LOCATION MONTESA WAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, isotic, mesic Aquandic Dystrudepts
TYPICAL PEDON: Montesa medial silt loam, on southeast-facing 7 percent slope under grass pasture at 35 feet elevation. (Colors are for moist soil unless otherwise stated. When described, the soil was moist throughout.)
Ap--0 to 10 inches; brown (7.5YR 4/4) medial silt loam, light yellowish brown (10YR 6/4) dry; moderate medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; many medium and fine roots; many very fine irregular pores; very strongly acid (pH 5.0); clear wavy boundary. (4 to 12 inches thick)
A--10 to 18 inches; brown (7.5YR 4/4) medial silt loam, light yellowish brown (10YR 6/4) dry; moderate fine, medium and coarse subangular blocky structure; slightly hard, friable, nonsticky and slightly plastic; medium, fine and very fine roots; many very fine irregular pores; very strongly acid (pH 4.8); abrupt wavy boundary. (0 to 12 inches thick)
Bw--18 to 25 inches; strong brown (7.5YR 5/6) fine sandy loam, reddish yellow (7.5YR 6/6) dry; dark brown (7.5YR 3/4) rubbed, strong brown (7.5YR 5/6) rubbed dry; common medium distinct red (2.5YR 4/8) and light brownish gray (10YR 6/2) mottles, yellowish red (5YR 5/8) and light gray (10YR 7/2) dry; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few coarse and medium roots; common fine and very fine irregular pores; strongly acid (pH 5.2); abrupt wavy boundary. (5 to 13 inches thick)
C--25 to 60 inches; pale brown (10YR 6/3) silt loam, very pale brown (10YR 7/3) dry, dark yellowish brown (10YR 4/4) rubbed, light brownish gray (10YR 6/2) rubbed dry; common large prominent red (2.5YR 4/8) mottles, yellowish red (5YR 5/8) dry; massive; slightly hard, very friable, nonsticky and slightly plastic; few fine and very fine roots; few fine and very fine irregular pores; moderately acid (pH 5.6).
TYPE LOCATION: Wakiakum County, Washington; approximately 1 mile northwest of the town of Skamakowa on the west side of State Highway 4; 800 feet west, 1,300 feet south of the NE corner section 7, T.9N., R.6W.
RANGE IN CHARACTERISTICS: The solum is 20 to 35 inches thick. Depth to mottles with chroma of 2 or less ranges from 15 to 24 inches. The 10 to 40 inch control section has 10 to 15 percent clay, 20 to 40 percent fine sand or coarser material, and less than 15 percent fragments larger than 2 mm. The mean annual soil temperature is 48 to 51 degrees F. Soil reaction ranges from moderately acid to very strongly acid throughout.
The A horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 5 or 6 dry, and chroma of 2 through 4 moist or dry. Where moist value is 3 and moist chroma is 2 or 3, the horizon is less than 10 inches thick. This horizon is loam or silt loam and has granular or subangular blocky structure.
The B horizon has hue of 7.5YR, 10YR or 2.5Y, value of 4 or 5 moist, 5 or 6 dry, and chroma of 2 through 6 moist or dry. It is silt loam, loam, or fine sandy loam. This horizon has weak or moderate subangular blocky structure.
The C horizon has hue of 10YR or 2.5Y, value of 4 through 6 moist, 4 through 7 dry, and chroma of 3 or 4 moist or dry. It is mainly silt loam, but is stratified layers of silt loam, loam, and fine sandy loam in some pedons. It ranges from loamy sand to silty clay loam below depths of 40 inches in some pedons.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Montesa soils are on alluvial fans and stream terraces at elevations ranging from 25 to 300 feet. Slopes are 1 to 8 percent. These soils formed in alluvium weathered from igneous and sedimentary rocks from adjacent uplands and mountainous areas. They occur in a humid marine climate with cool, wet winters and cool, dry summers. The annual precipitation ranges from 70 to 110 inches. The mean January temperature is 39 degrees F.; the mean July temperature is 60 degrees F.; and the mean annual temperature is 50 degrees F. The growing season (28 degrees F.) is 200 to 240 days or (32 degrees F.) 160 to 190 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aabab, Arta, Astoria, Boistfort, Bunker, Elochoman, Grehalem, Knappa, Lytell, Skamo, Wankiakum, and Zenker soils. Asbab soils have a fine, silty control section. Arta soils are moderately well drained and have an umbric epipedon. Astoria, Boisfort, Bunker, Elochman, Lytell, Wahkiakum, and Zenker soils are well drained and have a medial control section. Grehalem soils are well drained and have fine, loamy control section. Knappa soils are well drained and have an umbric epipedon more than 20 inches thick. Skamo soils have an umbric epipedon and a fine control section.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff; moderately slow permeability.
USE AND VEGETATION: Timber production, hay crops, and pasture are the principal uses. Small areas have been cleared for homesites. Native vegetation is red alder, western hemlock, Douglas fir, Sitka spruce, and western red cedar. Major understory species are salmonberry, red huckleberry, Oregon grape, swordfern, and brachenfern.
DISTRIBUTION AND EXTENT: Southwestern Washington and possibly northwestern Oregon. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Pacific County, Washington, 1978.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon
Cambic horizon - from 18 to 25 inches (Bw horizon)
Aquic conditions - the zone beginning at 18 inches having less than 50 percent of the matrix with redox depletions with chroma 2 and accompanying redox concentrations.
Aquandic feature - assumed bulk density of less than 1 glcm3 within the 0 to 18 inch zone and assumed ammonium oxalate aluminum plus one-half iron of 1.0 to 1.9 percent throughout.