sedimentary and metasedimentary rocks dominantly quartzite and sandstone. The average annual temperature ranges from 36 to 42 degrees F, and the average annual precipitation ranges from 22 to 30 inches. The frost-free season is less than 50 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cedarhill, Greys, Harkness, Ireland, Mikesell, Sedgway, and Toponce series. Cedarhill and Ireland soils have calcic horizons and are loamy skeletal. Greys soils are fine-silty. Harkness and Mikesell soils lack mollic epipedons. Sedgway soils are loamy-skeletal. Toponce soils have mollic epipedons thicker than 16 inches. The Cedarhill and Ireland soils are on south and west-facing slopes where associated with Beaverdam. The Greys and Toponce soils are on mountain footslopes at lower elevations and on slopes of less than 30 percent. The Harkness and Mikesell soils are at higher elevations on mountain slopes, but where they are associated with Beaverdam they will occupy the colder positions. The Sedgway soil is on mountain slopes, but usually occupies a more convex position higher on the slope.
DRAINAGE AND PERMEABILITY: Well drained; runoff is very rapid; slow permeability.
USE AND VEGETATION: These soils are used mainly for timber production and grazing. The principal native plants at climax are an overstory of Douglas-fir and an understory dominated by pine reedgrass.
DISTRIBUTION AND EXTENT: Southeastern Idaho; MLRA 13. This series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Bannock County, Idaho, 1983.