LOCATION BESTROM WAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Vitrandic Haploxerepts
TYPICAL PEDON: Bestrom silt loam, woodland. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 0.5 inch; needles, leaves, and twigs; abrupt smooth boundary. (1/2 to 2 inches thick)
A--0.5 to 6 inches; grayish brown (10YR 5/2) ashy silt loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine and medium roots; many fine pores; 10 percent pebbles; neutral (pH 6.8); clear wavy boundary. (4 to 6 inches thick)
Bw1--6 to 11 inches; brown (10YR 5/3) gravelly loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and medium roots; common fine pores; 25 percent pebbles; neutral (pH 6.8); clear wavy boundary. (4 to 8 inches thick)
Bw2--11 to 16 inches; brown (10YR 5/3) gravelly loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and medium roots; common fine pores; 30 percent pebbles; neutral (pH 6.8); clear wavy boundary. (4 to 6 inches thick)
BC--16 to 24 inches; light yellowish brown (10YR 6/4) gravelly loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine and medium roots; few fine pores; 30 percent pebbles; neutral (pH 6.6); clear wavy boundary. (6 to 10 inches thick)
C--24 to 37 inches; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; massive; hard, friable, slightly sticky and slightly plastic; few fine and medium roots; few fine pores; 33 percent pebbles; neutral (pH 6.6). (0 to 13 inches thick)
2R--37 inches; basalt.
TYPE LOCATION: Stevens County, Washington; 50 feet south and 2,100 feet east of the NW corner of sec. 8, T. 29 N., R. 40 E., W.M.
RANGE IN CHARACTERISTICS: Depth to a lithic contact is 20 to 40 inches. The soil is moist in all horizons during part of the year, but is dry in all parts between depths of 8 and 24 inches or to a lithic contract of 60 to 80 consecutive days during summer and autumn. The volcanic ash mantle is 4 to 6 inches thick. Mean annual soil temperature is 47 degrees to 51 degrees F. The particle size control section has 5 to 35 percent rock fragments. The soil is slightly acid or neutral.
The A horizon has value of 4 or 5 dry, 2 or 3 moist and chroma of 2 or 3 moist and dry. It is loam or silt loam. It has 5 to 15 percent rock fragments.
The Bw horizon has value of 5 or 6 dry, 3 or 4 moist and chroma of 3 or 4 moist and dry. It is loam, silt loam, or sandy loam and has less than 0.6 percent organic carbon. It is 15 to 35 percent rock fragments.
The BC and C horizons have value of 5 or 6 dry, 3 or 4 moist and chroma of 3 or 4 moist and dry. They are loam or sandy loam and have 20 to 25 percent rock fragments.
COMPETING SERIES: These are the Barron, Cassolary, Clayton, Frailey, Green Bluff, Koerling, Koseth, Scala, Siskiyou and Stoner series. Barron, Clayton, Cassolary, Frailey, Green Bluff, Koerling, Loseth, Scala, and Stoner soils lack a lithic contact at a depth of 20 to 40 inches. Siskiyou soils have a paralithic contact at a depth of 20 to 40 inches.
GEOGRAPHIC SETTING: Bestrom soils are on glaciated uplands at elevations of 1,800 to 2,800 feet. Slopes are 0 to 40 percent. They formed in glacial till with a thin mantle of volcanic ash and loess and are underlain by basalt or granitic bedrock. The climate is characterized by warm, dry summers and cool moist winters. Mean annual precipitation is 18 to 21 inches. Mean annual temperature is 45 degrees to 49 degrees F. Frost-free season is 100 to 125 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bernhill and Dehart soils and the competing Clayton, Green Bluff, and Koerling soils. all of these soils lack a lithic contact at a depth of 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; very slow to very rapid runoff; moderate permeability.
USE AND VEGETATION: Used mainly for woodland and grazing. Small areas are cleared and small grains, alfalfa, and grass are the principal crops. Vegetation is ponderosa pine, Douglas-fir, wild rose, snowberry, hawthorne, ceanothus, pinegrass, Idaho fescue, bluebunch wheatgrass, and other annual grasses.
DISTRIBUTION AND EXTENT: Northeastern Washington. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Stevens County, Washington, 1978.
REMARKS: Diagnostic horizons and features:
Ochric epipedon- the zone from the soil surface to 6 inches (A horizon).
Cambic horizon - the zone from 7 to 24 inches (Bw and BC horizons).
Lithic contact - at 37 inches (top of 2R horizon)