LOCATION HEMBRE OR

Established Series
Rev. GEO/RHM/RWL
06/2011

HEMBRE SERIES

The Hembre series consists of deep, well drained soils that formed in colluvium and residuum weathered from basalt. Hembre soils are on mountains. Slopes are 3 to 90 percent. The mean annual precipitation is about 80 inches and the mean annual air temperature is about 48 degrees F.

TAXONOMIC CLASS: Fine-loamy, isotic, mesic Andic Humudepts

TYPICAL PEDON: Hembre medial silt loam, old burned-over woodland. (Colors are for moist soil unless otherwise noted.)

Oi--0 to 1 inch; slightly decomposed litter of needles, twigs, leaves.

A1--1 to 6 inches; dark reddish brown (5YR 3/2) medial silt loam, brown (7.5YR 4/4) dry; strong fine granular structure; weakly smeary; soft, friable, slightly sticky and slightly plastic; many fine roots; many very fine irregular pores; common very fine fragments of basalt; common very fine concretions; strongly acid (pH 5.2); clear smooth boundary.

A2--6 to 13 inches; dark reddish brown (5YR 3/2) medial silt loam, brown (7.5YR 5/4) dry; moderate fine subangular blocky structure; weakly smeary; soft, friable, slightly sticky and slightly plastic; many fine roots; many very fine pores; common very fine fragments of basalt; common very fine concretions; very strongly acid (pH 5.0); clear smooth boundary. (Combined A horizon is 10 to 19 inches)

Bw1--13 to 20 inches; dark reddish brown (5YR 3/4) silty clay loam, reddish yellow (7.5YR 6/6) dry; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; common fine roots; common very fine pores; few fine concretions; very strongly acid (pH 4.8); clear smooth boundary.

Bw2--20 to 31 inches; reddish brown (5YR 4/4) silty clay loam, reddish yellow (7.5YR 6/6) dry; moderate fine subangular blocky structure; friable, slightly sticky and moderately plastic; few fine roots; common very fine pores; few fine fragments of basalt; few fine concretions; very strongly acid (pH 4.8); clear smooth boundary. (combined Bw horizon is 14 to 32 inches thick)

BC--31 to 45 inches; yellowish red (5YR 4/6) gravelly silt clay loam, reddish yellow (5YR 6/6) dry; weak fine subangular blocky structure; firm, slightly sticky and moderately plastic; few medium roots; common very fine pores; 35 percent basalt gravel; very strongly acid (pH 4.8); abrupt wavy lower boundary. (9 to 16 inches thick)

R--45 inches; basalt containing a few fractures.

TYPE LOCATION: Yamhill County, Oregon; about 1/4 mile north of Neverstill Junction with the Turner Creek road, 50 feet east of road; NW1/4 SE1/4 SE1/4 section 1, T.2S., R.6W., W.M.

RANGE IN CHARACTERISTICS: The soils are usually moist and they are dry for less than 45 consecutive days in all parts between depths of 4 and 12 inches. The mean annual soil temperature ranges from 47 to 53 degrees F. The depth to bedrock and thickness of the solum is most commonly 40 more than 60 inches. The solum is strongly or very strongly acid. The umbric epipedon is 10 to 20 inches. The upper 3 to 7 inches of the epipedon has an acid-oxalate aluminum plus one-half iron of 2.0 to 3.0 percent, a moist bulk density of 0.75 to 0.90 g/cc, phosphate retention of more than 85 percent, and 15-bar moisture of more than 15 percent. The lower part to a depth of 20 inches has an acid-oxalate aluminum plus one-half iron of 1.0 to 3.0 percent and a moist bulk density of 0.75 to 1.0 g/cc. Andic soil properties do not extend beyond 14 inches.

The A horizon has hue of 7.5YR or 5YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and 3 or 4 dry. The A1 horizon is medial silt loam and the A2 horizon is silt loam or medial silt loam. Fragments of rock and concretions of 1 to 2 mm. size are common to many in the A horizon. It has 0 to 15 percent rock fragments of which 0 to 15 percent are basalt gravel, 0 to 15 percent are cobbles, and 0 to 15 percent are stones.

The Bw horizon has value of 3 or 4 moist, 4 to 6 dry and chroma of 4 to 6 moist and dry. Texture is silty clay loam that ranges to a heavy silt loam. The Bw1 and Bw2 horizons have a rock fragment content similar to the A horizon.

The BC horizon has value of 4 to 6 moist and dry, and chroma of 4 to 6 moist and dry. Texture is silty clay loam or silty loam and has 0 to 35 percent rock fragments of which 0 to 35 percent are gravel, 0 to 15 percent are cobbles, and 0 to 15 percent are stones.

COMPETING SERIES: These are the Bohannon, Gobar, Kinney, and Preacher soils. Bohannon soils are 20 to 30 inches deep to sandstone. Kinney and Preacher soils have hue of 10YR or 7.5YR in the control section. Gobar soils have a paralithic contact at 40 to 60 inches.

GEOGRAPHIC SETTING: The Hembre soils are on summits, benches and side slopes of mountains at elevations of 200 to 2,800 feet in the Coast Range. The soils formed in residuum weathered from basalt and breccia. Winter is cool and moist, and summer is warm and dry. The mean annual precipitation is 60 to 120 inches. The mean July temperature is 61 degrees F. and the mean January temperature is 38 degrees F. The mean annual temperature is 45 to 53 degrees F. The frost-free period is about 100 to 210 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kilchis, Klickitat and Neskowin soils where the soil is formed in residuum from basalt. Kilchis and Klickitat soils contain more than 50 percent coarse fragments in their sola. The Kilchis soils, in addition, are less than 20 inches deep to bedrock. Neskowin soils have thick black A horizons and an isomesic soil temperature regime. Astoria, Blachly, and Winema soils are associated where underlying rocks are sedimentary. All of these soils have fine texture in the B horizon. Also, Astoria soils have 10YR or 7.5YR hue, Blachly soils have 2.5YR hue, and Winema soils have thick black A horizons and an isomesic soil temperature regime.

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

USE AND VEGETATION: Timber production and some pasture. Native vegetation is Douglas-fir and western hemlock, alder, vine maple, swordfern and salal.

DISTRIBUTION AND EXTENT: Northern Coast Range in Oregon; MLRA 1. The soil is extensive.

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

SERIES ESTABLISHED: Tillamook County, Oregon, 1956.

REMARKS: Diagnostic horizons and features of this pedon include:
Umbric epipedon - from 1 to 13 inches (A1 and A2 horizons).
Cambic horizon - from 13 to 33 inches (Bw1 and Bw2 horizons).
Particle-size class - from 11 to 41 inches with 25 to 32 percent clay and greater than 15 percent coarser than very fine sand.
Andic feature - from 1 to 13 inches (A1 and A2 horizons) and also meeting andic soil properties.

Depths to diagnostic horizons and features are measured from the top of the first mineral layer.

A proposal was submitted to NSSC (2000) to revise the definition of medial to also include those soil properties qualifying for the Andic subgroup under criteria #1 for andic soil properties. If accepted, medial modifiers would be used for those horizons meeting the andic subgroup criteria although not always meeting andic soil properties.

ADDITIONAL DATA: characterization data for one pedon (S84-Oreg.-041-002; #84P896) from Lincoln County Area, Oregon; Lincoln National Soil Survey Lab.

National Cooperative Soil Survey
U.S.A.