LOCATION OESCHGER CA

Established Series
Rev SAA/ET
10/2016

OESCHGER SERIES

The Oeschger series consists of very deep, well drained soils formed in colluvium and residuum from sandstone with minor amounts of siltstone and gravelly conglomerate. Oeschger soils are on mountains. Slopes range from 15 to 110 percent. The mean annual precipitation is about 1525 mm and the mean annual air temperature is about 11 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, isomesic Typic Dystrudepts

TYPICAL PEDON: Oeschger loam - on a southwest facing convex slope of 50% under coast redwood, tanoak, Pacific madrone, blueblossom, and Douglas iris at 185 meters elevation. (Colors are for moist soil unless otherwise noted. When described on May 13, 2005, the soil was moist throughout.)

A--0 to 18 centimeters; brown (10YR 4/3) loam, pale brown (10YR 6/3) dry; weak very fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and common fine roots throughout; many very fine and common fine irregular pores; moderately acid (pH 5.8); clear smooth boundary. (10 to 60 centimeters thick)

Bt1--18 to 50 centimeters; brown (10YR 4/3) fine sandy loam, very pale brown (10YR 7/3) dry; moderate medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots throughout; many fine and common very fine irregular pores; common faint brown (7.5YR 4/2) clay films bridging sand grains; 2 percent gravel; moderately acid (pH 5.8); gradual smooth boundary.

Bt2--50 to 79 centimeters; brown (10YR 4/3) fine sandy loam, very pale brown (10YR 7/3) dry; moderate medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots throughout; common fine, very fine, and coarse irregular pores; few faint brown (7.5YR 4/2) clay films on all faces of peds; 15 percent fine distinct brown (7.5YR 4/4) mottles around rock fragments; 5 percent gravel; moderately acid (pH 5.6); gradual smooth boundary. (Combined thickness of the Bt horizons is 20 to 150 centimeters thick)

C1--79 to 125 centimeters; olive brown (2.5Y 4/3) paragravelly fine sandy loam, pale yellow (2.5Y 7/3) dry; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots throughout; common very fine and fine irregular pores; 15 percent fine distinct brown (7.5YR 4/4) mottles around rock fragments; 20 percent paragravel; moderately acid (pH 5.8); gradual wavy boundary.

C2--125 to 160 centimeters; olive brown (2.5Y 4/3) paragravelly fine sandy loam, pale yellow (2.5Y 7/3) dry; massive; moderately hard, very friable, nonsticky and nonplastic; common very fine, fine, and medium roots throughout; very few irregular pores, 25 percent paragravel; moderately acid (pH 5.8). (combined thickness of the C horizons is 0 to 100 centimeters thick)

TYPE LOCATION: Humboldt County, California; about 1.8 kilometers east of the town of Shively; USGS Redcrest Quadrangle; WGS84 Decimal 40.4336389 latitude and -123.9485556 longitude; UTM Zone 10 419545mE, 4476320mN; NAD 83.

RANGE IN CHARACTERISTICS:

Soil moisture: The soil moisture control section is not dry in any part for as long as 90 cumulative days in normal years. The soils have a udic soil moisture regime.

Soil Temperature: The mean annual soil temperature at 50 centimeters is 10 to 13 degrees C. The difference between mean summer and mean winter soil temperature is less than 6 degrees C. The soils have an isomesic soil temperature regime.

Particle size control section (weighted average):
Rock fragments: 0 to 14 percent indurated rounded gravel from conglomerate of mixed sources.
Pararock fragments: 0 to 14 percent very weakly cemented sandstone paragravel
Clay content: 10 to 17 percent

A horizon:
Hue: 7.5YR, 10YR or 2.5Y
Value: 2 through 4, 4 through 6 dry
Chroma: 1 through 3, moist or dry
Texture of fine earth: loam or very fine sandy loam
Rock fragments: 0 to 5 percent gravel
Clay content: 13 to 22 percent
Reaction: moderately acid to neutral

Bt or Bw horizons:
Hue: 7.5YR, 10YR, 2.5Y
Value: 3 through 6, 5 through 7 dry
Chroma: 2 through 4, moist or dry
Texture of fine earth: loam, very fine sandy loam, fine sandy loam, sandy loam
Rock fragments: 0 to 14 percent gravel
Parafragments: 0 to 34 percent paragravel
Clay content: 12 to 19 percent
Reaction: strongly acid to moderately acid

C horizons, when present:
Hue: 10YR, 2.5Y
Value: 4 or 5, 5 or 6 dry
Chroma: 3 or 4, moist or dry
Texture of fine earth: fine sandy loam, sandy loam, and loamy sand
Rock fragments: 0 to 14 percent gravel
Parafragments: 0 to 34 percent paragravel
Clay content: 5 to 15 percent
Reaction: strongly acid to moderately acid

COMPETING SERIES: There are no other series in this family.

GEOGRAPHIC SETTING: Oeschger soils are on mountain slopes and ridges. Slopes are 15 to 110 percent. Elevations are 30 to 640 meters. These soils formed in colluvium and residuum from sandstone with minor amounts of siltstone and gravelly conglomerate. The climate is humid with cool foggy summers and cool wet winters. Mean annual precipitation is 1140 to 2160 millimeters. Mean January temperature is about 9 degrees C, mean July temperature is about 14 degrees C, and the mean annual temperature is 10 to 13 degrees C. Frost free season is about 240 to 300 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Nanningcreek (T), and Scotiabluffs (T), soils. Nanningcreek soils have redoximorphic features between 50 and 100 centimeters of the mineral soil surface. Scotiabluffs soils are moderately deep to a paralithic contact. Nanningcreek soils are on linear to concave positions on mountain slopes. Scotiabluff soils are on convex positions on ridges and mountain slopes.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, medium to high runoff, moderately high saturated hydraulic conductivity.

USE AND VEGETATION:
This soil is used for timber production, wildlife habitat, watershed, and recreation. Natural vegetation includes redwood, Douglas-fir, Sitka spruce, grand fir, tanoak, red alder, Pacific madrone, California hazel, California huckleberry, salal, thimbleberry, red huckleberry, and western swordfern.

DISTRIBUTION AND EXTENT: Coastal Redwood Belt; MLRA 4B. The series is not extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Humboldt County Soil Survey, Central Part, California, 2016; proposed 2010. The name is from Oeschger Creek.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Ochric epipedon - the zone from 0 to 18 centimeters (A horizon).
2. Cambic horizon - the zone from 18 to 79 centimeters (Bt1, Bt2 horizons).
3. Particle-size control section - the zone from 25 to 100 centimeters (Bt1, Bt2, and C1 horizons) averages 16 percent clay and 61.86 percent fine sand or coarser by weight.

ADDITIONAL DATA:

NASIS User Pedon ID 05CA600020

Keys to Soil Taxonomy, 12th edition

National Cooperative Soil Survey
U.S.A.