LOCATION CONTO WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic Andic Haplocryods
TYPICAL PEDON: Conto ashy silt loam - on a north-northeast-facing convex slope of 40 percent under a coniferous forest at 5,200 feet elevation. (Colors are for dry soil unless otherwise stated.)
Oa--0 to 1 inch; decomposed needles, leaves, twigs, bark, cones, and mosses; abrupt smooth boundary. (0 to 12 inches thick)
E--1 to 4 inches; gray (10YR 6/1) ashy very fine sandy loam, dark gray (10YR 4/1) moist; weak fine subangular blocky structure; slightly hard, friable, nonsticky and slightly plastic; few very fine and fine, common medium, and coarse roots; 10 percent pebbles; very strongly acid (pH 4.6); abrupt wavy boundary. (1/2 to 4 inches thick)
Bs1--4 to 8 inches; brown (7.5YR 5/4) ashy silt loam, brown (7.5YR 4/4) moist; weak very fine and fine subangular blocky structure; soft, very friable, nonsticky and slightly plastic; moderately smeary; common very fine, fine, medium, and coarse roots; 10 percent pebbles; moderately acid (pH 5.6); clear wavy boundary. (1 to 4 inches thick)
Bs2--8 to 13 inches; brownish yellow (10YR 6/6) ashy silt loam, dark yellowish brown (10YR 4/6) moist; weak very fine and fine subangular blocky structure; soft, very friable, nonsticky and slightly plastic; weakly smeary; common very fine, fine, medium, and coarse roots; 10 percent pebbles; moderately acid (pH 5.8); clear wavy boundary. (4 to 7 inches thick)
2C1--13 to 18 inches; light yellowish brown (2.5Y 6/4) very gravelly sandy loam, olive brown (2.5Y 4/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; 35 percent pebbles and 5 percent cobbles; very strongly acid (pH 5.0); clear wavy boundary. (3 to 7 inches thick)
2C2--18 to 35 inches; olive (5Y 5/3) very gravelly sandy loam, olive (5Y 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots; 40 percent pebbles and 5 percent cobbles; very strongly acid (pH 4.8); clear wavy boundary. (15 to 20 inches thick)
2C3--35 to 60 inches; pale olive (5Y 6/3) very gravelly sandy loam, olive (5Y 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; very strongly acid; 45 percent pebbles and 10 percent cobbles; very strongly acid (pH 4.6).
TYPE LOCATION: Pend Oreille County, Washington; 10 miles northeast of Metaline Falls; 1,850 feet east and 1,600 feet north of the southwest corner of section 13, T. 40 N., R. 44 E., WM. (photo #F16-1373-5-100).
RANGE IN CHARACTERISTICS: The mean annual soil temperature at 20 inches ranges from 38 to 41 degrees F. Solum thickness and thickness of the volcanic ash and loess mantle is 7 to 14 inches. The particle-size control section averages 35 to 60 percent coarse fragments. Soil reaction ranges from very strongly acid to moderately acid.
The E horizon has value of 6 or 7 dry, 4 or 5 moist, and chroma of 1 or 2 dry or moist.
The Bs1 horizon has hue of 5YR and 7.5YR, value of 5 through 7 dry, 3 or 4 moist, and chroma of 4 through 6 dry, 3 or 4 moist. It is ashy sandy loam or ashy silt loam. In some pedons, at higher elevations, the upper part of the Bs has brittle, slightly hard to hard consistence and has moist hue of 2.5YR.
The Bs2 horizon has hue of 5YR, 7.5YR, or 10YR, value of 5 through 7 dry, 3 or 4 moist, and chroma of 4 through 6 dry, 3 or 4 moist. It is ashy sandy loam or ashy silt loam.
The 2C horizon has hue of 10YR, 2.5Y, or 5Y, value of 5 or 6 dry and chroma of 3 or 4 dry and moist. Coarse fragments average from 35 to 60 percent.
COMPETING SERIES: These are the Nimue and Springsteen series. The Nimue soils have a loamy sand E horizon and receive 70 to 120 inches of precipitation. The Springsteen soils are moderately deep to a paralithic contact.
GEOGRAPHIC SETTING: Conto soils are on foothills at elevations of 4,000 to 5,800 feet. They formed in glacial till with a mantle of volcanic ash and loess. Slopes range from 0 to 65 percent and usually have long and concave surfaces. The mean annual precipitation ranges from 40 to 50 inches. The frost-free season is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Belzar, Brickel, Buhrig, Huckleberry, and Threemile, and the competing Uncas soiils. All these soiis except Deemer and Uncas soils lack a spodic horizon. In addition, Belzar soils are frigid and 20 to 40 inches deep to limestone. Brickel soils have a mollic epipedon. Buhrig soils are 20 to 40 inche deep to bedrock. Deemer soils are medial-skeletal. Huckleberry soils are medial over loamy-skeletal. Threemile soils are frigid.
DRAINAGE AND PERMEABILITY: Well drained; slow to very rapid runoff; moderate permeability.
USE AND VEGETATION: Woodland, wildlife habitat, watershed, and recreation. Native vegetation includes Douglas-fir, grand fir, subalpine fir, western hemlock, Engelmann spruce, western redcedar, western larch and lodgepole pine, with an understory of Sitka alder, common beargrass, prince's pine, pachystima, common snowberry, ceanothus, serviceberry, strawberry, and fescue.
DISTRIBUTION AND EXTENT: Northeastern Washington State. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Pend Oreille County Area, Washington, l981.
REMARKS: Diangostic horizons and features recognized in this pedon are an albic horizon from 1 to 4 inches, a spodic horizon from 4 to 13 inches formed in volcanic ash, with an estimated moist bulk density of less than 1.0 g/cc and acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of more than 1.0 percent. This description reflects a change in classification from Loamy-skeletal, mixed Andic Haplocryods to Loamy-skeletal, isotic Andic Haplcryods.