LOCATION ELKRIDGE ID

Established Series
Rev. PNP-BDG-EMM
06/2013

ELKRIDGE SERIES

The Elkridge series consists of very deep, well drained soils on canyon sides, escarpments, valley sides, ridges, structural benches, and hill slopes. They formed in volcanic ash and loess over material weathered from basalt rock. Slopes are 10 to 75 percent. They have moderately high saturated hydraulic conductivity. The average annual precipitation is about 33 inches and the average annual temperature is about 42 degrees F.

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 silt loam
Clay content - 8 to 15 percent
Rock fragments - 0 to 15 percent gravel
Reaction - 5.8 to 7.0
Acid-oxalate extractable Al+1/2Fe - 1.2 to 2.25 percent
Bulk density - 0.60 to 0.95 g/cc

Bw horizon
Hue - 10YR or 7.5YR dry
Value - 5 or 6 dry, 3 or 4 moist
Textures - ashy silt loam or ashy loam
Clay content - 8 to 18 percent
Rock fragments - 0 to 15 percent gravel
Reaction - 6.1 to 7.0
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 - loam, silt loam, clay loam or silty clay loam
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 - 5.3 to 7.0

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Elkridge soils are on canyon sides, escarpments, valley sides, ridges, structural benches, and hill slopes at elevations of 1,600 to 4,000 feet (489 to 1219 meters) and have slopes of 10 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 46 degrees F. The average annual precipitation ranges from 29 to 50 inches (737 to 1270 mm) and the frost-free period is 50 to 120 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 SATURATED HYDRAULIC CONDUCTIVITY: Well drained; saturated hydraulic conductivity is moderately high.

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. MLRA43A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) 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).

National Cooperative Soil Survey
U.S.A.