LOCATION JACOT ID+WA

Established Series
Rev. SMM-RWL-RJS
10/2016

JACOT SERIES

The Jacot series consists of very deep, well drained soils on hillslopes, mountain slopes and ridges. They formed in colluvium weathered from gneiss or granitic bedrock with a thick mantle of volcanic ash. Slopes are 3 to 80 percent. The average annual precipitation is about 965 mm and the average annual temperature is about 6.1 degrees C.

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 884 meters elevation. When described on June 29, 1982, the soil was slightly moist throughout.

Oi--0 to 1 cm; slightly decomposed needles, leaves and twigs.

Oe--1 to 5 cm; decomposed organic matter mixed with Mt. St. Helens volcanic ash.

A--5 to 15 cm; 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. (5 to 10 cm thick)

Bw--15 to 40 cm; 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. (25 to 60 cm thick)

2Bt1--40 to 56 cm; 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. (15 to 30 cm thick)

2Bt2--56 to 107 cm; 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. (46 to 58 cm thick)

2C1--107 to 127 cm; 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. (20 to 30 cm thick)

2C2--127 to 157 cm; 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 457 meters east and 610 meters north of the southwest corner of Section 10, T. 45 N., R. 3 E. Latitude - 47 degrees, 15 minutes, 31.5 seconds W; Longtuide - 116 degrees, 4 minutes, 5.8 seconds N. NAD 83. USGS quadrangle - Marble Creek, ID.

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 (5.5 to 7.8 degrees C).
Average summer soil temperature - 47 to 50 degrees F. (8.3 to 10 degrees C) with an O horizon.
Depth to bedrock - greater than 150 cm
Solum thickness - 90 to 132 cm
Volcanic ash mantle*
*Thickness - 35 to 71 cm
*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 dry or moist
Value - 3 to 6 dry, 2.5 to 4 moist
Chroma - 2 to 4 dry or moist
Rock fragments - 0 to 20 percent gravel
Bulk density - 0.60 to 1.0 g/cc
Reaction - 5.4 to 7.3

Bw horizons
Hue - 7.5YR or 10YR dry or moist
Value - 5 to 7 dry, 3 or 4 moist
Chroma - 2 to 6 dry or moist
Textures - ashy silt loam, ashy loam or ashy fine sandy loam
Rock fragments - 0 to 20 percent gravel
Bulk density - 0.65 to 1.10 g/cc
Reaction - 5.3 to 7.3

2Bt1, 2Bt2 horizons
Hue - 7.5YR, 2.5Y or 10YR dry or moist
Value - 5 to 8 dry, 3 to 6 moist
Chroma - 3 to 6 dry, 3 or 4 moist
Textures - loam, fine sandy loam, sandy loam or coarse sandy loam
Clay content - 5 to 18 percent
Rock fragments - 2 to 30 percent gravel, 0 to 6 percent cobbles
Reaction - 4.6 to 6.5

2BC horizon - present in some pedons
Hue - 10YR or 2.5Y dry or moist
Value - 5 to 8 dry, 4 to 6 moist
Chroma - 3 to 6 dry or moist
Textures - sandy loam, coarse sandy loam, loamy sand or loamy coarse sand
Clay content - 3 to 19 percent
Rock fragments - 0 to 40 percent gravel, 0 to 5 percent cobbles
Reaction - 4.5 to 6.5

2C1, 2C2 horizons
Hue - 10YR or 2.5Y dry or moist
Value - 7 or 8 dry, and 5 to 7 moist
Chroma - 3 to 6 dry, and 2 to 6 moist
Textures - loamy sand, loamy coarse sand or coarse sand
Clay content - 3 to 10 percent
Rock fragments - 0 to 55 percent gravel, 0 to 5 percent cobbles
Reaction - 5.1 to 6.5
Base saturation - 35 to 50 percent

COMPETING SERIES:
Dowper - have greater than 20 percent clay in the lower subsoil
Mackatie - are deep to a paralithic contact
Turpentine - are deep to a paralithic contact
Secunda - have less than 15 percent coarse and very coarse sand and more than 40 percent very fine sand or fine sand in the subsoil beneath the ash cap
Tamara - have 2Btb horizons with greater than 20 percent clay
Tomodo - have fragic characteristics between 50 and 130 cm.
Turpentine - are deep to a paralithic and/or lithic contact

GEOGRAPHIC SETTING:
Landforms - hillslopes, mountain slopes and ridges
Elevations - 670 to 1,585 meters
Aspect - all aspects
Slopes - 3 to 80 percent
Parent material - colluvium weathered from gneiss or granitic bedrock with a thick mantle of volcanic ash
Mean annual precipitation - 625 to 1,350 mm
Mean annual air temperature - 3.3 to 7.2 degrees C.
Frost-free season - 50 to 120 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blackprince, Hugus, and Keeler 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 SATURATED HYDRAULIC CONDUCTIVITY: Well drained; moderately high saturated hydraulic conductivity in the upper part and high to very high 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 and eastern Washington. This soil is moderately extensive. MLRA 43A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Benewah County, Idaho, 1975.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - zone from 0 to 15 cm (Oi, Oe, A horizons).
Cambic horizon - zone from 15 to 40 cm (Bw horizon).
Argillic horizon - zone from 40 to 107 cm (2Bt1, 2Bt2 horizons).
Volcanic ash mantle - zone from 5 to 40 cm (A, Bw horizons).
Particle size control section - zone from 5 to 105 cm (A, Bw, 2Bt1, part of 2Bt2 horizons).

Additional information: Jacot soils should be further investigated to determine typical mineralogy (isotic vs. mixed), if mixed then the cation-exchange activity class will need to be evaluated.

National Cooperative Soil Survey
U.S.A.