LOCATION BOULDERJUD WATentative Series
TAXONOMIC CLASS: Ashy over loamy-skeletal, amorphic over isotic, frigid Typic Udivitrands
TYPICAL PEDON: Boulderjud ashy silt loam, on a north-facing, linear, 60 percent slope under conifers at an elevation of 3,280 feet. (When described on July 9, 2001, the soil was moist throughout. Colors are for moist soil unless otherwise noted. All textures are apparent field textures.)
Oi--0 to 1 inch; slightly decomposed needles and twigs.
Oe--1 to 2 inches; moderately decomposed organic matter. (Combined thickness of the O horizons is 2 to 3.5 inches)
A--2 to 6 inches; dark brown (7.5YR 3/4) ashy silt loam, brown (7.5YR 5/4) dry; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and slightly plastic; many very fine and fine roots; many very fine and fine irregular and tubular pores; 5 percent fine gravel; neutral (pH 6.8); clear wavy boundary. (2 to 8 inches thick)
Bw--6 to 16 inches; dark yellowish brown (10YR 4/6) ashy silt loam, brownish yellow (10YR 6/6) dry; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and slightly plastic; many very fine and fine, common medium and few coarse roots; common very fine and fine irregular and tubular pores; 10 percent fine gravel; neutral (pH 7.0); abrupt wavy boundary. (10 to 19 inches thick)
2Bt--16 to 26 inches; brown (10YR 4/3) very gravelly sandy loam, pale brown (10YR 6/3) dry; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine tubular pores; 5 percent distinct clay bridging between sand grains; 35 percent fine and 10 percent medium gravel; neutral (pH 6.8); clear wavy boundary. (6 to 16 inches thick)
2BC--26 to 36 inches; yellowish brown (10YR 5/6) very gravelly sandy loam, very pale brown (10YR 7/4) dry; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; many fine interstitial pores; 35 percent gravel and 10 percent cobbles; 10 percent fine mica flakes; neutral (pH 6.6); gradual wavy boundary. (2 to 15 inches thick)
2C--36 to 56 inches; light olive brown (2.5Y 5/3) very cobbly loamy sand, pale yellow (2.5Y 8/3) dry; massive; slightly hard, friable, nonsticky and nonplastic; few very fine roots; many very fine interstitial pores; 30 percent gravel and 20 percent cobbles; 10 percent fine and medium mica flakes; neutral (pH 6.7); clear irregular boundary. (0 to 10 inches thick)
2Cr--56 to 79 inches; weakly cemented highly weathered granitics with less than 5 percent pockets of finer material. Can be dug easily with a spade.
TYPE LOCATION: Spokane County, Washington; About 4 miles east of Elk, WA, about 2600 feet east and 650 feet south of the northwest corner of section 17, T. 29 N., R. 45 E; USGS Camden topographic quadrangle; (Latitude 48 degrees, 0 minutes, 51.51 seconds N. and Longitude 117 degrees, 8 minutes, 43.15 seconds W.) NAD 83.
RANGE IN CHARACTERISTICS:
(Depth to diagnostic horizons and features are measured from the top of the first mineral layer.)
Depth to weathered bedrock -40 to 60 inches
Mean annual soil temperature - 42 to 45 degrees F
Average summer soil temperature - 48 to 50 degrees F. with an O horizon
Soil moisture - dry for less than 25 to 35 consecutive days in August and September in all parts between depths of 4 and 12 inches - moist - from mid-September through July
Volcanic ash mantle -15 to 25 inches thick
Estimated properties of the ash influenced layer:
Volcanic glass content - 30 to 65 percent,
Acid-oxalate extractable Al + 1/2 Fe -1.0 to 3.0 percent
Phosphate retention -55 to 90 percent
15 bar water retention on air dried samples - 7 to 12 percent
A horizon
Hue - 10YR or 7.5YR
Value - 2 to 4 moist and 3 to 5 dry
Chroma -2 to 4 moist or dry
Clay content - 5 to 8 percent
Gravel content - 0 to 5 percent fine
Bw horizon
Hue of 10YR or 7.5YR,
Value - 3 or 4 moist and 4 to 6 dry
Chroma - 4 to 6 moist or dry
Clay content - 5 to 8 percent
Gravel (fine) content - 0 to 10 percent
Reaction - slightly acid or neutral
2Bt or 2Bw horizon
Hue -10YR or 7.5YR
Value - 3 to 5 moist and 4 to 7 dry
Chroma - 3 to 6 moist or dry
Texture - GRV-L, CBV-SL, GRV-SL
Gravel content - 15 to 45 percent
Cobble content - 0 to 20 percent
Rock fragment (total) content - 40 to 60 percent
Clay content - 5 to 10 percent
Lamellae - few thin faint and discontinuous, present in some pedons
Clay bridging between sand grains - 0 to 5 percent faint
Reaction - strongly acid to neutral
2C horizon - when present
Hue - 2.5Y or 10YR
Value - 4 to 6 moist and 6 to 8 dry
Chroma -3 or 4 moist or dry.
Texture - GRV-LS, CBV-LS, GRV-LCOS
Gravel content - 30 to 55 percent gravel
Cobble content - and 0 to 20 percent
Rock fragment (total) content - 40 to 60 percent
Clay content - 2 to 5 percent
Reaction - strongly acid to neutral
COMPETING SERIES: These are the Ferguson, and Honeyjones , series. Ferguson soils are more than 60 inches to bedrock and are dominated by subrounded and rounded rock fragments of glacial origin in the lower particle-size control section. Honeyjones soils are more than 60 inches to bedrock, have silt loam and loam textures and have 65 to 90 percent rock fragments in the substratum. The Bouldercreek and Stevie soils have a similar classification except for mixed mineralogy. They are all more than 60 inches to bedrock. In addition, Bouldercreek soils have 70 to 85 percent rock fragments in the substratum. Stevie soils have 2E/Bw horizons, and have 60 to 80 percent rock fragments in the substratum.
GEOGRAPHIC SETTING: The Boulderjud soils are on moderately dissected mountain backslopes. Slope ranges from 15 to 60 percent. The soils formed in a thick layer of coarse silty volcanic ash over weathered residuum from quartz-monzonite and other granitics. Elevations are 3,000 to 4,400 feet. The climate is characterized by cool moist winters and warm dry summers. The mean annual precipitation is 30 to 40 inches. The mean annual temperature is 42 to 46 degrees F. The frost-free period is 80 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brodeer, Hysing, and Jacot soils. Brodeer soils are ashy over loamy with more than 18 percent clay in the lower part of the control section and are on adjacent footslopes at lower elevations. Hysing soils are ashy over sandy or sandy-skeletal and are on highly dissected adjacent convex foothill slopes at lower elevations. Jacot soils are ashy over loamy with less than 18 percent clay in the lower part of the control section and are on highly dissected linear foothill slopes at lower elevations.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate in the subsoil and rapid in the substratum.
USE AND VEGETATION: These soils are used for rural homesites, timber production, recreation, water supply, and wildlife habitat. Potential natural vegetation is western hemlock, western redcedar, grand fir, Douglas-fir, western larch, lodgepole pine, western white pine, Rocky Mountain maple, with an understory of British Columbia wild ginger, bride's bonnet, Idaho goldthread, longtube twinflower, oneleaf foamflower, darkwoods violet, Piper's anemone, pyrola, pipsissewa, and starry false lily of the valley.
DISTRIBUTION AND EXTENT: Eastern Washington, U.S.A.; MLRA 43. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Spokane County, Washington, 1999. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Ochric epipedon - the zone from 2 to 6 inches (A horizon)
Cambic horizon - the zone from 6 to 26 inches (Bw and 2Bthorizons)
Andic soil properties - the zone from 2 to 16 inches (A and Bw horizons).
Particle-size control section - the zone from 2 to 42 inches (A, Bw, 2Bt, 2BC and part of the 2C horizon)
The type location for Boulderjud series was moved to reflect isotic mineralogy which is assumed typical for the series in the western hemlock/wild ginger habitat type.
ADDITIONAL DATA: Laboratory data available for sample number S00WA-063-005 Spokane County, Washington; NSSL, Lincoln, NE.