LOCATION IDANHA OR
Tentative Series
JGM/KMS
01/2017
IDANHA SERIES
Landscape--western Cascade Mountains
Landform--glacially influenced structural benches, mountain slopes, complex landslides
Slope--0 to 90 percent
Parent material--colluvium or slide deposits derived from igneous rock mixed with till and volcanic ash throughout
Mean annual precipitation--2600 mm
Mean annual air temperature--about 6 degrees C
Depth class--very deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Medial-skeletal, amorphic Typic Haplocryands
TYPICAL PEDON: Idanha gravelly medial silt loam on a 23-percent, forested slope at an elevation of 1018 m
Oe--0 to 2 cm; moderately decomposed plant material; clear smooth boundary
A--2 to 22 cm; gravelly medial silt loam, brown (7.5YR 5/2) dry, very dark brown (7.5YR 2.5/2) moist; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine to very coarse roots; many fine tubular pores and common medium irregular pores; 20 percent gravel; very strongly acid (pH 5.0); clear smooth boundary
Bw1--22 to 48 cm; very gravelly medial silt loam, brown (7.5YR 5/3) dry, dark brown (7.5YR 3/3) moist; weak very fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine to medium and common coarse and very coarse roots; many fine tubular pores and many medium irregular pores; 50 percent gravel; strongly acid (pH 5.2); gradual smooth boundary
Bw2--48 to 83 cm; extremely gravelly medial silt loam, grayish brown (10YR 5/2) dry, dark grayish brown (10YR 4/2) moist; weak very fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine and common medium to very coarse roots; common fine tubular pores and many medium irregular pores; 70 percent gravel, 2 percent cobbles, and 2 percent stones; strongly acid (pH 5.4); gradual wavy boundary
Bw3--83 to 150 cm; extremely gravelly medial silt loam, grayish brown (10YR 5/2) dry, brown (10YR 4/3) moist; weak very fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine to coarse roots; common fine tubular pores and many medium irregular pores; 60 percent gravel and 5 percent cobbles; moderately acid (pH 5.6)
TYPE LOCATION: Linn County, Oregon, 4.2 km south of Idanha; 475 m south and 340 m west of the northeast corner of section 32, T. 10 S., R. 6 E.; latitude 44.6653056, longitude -122.0952778, datum WGS 84 (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Dry days--less than 45 consecutive days following summer solstice
Mean annual soil temperature--4 to 6 degrees C
Thickness of umbric epipedon--25 to 50 cm
Reaction--5.0 to 6.0 throughout all mineral horizons
Thickness of andic soil properties--greater than 150 cm (below mineral soil surface)
Estimated properties of layers with andic soil properties
*1/3-bar bulk density--0.60 to 0.90 g/cm3
*Phosphate retention--greater than 85 percent
*Ammonium oxalate extractable Al + Fe--2 to 4 percent
*15-bar water retention--30 to 70 percent (undried samples), greater than 15 percent (dried samples)
*0.02- to 2.0-mm fraction--greater than 30 percent
*Volcanic glass content in 0.02- to 2.0-mm fraction--5 to 30 percent
Particle-size control section
*Clay content--18 to 27 percent
*Total fragment content--35 to 75 percent
O horizon
*Thickness--1 to 6 cm
A horizon
*Hue--7.5YR, 10YR
*Value--2 to 3 moist, 3 to 5 dry
*Chroma--2 or 3 moist or dry
*Fine-earth texture--medial silt loam
*Clay content--15 to 20 percent
*Sand content--15 to 45 percent
*Total fragment content--15 to 35 percent
*Gravel content--15 to 25 percent
*Cobble content--0 to 15 percent
*Stone content--0 to 5 percent
*Thickness--20 to 36 cm
Bw1 horizon
*Hue--7.5YR, 10YR
*Value--2 or 3 moist, 3 to 5 dry
*Chroma--2 or 3 moist or dry
*Fine-earth texture--medial loam, medial silt loam
*Clay content--18 to 27 percent
*Sand content--20 to 45 percent
*Total fragment content--35 to 60 percent
*Gravel content--20 to 55 percent
*Cobble content--0 to 20 percent
*Stone content--0 to 5 percent
*Thickness--0 to 36 cm
Bw2 and Bw3 horizons
*Hue--7.5YR, 10YR
*Value--3 to 5 moist, 5 to 7 dry
*Chroma--3 or 4 moist, 3 to 6 dry
*Fine-earth texture--medial loam, medial silt loam
*Clay content--18 to 27 percent
*Sand content--15 to 45 percent
*Total fragment content--50 to 75 percent
*Gravel content--20 to 70 percent
*Cobble content--2 to 30 percent
*Stone content--0 to 20 percent
COMPETING SERIES:
Divers--ochric epipedon
Highcamp--100 to 150 cm deep to lithic contact
Holderman--ochric epipedon
Hummington--50 to 100 cm deep to lithic contact
Kinzel--less than 18 percent clay in particle-size control section
Oatman--ochric epipedon
Ohana--50 to 100 cm deep to densic layer; ochric epipedon
Otwin--ochric epipedon; bulk density of 0.85 to 1.00 g/cm3 throughout
GEOGRAPHIC SETTING:
Elevation--1100 to 1500 m
Climate--cool, dry summers; cold, wet winters
Mean annual precipitation--2300 to 2900 mm
Mean annual air temperature--5.0 to 7.5 degrees C
Frost-free period--60 to 105 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Icecap--50 to 100 cm deep to lithic contact; in convex positions and on shoulders
Longbow--less than 35 percent rock fragments; in linear and slightly concave positions
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Saturation in normal years--none within profile
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--moderately high
USE AND VEGETATION:
Use--watershed, recreation, wildlife habitat, timber production
Potential natural vegetation--Pacific silver fir, Douglas-fir, western hemlock, Pacific rhododendron, Alaska blueberry, dwarf Oregon grape, bunchberry dogwood, twinflower, beargrass, queencup beadlily; commonly supports a Pacific silver fir/rhododendron-Alaska huckleberry/bunchberry dogwood (CFS654) plant association (Field Guide to the Forested Plant Associations of the Westside Central Cascades of Northwest Oregon)
DISTRIBUTION AND EXTENT: Central western Cascade Mountains, Oregon; MLRA 3; small extent
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Willamette National Forest, Linn County, Oregon; name from town of Idanha
REMARKS:
Diagnostic horizons and features recognized in this pedon
*Particle-size control section--zone from 2 to 102 cm
*Umbric epipedon--zone from 2 to 48 cm
*Cambic horizon--zone from 48 to 150 cm
*Andic soil properties--zone from 2 to 150 cm
*Volcanic glass--zone from 2 to 150 cm
06/2016--Assumed to meet criteria 2 (no ash required) for andic soil properties, in the 12th edition of Keys to Soil Taxonomy. It is also assumed that enough ash is present for the soils to meet criteria 3. Additional lab data is needed to confirm the degree of ash influence.
ADDITIONAL DATA: Type location user site ID--2014OR043630
National Cooperative Soil Survey
U.S.A.