LOCATION MULVAHILL OR
Tentative Series
KLM/JRD
02/2025
MULVAHILL SERIES
Landscape--Valley
Landform--meadows, stream terraces
Slope--0 to 3 percent
Parent Material--clayey alluvium with an influence of volcanic ash in the surface
Mean annual precipitation--about 380 mm
Mean annual air temperature--about 6 degrees C
Depth class--very deep
Drainage class--somewhat poorly drained
Soil moisture regime--xeric
Soil temperature regime--cryic
Soil moisture subclass--aquic
TAXONOMIC CLASS: Fine, smectitic Aquic Palecryolls
TYPICAL PEDON: Mulvahill ashy silt loam - meadow, on a one percent slope at an elevation of 1350 meters. (Colors are for moist soil unless otherwise noted.)
A1--0 to 10 centimeters; very dark brown (10YR 2/2) ashy silt loam, very dark grayish brown (10YR 3/2), dry; moderate very fine granular structure; very friable, soft, slightly sticky, slightly plastic; many very fine and fine roots throughout; neutral (pH 7.2); clear wavy boundary
A2--10 to 41 centimeters; black (10YR 2/1) clay, dark gray (10YR 4/1), dry; strong medium platy structure parts to moderate fine subangular blocky structure; very firm, moderately hard, moderately sticky, very plastic; common very fine roots at top of horizon; moderately alkaline (pH 7.9); abrupt wavy boundary
2Bwb--41 to 54 cm; very dark grayish brown (10YR 3/2) ashy sandy loam, gray (10YR 6/1), dry; moderate thick platy structure; friable, slightly hard, slightly sticky, slightly plastic; few very fine roots throughout and few fine and medium roots throughout; moderately alkaline (pH 8.1); clear smooth boundary
3Btb--54 to 89 cm; very dark grayish brown (10YR 3/2) clay, gray (10YR 5/1), dry; moderate and strong coarse prismatic structure; firm, very hard, moderately sticky, very plastic; few very fine and fine roots throughout; 40 percent distinct clay films on all faces of peds; 2 percent fine faint iron-manganese masses in matrix and 5 percent fine faint iron depletions in matrix; moderately alkaline (pH 8.2); clear smooth boundary
3Bwb1--89 to 124 cm; dark grayish brown (10YR 4/2) clay loam, light brownish gray (10YR 6/2), dry; moderate coarse subangular blocky structure; friable, hard, moderately sticky, moderately plastic; few very fine roots throughout; faint silt coats; 5 percent iron-manganese masses in matrix and 8 percent medium prominent iron depletions in matrix surrounding redox concentrations; moderately alkaline (pH 8.4); clear smooth boundary
3Bwb2--124 to 157 cm; dark grayish brown (10YR 4/2) clay loam, light brownish gray (10YR 6/2), dry; moderate coarse subangular blocky structure; friable, moderately hard, moderately sticky, moderately plastic; few very fine and medium roots throughout; faint silt coats; 3 percent fine prominent iron-manganese nodules in matrix and 15 percent medium distinct iron depletions in matrix surrounding redox concentrations and 20 percent medium prominent dark yellowish brown (10YR 4/6), moist, iron-manganese masses in matrix; moderately alkaline (pH 8.1); abrupt smooth boundary
4C--157 to 185 cm; greenish black (5GY 2.5/1) very gravelly sandy clay loam, light yellowish brown (2.5Y 6/3), dry; weak medium subangular blocky structure; friable, soft, moderately sticky, moderately plastic; few very fine roots throughout; reduced matrix; 55 percent rounded gravels; moderately alkaline (pH 8.1)
TYPE LOCATION: Crook County, Oregon; located about 25 km south of the town of Mitchell; 650 m north and 510 m west of the SE corner of section 23, T. 14 S., R. 21 E. Williams Prairie 7.5' USGS Quad.
Latitude-- 44.341278
Longitude-- -120.1699
Datum--WGS84 (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--5 to 8 degrees C
Mean annual summer soil temperature--less than 13 degrees C
Soil Moisture--Xeric soil moisture regime bordering aquic
Depth to redoximorphic features--50 to 80 cm
Thickness of mollic epipedon--25 to 50 cm
Reaction--neutral to moderately alkaline
Volcanic ash influenced layers:
0 to 18 cm thick
Volcanic glass content in the 0.02 to 2.0 mm fraction--20 to 40 percent
Ammonium oxalate extractable Al plus 1/2 Fe--less than 0.40
Particle Size Control Section:
Clay Content--30 to 55 percent
Weighted Average Clay Content--35 to 45 percent
Ap1 horizon
Hue--10YR
Value--2 moist, 3 or 4 dry
Chroma--1 or 2 moist or dry
Fine earth texture--ashy silt loam, ashy loam
Clay content--18 to 27 percent
Sand content--20 to 40 percent
Organic matter content--3 to 6 percent
Ap2 horizon
Hue--10YR
Value--2 moist, 3 or 4 dry
Chroma--1 or 2 moist or dry
Fine earth texture--clay or clay loam
Clay content--30 to 50 percent
Organic matter content--2 to 4 percent
2Bwb horizon
Hue--10YR or 2.5Y
Value--3 or 4 moist, 6 or 7 dry
Chroma--1 or 2 moist or dry
Fine earth texture--ashy sandy loam, ashy loamy sand, ashy loamy coarse sand
Clay content--5 to 18 percent
Sand content--55 to 80 percent
Organic matter content--0.5 to 1.5 percent
Total pumice paragravels--0 to 10 percent
3Btb horizon
Hue--10YR
Value--2 or 3 moist, 3 to 5 dry
Chroma--1 or 2 moist and dry
Fine earth texture--clay, or clay loam
Clay content--35 to 55 percent
Sand content--15 to 40 percent
Organic matter content--1.0 to 2.0 percent
3Bwb horizons
Hue--10YR
Value--3 or 4 moist, 5 or 6 dry
Chroma--2 to 3 moist, 2 or 3 dry
Fine earth texture--clay loam or clay
Clay content--30 to 50 percent
Sand content--15 to 40 percent
Organic matter content--0.5 to 1.0 percent
Total Fragments--0 to 10 percent
4C horizon(s)
Hue--10Y, 5GY or 10GY moist, 2.5Y, 2.5Y or 10YR dry
Value--less than 5 moist, 5 or 6 dry
Chroma--less than 2 moist, 2 to 4 dry
Fine earth texture--sandy loam, sandy clay loam, clay loam
Clay content--18 to 40 percent
Sand content--40 to 60 percent
Organic matter content--0.0 to 0.5 percent
Total Fragments--35 to 90 percent
Gravel--35 to 90 percent
Cobbles--0 to 10 percent
COMPETING SERIES:
Pothole--depth to redoximorphic features less than 50 cm; have greater than 18cm of volcanic ash in the surface
GEOGRAPHIC SETTING:
Elevation--1250 to 1350 m
Slope--0 to 3 percent
Climate--cool wet winters, mild dry summers
Mean annual precipitation--300 to 450 mm
Mean annual air temperature-- 5 to 8 degrees C
Frost-free period-- 30 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Gerow--greater than 18cm of volcanic ash in the surface, averages less than 35% clay in the control section
Silvies--depth to redoximorphic features less than 50cm
DRAINAGE AND PERMEABILITY:
Drainage--somewhat poorly drained, seasonal episaturation and endosaturation
Saturated hydraulic conductivity (Ksat)--low
USE AND VEGETATION:
Use--livestock grazing, meadow hay production, wildlife habitat
Vegetation--Nebraska sedge, tufted hairgrass and other sedges and rushes
Typical Ecological Site--Cold Meadow (R010XY002OR)
DISTRIBUTION AND EXTENT:
Central Oregon; MLRA B-10; small extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED:
Crook County Area, Oregon 2015; the name is derived from a nearby homestead
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section--54 to 104 cm
Mollic epipedon--0 to 41 cm
Cambic horizon--89 to 157 cm
Argillic horizon--54 to 157 cm
Horizons containing enough volcanic ash to meet the vitrandic criteria--0 to 10 cm and 41 to 54 cm (A1 and 2Bwb horizons)
Aquic conditions--endosaturation from 54 to 185cm, April through June. Short duration episaturation can occur above the buried ash layer (0 to 41 cm) on some years.
The Mulvahill soil was created to capture somewhat poorly drained meadow soils found near Big Summit Prairie in Crook County, Oregon. These soils often have a thin surface to heavy clay loam or clay and are readily identified by the buried layer of Mt. Mazama ash and pumice. This buried ash layer occurs from depths of 10 to 50 cm below the soil surface.
National Cooperative Soil Survey
U.S.A.