LOCATION LOPER WAEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Mollic Hapludalfs
TYPICAL PEDON: Loper silt loam--forest, on a 35 percent north-facing slope at an elevation of 1,200 feet. (Colors are to moist soil unless otherwise noted. All textures are apparent field textures.)
Oi & Oa--2 to 0 inches; needles, leaves, and twigs in various stages of decomposition; abrupt smooth boundary. (l to 4 inches thick)
A1--0 to 4 inches; dark brown (7.5YR 3/2) and dark reddish brown (5YR 2/2) silt loam, reddish brown (5YR 4/2) dry; weak medium subangular blocky structure parting to moderate fine subangular blocky parting to moderate medium granular; slightly hard, very friable, slightly sticky and slightly plastic and weakly smeary; many very fine, fine and coarse roots throughout; many very fine and fine vesicular and tubular pores; l0 percent cobbles and l0 percent pebbles from igneous rocks; strongly acid (pH 5.l); clear smooth boundary. (3 to 6 inches thick)
A2--4 to 12 inches; dark brown (7.5YR 3/2) and dark reddish brown (5YR 2/2) silt loam, reddish brown (5YR 4/2) dry; weak medium subangular blocky structure parting to moderate fine subangular blocky; slightly hard, friable, slightly sticky and slightly plastic and weakly smeary; many very fine, fine and coarse roots throughout; many very fine and fine vesicular and tubular pores; l0 percent cobbles and l0 percent pebbles from igneous rocks; strongly acid (pH 5.3); gradual smooth boundary. (7 to 10 inches thick)
BA--12 to 20 inches; brown (7.5YR 4/4) and dark brown (7.5YR 3/4) loam, brown (7.5YR 5/4) dry; weak medium subangular blocky structure parting to moderate fine subangular blocky; slightly hard, friable, slightly sticky and slightly plastic and weakly smeary; many very fine, fine and coarse roots throughout; many very fine and fine vesicular and tubular pores; 5 percent cobbles and l0 percent pebbles from igneous rocks; strongly acid (pH 5.4); clear smooth boundary. (6 to 10 inches thick)
Bt1--20 to 28 inches; brown (7.5YR 4/4) and dark brown (7.5YR 3/4) loam, brown (7.5YR 5/4) dry; weak medium subangular blocky structure parting to moderate fine subangular blocky; slightly hard, friable, slightly sticky and slightly plastic and weakly smeary; common to many very fine to coarse roots throughout; many very fine and fine vesicular and tubular pores; 5 percent cobbles, l0 percent hard pebbles and 20 percent soft pebbles; moderately acid (pH 5.6); clear smooth boundary. (7 to l0 inches thick)
2Bt2--28 to 44 inches; dark reddish brown (5YR 3/3) clay loam, reddish brown (5YR 5/4) dry; moderate medium subangular blocky structure parting to moderate fine subangular blocky; hard, firm, sticky and plastic; many discontinuous distinct dark reddish brown (5YR 3/3) clay films on faces of peds; common to many fine to coarse roots throughout; many very fine and fine vesicular and tubular pores; 5 percent hard pebbles and 30 percent soft pebbles; strongly acid (pH 5.3); clear wavy boundary. (l4 to 20 inches thick)
2Bt3--44 to 60 inches; reddish brown (5YR 4/4) and dark brown (7.5YR 3/4) clay loam, yellowish red (5YR 5/6) dry; moderate medium subangular blocky structure parting to moderate fine subangular blocky; hard, firm, very sticky, very plastic; many discontinuous distinct dark reddish brown (2.5YR 3/3) clay films on faces of peds; common to many fine to coarse roots throughout; many very fine and fine vesicular and tubular pores; 5 percent hard pebbles and 35 percent soft pebbles; strongly acid (pH 5.4).
TYPE LOCATION: Cowlitz County, Washington, about 7 miles west of Castle Rock, 750 feet west, l,500 feet south of the northeast corner section l5, T. 9 N., R. 3 W.
RANGE IN CHARACTERISTICS: These soils are usually moist and are dry for less than 45 consecutive days following summer solstice. The average annual soil temperature ranges from 49 to 5l degrees F. The umbric epipedon is l0 to l5 inches thick. The upper l4 to 20 inches of the soil is dominated by amorphous material. The argillic horizon ranges from 35 to 60 percent clay. Reaction ranges from moderately acid to strongly acid throughout the profile. Base saturation (by sum of cations) averages from l5 to 65 percent throughout the profile, and is more than 35 percent at 1.5 meters.
The A horizon has hue of 7.5YR or 5YR, value and chroma of 2 or 3 moist or dry. It has 0 to l0 percent cobbles and 0 to l0 percent pebbles.
The Bt horizon has value and chroma of 3 or 4 moist or dry. Texture is loam or clay loam, with 0 to 5 percent cobbles, 5 to l0 percent pebbles and 20 to 30 percent soft weathered pebbles.
The 2Bt horizon has hues of 5YR or 7.5YR, value of 3 or 4 moist, 4 or 5 dry, and chroma of 3 or 4 moist 4 through 6 dry. Texture is clay loam or clay. This horizon has 0 to 5 percent hard pebbles and 25 to 50 percent soft weathered pebbles.
COMPETING SERIES: These are the Basco, Belpre, Brooke, Caleast, Fleming, Mcafee, Pucdin, and Salvisa series. All of these soils have bulk density (at 1/3 bar) of more than 0.95 g/cc or ratio of 15 bar water to clay of 1.25 or more or a ratio of CEC (at pH near 8) to 15 bar water of < 1.5 and more exchange acidity than the sum of the bases plus KC1 extractable aluminum throughout.
GEOGRAPHIC SETTING: Loper soils are on hillsides and benches at elevation of 700 to l,800 feet. Slopes are 20 to 65 percent. These soils formed in basaltic colluvium with an admixture of volcanic ash and loess overlying highly weathered pyroclastic breccia. The climate is marine with cool, dry summers and mild wet winters. The average annual precipitation is 60 to 80 inches. Average January temperature is about 37 degrees F., the average July temperature is about 6l degrees F., and the average annual temperature is 48 to 50 degrees F. The growing season (28 degrees F.) is 200 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Boistfort, Bunker, Germany, Katula, Lates, Murnen and Raught soils. All of these soils have base saturation of less than 35 percent throughout. In addition Boistfort, Bunker soils have a cambic horizon. Katula soils also have a lithic contact at 20 to 40 inches. Lates and Murnen soils also are frigid.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: Used for timber production, watershed and wildlife habitat. Vegetation is Douglas-fir, red alder, bigleaf maple, western redcedar, and western hemlock, with an understory of salal, cascade Oregongrape, red huckleberry, western brackenfern, western swordfern, vine maple, violet, and Oregon oxalis.
DISTRIBUTION AND EXTENT: Cowlitz County, Washington. series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Cowlitz County, Washington, l97l.
REMARKS: Diagnostic horizons and features recognized in this pedon are an umbric epipedon from the mineral surface to 12 inches, soil dominated by amorphous material from the mineral surface to 20 inches and an argillic horizon from 20 to 60 inches. Characterization data are available on this pedon. Laboratory Number is S84WA-015-004. This soil should be classified as an Andeptic Haploxeralfs if such were provided in Soil Taxonomy.