LOCATION ECOLA OR

Established Series
Rev. PRP/GLG/RWL
06/2011

ECOLA SERIES

The Ecola series consists of moderately deep, well drained soils that formed in colluvium weathered from sedimentary rock. Ecola soils are on coastal hill and mountains and have slopes of 0 to 90 percent. The mean annual precipitation is about 80 inches and the mean annual temperature is about 50 degrees F.

TAXONOMIC CLASS: Fine-silty, isotic, isomesic Andic Humudepts

TYPICAL PEDON: Ecola medial silt loam, forestland. (Colors are for moist soil unless otherwise noted.)

Oi--0 to 3 inches; slightly decomposed litter of needles, twigs, moss, roots.

A--3 to 10 inches; very dark grayish brown (10YR 3/2) medial silt loam, brown (10YR 5/3) dry; strong fine granular structure; friable, slightly sticky, slightly plastic and slightly smeary; many fine, medium and coarse roots; many very fine to medium irregular pores; common fine shot; strongly acid (pH 5.2); abrupt smooth boundary. (7 to 10 inches thick)

AB--10 to 19 inches; dark brown (10YR 3/3) silty clay loam, brown (10YR 5/3) dry; strong fine and medium subangular blocky structure; friable, slightly sticky, slightly plastic and slightly smeary; common fine and medium roots; many very fine tubular pores; few fine and medium siltstone paragravel; strongly acid (pH 5.2); abrupt smooth boundary. (0 to 10 inches thick)

Bw--19 to 36 inches; dark yellowish brown (10YR 4/4) silty clay loam, yellowish brown (10YR 5/4) dry; moderate fine subangular blocky structure; firm, slightly sticky, moderately plastic and slightly smeary; few fine roots; many very fine tubular pores; few fine and medium siltstone paragravel; very strongly acid (pH 4.8); clear wavy boundary. (10 to 24 inches thick)

C--36 to 40 inches; dark yellowish brown (10YR 4/4) very paragravelly silty clay loam, yellowish brown (10YR 5/6) dry; massive; firm, moderately sticky and moderately plastic; about 60 percent fine and medium siltstone paragravel; very strongly acid (pH 4.8); clear wavy boundary. (0 to 6 inches thick)

Cr--40 inches; variegated yellowish brown (10YR 5/4) and reddish brown (5YR 4/3) partially weathered siltstone.

TYPE LOCATION: Clatsop County, Oregon; at the junction of the CZ Mainline II and Lewis and Clark crossover roads; SE1/4SW1/4 section 2, T. 7 N., R. 10 W.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 50 to 55 degrees F. The difference between mean winter and mean summer soil temperature varies from 5 to 9 degrees F. The soil is usually moist and is dry for less than 45 consecutive days between 4 and 12 inches. Depth to a paralithic contact is 20 to 40 inches. The umbric epipedon is 14 to 25 inches thick. Andic properties range from 7 to 10 inches. The particle-size control section has less than 15 percent sand coarser than very fine sand. It is extremely acid to strongly acid.

The A horizon has hue of 10YR and 7.5YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It has 0 to 15 percent pararock fragments. It has an estimated phosphate retention of more than 85 percent, acid-oxalate extractable aluminum plus one-half iron of 2.0 to 3.0 percent, 15-bar moisture of more than 15 percent (air-dried) and a moist bulk density of less than 0.90 g/cc.

The AB horizon, when present, has hue of 10YR to 7.5YR, value of 3 moist, 4 or 5 dry and chroma of 3 or 4 moist and dry. Texture is silt loam, medial silt loam, or silty clay loam and has 0 to 30 percent pararock fragments. It has 25 to 30 percent clay by field estimate, acid-oxalate extractable aluminum plus one-half iron of 1.0 to 3.0, and moist bulk density of 0.90 to 1.20.

The Bw horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 4 or 5 dry, and chroma of 3 to 6 moist and dry. It averages 22 to 35 percent clay and 0 to 60 percent siltstone pararock fragments. It is silt loam or silty clay loam.

The C horizon, when present, averages 27 to 35 percent clay and 0 to 60 percent siltstone pararock fragments.

COMPETING SERIES: These are the Knappa, Templeton, and Walluski series. Knappa and Walluski soils are very deep to bedrock. In addition, Knappa soils have an umbric epipedon 20 to 30 inches thick, and when present, have rounded and subrounded rock and pararock fragments of alluvial origin. Templeton soils are 40 to greater than 60 inches to bedrock. Walluski soils also have redox depletions at a depth of 24 to 40 inches.

GEOGRAPHIC SETTING: Ecola soils are on ridgetops and side slopes of hills and mountains in the Coast Range. Elevation is 50 to 1,800 feet. Slopes are 0 to 90 percent. The soils formed in colluvium weathered from sedimentary bedrock. The climate is cool and wet during the winter. The mean annual precipitation of 60 to 110 inches. Many summer days have fog or low cloud cover during the mornings. The mean January temperature is 38 degrees F., and average July temperature is 59 degrees F. The mean annual temperature is 46 to 53 degrees F. The frost-free period is 100 to 245 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Astoria, Hembre, Svensen and competing Templeton soils. Astoria soils are deeper than 40 inches to a paralithic contact. Hembre soils are over a lithic contact. Svensen soils have less than 27 percent clay in the control section. All of these soils are on side slopes and ridgetops of mountains.

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

USE AND VEGETATION: Primarily timber production. Also used for recreation and wildlife habitat. Native vegetation is Douglas-fir, western hemlock, Sitka spruce, red alder, salal, salmonberry, vine maple, and western swordfern.

DISTRIBUTION AND EXTENT: Northwest Oregon; MLRA 4A. The soil is inextensive.

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

SERIES ESTABLISHED: Clatsop County, Oregon, 1984.

REMARKS: Ecola soils were included in the Astoria series in old soil survey publications.

Diagnostic horizons and features recognized in this pedon:
Umbric epipedon - from 3 to 19 inches (A and AB horizons)
Cambic horizon - from 19 to 36 inches (Bw horizon)
Andic feature - from 3 to 10 inches (A horizon) also meeting andic soil properties. Particle-size control section - from 13 to 43 inches.

Depth 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: Reference sample #S84OR-007-001; NSSL, Lincoln, NE.

National Cooperative Soil Survey
U.S.A.