LOCATION JACOT ID+WAEstablished Series
TAXONOMIC CLASS: Ashy over loamy, amorphic over isotic, frigid Alfic Udivitrands
TYPICAL PEDON: Jacot ashy silt loam, forest, on a northwest-facing slope of 40 percent at 2,900 feet elevation. When described on June 29, 1982, the soil was slightly moist throughout.
Oi--0 to 0.5 inches; slightly decomposed needles, leaves and twigs.
Oe--0.5 to 2 inches; decomposed organic matter mixed with Mt. St. Helen's volcanic ash.
A--2 to 6 inches; pale brown (10YR 6/3) ashy silt loam, brown (10YR 4/3) moist; weak fine subangular blocky structure parting to moderate fine granular; soft, very friable; nonsticky and slightly plastic; many very fine, fine and few medium and coarse roots; many very fine and fine tubular pores; 10 percent gravel; slightly acid (pH 6.5); clear wavy boundary. (2 to 4 inches thick)
Bw--6 to 16 inches; light yellowish brown (10YR 6/4) ashy silt loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and slightly plastic; many very fine, common fine, and medium, and a few coarse roots; common very fine and fine tubular pores; 10 percent gravel; neutral (pH 6.8); clear wavy boundary. (10 to 24 inches thick)
2Bt1--16 to 22 inches; very pale brown (10YR 7/4) gravelly sandy loam, yellowish brown (10YR 5/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine and medium roots; common very fine tubular and many very fine and fine irregular pores; few faint clay films on faces of peds and in pores; 20 percent gravel; strongly acid (pH 5.5); clear wavy boundary. (6 to 12 inches thick)
2Bt2--22 to 42 inches; pale yellow (2.5Y 7/4) gravelly sandy loam, light olive brown (2.5Y 5/4) moist; weak medium and coarse subangular blocky structure; slightly hard, friable, nonsticky and slightly plastic; few very fine, fine and medium roots; many very fine and fine irregular pores; few faint clay films on faces of peds and in pores; 25 percent gravel; strongly acid (pH 5.5); clear wavy boundary. (18 to 23 inches thick)
2C1--42 to 50 inches; pale yellow (2.5Y 8/4) gravelly loamy sand, light yellowish brown (2.5Y 6/4) moist; massive; slightly hard, friable, nonsticky and nonplastic; few very fine roots; many very fine and fine irregular pores; 30 percent gravel; moderately acid (pH 5.7); gradual wavy boundary. (9 to 11 inches thick)
2C2--50 to 62 inches; pale yellow (2.5Y 8/4) very gravelly loamy sand, light yellowish brown (2.5Y 6/4) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; many very fine and fine irregular pores; 45 percent gravel; moderately acid (pH 5.7).
TYPE LOCATION: Shoshone County, Idaho; approximately 2 miles west of the community of Marble Creek; about 1,500 feet east and 2,000 feet north of the southwest corner of Section 10, T. 45 N., R. 3 E.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry for 25 to 35 consecutive days, moist in the fall through early summer, dry August to September. Udic moisture regime.
Average annual soil temperature - 42 to 46 degrees F.
Average summer soil temperature - 47 to 50 degrees F. with an 0 horizon. Frigid temperature regime.
Depth to bedrock - greater than 60 inches
Solum thickness - 36 to 52 inches
Volcanic ash mantle
Thickness - 14 to 28 inches
Volcanic glass content - 40 to 60 percent
Acid-oxalate extractable Al plus 1/2 Fe - 1.0 to 2.0 percent
Phosphate retention - 60 to 70 percent
15-bar water retention - 7 to 12 percent
Moist bulk density - 0.65 to 0.90 g/cc
A horizon
Hue - 10YR or 7.5YR
Value - 3 to 6 dry, 2.5 to 4 moist
Chroma - 2 to 4 dry and moist
Textures - ASHY-SIL, GR-ASHY-SIL
Gravel - 0 to 20 percent
Bulk density - 0.65 to 0.85 g/cc
Reaction - strongly acid to neutral
Bw horizons
Hue - 7.5YR or 10YR
Value - 5 to 7 dry, 3 or 4 moist
Chroma - 2 to 4 dry and moist
Textures - ASHY-SIL, GR-ASHY-SIL, ASHY-L
Gravel - 3 to 20 percent
Bulk density - 0.65 to 0.85 g/cc
Reaction - strongly acid to neutral
2Bt horizons
Hue - 7.5YR or 10YR moist
Value - 5 to 8 dry, 3 to 6 moist
Chroma - 4 to 6 dry, 3 or 4 moist
Textures - L, SL, GR-L, GR-SL, FSL, COSL
Clay content - 5 to 18 percent
Rock fragments - 3 to 30 percent, mainly gravel with 0 to 6 percent cobbles
Reaction - very strongly acid to slightly acid
2BC horizons
Hue - 10YR or 2.5Y dry or moist
Value - 4 to 6 moist
Chroma - 3 to 6 moist
Textures - LS, LCOS, GR-COSL, GR-LS, GR-LCOS
Clay content - 3 to 19 percent
Rock fragments - 0 to 15 percent gravel, 0 to 5 percent cobbles, 0 to 20 percent total rock fragment content
Reaction - strongly acid or moderately acid
2C horizon
Hue - 10YR or 2.5Y
Value - 7 or 8 dry and 5 to 7 moist
Chroma - 3 to 6 dry and 2 to 6 moist
Textures - GR-COS, GR-LS, GR-LCOS, GRV-COS, GRV-LS, GRV-LCOS, LS, LCOS
Clay content - 3 to 10 percent
Rock fragments - 0 to 55 percent, mainly gravel, with 0 to 5 percent cobbles
Reaction - very strongly acid to slightly acid
Base saturation - 35 to 50 percent
COMPETING SERIES: These are the Mackatie and Tamara series. Mackatie soils are deep to a paralithic contact. Tamara soils have 2Btb horizons with greater than 20 percent clay.
GEOGRAPHIC SETTING: Jacot soils are on all aspects of foothills, mountain slopes and ridges. These soils formed in material weathered from gneiss or granitic bedrock with a thick mantle of volcanic ash. Slopes are 5 to 80 percent. Elevations are 2,200 to 5,200 feet. The climate is cool, humid with warm, moist summers and cool, wet winters. The average annual precipitation is 30 to 50 inches; average annual temperature is 38 to 45 degrees F; and the frost-free season is 50 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the proposed Blackprince(T), Hugus(T), and Keeler(T) soils, and the Garveson and Kruse soils. Blackprince soils are on south-facing convex slopes and are xeric and loamy-skeletal. Garveson soils are on convex foothill slopes and are medial over sandy or sandy-skeletal. Hugus soils are on north-facing foothills and dissected terraces and are loamy-skeletal. Keeler and Kruse soils are fine-loamy and are on south, east, and west-facing foothill slopes.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability in the upper part and rapid to very rapid permeability in the lower part.
USE AND VEGETATION: These soils are used for timber production, livestock grazing, recreation, wildlife habitat, and watershed. Potential natural vegetation is mainly western hemlock, western redcedar, western white pine, grand fir, Douglas fir, western larch, and lodgepole pine, with an understory of queencup beadlily, American trailplant, Columbia brome, violet, starry false-Solomon's-seal, sweetscented bedstraw, goldthread, longtube twinflower, Oregon fairybells, oneleaf foamflower, piper anemone, and western rattlesnake plantain.
DISTRIBUTION AND EXTENT: Northern Idaho. This soil is not extensive.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Benewah County, Idaho, 1975.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 2 to 6 inches (A horizon).
Cambic horizon - The zone from 6 to 16 inches (Bw horizon).
Argillic horizon - The zone from 16 to 42 inches (2Bt1 and 2Bt2 horizons).
Volcanic ash mantle - The zone from 2 to 16 inches (A and Bw horizons).
Particle size control section - The zone from 2 to 42 inches (The A, Bw, 2Bt1, and 2Bt2 horizons).