LOCATION O BRIEN WA

Established Series
Rev. RFP/RJE/TDT
04/2022

O BRIEN SERIES

The O Brien series consists of very deep, well drained soils that formed in loess over gravelly glacial outwash. These soils are on outwash terraces on till plains and have slopes from 0 to 15 percent. The mean annual temperature is about 50 degrees F., and the mean annual precipitation is about 100 inches.

TAXONOMIC CLASS: Medial over loamy-skeletal, ferrihydritic over isotic, isomesic Typic Fulvudands

TYPICAL PEDON: O Brien medial silt loam-forested (Colors are for moist soil unless otherwise stated. All textures are apparent field textures.)

Oi--0 to 2.5 inches; slightly decomposed needles, twigs, and mosses.

Oe--2.5 to 3 inches; moderately decomposed organic material.

A--3 to 16 inches; very dark grayish brown (10YR 3/2) medial silt loam; dark brown (10YR 3/3) dry; weak very fine and fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine, fine, and medium, few coarse roots; 5 percent subangular or rounded gravel and 1 percent subangular and rounded cobbles; very strongly acid (pH 4.6); clear wavy boundary. (5 to 15 inches thick)

Bw1--16 to 31 inches; brown (10YR 4/3) medial silt loam, brown (10YR 5/3) dry; weak very fine and fine subangular blocky structure; slightly hard, friable, nonsticky, and nonplastic; common very fine and fine, few medium roots; 5 percent subangular blocky or rounded gravel and 5 percent subangular and rounded cobbles; very strongly acid (pH 4.8); gradual wavy boundary. (9 to 21 inches thick)

Bw2--31 to 34 inches; dark yellowish brown (10YR 4/6) gravelly medial silt loam, light yellowish brown (10YR 6/4) dry; moderate very fine and fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine, few fine roots; 15 percent rounded gravel and 5 percent rounded cobbles; very strongly acid (pH 5.0); clear smooth boundary. (0 to 13 inches thick)

2C1--34 to 38 inches; yellowish brown (10YR 5/4) very gravelly loam, light yellowish brown (10YR 6/4) dry; massive; slightly hard, friable, nonsticky and nonplastic; few very fine roots; 40 percent rounded gravel and 5 percent rounded cobbles; very strongly acid (pH 5.0); abrupt smooth boundary. (3 to 5 inches thick)

2C2--38 to 63 inches; brown (10YR 4/3) very gravelly sandy loam, light yellowish brown (10YR 6/4) dry; massive; soft, very friable, nonsticky and nonplastic; 50 percent rounded gravel and 5 percent rounded cobbles; very strongly acid (pH 5.0).

TYPE LOCATION: Grays Harbor County, Washington, near logging road 6,000, 1.2 miles west of county road 104; 2,000 feet east and 2,400 feet south of the NW corner of sec. 15, T. 20 N., R. 11 W.

RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 47 to 52 degrees F. The difference between mean summer and winter soil temperature is 5 to 7 degrees. The soils are usually moist and are dry for less than 45 consecutive days; udic moisture regime. Depth to outwash material is 20 to 40 inches. The upper part of the particle-size control section has andic soil properties with phosphate retention of 85 to 100 percent, moist bulk density of 0.70 to 0.90 g/cc, acid oxalate extractable aluminum plus one-half the iron of 2 to 4 percent, and 15 to 25 percent apparent clay. The lower part of the particle-size control section has 35 to 60 percent rock fragments. Hue is 10YR or 7.5YR. The soils may have an ochric or umbric epipedon.

The A horizon has 0 to 5 percent gravel and has 10 to 20 percent organic matter. Value is 2 or 3 moist, 3 or 4 dry and chroma of 2 to 4 moist and 3 or 4 dry. It is extremely or very strongly acid.

The Bw horizon has value of 3 or 4 moist and 5 or 6 dry, and chroma of 3 to 6 moist and dry. It is very strongly acid or strongly acid. It has 0 to 15 percent gravel and has 5 to 20 percent organic matter.

The 2Bw or 2C horizon contains 35 to 60 percent gravel and has 1 to 5 percent organic matter. Moist bulk density is 1.25 to 1.35 g/cc. Value is 4 or 5 moist, 6 dry and chroma of 3 to 6 moist and dry. It is loam, sandy loam or silt loam.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: O Brien soils are on glacial outwash terraces. These soils formed in material weathered from glacial outwash. Elevations range from 100 to 980 feet. They occur in a coastal marine climate with cool, wet winters and cool, dry summers. Annual precipitation is 90 to 120 inches. The mean January temperature is 38 degrees F., mean July temperature is 60 degrees F.; and the mean annual temperature is about 50 degrees F. The growing season is 180 to 220 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Copalis, Halbert, Hoquiam, LeBar, Nordby and Willaby. The Copalis, Hoquiam, and LeBar soils are medial in the control section. Halbert soils have an aquic moisture regime. Nordby soils are loamy-skeletal. Willaby soils have a fine control section.

DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate over slow permeability.

USE AND VEGETATION: Principal uses are timber production, wildlife habitat, and recreation. The major tree species are Douglas-fir, western hemlock with some red alder. Understory species include salal, blue and red huckleberry, western brackenfern, deer fern, cascara, and salmonberry.

DISTRIBUTION AND EXTENT: Northern Grays Harbor County, Washington, MLRA 4A. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Grays Harbor County Area, Pacific and Wahkiakum Counties, Washington, 1979.

REMARKS: Diagnostic horizons and other features.
Umbric epipedon - 3 to 16 inches, the series is allowed to have an ochric epipedon
Cambic horizon - 16 to 34 inches
Andic soil properties - 3 to 34 inches

National Cooperative Soil Survey
U.S.A.