LOCATION DRYPOK ORTentative Series
TAXONOMIC CLASS: Ashy, glassy, frigid Humic Vitrixerands
TYPICAL PEDON: Drypok ashy sandy loam, upland forest. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 1 inches; slightly decomposed litter of ponderosa pine needles.
A--1 to 4 inches; dark brown (10YR 3/3) ashy sandy loam, very dark brown (10YR 2/2) moist; strong thin to medium platy structure; soft, friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine vesicular pores; 5 percent gravel; slightly acid (pH 6.2); abrupt smooth boundary. (2 to 5 inches thick)
AB--4 to 13 inches; dark brown (10YR 3/3) ashy sandy loam, very dark brown (10YR 2/2) moist; moderate medium platy structure that parts to moderate fine and medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; many very fine, fine, medium and coarse roots; many very fine and fine irregular pores; 5 percent gravel; slightly acid (pH 6.4); clear smooth boundary. (8 to 10 inches thick)
Bw--13 to 24 inches; dark brown (10YR 3/3) ashy sandy loam, very dark brown (10YR 2/2) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, fine, medium and coarse roots; many very fine and fine irregular pores; 10 percent gravel; slightly acid (pH 6.4), clear smooth boundary. (10 to 15 inches thick)
2Cr--24 to 34 inches; very dark grayish brown (10YR 3/2) weathered rhyolite, with common very fine and fine roots in cracks..
TYPE LOCATION: Crook County, Oregon; southwest 1/4, section 12, T. 18 S., R. 18 E.
Latitude 44 degrees, 01 minutes, 09 seconds
Longitude 120 degrees, 30 minutes, 53 seconds
UTM Coordinates: Zone: 10; Northing: 4877004.5; Easting: 699192.8
RANGE IN CHARACTERISTICS:
Soil temperature: frigid regime
mean annual soil temperature: 40 to 45 degrees F.
mean summer soil temperature: 44 to 49 degrees F.
mean winter soil temperature: 32 to 36 degrees F.
Soil moisture: xeric regime, dry 60 to 90 consecutive days in summer and early fall
Particle-size control section: mineral surface to the paralithic contact
clay content (weighted average): 5 to 18 percent
rock fragment content (weighted average): 0 to 15 percent
Diagnostic horizons and features:
andic soil properties: upper boundary at the mineral surface; 20 to 40 inches thick
Al+1/2Fe - 0.4 to 1.0 percent (ammonium oxalate)
P retention - 25 to 50 percent
0.2 to 2.0 mm fraction - 60 to 80 percent of fine earth
glass content - 30 to 60 percent of 0.2 to 2.0 fraction
water content at 1500 kPa - 8 to 12 percent (dried samples)
mollic epipedon - 20 to 40 inches thick
paralithic contact, depth - 20 to 40 inches
Major horizons:
A horizon and Bw horizon
color, moist - 10YR 2/2, 2/3 3/2, 3/3
color, dry - 10YR 3/2, 3/3, 4/2, 4/3
texture - ashy loamy sand, ashy sandy loam, ashy fine sandy loam
clay content: - 8 to 18 percent
rock fragments - 0 to 15 percent
gravel - 0 to 15 percent
cobble - 0 to 5 percent
stones - 0 to 5 percent
reaction - slightly acid pH: 6.1 to 6.5
COMPETING SERIES:
Cobey - very deep
Ermabell - very deep; dry 90 to 110 consecutive days in summer
Laidlaw - very deep; dry 90 to 110 consecutive days in summer
Lundgren - very deep; dry 90 to 110 consecutive days in summer
Pilotbutte - very deep
Retep - the lower part of the particle-size control section has 18 to 27 percent clay
Suttle - very deep; umbric epipedon; somewhat poorly drained
Trailcreek - dry 90 to 110 consecutive days in summer; lack an O horizon
Wanoga - dry 90 to 110 consecutive days in summer
GEOGRAPHIC SETTING:
Landform: ash pockets in swales and on the lee side of small ridges and outcroppings on ridges, plateau tops and mountain sideslopes
Slope gradient: 5 to 40 percent
Parent material: volcanic ash over residuum
Lithology: tuffaceous rhyolite, pyroclastic tuff, basalt
Elevation: 4000 to 6000 feet
Climate: cold, wet winters and hot, dry summers
Mean annual precipitation: 15 to 20 inches
Mean annual temperature: 40 to 45 degrees F.
Frost-free period: 60 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Aldig occur on upper backslopes
Maule (T) occur on convex moun tain backslopes; argillic horizon below the ash layer.
Merlin occur on plateau crests on shoulders; shallow to bedrock, argillic horizon
Mocosprings (T) occur on concave lower backslopes; argillic horizons, vertic
Vermau (T) occur on upland benches; heavy argillic horizons
Sintuf (T) occur on plateau crests on shoulders
DRAINAGE AND PERMEABILITY:
Drainage: well drained
Permeability: rapid
USE AND VEGETATION:
Use: woodland, rangeland, wildlife habitat, and water supply
Natural vegetation: ponderosa pine, pinegrass, Idaho fescue and Columbia needlegrass
DISTRIBUTION AND EXTENT:
Distribution--Central Oregon
MLRA--43c, Blue Mountains-Seven Devils
Extent: moderate
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Crook County, Oregon; 2005
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
andic soil properties 1 to 24 inches
mollic epipedon 1 to 24 inches
Plant association: CPG-222, ponderosa pine/elk sedge (Hall, 1989, Plant Association and Management Guide for the Ochoco and Southern Blue Mountain Area)
Plant association groups: dry, pine; moist, pine