LOCATION BREQUITO IDEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Andic Hapludalfs
TYPICAL PEDON: Brequito ashy silt loam, forested, on a 15 percent slope at 3,400 feet elevation. Aspect is north. When described on November 11, 1991, the soil was saturated to 17 inches and moist below to 64 inches. (Colors are for dry soil unless otherwise stated).
Oi--0 to 1 inch; fresh and partially decomposed needles, twigs, moss, and leaves.
Oe--1 to 3 inches; decomposed needles, twigs, moss, leaves, and roots.
A--3 to 5 inches; dark grayish brown (10YR 4/2) ashy silt loam, dark brown (7.5YR 3/3) moist; weak very fine and fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine irregular pores; 1 percent fine rounded iron-manganese concretions; neutral (pH 6.7); abrupt wavy boundary. (2 to 5 inches thick)
Bw--5 to 11 inches; light yellowish brown (10YR 6/4) ashy silt loam, dark brown (7.5YR 3/4) moist; weak fine and medium granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine irregular pores; 3 percent fine rounded iron-manganese concretions; neutral (pH 6.7); abrupt wavy boundary. (3 to 11 inches thick)
2B/E1--11 to 15 inches; B - yellowish brown (10YR 5/4) silt loam, brown (10YR 4/3) moist; E - pale brown (10YR 6/3), yellowish brown (10YR 5/4) moist; moderate medium to coarse subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; many very fine and fine and few coarse roots; common very fine and fine irregular and few very fine and fine tubular pores; common faint clay films on faces of peds; common distinct skeletans on faces of peds and in pores; 1 percent fine charcoal; 3 inch wide krotovina filled with volcanic ash; 1 percent fine mica flakes; neutral (pH 6.8); clear wavy boundary.
2B/E2--15 to 20 inches; B - light yellowish brown (10YR 6/4) silt loam, brown (10YR 5/3) moist; E - very pale brown (10YR 7/4), yellowish brown (10YR 5/4) moist; weak medium and coarse prismatic structure parting to moderate fine and medium subangular blocky; hard, firm, slightly sticky and slightly plastic; common fine and medium roots throughout and common coarse roots along ped faces; common very fine and fine irregular and tubular pores; common faint clay films on faces of peds; common distinct skeletans on faces of peds and in pores; 1 percent fine mica flakes; slightly acid (pH 6.3); gradual wavy boundary. (Combined thickness of 2B/E horizons is 0 to 16 inches)
2Bt1--20 to 28 inches; light yellowish brown (10YR 6/4) silty clay loam, yellowish brown (10YR 5/4) moist; moderate very coarse prismatic structure parting to moderate medium and coarse subangular blocky; very hard, firm, sticky and plastic; common very fine and fine and few medium and coarse roots along ped faces and few very fine and fine roots in interior of peds; common very fine and fine irregular and tubular pores; common, distinct clay films on faces of peds and in pores; 1 percent fine mica flakes; slightly acid (pH 6.1); gradual smooth boundary.
2Bt2--28 to 37 inches; very pale brown (10YR 7/4) silty clay loam, yellowish brown (10YR 5/4) moist; moderate very coarse prismatic structure parting to strong and coarse subangular blocky; very hard, firm, sticky and plastic; common fine and medium roots along ped faces and few very fine roots in interior of peds; few very fine and fine irregular and tubular pores; many distinct clay films on faces of peds and in pores; 2 percent fine mica flakes; 2 percent rounded quartz gravel; moderately acid (pH 5.6); clear irregular boundary.
2Bt3--37 to 48 inches; very pale brown (10YR 7/4) clay loam, yellowish brown (10YR 5/4) moist; weak very coarse prismatic structure parting to moderate medium and coarse subangular blocky; very hard, firm, sticky and plastic; common very fine and fine roots along ped faces; common very fine and fine irregular and tubular pores; common distinct clay films on faces of peds; 2 percent fine mica flakes; 2 percent rounded quartz gravel; moderately acid (pH 5.6); clear smooth boundary. (Combined thickness of the 2Bt horizons is 7 to 43 inches)
3BC--48 to 62 inches; very pale brown (10YR 8/4) loam, light yellowish brown (10YR 6/4) moist; weak very coarse prismatic structure parting to moderate medium and coarse subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and fine irregular and few very fine tubular pores; 0.5 to 1 inch thick clay bands 2 to 3 inches apart, dark yellowish brown (10YR 4/4) loam with common distinct clay films; 5 percent fine mica flakes; 5 percent gravel; strongly acid (pH 5.4); clear smooth boundary.
3C--62 to 67 inches; yellow (10YR 8/6) loam, light yellowish brown (10YR 6/4) moist; massive; slightly hard, friable, nonsticky and nonplastic; few very fine roots; common very fine and fine irregular pores; 0.13 to 0.25 inch thick clay bands in horizontal and vertical cracks, strong brown (7.5YR 4/6) loam; 5 percent gravel; strongly acid (pH 5.3).
TYPE LOCATION: Clearwater County, Idaho; about 4 miles east of Weippe, Idaho, about 400 feet north and 1,600 feet east of the southwest corner of sec. 9. T. 35 N., R. 5 E.; Latitude - 46 degrees, 23 minutes, 03 seconds North; Longitude - 115 degrees, 50 minutes, 27 seconds West.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 39 to 45 degrees F. Frigid temperature regime.
Soil moisture - usually moist year around and not dry for 45 consecutive days during June to October. Udic moisture regime.
Thickness of volcanic ash - 7 to 13 inches.
Volcanic glass content - 25 to 35 percent
A horizon
Hue - 7.5YR or 10YR
Value - 4 to 6 dry, 2.5 or 3 moist
Chroma - 2 to 4 dry or moist
Texture - ASHY-SIL, ASHY-L, GR-ASHY-L
Clay content - 8 to 12 percent
Rock fragments - 0 to 15 percent gravel
Reaction - strongly acid to neutral
Bulk density - 0.65 to 0.90 g/cc
Ammonium oxalate extractable Al plus 1/2 Fe - 1.2 to 2.25
Bw horizon
Hue - 7.5YR or 10YR
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 or 4 moist
Texture - ASHY-SIL, ASHY-L
Clay content - 8 to 12 percent
Rock fragments - 0 to 5 percent gravel
Reaction - strongly acid to neutral
Bulk density - 0.75 to 1.20 g/cc
Ammonium oxalate extractable Al plus 1/2 Fe - 1.0 to 2.35
2Bw horizon (present in some pedons)
Hue - 7.5YR or 10YR moist
Value - 5 or 6 dry, 4 moist
Chroma - 3 or 4 dry or moist
Clay content - 17 to 20 percent
Rock fragments - 0 to 5 percent gravel
Reaction - moderately acid or slightly acid
2EB or 2BE horizons (present in some pedons)
Hue - 10YR dry, 7.5YR or 10YR moist
Value - 6 dry, 3 to 5 moist
Chroma - 4 dry, 3 or 4 moist
Clay content - 16 to 18 percent
Rock fragments - 0 to 1 percent gravel
Reaction - moderately acid
2B/E horizons
B part:
Hue - 7.5YR or 10YR
Value - 5 to 7 dry, 3 to 5 moist
Chroma - 3 or 4 dry, 3 to 6 moist
Texture - SIL, L, CL, SCL
Clay content - 18 to 27 percent
E part:
Hue - 7.5YR or 10YR
Value - 5 to 7 dry, 3 to 5 moist
Chroma - 3 or 4 dry, 3 to 8 moist
Texture - L, SIL
Clay Content - 16 to 20 percent
Rock fragments - 0 to 5 percent gravel
Reaction - strongly acid to neutral
2Bt horizons
Hue - 7.5YR or 10YR
Value - 4 to 7 dry, 3 to 6 moist
Chroma - 2 to 6 dry or moist
Texture - L, CL, SICL, SIL, GR-L, GR-SIL, PGR-L
Clay Content - 18 to 32 percent
Rock fragments - 0 to 15 percent gravel, 0 to 5 percent cobbles, 0 to 20 percent total rock fragments
Reaction - very strongly acid to slightly acid
3Bt horizons (present in some pedons)
Hue - 5YR to 10YR
Value - 4 to 7 dry, 3 to 5 moist
Chroma - 2 to 6 dry, 3 to 6 moist
Texture - L, SCL, CL, SL, GR-L, SIL
Clay Content - 16 to 27 percent
Rock fragments - 0 to 20 percent gravel, 0 to 2 percent cobbles, 0 to 22 percent total rock fragments
Reaction - very strongly acid or strongly acid
3BC horizon (absent in some pedons)
Hue - 7.5YR or 10YR dry, 2.5YR to 10YR moist
Value - 6 to 8 dry, 4 to 6 moist
Chroma - 4 to 6 moist
Texture - L, SL, GR-L, GRV-L, CBV-SL, LS, GR-SICL
Clay Content - 10 to 28 percent
Coarse fragments - 0 to 40 percent gravel, 0 to 20 percent cobbles, 0 to 45 percent total rock fragments
Reaction - very strongly acid to moderately acid
3C horizon (absent in some pedons)
Hue - 7.5YR or 10YR moist
Value - 5 to 8 dry, 4 to 6 moist
Chroma - 4 to 6 dry, 3 to 6 moist
Texture - L, SL, SCL, GR-SL, GR-LS, GRV-SL
Clay Content - 5 to 22 percent
Rock fragments - 5 to 45 percent gravel
Reaction - extremely acid to moderately acid
COMPETING SERIES: These are the Bandmill, Riswold and Scaler series. Bandmill and Riswold soils have greater than 26 percent clay below 40 inches. Scaler soils are paramicaceous in the subsoil.
GEOGRAPHIC SETTING: Brequito soils are on mountain slopes, ridges, and summits at elevations of 1,600 to 4,300 feet with slopes of 5 to 75 percent. These soils are formed in loess over colluvium and residuum from granitic and low mica metamorphic rock with a thin mantle of volcanic ash. The average annual temperature is 38 to 44 degrees F. and the average precipitation is 25 to 55 inches. The frost free season is 50 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brodeer, Mushel, and Lado series. Brodeer soils are on steep concave mountain side slopes, have thick volcanic ash mantles, and less than 24 percent clay in the argillic horizon. Mushel soils are on convex mountain side slopes, have thin volcanic ash mantles, and less than 20 percent clay in the argillic horizon. Lado soils are on concave mountain side slopes, have thick volcanic ash mantles, and more than 24 percent clay in the argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained, medium to very rapid runoff, moderately slow permeability.
USE AND VEGETATION: These soils are used for timber production, livestock grazing, wildlife habitat, watershed, and recreation. Potential natural vegetation is western red cedar, grand fir, western larch, western white pine, Douglas-fir, and ponderosa pine with an understory of queencup beadlily, coolwort foamflower, princes pine, western goldthread, and bunchberry dogwood.
DISTRIBUTION AND EXTENT: North Central Idaho. Brequito soils are moderately extensive.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Clearwater County, Idaho, 2003.
REMARKS: Diagnostic horizons and other features recognized in this pedon are:
Ochric epipedon - The zone from 3 to 11 inches (A and Bw horizons).
Argillic horizon - The zone from 11 to 48 inches (2B/E1, 2B/E2, 2Bt1, 2Bt2 and 2Bt3 horizons).
Particle size control section - The upper 20 inches of the argillic horizon (2B/E1, 2B/E2, 2Bt1, and part of 2Bt2 horizons).
ADDITIONAL DATA: Laboratory data is available for this series: Soil survey sample no. S92ID-035-030 (project no. 92P 181, pedon no. 92P968) (this pedon) from Clearwater County Idaho by NSSL, Lincoln, NE.