LOCATION FOURBEAVER OR
Established Series
Rev. RLW/KMS
11/2018
FOURBEAVER SERIES
Landscape--mountains
Landform--mountain slopes
Slope--0 to 60 percent
Parent material--colluvium and residuum derived from hard igneous extrusive rock with a minor influence of volcanic ash in the upper part
Mean annual precipitation--about 510 mm
Mean annual air temperature--about 5 degrees C
Depth class--shallow to lithic bedrock
Drainage class--well drained
Soil moisture regime--xeric
Soil temperature regime--frigid
Soil moisture subclass--typic
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Lithic Ultic Argixerolls
TYPICAL PEDON: Fourbeaver ashy loam, forested, on a 2-percent slope at an elevation of 1393 m
Oi--0 to 1 cm; slightly decomposed plant material
A--1 to 11 cm; very cobbly ashy loam, brown (7.5YR 4/3) dry, black (7.5YR 2.5/1) moist; moderate medium subangular blocky structure; slightly hard, firm, slightly sticky and nonplastic; very few very fine and fine and moderately few medium roots throughout; common medium tubular pores; 15 percent gravel, 30 percent cobbles, and 10 percent stones; slightly acid (pH 6.5); clear wavy boundary
2Bt--11 to 32 cm; very cobbly clay loam, brown (7.5YR 4/2) dry, dark brown (7.5YR 3/2) moist; strong medium subangular blocky structure; very hard, very firm, moderately sticky and slightly plastic; very few very fine and fine and moderately few medium roots throughout; common medium tubular pores; 60 percent clay films on all faces of peds; 25 percent gravel, 25 percent cobbles, and 5 percent stones; slightly acid (pH 6.4); abrupt wavy boundary
2Bt--32 to 46 cm; very cobbly clay, brown (7.5YR 5/2) dry, brown (7.5YR 4/2) moist; moderate medium prismatic structure; extremely hard, very firm, very sticky and very plastic; very few fine and moderately few medium roots throughout; common medium and fine tubular pores; 60 percent clay films on all faces of peds; 20 percent gravel, 30 percent cobbles, and 5 percent stones; slightly acid (pH 6.4); abrupt irregular boundary
2R--46 cm; andesite
TYPE LOCATION: Grant County, Oregon; in the NE1/4NW1/4SW1/4 of section 30, T. 9 S., R. 33 E., latitude 44.7563040, longitude -118.7942260, datum WGS 84 (source of coordinates unknown, but may have been manually estimated from a pin prick on a hard copy map)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--4 to 8 degrees C
Soil moisture--dry 60 to 90 consecutive days following summer solstice
Depth to lithic contact--25 to 50 cm
Thickness of mollic epipedon--18 to 50 cm
Base saturation--65 to 75 percent (by sum of cations) in at least one mineral horizon
Thickness of layers influenced by volcanic ash--5 to 15 cm
Estimated properties of layers influenced by volcanic ash
*Ammonium oxalate extractable Al + Fe--0.4 to 1.0 percent
*0.02- to 2.0-mm fraction--more than 30 percent
*Volcanic glass in the 0.02- to 2.0-mm fraction--5 to 20 percent
Particle-size control section
*Clay content--35 to 55 percent
*Total rock fragment content--35 to 75 percent
A horizon
Hue--7.5YR or 10YR dry or moist
Value--2.5 to 4 moist, 4 or 5 dry
Chroma--1 or 2 moist, 2 or 3 dry
Fine-earth texture--ashy loam
Clay content--15 to 27 percent
Sand content--25 to 50 percent
Organic matter content--4 to 8 percent
Total rock fragment content--15 to 60 percent
Gravel content--5 to 40 percent
Cobble content--10 to 35 percent
Stone content--0 to 15 percent
Reaction--5.6 to 6.5
2Bt horizon
Hue--7.5YR or 10YR dry or moist
Value--3 to 4 moist, 4 or 5 dry
Chroma--2 to 4 moist or dry
Fine-earth texture--clay, clay loam
Clay content--30 to 60 percent
Sand content--25 to 45 percent
Organic matter content--1 to 4 percent
Total rock fragment content--35 to 90 percent
Gravel content--15 to 50 percent
Cobble content--15 to 50 percent
Stone content--5 to 20 percent
Reaction--5.6 to 6.5
COMPETING SERIES:
Hafmau--sandy loam ash-influenced layers; ash influence more than 18 cm thick in upper part
Polecreek--no volcanic ash in upper part
GEOGRAPHIC SETTING:
Elevation--1170 to 1650 m
Climate--cool, wet winters; hot, dry summers
Mean annual precipitation--420 to 680 mm
Mean annual temperature--2 to 7 degrees C
Frost-free season--25 to 130 days
GEOGRAPHICALLY ASSOCIATED SOILS: None given
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Saturation during normal years--none
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--moderately high over moderately low
USE AND VEGETATION:
Use--recreation, timber production, livestock grazing, wildlife habitat
Potential natural vegetation--ponderosa pine, common snowberry, pinegrass, Idaho fescue, elk sedge, heartleaf arnica, white spirea, American vetch, Wheeler bluegrass, baldhip rose, western juniper, blue wildrye, Douglas-fir, tailcup lupine, Saskatoon serviceberry, mountain brome, bluebunch wheatgrass, common yarrow, low Oregon grape
DISTRIBUTION AND EXTENT: Eastern Oregon; MLRA 10; small extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Malheur National Forest, Oregon; 2018
REMARKS:
Diagnostic horizons and other features recognized in this pedon
*Mollic epipedon--zone from 1 to 46 cm
*Argillic horizon--zone from 11 to 46 cm
*Volcanic glass--zone from 1 to 11 cm
*Particle-size control--zone from 11 to 46 cm
*Depth to lithologic discontinuity--11 cm
National Cooperative Soil Survey
U.S.A.