LOCATION LOSTFORK ORTentative Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Aquandic Cryaquolls
TYPICAL PEDON: Lostfork gravelly ashy loam, on a 2 percent slope, meadow, at an elevation of 5,200 feet. (Colors are for moist soil unless otherwise noted. When described on August 23, 2001, the upper 32 inches was dry and the soil was moist below.)
A1--0 to 8 inches; very dark grayish brown (10YR 3/2) gravelly ashy loam, brown (10YR 4/3) dry; weak fine granular structure; soft, very friable, moderately sticky and moderately plastic; many very fine roots; many very fine interstitial pores; common fine and medium faint strong brown (7.5YR 4/6) and yellowish brown (10YR 5/4) redox concentrations; 20 percent gravel; neutral (pH 6.8); gradual smooth boundary.
A2--8 to 14 inches; very dark grayish brown (10YR 3/2) very gravelly ashy loam, grayish brown (10YR 5/2) dry; weak fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine and fine and common medium roots, few medium; common very fine interstitial pores; common fine and medium faint strong brown (7.5YR 4/6) and yellowish brown (10YR 5/4) redox concentrations; 30 percent gravel and 5 percent cobbles; neutral (pH 7.2); clear smooth boundary.
A3--14 to 23 inches; dark brown (10YR 3/3) very gravelly ashy loam, dark grayish brown (10YR 4/2) dry; massive; hard, firm, nonsticky and nonplastic; many very fine and common fine and medium roots, few fine tubular pores; 30 percent gravel and 5 percent cobbles; common fine and medium faint strong brown (7.5YR 4/6) and yellowish brown (10YR 5/4) redox concentrations; neutral (pH 7.3); clear smooth boundary. (The combined thickness of the A horizons is 20 to 35 inches thick)
2C1--23 to 34 inches; brown (10YR 4/3) extremely gravelly sandy loam, brown (10YR 5/3) dry; single grain; loose, nonsticky and nonplastic; many very fine roots; common fine and medium faint strong brown (7.5YR 4/6) and yellowish brown (10YR 5/4) redox concentrations; 45 percent gravel and 20 percent cobbles; slightly alkaline (pH 7.5).
2C2--34 to 60 inches; dark grayish brown (10YR 4/2) extremely gravelly loamy sand, grayish brown (10YR 5/2) dry; single grain; loose, nonsticky and nonplastic; common very fine roots; common fine distinct strong brown (7.5YR 4/6) and yellowish brown (10YR 5/4) redox concentrations; 45 percent gravel and 20 percent cobbles; slightly alkaline (pH 7.5).
TYPE LOCATION: Grant County, Oregon; in Logan Valley adjacent to McCoy Creek; 2,300 feet east and 1,800 feet south of the northwest corner of section 4, T.16S., R.34E. (Latitude 44 degrees 12 minutes 51 seconds north, Longitude 118 degrees 38 minutes 28 seconds west).
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 42 to 46 degrees F. and the mean summer temperature is less than 55 degrees F. The soil is saturated throughout in the spring. Depth to bedrock is greater than 60 inches. Depth to the 2C horizon and thickness of the mollic epipedon is 20 to 35 inches. The particle-size control section averages 18 to 27 percent clay and 35 to 60 percent rounded rock fragments. The mollic epipedon has 10 to 30 percent glass. Acid oxalate extractable aluminum plus one-half the iron is 0.3 to 0.7.
The A1 horizon has value of 2 or 3 moist, 3 or 4 dry and chroma of 2 or 3 moist and dry. Organic matter content is 5 to 20 percent. It is gravelly ashy loam. mucky ashy silt loam, or mucky ashy silty clay loam. It contains 0 to 30 percent gravel and 20 to 35 percent clay.
The A2 and A3 horizons has value of 2 or 3 moist, 3 to 5 dry and chroma of 1 or 2 moist and dry. It is ashy loam, ashy sandy loam or ashy clay loam with 15 to 35 percent gravel, 0 to 5 percent cobbles, and 15 to 30 percent clay.
The 2C horizons have value 2 to 4 moist, 3 to 5 dry and chroma of 1 through 3 moist and dry. It is sandy loam, loamy sand or sand with 40 to 70 percent gravel and 0 to 20 percent cobbles and 5 to 15 percent clay.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Lostfork soils are on stream terraces and flood plains in glacial outwash plains at elevations of 3,600 to 5,600 feet. These soils formed in mixed alluvium and volcanic ash. The climate is characterized by cold, wet winters and cool, dry summers. The mean annual precipitation is 14 to 28 inches, the mean annual temperature is 40 to 44 degrees F, and the frost-free period is 10 to 30 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These include Damon, Silvies, Luckybutte, and Raycreek. The Damon soils are on stream terraces, are fine-silty, and lack gravel in the upper 40 inches. The Silvies soils are on flood plains, are fine, and lack gravel in the upper 40 inches. The Luckybutte soils are on flood plains along stream channels or abandon stream channels, and are fine-loamy over sandy or sandy-skeletal. The Raycreek soils are located on adjacent ponderosa pine sites on hills and footslopes, are well drained, are fine-loamy, and have bedrock at 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Very poorly or poorly drained; permeability is moderate over rapid.
USE AND VEGETATION: This soil is used mainly for livestock grazing and wildlife habitat. The soil is in Mountain Meadow R01XY002OR (poorly drained) and slightly lower areas are in Wet Mountain Meadow R01XY001OR (very poorly drained). Native vegetation is sedges, rushes, tufted hairgrass, and willow.
DISTRIBUTION AND EXTENT: South central Oregon. MLRA 10. This series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Grant County, Oregon, 2004.
REMARKS: Diagnostic horizons and other features:
Mollic epipedon - the zone from the surface of the soil to a depth of 23 inches, dark colors in the 2C horizon are from basaltic sands.
Aquic feature - redox concentrations throughout.
The ashy material in the A horizons are reworked alluvium from Mt. Mazama.