LOCATION FREN ORTentative Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Vitrandic Haploxerolls
TYPICAL PEDON: Fren ashy sandy loam, on a northerly ravine slope of 52 percent in sagebrush steppe at elevation of 3,500 feet. (Colors are for dry soil unless otherwise noted.)
A1--0 to 4 inches; brown (10YR 5/3) ashy sandy loam, very dark grayish brown (10YR 3/2) moist; weak thin platy structure parting to weak fine granular soft, very friable, slightly sticky and nonplastic; many very fine and fine roots; many irregular pores; neutral; clear wavy boundary. (3 to 7 inches thick)
A2--4 to 18 inches; brown (10YR 5/3) ashy sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and few medium roots; many irregular pores; neutral; abrupt wavy boundary. (7 to 15 inches thick)
2AB--18 to 27 inches; brown (10YR 4/3) loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; many roots; few very fine tubular pores; neutral; clear wavy boundary. (6 to 12 inches thick)
2Bw--27 to 35 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common roots; few very fine tubular pores; slightly alkaline; clear wavy boundary. (5 to 12 inches thick)
2Bk1--35 to 51 inches; pale brown (10YR 6/3) loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common roots; few very fine tubular pores; strongly effervescent; moderately alkaline; clear wavy boundary. (10 to 20 inches thick)
3Bk2--51 to 65 inches; pale brown (10YR 6/3) clay loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; slightly hard, friable, strongly effervescent; moderately alkaline.
TYPE LOCATION: Crook County, Oregon; west of Bear Creek and Highway 27; NE1/4 NW1/4 section 16, T. 18 S., R. 17 E.
RANGE IN CHARACTERISTICS:
Soil moisture - These soils are usually moist in winter and spring. They are warmer than 41 degrees F. from April 15 to November 1, and they are dry within this period after July 1.
Mean annual soil temperature - 44 to 47 degrees F.
Depth to bedrock - More than 60 inches.
Mollic epipedon thickness - 20 to 35 inches.
Vitrandic intergrade properties - The soil to a depth of 10 to 20 inches has about 15 to 30 percent volcanic glass and 0.2 to 1.0 percent acid oxalate extractable aluminum plus one-half acid oxalate extractable iron.
Depth to identifiable secondary carbonates - 20 to 35 inches.
Reaction - Neutral in the upper part and neutral through moderately alkaline in the lower part.
Particle-size control section - Clay content: 12 to 18 percent; Rock fragments: 0 to 35 percent, mainly gravel. Lithology of fragments are volcanic rocks such as basalt.
A horizons - Value: 2 or 3 moist.
Chroma: 2 or 3 dry.
Rock fragments: 0 to 15 percent gravel.
B horizons - Value: 3 or 4 moist.
Structure: Weak or moderate subangular blocky structure.
Texture: Loam, sandy loam, or gravelly loam.
COMPETING SERIES: These are the Dinkelman, Kilmerque, Lostcreek, and Republic series.
Dinkelman and Republic soils are dry for 60 to 75 consecutive days following the summer solstice. Kilmerque soils are moderately deep to paralithic contacts. Lostcreek soils are dry for 45 to 60 consecutive days following the summer solstice.
GEOGRAPHIC SETTING: Fren soils are on ravines. They typically occur on north-facing backslopes. These soils formed in volcanic ash over colluvium weathered from basalt. Slopes are 15 to 60 percent. Elevations range from 3,400 to 4,500 feet. The climate is semiarid and characterized by cold, moist winters and warm, dry summers. The mean annual precipitation is 10 to 14 inches. The mean annual temperature is 43 to 45 degrees F., average January temperature is 27 to 29 degrees F., and average July temperature is 59 to 61 degrees F. The frost-free period is 50 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Lorella, Simas, and Stukel soils. All of these soils are mesic and are on adjacent southerly slopes. Lorella and Stukel soils also are shallow over bedrock. Simas soils are clayey and have abrupt clay increase.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Fren soils are used for livestock grazing and wildlife habitat. The native vegetation is mainly basin big sagebrush, mountain big sagebrush, Idaho fescue, bluebunch wheatgrass, and Thurber's needlegrass.
DISTRIBUTION AND EXTENT: Central Oregon east of the Cascade Mountains; MLRA 10. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Prineville District Area, BLM, Crook County, Oregon, 1980. The name is coined.
REMARKS: This revision of December 2002 updates the taxonomic class by adding the superactive cation exchange activity class. Responsibility for the series was transferred from the Reno to Portland MLRA office. Future study is needed to accurately determine the amount of volcanic glass in this series.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 35 inches (A1, A2, 2AB, and 2Bw horizons).
Vitrandic intergrade properties - The zone from the soil surface to 18 inches (A1 and A2 horizons).
Cambic horizon - The zone from 35 to 65 inches (2Bk1 and 3Bk2 horizons).
Identifiable secondary carbonates - The zone from 35 to 65 inches (2Bk1 and 3Bk2 horizons).
Particle-size control section - The zone from 10 to 40 inches (2AB and 2Bw horizons and parts of the A2 and 2Bk1 horizons).