LOCATION JONAS WAEstablished Series
TAXONOMIC CLASS: Medial over loamy, ferrihydritic over isotic, frigid Typic Hapludands
TYPICAL PEDON: Jonas gravelly medial silt loam - under a coniferous forest on a 51 percent northeast-facing concave upper back slope at an elevation of 2,240 feet. (The soil was moist when described. Colors are for moist soil unless otherwise stated. All textures are apparent field textures.)
Oe--0 to 1 inch; moderately decomposed needles, twigs, and bark.
A1--1 to 6 inches; very dark grayish brown (10YR 3/2) gravelly medial silt loam, brown (10YR 5/3) dry; weak fine and medium granular structure; soft, very friable, slightly sticky and slightly plastic and weakly smeary; many fine and common medium roots; many fine irregular pores; 30 percent 2 to 5 mm size shot-like aggregates and 20 percent pebbles; strongly acid (pH 5.5); clear wavy boundary. (3 to 9 inches thick)
A2--6 to 17 inches; very dark grayish brown (10YR 3/2) very cobbly medial silt loam, brown (10YR 5/3) dry; weak fine and medium subangular blocky and weak fine and medium granular structure; slightly hard, friable, slightly sticky and slightly plastic and weakly smeary; many fine and medium and few coarse roots; many fine irregular pores; 25 percent andesite pebbles, 30 percent andesite cobbles; strongly acid (pH 5.3); clear wavy boundary. (0 to 12 inches thick)
Bw1--17 to 28 inches; dark brown (10YR 3/3) cobbly medial loam, pale brown (10YR 6/3) dry; weak medium subangular blocky structure parting to weak fine and very fine subangular blocky; hard, friable, slightly sticky and slightly plastic and weakly smeary; common fine and few medium roots; common fine and very fine pores; 10 percent andesite pebbles, 10 percent andesite cobbles; strongly acid (pH 5.1); clear wavy boundary. (10 to 22 inches thick)
Bw2--28 to 42 inches; dark brown (10YR 4/3) cobbly clay loam, very pale brown (10YR 7/4) dry; weak coarse subangular blocky structure; hard, friable, slightly sticky and moderately plastic; few fine and medium roots; few fine pores; 10 percent andesite pebbles, 20 percent andesite cobbles; strongly acid (pH 5.1); clear wavy boundary. (8 to 20 inches thick)
Bw3--42 to 61 inches; dark yellowish brown (10YR 4/4) cobbly clay loam, very pale brown (10YR 7/4) dry; weak coarse subangular blocky structure; hard, friable, slightly sticky and moderately plastic; few fine pores; 10 percent andesite pebbles, 20 percent andesite cobbles; strongly acid (pH 5.1).
TYPE LOCATION: Lewis County, Washington; northeast quarter, northeast quarter, southeast quarter, sec. 5, T. 14 N., R. 4 E. W.M.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 42 to 46 degrees F. The umbric epipedon is 10 to 20 inches thick. Depth to unweathered bedrock ranges from 40 to more than 60 inches. Rock fragments in the particle-size control section range from 15 to 35 percent. The soil is strongly acid or moderately acid throughout. The soil moisture control section is usually moist but is dry for 30 to 45 consecutive days after the summer solstice; udic moisture regime.
The A horizon has hue of 7.5YR or 10YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. Pebbles range from 10 to 30 percent in the upper part and 25 to 30 percent andesite pebbles and 10 to 30 percent andesite cobbles in the lower part. Structure is weak or moderate.
The Bw horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 5 to 7 dry, and chroma of 3 or 4 moist and 3 through 6 dry. The horizon averages 15 to 35 percent rock fragments, including 5 to 15 percent andesite pebbles and 5 to 30 percent andesite cobbles. It is gravelly loam, gravelly clay loam, cobbly loam, cobbly clay loam, gravelly silty clay loam, cobbly silty clay loam or very gravelly loam. Some pedons have thin patchy clay films on some faces of peds and on some rock fragments.
COMPETING SERIES: These are the Beigle, Hyas, Lates, Moe, Murnen, Vailton, Wilhoit, and Xeno series. Beigle soils are silt loam or loam in the particle-size control section. Hyas soils have 15 to 40 percent soft rock fragments in the control section. Lates soils are 20 to 40 inches deep to basalt. Moe soils are less than 15 percent hard rock fragments and 35 to 45 percent apparent clay in the Bw horizon. Murnen soils have an apparent silt loam texture and have less than 15 percent rock fragments in the particle-size control section. Vailton soils have soft siltstone fragments and no hard rock fragments in the particle-size control section. Wilhoit soils have an umbric epipedon 20 to 30 inches thick. Xeno soils are 15 to 55 weathered breccia and lack lithic rock fragments in the particle-size control section.
GEOGRAPHIC SETTING: Jonas soils are on upland benches, hillsides, broad ridge tops, and mountain backslopes. Elevation ranges from 1,800 to 2,800 feet. Slopes are 5 to 90 percent. These soils formed in residuum and colluvium from andesite with an admixture of volcanic ash and pumice in the upper part. Average annual precipitation is 60 to 90 inches. Mean January temperature is about 30 degrees F, mean July temperature is about 61 degrees F, mean annual temperature is 42 to 45 degrees F. The growing season (28 degrees F) is 140 to 190 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dobbs, Pheeney, Reichel, Stahl, Wilkeson, and Zynbar soils. Dobbs and Pheeney soils are medial-skeletal and moderately deep. Reichel and Stahl soils have a cryic temperature regime. Wilkeson soils have an argillic horizon. Zynbar soils have a bulk density of less than 0.85 grams per cubic centimeter.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff; moderate permeability.
USE AND VEGETATION: Used for timber production, watershed and wildlife habitat. Vegetation is Douglas-fir, western hemlock, red alder, bigleaf maple and western redcedar with an understory of vine maple, red huckleberry, western swordfern, salal, Oregon-grape, western brackenfern, deer fern, pathfinder, bedstraw, longtube twinflower, redwood violet, wild ginger, trailing blackberry, Oregon oxalis, blue-leaved huckleberry, and Pacific trillium.
DISTRIBUTION AND EXTENT: Foothills and mountainslopes on the west slopes of the Cascade Range in southwestern Washington. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Lewis County, Washington, 1979.
Classification only updated 3/94 because of recent amendments to Soil Taxonomy. Diagnostic horizons and features recognized in this pedon are:
a.umbric epipedon from the mineral surface to 16 inches and a cambic horizon from 16 to 60 inches. This description reflects a change in classification based on amendment 16. The upper 7 to 14 inches has an estimated moist bulk density of less than 1.00 g/cc, volcanic glass content of less than 5 percent, acid-oxalate extractable aluminum plus one-half iron of more than 2 percent. Bulk density is more than 0.90 g/cc below 14 inches.