LOCATION BACONA OREstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, active, mesic Typic Palehumults
TYPICAL PEDON: Bacona silt loam - wooded. (Colors are for moist soil unless otherwise noted.)
O--2 inches to 0; leaves, twigs, moss and woody materials.
A1--0 to 3 inches; dark brown (7.5YR 3/2) silt loam, brown (7.5YR 4/3) dry; moderate very fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine irregular pores; 15 percent 2 to 5 millimeter concretions; strongly acid; abrupt smooth boundary. (2 to 6 inches thick)
A2--3 to 6 inches; dark brown (7.5YR 3/4) silt loam, brown (7.5YR 4/4) dry; moderate fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine irregular pores; 15 percent 2 to 5 millimeter concretions; strongly acid; clear smooth boundary. (3 to 6 inches thick)
AB--6 to 12 inches; reddish brown (5YR 4/4) silt loam, yellowish red (5YR 5/6) dry; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine tubular pores; 5 percent 2 to 5 millimeter concretions; strongly acid; clear smooth boundary. (0 to 8 inches thick)
Bt1--12 to 33 inches; reddish brown (5YR 4/4) heavy silt loam, yellowish red (5YR 5/6) dry; moderate medium subangular blocky structure; slightly hard, friable, sticky and plastic; common fine roots; many very fine tubular pores; 5 percent 2 to 5 millimeter concretions; strongly acid; gradual wavy boundary. (10 to 24 inches thick)
2Bt2--33 to 50 inches; yellowish red (5YR 4/6) silty clay loam, yellowish red (5YR 5/8) dry; moderate medium subangular blocky structure; hard, firm, sticky and plastic; few fine roots; many very fine tubular pores; few thin and moderately thick clay films on faces of peds and in pores; strongly acid; gradual wavy boundary. (15 to 30 inches thick)
2Bt3--50 to 60 inches; yellowish red (5YR 4/6) silty clay loam, yellowish red (5YR 5/8) dry; weak coarse subangular blocky structure; hard, friable, slightly sticky and plastic; few fine roots; many very fine tubular pores; common moderately thick and thick continuous clay films on faces of peds and in pores; strongly acid.
TYPE LOCATION: Columbia County, Oregon; southeast 1/4 southeast 1/4, sec. 21, T. 6 N., R. 3 W.
RANGE IN CHARACTERISTICS: The soil is usually moist but is dry for less than 45 consecutive days between depths of 4 to 12 inches. The mean annual soil temperature is 47 to 54 degrees F. Depth to bedrock is 60 inches or more.
The A horizon has hue of 5YR, 7.5YR or 10YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It has 18 to 25 percent clay and 5 to 15 percent 2 to 5 millimeter concretions. It is strongly acid to slightly acid.
The Bt horizon has hue of 7.5YR or 5YR, value of 5 or 6 dry, and chroma of 4 to 6 dry and moist. It dominantly is silt loam but the lower part is silty clay loam in some pedons. It averages 25 to 35 percent clay and less than 15 percent coarser than very fine sand. It is strongly acid or medium acid.
The 2Bt horizon has hue of 5YR or 2.5YR, value of 5 or 6 dry, and chroma of 4 to 6 moist and 4 to 8 dry. It is silty clay loam or silty clay and averages 35 to 50 percent clay and up to 5 percent 2 to 5 millimeter concretions. It is strongly acid or medium acid.
COMPETING SERIES: This is the closely related Vernonia series. Vernonia soils have more than 35 base saturation.
GEOGRAPHIC SETTING: Bacona soils are on mountains at elevations of 400 to 1,600 feet. Slopes are 3 to 30 percent. The soils formed in eolian material mixed with colluvium weathered from sedimentary bedrock. The climate is characterized by cool wet winters and warm moist summers. Mean July temperature is 60 to 63 degrees F; mean January temperature is 35 to 37 degrees F; mean annual temperature is 45 to 52 degrees F. The mean annual precipitation is 60 to 75 inches. The frost-free season is 100 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Glohm, Kenusky, Mayger, and the competing Vernonia soils. Glohm soils are moderately well drained and have a fragipan. Kenusky soils are poorly drained and have a clayey argillic horizon. Mayger soils are somewhat poorly drained and fine textured.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used for timber production, recreation and wildlife habitat. Native vegetation is Douglas-fir, western hemlock, red alder, western redcedar, vine maple, cascade Oregon-grape, red huckleberry, blue elderberry, salal, and western swordfern.
DISTRIBUTION AND EXTENT: The Coast Range in northwestern Oregon. This series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Columbia County, Oregon, 1983.