LOCATION FROSTVALLEY CA
Tentative Series
IRD: JWH/JTB/SAA/ET
04/2016
FROSTVALLEY SERIES
The Frostvalley series consists of very deep, well drained soils formed in alluvium derived from mixed sedimentary sources. Frostvalley soils are on stream terraces in mountain river valleys. Slopes range from 0 to 9 percent. Mean annual precipitation is about 1650 mm and the mean annual temperature is about 8 degrees C.
TAXONOMIC CLASS: Fine-loamy, isotic, mesic Cumulic Humixerepts
TYPICAL PEDON: Frostvalley loam on a northwest facing 3 percent slope under grass at an elevation of 750 meters. (Colors are for dry soil unless otherwise noted. When described on 7/31/09, the soil was moist throughout.)
A1--0 to 8 centimeters; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure parting to moderate fine granular; very friable, moderately hard, slightly sticky and slightly plastic; common fine and many very fine roots throughout; few fine and very fine tubular pores; 10 percent gravel; strongly acid (pH 5.4); clear smooth boundary.
A2--8 to 50 centimeters; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; moderately hard, very friable, slightly sticky and slightly plastic; few fine and common very fine roots throughout; few fine, common medium and very fine tubular pores; 5 percent gravel; strongly acid (pH 5.4); clear smooth boundary. (Combined thickness of the A horizon is 50 to 100 centimeters)
AB--50 to 90 centimeters; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate fine granular structure; moderately hard, very friable, slightly sticky and slightly plastic; few fine and common very fine roots throughout; common fine, few medium, and common very fine tubular pores; 5 percent gravel; strongly acid (pH 5.4); clear smooth boundary.
Bw--90 to 120 centimeters; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; moderately hard, very friable, slightly sticky and slightly plastic; few fine and very fine roots throughout; common fine, medium and very fine irregular pores; 25 percent gravel; moderately acid (pH 5.8); clear smooth boundary. (0 to 50 centimeters)
C--120 to 160 centimeters; light yellowish brown (2.5Y 6/3) very gravelly sandy loam, olive brown (2.5Y 4/3) moist; massive structure; loose,loose, slightly sticky and nonplastic; common fine, medium, and very fine irregular pores; 35 percent gravel and 5 percent cobble; moderately acid (pH 6.0). (Combined thickness of the C horizon is 50 to 100 centimeters)
TYPE LOCATION: Humboldt County, California; about 7.5 kilometers south on Highway 36 from Buck Mt. School, and 1 kilometer north; USGS 7.5 minute Quadrangle Larabee Valley, CA; WGS84 Decimal degrees 40.4498978 latitude, -123.6824047 longitude; UTM Zone 10 442134mE, 4477917mN; NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is dry in all parts for 45 or more consecutive days after the summer solstice and moist in all parts from November through May. The soils have a xeric soil moisture regime.
Soil Temperature: The mean annual soil temperature at 50 centimeters (20 inches) is 10 to 12 degrees C. The average summer soil temperature is about 18 degrees C and the average winter soil temperature is about 6 degrees C. The soil has a mesic temperature regime.
Thickness of the umbric epipedon: 50 to 100 centimeters
Base Saturation: less than 60 percent by ammonium acetate in all horizons between 25 and 75 centimeters from the mineral soil surface
Particle size control section (weighted average):
Rock fragments: 0 to 35 percent gravel, 0 to 5 percent cobbles and stones
Clay content: 18 to 25 percent
A horizon:
Hue: 10YR or 2.5Y
Value: 3 to 5, 2 or 3 moist
Chroma: 1 to 3, moist or dry
Clay content: 15 to 25 percent
Rock fragments: 0 to 14 percent gravel
Reaction: strongly acid
Bw horizon:
Hue: 10YR or 2.5Y
Value: 5 or 6, 3 or 4 moist
Chroma: 2 to 4, moist or dry
Clay content: 16 to 25 percent
Rock fragments: 0 to 35 percent gravel, 0 to 5 percent cobbles
Reaction: strongly to moderately acid
C horizon:
Hue: 10YR or 2.5Y
Value: 5 or 6, 3 or 4 moist
Chroma: 2 to 4, moist or dry
Texture: sandy loam, loam, loamy sand or sand
Clay content: 5 to 15 percent
Rock fragments: 15 to 75 percent gravel, 5 to 35 percent cobbles, 0 to 5 percent stones
Reaction: moderately acid
COMPETING SERIES: There are no competing series in this family.
GEOGRAPHIC SETTING: Frostvalley soils are on linear to slightly convex positions on stream terraces in mountain river valleys. Slopes are 0 to 9 percent. Elevations are 730 to 825 meters. These soils formed in slope alluvium from mixed sedimentary sources including sandstone and mudstone. The climate is subhumid with warm, dry summers with a marine layer influence and cool, wet winters. Mean annual precipitation is 1525 to 1780 millimeters. The mean annual temperature is 7 to 9 degrees C. Frost free season is about 60 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Mulecreek soil. Mulecreek soils have redoximorphic features between 50 and 100 centimeters below the mineral soil surface.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; negligible to low runoff; moderately high saturated hydraulic conductivity.
USE AND VEGETATION: This soil is used mainly for pasture, hay, and orchards. The vegetation is perennial and annual grasses and forbs including oats, soft brome, smooth brome, ryegrass, bristly dogstail grass, foxtail, and medusahead.
DISTRIBUTION AND EXTENT: Coastal Redwood Belt, MLRA 5. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Humboldt County Soil Survey, Central Part, California, 2014. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Umbric epipedon: The zone from 0 to 50 centimeters. (A1 and A2 horizons)
2. Cambic horizon: The zone from 50 to 120 centimeters. (AB and Bw horizons)
3. Particle size control section: The zone from 25 to 100 centimeters (A2, Bw, and C horizons)
4. Isotic feature: 15 bar water/clay is 0.6 or more and the NaF pH is greater than 8.4 in all horizons
5. Cumulic feature: Holocene organic carbon content greater than 0.2 percent at a depth of 125 centimeters below the mineral surface.
ADDITIONAL DATA:
NASIS User Pedon ID 09CA600364
NSSL, Pedon No. 05N0654
Keys to Soil Taxonomy, 12th edition.
National Cooperative Soil Survey
U.S.A.