LOCATION MIDDLERES ORTentative Series
TAXONOMIC CLASS: Ashy, glassy, frigid Aquandic Endoaquolls
TYPICAL PEDON: Middleres ashy mucky loam--on 1 percent slope at an elevation of 4,988 feet--rangeland. (Colors are for moist soil unless otherwise noted. When described on September 9, 1998 the soil was moist to saturated with a water table at 46 inches.)
Oe--0 to 2.5 inches; very dark grayish brown (10YR 3/2) moderately decomposed plant material, dark brown (10YR 3/3) dry; about 50 percent fibers after rubbing which are dead roots and stems of grass and grass-like plants; clear smooth boundary. (0 to 3 inches thick)
A1--2.5 to 4.5 inches; very dark gray (10YR 3/1) ashy mucky loam, gray (10YR 5/1) dry; weak thin platy structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, common fine, and common medium roots; many very fine and fine dendritic tubular and irregularly shaped pores; neutral (pH 6.6); clear smooth boundary. (2 to 6 inches thick)
A2--4.5 to 8 inches; very dark gray (10YR 3/1) ashy loam, dark gray (10YR 4/1) dry; moderate medium and thin platy structure; slightly hard, friable, moderately sticky and slightly plastic; many very fine, common fine, and common medium roots; many very fine and many fine dendritic tubular and irregularly shaped pores; neutral (pH 6.8); gradual smooth boundary. (4 to 10 inches thick)
Bq--8 to 14 inches; very dark gray (10YR 3/1) ashy loam, gray (10YR 5/1) dry; moderate medium and thin platy structure; slightly hard, friable and brittle, moderately sticky and slightly plastic; common very fine, common fine, and common medium roots; common very fine and common fine dendritic tubular and irregularly shaped pores; neutral (pH 6.8); clear smooth boundary. (0 to 11 inches thick)
2C1--14 to 26 inches; dark grayish brown (10YR 4/2) ashy sand, light gray (10YR 7/2) dry; single grain; loose, nonsticky and nonplastic; few very fine, few medium, and common fine roots; many interstitial pores; common fine prominent strong brown (7.5YR 5/8) masses of iron accumulation; 3 percent basalt pebbles; neutral (pH 7.0); clear smooth boundary.
2C2--26 to 32 inches; dark grayish brown (10YR 4/2) ashy sand, light gray (10YR 7/2) dry; single grain; loose, nonsticky and nonplastic; very few very fine and very few fine roots; many interstitial pores; common fine prominent reddish yellow (10YR 7/6) masses of iron accumulation; neutral (pH 7.0); clear smooth boundary.
2C3--32 to 39 inches; dark grayish brown (10YR 4/2) paragravelly ashy sand, light gray (10YR 7/2) dry; single grain; loose, nonsticky and nonplastic; very few very fine and very few fine roots; many interstitial pores; 20 percent fine pumice paragravel; common fine distinct reddish yellow (10YR 7/6) masses of iron accumulation; neutral (pH 6.8); clear smooth boundary.
2C4--39 to 60 inches; light brownish gray (10YR 6/2) paragravelly ashy sand, light gray (10YR 7/2) dry; single grain; loose, nonsticky and nonplastic; few very fine and few fine roots; many interstitial pores; 20 percent fine pumice paragravel; many fine distinct grayish brown (2.5Y 5/2) zones of iron depletion; neutral (pH 7.0). (Combined thickness of the C horizons to 60 inches is 30 to 48 inches.)
TYPE LOCATION: Lake County, Oregon; in Sycan Marsh; about 400 feet north and 800 feet east of the southwest corner of section 10, T. 32 S., R. 14 E.; USGS Sycan Marsh East 7.5 minute topographic quadrangle; 42 degrees 49 minutes 2.9 seconds north latitude and 121 degrees 3 minutes 7.2 seconds west longitude, NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture - Very moist to saturated in the moisture control section during winter and spring, moist in summer and fall; aquic moisture regime.
Mean annual soil temperature - 42 to 45 degrees F.
Mollic epipedon thickness - 7 to 20 inches, includes the Bq or Bw horizons in some pedons.
Depth to aquic conditions - 0 to 20 inches.
Depth to lithologic discontinuity of sandy materials - 14 to 35 inches.
Particle-size control section - Clay content: 12 to 40 percent in the upper part and 0 to 10 percent in the lower part; Rock fragments: averages 0 to 5 percent, mainly pebbles. Lithology of rock fragments is basalt.
Volcanic glass content: 25 to 40 percent in the upper part in coarse silt through fine sand fractions and 50 to 95 percent in the lower part in coarse silt through very coarse sand fractions.
Reaction - Slightly acid or neutral.
Other features - It is assumed that enough active ferrous iron occurs in the A and B horizons, when aquic conditions are present, to give positive reactions to alpha,alpha-dipyridyl.
O horizon (when present) - Texture: Slightly decomposed or moderately decomposed plant material.
Rubbed fiber content: 25 to 80 percent composed of parts of grass and grass-like plants.
Other features: Where it occurs, this horizon is too thin to be a histic epipedon.
A horizons - Hue: 10YR or 7.5YR.
Value: 2 or 3 moist, 4 or 5 dry.
Chroma: 1 or 2, moist or dry.
Organic matter content: 4 to 12 percent.
Bq or Bw horizons - Value: 2 or 3 moist, 5 through 8 dry.
Chroma: 1 or 2, moist or dry.
Texture: Ashy loam, ashy clay loam, or ashy silt loam.
Clay content: 12 to 40 percent.
Rock fragments: 0 to 5 percent gravel.
Pararock fragments: 0 to 10 percent fine pumice paragravel.
Organic matter content: 0.5 to 2 percent.
Other features: Pedons with Bq horizons exhibit a brittle manner of failure when moist; some pedons have thin subhorizons which meet andic soil property criteria.
C horizons (when present) - Hue: 10YR or 2.5Y.
Value: 3 through 6 moist, 5 through 8 dry.
Chroma: 1 through 4, moist or dry.
Texture: Ashy sandy clay loam, ashy clay loam, ashy loam, ashy fine sandy loam, or ashy coarse sandy loam.
Clay content: 12 to 30 percent.
Rock fragments: 0 to 5 percent gravel.
Pararock fragments: 0 to 10 percent fine pumice paragravel.
Redoximorphic features: Redox concentrations occur as masses of iron accumulation; redox depletions may also occur as zones of iron depletion.
2C horizons - Hue: 10YR or 2.5Y.
Value: 3 through 6 moist, 5 through 8 dry.
Chroma: 1 through 4, moist or dry.
Texture: Ashy sand, ashy coarse sand, ashy loamy coarse sand, or paragravelly ashy sand.
Clay content: 0 to 10 percent.
Rock fragments: 0 to 10 percent gravel.
Pararock fragments: 0 to 30 percent fine pumice paragravel.
Redoximorphic features: Redox concentrations occur as masses of iron accumulation; redox depletions may also occur as zones of iron depletion.
COMPETING SERIES: This is the Paulina (T) series. Paulina soils do not have ashy sandy textures in the particle-size control section.
GEOGRAPHIC SETTING: Middleres soils are on lake terraces. These soils formed in alluvium derived from volcanic ash and pumice. Slopes are 0 to 1 percent. Elevations range from 4,900 to 5,500 feet. The climate is semiarid and characterized by cold, moist winters and warm, dry summers. The mean annual precipitation is 10 to 12 inches much of which comes as snow. The mean annual temperature is 40 to 43 degrees F. The frost-free period is 30 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the proposed Lousecreek and Shakecreek soils. Lousecreek and Shakecreek soils have cryic temperature regime and are on channels and depressions. Shakecreek soils have a clayey substratum. Lousecreek soils are very poorly drained.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained and poorly drained; high surface runoff; moderate or moderately slow permeability in the upper part over rapid permeability in the lower part. Endosaturation is present with an apparent seasonal high water table between 0.8 and 1.7 feet (shallow free water occurrence class) from January to June. Water levels drop as low as 4 feet between July and December. Cumulative annual duration class is Permanent. These soils are susceptible to frequent ponding for very long duration from March through June with water up to 1 foot deep. Some phases are susceptible to rare flooding for brief periods between March and May.
USE AND VEGETATION: Middleres soils are used for livestock grazing and wildlife habitat. The vegetation is mainly Cusick's bluegrass, mat muhly, tufted hairgrass, and pull-up muhly.
DISTRIBUTION AND EXTENT: South-central Oregon. These soils are not extensive. MLRA 6.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES PROPOSED: Lake County (Fremont National Forest Area), Oregon, 1998.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Organic soil materials - The zone from the soil surface to 2.5 inches (Oe horizon).
Mollic epipedon - The zone from 2.5 to 14 inches (A1, A2, and Bq horizons)
Aquic conditions - The conditions of endosaturation, reduction, and redoximorphic features between the soil surface and 60 inches at certain times during normal years (parts of the Oe, A1, A2, Bq, 2C1, 2C2, 2C3, and 2C4 horizons).
Major lithologic discontinuity - The change to sandy materials at 14 inches.
Particle-size control section and ashy substitute class with glassy mineralogy - The zone from 10 to 40 inches (2C1, 2C2, and 2C3 horizons and part of the Bq horizon).
ADDITIONAL DATA: Two pedons of Middleres are reference sampled for the Soil Survey Laboratory, Lincoln, NE, as soil survey sample numbers S97OR-037-005 and S97OR-037-006. Data on A and Bw horizons is available for depths of 2 to 11 and 11 to 17 inches, respectively.