LOCATION FASTJET ORTentative Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Vitrandic Argixerolls
TYPICAL PEDON: Fastjet ashy silt loam at an elevation of 1,500 meters, rangeland. (Colors are for dry soil unless otherwise noted.) The surface is partly covered by 2 percent gravel.
A--0 to 12 cm; grayish brown (10YR 5/2) ashy silt loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium granular structure; soft, very friable, slightly sticky, slightly plastic; many fine and very fine roots and common medium roots; common fine interstitial and very fine tubular pores; 2 percent gravel; slightly alkaline (pH 7.4); clear smooth boundary. (10 to 25 cm thick)
Bt1--12 to 20 cm; brown (10YR 4/3) gravelly ashy silt loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; many fine and very fine roots and common medium roots; many fine and medium irregular pores; 10 percent faint clay films on all faces of peds; 10 percent fine gravel, 10 percent gravel, and 2 percent cobbles; slightly alkaline (pH 7.4); clear smooth boundary. (8 to 28 cm thick)
Bt2--20 to 42 cm; brown (10YR 4/3) silty clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; moderately hard, firm, slightly sticky, slightly plastic; common fine and very fine roots; many fine irregular and common fine interstitial and tubular pores; 10 percent distinct clay films on all faces of peds; 5 percent fine gravel and 5 percent gravel; slightly alkaline (pH 7.4); clear smooth boundary. (7 to 30 cm thick)
Bt3--42 to 52 cm; brown (10YR 4/3) silty clay loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, very firm, slightly sticky, slightly plastic; common fine roots; common fine tubular and interstitial pores; 10 percent distinct clay films on all faces of peds; slightly alkaline (pH 7.4); clear smooth boundary. (10 to 40 cm thick)
Cr--52 cm; moderately cemented tuff; slightly alkaline (pH 7.4).
TYPE LOCATION: Malheur County, Oregon; 10 miles southwest of Jordan Valley, Oregon; UTM 486538 easting and 4740916 northing, zone 11, NAD83 on the USGS Juniper Ridge 7.5 minute quadrangle, latitude 42 degrees 49 minutes and 14.5 seconds north and longitude 117 degrees 9 minutes and 52.8 seconds west, NAD83.
RANGE IN CHARACTERISTICS:
Soil moisture - The soil moisture control section is dry throughout in late summer and fall and moist in winter, spring, and early summer; xeric soil moisture regime.
Soil temperature - The mean annual soil temperature is 7 to 8 degrees C.
Mollic epipedon thickness - 25 to 50 cm, includes the upper part of the Bt horizon in some pedons.
Depth to paralithic contact - 50 to 95 cm.
Control section - Clay content - 18 to 35 percent.
Rock fragments - 5 to 35 percent, mainly gravel with tuff lithology.
A horizon -
Value: 4 to 6 dry, 3 to 5 moist.
Chroma: 2 or 3 dry or moist.
Reaction: Neutral through moderately alkaline.
Volcanic glass: Volcanic glass is estimated to range from 30 to 50 percent of the 0.02 to 2 mm fraction.
Bt horizons -
Value: 4 to 6 dry and 2 to 4 moist.
Chroma: 2 to 4 dry or moist.
Texture: Silty clay loam, clay loam, ashy silt loam.
Clay content: 18 to 35 percent.
Rock fragments: Averages 5 to 35 percent, mainly gravel.
Reaction: Neutral through moderately alkaline.
Volcanic glass: Volcanic glass is estimated to range from 5 to 30 percent of the 0.02 to 2 mm fraction in the upper Bt horizon.
COMPETING SERIES: These are the Luckycreek, Pinney, Powellbutte, and Runyon series. The Luckycreek and Pinney soils are greater than 100 cm to bedrock. The Powellbutte series is 50 to 100 cm to hard bedrock. The Runyon series has 5 to 20 percent volcanic glass in the A and upper Bt horizons.
GEOGRAPHIC SETTING: Fastjet soils are on lava plateaus and hillslopes. These soils formed in mixed volcanic ash and loess over residuum weathered from tuff. Slopes are 2 to 35 percent. Elevations are 1,430 to 1,585 meters. The climate is semiarid with cold, moist winters and warm, dry summers. The mean annual precipitation is 300 to 400 mm; mean annual temperature is 5 to 7 degrees C, and the frost free season is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Boost soils. Boost soils have greater than 35 percent clay in the argillic horizon.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, slow and very slow permeability, and moderately low saturated hydraulic conductivity.
USE AND VEGETATION: Rangeland and wildlife habitat. The present vegetation is mainly basin big sagebrush, Idaho fescue and antelope bitterbrush.
DISTRIBUTION AND EXTENT: Southeast Oregon; the soil is of small 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:
Mollic epipedon - The zone from the soil surface to about 42 cm (A, Bt1 and Bt2 horizons).
Argillic horizon - The zone from about 12 to 52 cm (Bt1, Bt2, and Bt3 horizons).
Vitrandic feature - Volcanic glass is 30 to 50 percent of the 0.02 to 2 mm fraction in the zone from 0 to 12 cm (A horizons). Volcanic glass is 5 to 30 percent of the 0.02 to 2 mm fraction in the zone from 12 to 20 cm (Bt1 horizon).
Particle-size control section - the zone from 12 to 52 cm (Bt1, Bt2, and Bt3 horizons).