LOCATION SUNCOLD ORTentative Series
TAXONOMIC CLASS: Fine, smectitic, mesic Abruptic Xeric Argidurids
TYPICAL PEDON: Suncold ashy silt loam, at an elevation of 1,330 meters, rangeland. (Colors are for dry soil unless otherwise noted.) The surface is partly covered by 3 percent cobbles and 2 percent gravel.
A--0 to 11 cm; pale brown (10YR 6/3) ashy silt loam, dark brown (10YR 3/3) moist; weak thick platy structure; soft, very friable, slightly sticky, slightly plastic; many very fine, fine, and medium roots; neutral (pH 7.2); clear wavy boundary. (5 to 28 cm thick)
Bt1--11 to 21 cm; brown (10YR 5/3) cobbly ashy silt loam, dark brown (10YR 3/3) moist; moderate medium and fine subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; many fine and very fine roots and common medium roots; common fine and very fine interstitial pores; 5 percent distinct clay films on all faces of peds; 7 percent gravel and 10 percent cobbles; slightly alkaline (pH 7.4); abrupt smooth boundary. (5 to 25 cm thick)
Bt2--21 to 31 cm; yellowish brown (10YR 5/4) cobbly silty clay loam, dark yellowish brown (10YR 4/4) moist; strong medium and fine subangular blocky structure; slightly hard, friable, moderately sticky, moderately plastic; common fine and very fine roots; common fine and very fine interstitial pores; 10 percent distinct clay films on all faces of peds; 5 percent gravel and 10 percent cobbles and 5 percent stones; slightly alkaline (pH 7.6); abrupt smooth boundary. (5 to 37 cm thick)
Bt3--31 to 44 cm; dark brown (10YR 3/3) cobbly clay, dark brown (10YR 3/3) moist; strong medium prismatic structure parting to strong medium angular blocky; hard, very firm, very sticky, very plastic; common fine and very fine roots; common very fine interstitial pores; 50 percent distinct pressure faces; 5 percent gravel and 10 percent cobbles and 5 percent stones; slightly alkaline (pH 7.8); clear smooth boundary.
Bt4--44 to 52 cm; dark yellowish brown (10YR 3/6) clay loam, dark yellowish brown (10YR 4/4) moist; moderate fine angular blocky structure; hard, very firm, moderately sticky, moderately plastic; common fine and very fine roots; common very fine interstitial pores; 30 percent distinct pressure faces; strongly effervescent; slightly alkaline (pH 7.8). (Combined thickness of Bt3 and Bt4 horizons is 8 to 27 cm)
Bkqm1--52 to 60 cm; dark yellowish brown (10YR 4/6) cemented material, dark yellowish brown (10YR 4/6) moist; massive; very hard, extremely firm, nonsticky, nonplastic; strongly cemented by secondary silica and calcium carbonate; strongly effervescent; moderately alkaline (pH 8.0). (8 to 13 cm thick)
Bkqm2--60 to 62 cm; cemented material; massive; rigid, very strongly cemented by secondary silica and calcium carbonate; moderately alkaline (pH 8.0). (2 to 25 cm thick)
R--62 cm; indurated basalt.
TYPE LOCATION: Malheur County, Oregon; Approximately 9 miles west of Jordan Valley, Oregon; UTM 478560 easting and 4762242 northing, zone 11, NAD83 on the USGS Cow Lakes 7.5 minute quadrangle; latitude 43 degrees 0 minutes 45.2 seconds north and longitude 117 degrees 15 minutes 47.1 seconds west, NAD83.
RANGE IN CHARACTERISTICS:
Soil moisture - The soil moisture control section is dry throughout in summer and fall and moist in winter and spring; the surface horizon is wet in April due to snowmelt; aridic soil moisture regime that borders on xeric.
Soil temperature - Mean annual temperature is 8 to 9 degrees C.
Depth to abrupt texture change - 15 to 30 cm
Depth to Duripan - 51 to 76 cm.
Depth to Bedrock - 56 to 80 cm.
Control section - Clay content - Averages 35 to 50 percent.
Rock fragments - Averages 5 to 35 percent, mainly cobbles.
A horizon -
Value: 5 to 7 dry, 3 to 5 moist.
Chroma: 2 or 3 dry or moist.
Reaction: Neutral to slightly alkaline.
Volcanic glass: Volcanic glass is estimated to range from 20 to 40 percent of the 0.02 to 2 mm fraction.
AB horizon (when present) -
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 or 3 dry or moist.
Texture: Ashy silt loam, ashy loam.
Clay content: 18 to 25 percent.
Rock fragments: Averages 5 to 35 percent, mainly gravel and cobbles.
Volcanic glass: Volcanic glass is estimated to range from 5 to 30 percent of the 0.02 to 2 mm fraction.
Bt1 horizons -
Value: 3 to 5 dry, 3 or 4 moist.
Chroma: 3 to 6 dry, 3 or 4 moist.
Texture: Ashy silt loam, ashy loam.
Clay content: 18 to 25 percent.
Rock fragments: Averages 10 to 35 percent, gravel, cobbles, and stones.
Volcanic glass: Volcanic glass is estimated to range from 5 to 30 percent of the 0.02 to 2 mm fraction.
Bt2, Bt3 and Bt4 horizons -
Value: 3 to 5 dry, 3 or 4 moist.
Chroma: 3 to 6 dry, 3 or 4 moist.
Texture: Clay, clay loam.
Clay content: 35 to 50 percent.
Rock fragments: Averages 5 to 30 percent, gravel, cobbles, and stones
Bkqm1 (and Bkqm2) horizon(s)
Value: 4 to 7 dry or moist.
Chroma: 4 to 6 dry, 2 to 6 moist.
Cementation: moderately cemented to very strongly cemented; some or all subhorizons have very strongly cemented rupture resistance.
COMPETING SERIES: These are the Bogusrim (OR), Catchell (ID), Chilcott (ID), Lookout (OR), Lovejoy (CA), Novacan (NV), Pigtail (ID), and Reno (NV) soils. Bogusrim soils have Bk horizons above the duripan. Catchell soils have Bk horizons above the duripan and have E horizons; Chilcott soils are greater than 152 cm to bedrock; Lookout soils have Bk horizons above the duripan; Lovejoy soils are greater than 152 cm to bedrock; Novacan, Pigtail, and Reno soils are greater than 152 cm to bedrock.
GEOGRAPHIC SETTING: Suncold soils are on lava plateaus. These soils formed in mixed loess and volcanic ash over residuum from basalt. Slopes are 2 to 15 percent. Elevations are 1,280 to 1,370 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 250 to 300 mm; mean annual temperature is 7 to 8 degrees C, and the frost-free period is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Bogusrim and Cowlake, soils. Cowlake soils have more than 35 percent rock fragments in the particle control section and are shallow to bedrock.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained, saturated in the upper part for two weeks or more in spring due to snowmelt, high runoff, slow and very slow permeability and moderately low saturated hydraulic conductivity.
USE AND VEGETATION: Rangeland and wildlife habitat. The present vegetation is mainly low sagebrush, bluebunch wheatgrass, and Sandberg's bluegrass.
DISTRIBUTION AND EXTENT: Southeast Oregon; the soil is of moderate extent. MLRA 25.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES PROPOSED: Malheur County, Oregon, Southern Part, 2008
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 11 cm (A horizon).
Argillic horizon - The zone from about 11 to 52 cm (Bt1, Bt2, Bt3, and Bt4 horizons).
Duripan- The cemented horizons from about 52 to 62 cm (Bkqm1 and Bkqm2 horizons).
Lithic contact - The contact with bedrock at 62 cm (R layer).
Ashy Textures - Volcanic glass is 20 to 40 percent of the 0.2 to 2 mm fraction in the zone from 0 to 11 cm (A horizons) and is 5 to 30 percent of the 0.2 to 2 mm fraction in the zone from 11 to 21 cm (Bt1 horizons).
Particle control section - The zone from 11 to 52 cm (Bt1, Bt2, Bt3, and Bt4 horizons).