LOCATION KOCH WAEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed, mesic Aquandic Humaquepts
TYPICAL PEDON: Koch gravelly loam (all colors are for moist soil unless otherwise stated).
A--0 to 6 inches; very dark gray (10YR 3/1) gravelly loam, dark gray (10YR 4/1) dry; few, fine faint dark yellowish brown mottles; weak fine and medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many roots; 20 percent pebbles, very strongly acid (pH 5.0); abrupt smooth boundary. (4 to 10 inches thick)
AC--6 to 22 inches; very dark grayish brown (10YR 3/2) very gravelly coarse sandy loam, grayish brown (10YR 4/2) dry; few fine distinct reddish brown mottles and very dark gray manganese stains; massive; hard, firm, nonsticky and nonplastic; weakly cemented by iron or manganese in some places; 45 percent pebbles, many roots; moderately acid (pH 5.7); gradual wavy boundary. (10 to 20 inches thick)
Cg1--22 to 34 inches; dark grayish brown (10YR 3/2) very gravelly loamy coarse sand; many prominent reddish brown mottles; massive, soft very friable, nonsticky and nonplastic; compact in place but loose when removed; 55 percent pebbles; pebbles are stained by iron and manganese; very few roots; moderately acid (pH 5.7); gradual wavy boundary.
Cg2--34 to 60 inches; gray (10YR 5/1), dark gray (10YR 4/1) and dark grayish brown (10YR 3/2) extremely gravelly sand, light gray (10YR 7/1), gray (10YR 6/1) and grayish brown (10YR 5/2) dry; few faint reddish brown mottles; massive, soft, very friable, nonsticky and nonplastic; compact in place, but loose when removed; 70 percent pebbles; some stains on pebbles; moderately acid (pH 6.0).
TYPE LOCATION: Mason County, Washington, about 1 mile west of Cloquallum. Near the northeast corner of sec. 17, T. 19N., R. 5 W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 53 degrees F. Rock fragments in the particle-size control section averages 40 to 70 percent by volume.
The A horizon has value of 1 to 3 moist, 3 to 5 dry, and chroma of 1 or 2 moist and dry. Reaction is very strongly acid or strongly acid.
The AC horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 1 to 3 and is mottled. It is gravelly coarse sandy loam or very gravelly coarse sandy loam. Reaction is strongly acid or moderately acid.
The Cg horizon has value of 3 to 5 moist, 5 to 7 dry, and chroma of 1 or 2 and has high chroma mottles. Texture is very gravelly loamy coarse sand, very gravelly sand or extremely gravelly sand. Reaction is moderately acid or slightly acid.
COMPETING SERIES: This is the Lemolo series in another family. Lemolo soils are loamy-skeletal.
GEOGRAPHIC SETTING: Koch soils formed in glacial drift in broad drainage channels on glacial outwash plains. Elevation is near sea level to 500 feet. Slopes are 0 to 3 percent. Koch soils are in a mild, marine climate. Summers are cool and dry, winters are mild and wet. Mean July temperature is about 60 degrees F. January temperature is about 39 degrees F. The mean annual temperature is about 50 degrees F. The average annual precipitation ranges from 50 to 80 inches. The growing season above 28 degrees F.
i. 160 to 215 days. The frost-free season above 32 degrees F. is 150 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Grove soils. Grove soils are somewhat excessively drained and have a xeric moisture regime.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained, moderately rapid permeability in the solum, and rapid or very rapid in the substratum. An apparent water table is as high as 1 to 2 feet from the surface at times from November to April.
USE AND VEGETATION: Used for woodland. Some is drained and used for cropland. Corn for silage, oats, barley, hay and pasture are common crops. Native vegetation is red alder, western redcedar, bigleaf maple and western hemlock, with an understory of elderberry, hardhack, western swordfern, salmonberry, vine maple, red huckleberry, bedstraw, and devilsclub.
DISTRIBUTION AND EXTENT: Puget lowlands in western Washington. The series is of very small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Mason County, Washington, 1953.
REMARKS: Classification only changed 4/94 because of recent amendments to Soil Taxonomy. This draft reflects a change in classification from coarse-loamy over sandy or sandy-skeletal, mixed, acid, mesic Cumulic Humaquepts to sandy-skeletal, mixed, nonacid, mesic Aquandic Humaquepts. Diagnostic horizons and features recognized in this pedon are an umbric epipedon from the mineral surface to 22 inches and an assumed aquic moisture regime. This draft reflects an update of a 1953 description. No new data is on hand. The classification is based on the 1953 description.
OSED scanned by SSQA. Last revised by state on 6/88.