LOCATION EAD OR
Established Series
Rev. GEO/AON
06/2011
EAD SERIES
The Ead series consists of moderately deep, well drained soils on mountains. The soils formed in colluvium and residuum from tuffaceous siltstone and sandstone. Slopes are 5 to 60 percent. The mean annual precipitation is about 65 inches and the mean annual temmerature is about 49 degrees F.
TAXONOMIC CLASS: Fine, isotic, mesic Pachic Humudepts
TYPICAL PEDON: Ead silty clay loam, cutover brush. (Colors are for moist soil unless otherwise noted.)
A--0 to 7 inches; very dark brown (10YR 2/2) silty clay loam, dark grayish brown (10YR 4/2) dry; moderate and strong very fine subangular blocky structure; hard, friable, slightly sticky and moderately plastic; many medium, fine and very fine roots; many very fine irregular pores; very strongly acid (pH 5.0); abrupt smooth boundary. (6 to 7 inches thick)
Bw1--7 to 13 inches; dark brown (7.5YR 3/2) silty clay, brown (7.5YR 4/3) dry; moderate fine subangular blocky structure; hard, firm, moderately sticky and very plastic; many fine roots; common fine irregular pores; very strongly acid (pH 4.8); clear smooth boundary. (5 to 10 inches thick)
Bw2--13 to 22 inches; brown (7.5YR 3/3) clay, dark brown (7.5YR 4/4) dry; moderate fine and very fine subangular blocky structure; firm, moderately sticky and very plastic; common fine roots; many very fine irregular pores; few very fine siltstone fragments; very strongly acid (pH 4.6); clear wavy boundary. (8 to 12 inches thick)
BC--22 to 33 inches; strong brown (7.5YR 5/6) silty clay, reddish yellow (7.5YR 6/6) dry; massive; firm, moderately sticky and moderately plastic; few fine roots; common fine irregular and tubular pores; 40 percent pinkish gray (7.5YR 7/2) and reddish yellow (7.5YR 6/6) partially weathered fragments of siltstone; few yellowish red (5YR 5/6) stains and coatings up to 3 inches in diameter; extremely acid (pH 4.4); gradual wavy boundary. (0 to 15 inches thick)
Crt--33 to 40 inches; very pale brown (10YR 7/3), pinkish gray (7.5YR 7/2), and reddish yellow (7.5YR 6/6) partially weathered siltstone that has few roots and has faint brown (7.5YR 4/4) clay films on fracture faces.
TYPE LOCATION: Yamhill County, Oregon; about 15 feet north of a fire road, 150 yards southeast of fire road junction, NW1/4 NE1/4 NW1/4 section 5, T.6S., R.8W.
RANGE IN CHARACTERISTICS: The soils are usually moist and are dry for less than 45 consecutive days throughout the control section during the 4 months following the summer solstice. The mean annual soil temperature is 50 to 54 degrees F. The depth to bedrock (paralithic contact) ranges from 20 to 40 inches. The umbric epipedon is 20 to 28 inches thick.
The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 moist and chroma of 2 or 3.
The Bw horizon has hue of 7.5YR or 10YR, value of 3 moist in the upper part and 3 or 4 in the lower part, and chroma of 2 or 3 moist but ranging to 4 in the lower part of the thicker sola, and 3 or 4 dry. It is silty clay or clay with 40 to 50 percent clay and 0 to 15 percent partially weathered gravel.
The BC horizon commonly has hue of 7.5YR but ranges to 5YR, has value of 4 or 5 moist and chroma of 4 through 6 moist and dry. It has 30 to 50 percent partially weathered rock fragments.
COMPETING SERIES: These are the
Acanod,
Astoria,
Fendall, McCully, and
Skamo series. Acanod, Astoria, McCully, and Skamo soils are deeper than 40 inches to bedrock. Astoria, Fendall, McCully and Skamo soils have umbric epipedons less than 20 inches thick.
GEOGRAPHIC SETTING: The Ead soils are on smooth, convex uplands in the Coast Range of Oregon. The soils are at 400 to 1,000 feet elevation and the slopes range from about 5 to 60 percent. The soils formed in colluvium and residuum weathered from tuffaceous siltstone and sandstone from the Nestucca formation and micaceous siltstone and sandstone from the Yamhill formation. The climate is subhumid with cool, moist winter, and warm, dry summers. The mean annual precipitation is 60 to 70 inches. Mean July temperature is 64 degrees F.; mean January temperature is 37 degrees F.; and mean annual temperature is 49 degrees F. The frost-free season is 145 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Knappa and Grande Ronde soils on terraces and the
Hembre and
Peavine soils and the competing
Astoria soils on the uplands. Knappa soils have thick A horizons and moderately fine textured B horizons. Grande Ronde soils are imperfectly drained. Peavine soils have 5YR or 2.5YR hue and have Bt horizons. Hembre soils have moderately fine textured B horizons, and have a lithic contact of basalt rock at depths of 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well-drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: These soils are used mainly for woodland, wildlife, recreation, and water supply. Douglas-fir with alder, big leaf maple, vine maple, salal and sword fern make up the dominant native vegetation.
DISTRIBUTION AND EXTENT: Along the eastern slopes of the Coast Range, principally in the South Yamhill River drainage; MLRA 1. The seies is of limited extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Yamhill County Area, Oregon. 1974.
REMARKS: Diagnostic horizons and other features:
Umbric epipedon - 0 to 22 inches
All depths to diagnostic horizons and features are measured from the top of the first mineral horizon.
National Cooperative Soil Survey
U.S.A.