LOCATION ELKRIDGE IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Andic Hapludalfs
TYPICAL PEDON: Elkridge ashy silt loam--on a 55 percent northwest-facing slope at an elevation of 2,780 feet - forested. (Colors are for dry soil unless otherwise stated.)
Oi--0 to 1.5 inches; undecomposed needles, twigs, moss, and leaves. (O horizons are is 1.5 to 2 inches thick)
A--1.5 to 6 inches; dark yellowish brown (10YR 4/4) ashy silt loam, dark brown (7.5YR 3/4) moist; weak fine granular structure; soft, very friable; many very fine roots; many very fine irregular pores; 5 percent gravel; neutral (pH 6.8); clear wavy boundary. (2 to 7 inches thick)
Bw--6 to 13 inches; yellowish brown (10YR 5/4) ashy silt loam, dark brown (7.5YR 3/4) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky; many very fine and fine roots; many very fine irregular pores; 5 percent gravel; neutral (pH 6.8); clear wavy boundary. (3 to 8 inches thick)
2Bt1--13 to 24 inches; brown (10YR 5/3) gravelly silt loam, brown (7.5YR 4/4) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, common fine and medium roots; many very fine irregular, many very fine and fine tubular pores; 15 percent gravel and 10 percent cobbles; common faint clay films of faces of peds and lining pores; many faint bleached silt coats on faces of peds; slightly acid (pH 6.4); clear smooth boundary. (6 to 12 inches thick)
2Bt2--24 to 41 inches; pale brown (10YR 6/3) very gravelly silt loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, common fine and medium roots; common very fine and fine tubular, common very fine irregular pores; 40 percent gravel and 10 percent cobbles; common faint clay films on faces of peds and lining pores; many faint silt coats on faces of peds; slightly acid (pH 6.2); clear smooth boundary. (12 to 18 inches thick)
2Bt3--41 to 54 inches; pale brown (10YR 6/3) extremely gravelly silt loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine and few fine roots; common very fine and fine tubular, common very fine irregular pores; 50 percent gravel and 20 percent cobbles; common faint and few distinct clay films on faces of peds and lining pores; common faint bleached silt coats on faces of peds; moderately acid (pH 6.0); gradual wavy boundary. (11 to 16 inches thick)
2Bt4--54 to 62 inches; light yellowish brown (10YR 6/4) extremely gravelly silty clay loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common very fine and few fine roots; common very fine and fine tubular common very fine irregular pores; 50 percent gravel and 20 percent cobbles; many faint and common distinct clay films on faces of peds and lining pores; common faint bleached silt coats on faces of peds; moderately acid (pH 6.0).
TYPE LOCATION: Clearwater County, Idaho; about 6 miles east of Southwick, Idaho; about 3,100 feet north and 1,100 feet east of the southwest corner of section 22, T. 38 N., R. 1 E.; Latitude - 46 degress, 37 minutes and 20 seconds North; Latitude - 116 degrees, 19 minutes and 29 seconds West. USGS Ahsahka Quadrangle.
RANGE IN CHARACTERISTICS:
Thickness of volcanic ash cap - 8 to 14 inches
Base saturation - 35 to 60 percent in argillic horizon
Average annual soil temperature - 39 to 45 degree F. Frigid temperature regime.
Soil moisture regime - not dry between depths of 4 to 12 inches for 45 consecutive days in summer and early fall. Udic moisture regime.
A horizon
Hue - 7.5YR or 10YR moist
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 3 or 4 dry, 2 to 4 moist
Textures - ASHY-SIL, GR-ASHY-SIL
Clay content - 8 to 15 percent
Rock fragments - 0 to 15 percent gravel
Reaction - moderately acid to neutral
Acid-oxalate extractable Al+1/2Fe - 1.2 to 2.25 percent
Bulk density - 0.65 to 0.95 g/cc
Bw horizon
Hue - 10YR or 7.5YR dry
Value - 5 or 6 dry, 3 or 4 moist
Textures - ASHY-SIL, GR-ASHY-SIL, GR-ASHY-L
Clay content - 8 to 18 percent
Rock fragments - 0 to 15 percent gravel
Reaction - slightly acid or neutral
Acid-oxalate extractable Al+1/2Fe - 1.2 to 2.35 percent
Bulk density - 0.75 to 1.2 g/cc
2Bt horizons
Hue - 10YR or 7.5YR dry, 2.5YR to 10YR moist
Value - 5 or 6 dry, 3 to 5 moist
Chroma - 3 to 6 dry, 2 to 4 moist
Textures - GRV-L, GRX-L, CB-L STX-L, GR-SIL, GRV-SIL, GRX-SIL, CB-SIL, CBV-SIL, GRV-CL, CBV-CL, CBX-CL, STX-CL, GR-SICL, GRV-SICL, GRX-SICL, CB-SICL, CBV-SICL, CBX-SICL
Clay content - 15 to 37 percent
Rock fragments - 15 to 50 percent gravel, 0 to 50 percent cobbles, 0 to 40 percent stones, 15 to 90 percent total rock fragment content (averages greater than 35 percent in upper 20 inches of the argillic)
Reaction - strongly acid to neutral
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Elkridge soils are on canyon sides, escarpments, valley sides, ridges, and hill slopes at elevations of 1,600 to 4,000 feet and have slopes of 20 to 75 percent. These soils have developed in volcanic ash and loess over material weathered from basalt rock. The average annual temperature ranges from 38 to 44 degrees F. The average annual precipitation ranges from 30 to 50 inches and the frost-free period is 50 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Grangemont, Kauder and Riswold soils. Grangemont soils are fine-silty and are on plateaus. Kauder soils are fine-silty, have a fragipan and are on plateaus. Riswold soils are ashy over loamy and are on canyon sides.
DRAINAGE AND PERMEABILITY: Well drained; runoff is rapid to very rapid on bare soil; permeability is moderately slow.
USE AND VEGETATION: This soil is used for timber production, woodland grazing, wildlife habitat, recreation and watershed. The natural vegetation is western red cedar, grand fir, Douglas fir, western larch, queencup beadlily, goldthread, Myrtle pachystima, sweetscented bedstraw and common prince's pine.
DISTRIBUTION AND EXTENT: Clearwater County, Idaho. The series is moderately extensive.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Clearwater County, Idaho, 2003.
REMARKS: The diagnostic horizons and other features recognized in this pedon are:
Andic soil properties - the zone from 1.5 to 13 inches. (A and Bw horizons)
Ochric epipedon - the zone from 1.5 to 6 inches (A horizon).
Cambic horizon - the zone form 6 to 13 inches (Bw horizon).
Argillic horizon - the zone from 13 to 62 inches (2Bt horizons).
Particle-size control section - the zone from 13 to 33 inches (2Bt1 and part of the 2Bt2 horizons).