LOCATION CAPEHORN ID
Established Series
Rev. CJW-GHL-KLS
01/2023
CAPEHORN SERIES
The Capehorn series consists of very deep, poorly drained soils that formed in glacial outwash and alluvium derived dominantly from granite, gneiss and schist, with a mantle of volcanic ash and loess. These soils are on small valley bottoms, low stream terraces and floodplains, and have slopes of 0 to 2 percent. Mean annual precipitation is about 910 mm and mean annual air temperature is about 6 degrees C.
TAXONOMIC CLASS: Medial over sandy or sandy-skeletal, mixed, nonacid Aeric Cryaquepts
TYPICAL PEDON: Capehorn silt loam - on a 1 percent slope in a cutover forested area. When described, the soil was moist throughout. (Colors are for moist soil unless otherwise stated.)
Oi--0 to 3 cm; needles, leaves, and twigs.
Oe--3 to 6 cm; decomposed organic matter.
E--6 to 9 cm; discontinuous light gray volcanic ash layer.
A--9 to 24 cm; dark yellowish brown (10YR 3/4) silt loam, yellowish brown (10YR 5/4) dry; moderate fine and medium granular structure; soft, very friable, slightly plastic; many very fine, common fine and medium roots; many very fine and common fine tubular pores; few fine iron and manganese stains; 5 percent fine pebbles; moderately acid (pH 6.0); clear wavy boundary. (8 to 18 cm thick)
Bs--24 to 44 cm; dark yellowish brown (10YR 4/4) gravelly silt loam, light yellowish brown (10YR 6/4) dry; weak medium and coarse sub- angular blocky structure; soft, very friable, slightly plastic; common very fine, fine, and few medium roots; common very fine and few fine tubular pores; few fine iron and manganese stains; 15 percent fine pebbles; moderately acid (pH 6.0); abrupt wavy boundary. (20 to 36 cm thick)
2Cg1--44 to 80 cm; light brownish gray (10YR 6/2) very gravelly loamy sand, very pale brown (10YR 8/2) dry; many medium and large prominent strong brown (7.5YR 5/6) mottles; single grain; loose; few very fine and fine roots; many very fine interstitial pores; 35 percent pebbles; slightly acid (pH 6.4); clear wavy boundary. (30 to 41 cm thick)
2Cg2--80 to 159 cm; light brownish gray (10YR 6/2) very gravelly sand, very pale brown (10YR 8/2) dry; many medium and large prominent strong brown (7.5YR 5/6) mottles; single grain; loose; few very fine roots; many very fine interstitial pores; 35 percent pebbles and 20 percent cobbles; slightly acid (pH 6.4).
TYPE LOCATION: Bonner County, Idaho; about 320 meters northwest of Indian Creek State Campground near Priest Lake; 185 meters south and 410 meters west of the northeast corner, sec. 27, T. 61 N., R. 4 W
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--4 to 7 degrees C
Mean summer soil temperature--6 degrees C
Volcanic ash mantle--0 to 3 cm
Depth to high water table: winter and spring--0 to 4 cm; summer and fall--0.5 to 1.5 meters
Solum thickness--30 to 50 cm
A horizon
Color hue--10YR or 2.5Y
Value--3 or 4 moist, 5 or 6 dry
Chroma --2 to 4, moist or dry
Rock fragment content--0 to 15 percent
Reaction--pH 5.1 to 6.0
Bs horizon
Hue--10YR or 2.5Y
Value--3 to 5 moist, 6 or 7 dry
Chroma--2 to 4, moist or dry
Texture--gravelly silt loam, silt loam, or very fine sandy loam
Mottles--few faint mottles may occur in the lower part of some pedons
Rock fragment content--0 to 20 percent
Reaction--pH 5.1 to 6.0
2Cg horizons
Hue--10YR, 2.5Y, or 5Y
Value--5 or 6 moist, 6 to 8 dry
Chroma--1 or 2, moist or dry
Mottles, moist color: Hue--5YR, 7.5YR, or 10YR; Value--4 or 5; Chroma--4 to 8
Rock fragment content--25 to 60 percent gravel, 0 to 20 percent cobbles, 0 to 5 percent stones
Reaction--pH 5.6 to 7.3
COMPETING SERIES: This is the
Hoodoo series in another family. Hoodoo soils are medial and have a frigid temperature regime.
GEOGRAPHIC SETTING:
Landform--small valley bottoms, low stream terraces, and floodplains
Elevations--630 to 1280 meters
Slopes--0 to 2 percent
Parent material--glacial outwash and alluvium with a mantle of volcanic ash and loess
Mean annual precipitation--760 to 1100 mm
Mean annual air temperature--5 to 6 degrees C
Frost-free period--60 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed
DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff. Moderate permeability in the solum and very rapid in the substratum. The soils are commonly flooded during the winter and spring months for long periods. They have a high water table at depths of 0 to 50 cm during winter and spring months.
USE AND VEGETATION: These soils are used for timber production, wildlife habitat, recreation, grazing and limited hay and pasture. Natural vegetation is mainly western hemlock, western redcedar, western white pine, black cottonwood, quaking aspen, paperbirch, sitka alder, and willow with an understory of Oregon boxleaf, rose, twinflower, violet, Piper's anemone, goldthread, thimbleberry, and devilsclub.
DISTRIBUTION AND EXTENT: Capehorn soils are inextensive in the panhandle area of Northern Idaho; MLRAs 43A and 44A.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Bonner County, Idaho, 1981
REMARKS: Converted to metric and O horizons were updated to start at zero. Competing series section was not updated. 12/2022
National Cooperative Soil Survey
U.S.A.