LOCATION MOLSON WAEstablished Series
TAXONOMIC CLASS: Ashy over loamy, glassy over mixed, superactive, frigid Humic Vitrixerands
TYPICAL PEDON: Molson ashy silt loam, cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 8 inches; very dark grayish brown (10YR 3/2) ashy silt loam, black (10YR 2/1) moist; moderate medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many roots; neutral (pH 6.8); clear smooth boundary. (6 to 10 inches thick)
A--8 to 18 inches; very dark grayish brown (10YR 3/2) ashy silt loam, black (10YR 2/1) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; common roots; many fine pores; neutral (pH 7.2); gradual smooth boundary. (6 to 12 inches thick)
2Bw--18 to 42 inches; yellowish brown (10YR 5/4) gravelly silt loam, dark yellowish brown (10YR 3/4) moist; weak medium prismatic structure; slightly hard, very friable, slightly sticky and slightly plastic; common roots; many medium and fine pores; 30 percent gravel, 3 percent cobbles; neutral (pH 7.1); clear smooth boundary. (20 to 36 inches thick)
2BC--42 to 50 inches; light gray (2.5Y 7/2) gravelly silt loam, olive brown (2.5Y 4/4) moist; massive; hard, firm, slightly sticky and slightly plastic; few roots; many medium and fine pores; 30 percent gravel, 3 percent cobbles; slightly effervescent; slightly alkaline (pH 7.6); diffuse wavy boundary. (0 to 12 inches thick)
2Cd--50 to 60 inches; light gray (5Y 7/2) gravelly loam, light olive brown (2.5Y 5/3) moist; massive; very hard, very firm, slightly sticky and slightly plastic; few roots; 30 percent gravel, 3 percent cobbles; slightly alkaline (pH 7.4).
TYPE LOCATION: Okanogan County, Washington; about 3/8 mile northeast of Lemanasky Lake and Pine Creek Road junction; 1,690 feet south and 1,350 feet west of NE corner section 1, T.36N., R.25E. (Latitude 48 degrees, 38 minutes, 59 seconds North., Longitude 119 degrees, 37 minutes, 50 seconds West; NAD 83)
RANGE IN CHARACTERISTICS:
Soil moisture: usually moist but are dry in all parts of the moisture control section for 75 to 90 consecutive days.
Soil temperature: 43 to 47 degrees F.
Rock fragments: 0 to 30 percent in ashy mantle and 10 to 35 percent in the 2Bw.
Mollic epipedon and thickness of andic soil properties: 14 to 20 inches thick.
Depth to the densic contact: 40 to 60 inches
A horizon
Value: 3 or 4 dry.
Chroma: 1 or 2, moist or dry.
Texture: ashy silt loam or ashy loam.
Structure: weak to moderate structure.
Rock fragments: 0 to 30 percent dominantly gravel size and stony to extremely stony surface phases are recognized.
Reaction: Slightly acid or neutral.
2Bw horizon
Value: 4 or 5 dry, 3 or 4 moist.
Chroma: 3 or 4, moist or dry.
Texture: silt loam, loam.
Structure: weak to moderate.
Rock fragments: 10 to 35 percent.
Reaction: neutral to moderately alkaline
2BC and 2Cd horizons
Hue: 10YR to 5Y.
Value: 5 to 7 dry, 3 to 5 moist.
Chroma: 2 to 4, moist or dry.
Texture: loam or silt loam.
Rock fragments: 15 to 35 percent.
Reaction: slightly or moderately alkaline.
Moist bulk density (g/cm3): 1.40 to 1.60 in the 2BC and 1.60 to 1.80 in the 2Cd horizons
COMPETING SERIES: These are the Barnellcreek and Sisters soils. Barnellcreek soils have redox concentrations and are dry in the moisture control section for 45 to 60 consecutive days. Sisters soils do not have a densic contact.
GEOGRAPHIC SETTING: Molson soils are on footslopes and backslopes of glaciated hills and mountains at elevations of 1,500 to 5,000 feet. Slopes range from 0 to 45 percent. Molson soils formed from glacial till of mixed mineralogy with a mantle of volcanic ash. The mean annual temperature is 43 degrees F. The mean annual precipitation is 14 to 18 inches. The frost free season is 95 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: Molson soils are associated with the Chesaw, Hunters, Koepke, Mires and Republic soils. Chesaw soils are sandy-skeletal and are on terraces, terrace escarpments and eskers. Hunters soils are fine-silty and are on terraces. Koepke soils have a mollic epipedon over 20 inches thick and are on footslopes and backslopes of glaciated hills and mountains and are forested. Mires soils are ashy over sandy or sandy-skeletal and are on terraces. Republic soils are coarse-loamy and are on alluvial fans, terraces, footslopes and backslopes of mountains.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: Production of alfalfa and grass hay, small grain and livestock grazing. The native plants are Idaho fescue, rough fescue, bluebunch wheatgrass, Sandberg bluegrass, ninebark, snowberry, ponderosa pine, and Douglas-fir.
DISTRIBUTION AND EXTENT: Ferry and Okanogan Counties, Washington. MLRA 43A. The Molson soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Okanogan County, Washington, 1971.
REMARKS: Diagnostic horizons and other features recognized in this pedon are:
Mollic epipedon - the zone from 0 to 18 inches (Ap and A horizons)
Cambic horizon - the zone from 18 to 42 inches (2Bw horizon)
Andic soil properties - the zone from 0 to 18 inches (Ap and A horizons)
Particle-size control section - the zone from 0 to 40 inches (Ap, A, 2Bw, and part of the 2BC horizon)
Densic contact -50 inches
Permeability rate of the till material needs review as it is typically considered to be slow or very slow.
This series was previously classified as medial over loamy, mixed, frigid Mollic Vitrandepts. In 2001 it was reclassified to to ashy over loamy, glassy over mixed, superactive, frigid Humic Vitrixerands.
This series along with associated Humic Vitrixerands in 43A in Washington need analysis for andic soil properties.