LOCATION MILLSTREET CA
Established Series
IRD: JWH/SAA/
10/2016
MILLSTREET SERIES
The Millstreet series consists of very deep, moderately well drained soils on uplifted terraces and fan remnants. These soils formed in mixed alluvium. Slopes range from 2 to 5 percent. Mean annual precipitation is about 1250 millimeters. Mean annual temperature is about 13 degrees C.
TAXONOMIC CLASS: Fine-silty, mixed, active, mesic Oxyaquic Humixerepts
TYPICAL PEDON: Millstreet silt loam on a 2 percent slope under permanent pasture. (Colors are for dry conditions unless otherwise noted.)
Ap--0 to 16 centimeters; very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; strong medium granular structure; friable, moderately hard, slightly sticky and moderately plastic; common very fine roots throughout; few fine tubular pores; 3 percent gravel; moderately acid (pH 5.8); clear smooth boundary.
A--16 to 53 centimeters; very dark brown (10YR 2/2) silty clay loam, dark grayish brown (10YR 4/2) dry; moderate fine granular structure; friable, moderately hard, slightly sticky and moderately plastic; common very fine roots throughout; 2 percent gravel; strongly acid (pH 5.5); abrupt smooth boundary. (Combined thickness of the A horizons is 50 to 80 cm.)
BA--53 to 68 centimeters; dark brown (10YR 3/3) silt loam, light brown (7.5YR 6/3) dry; 25 percent clay; moderate medium subangular blocky structure; friable, hard, slightly sticky and very plastic; few very fine roots throughout; 2 percent gravel; very strongly acid (pH 5.0); clear wavy boundary.
Bt1--68 to 77 centimeters; dark yellowish brown (10YR 4/4) silt loam, pale brown (10YR 6/3) dry; moderate medium subangular blocky structure; friable, hard, moderately sticky and very plastic; 5 percent faint clay films on all faces of peds; 5 percent fine distinct irregular iron-manganese masses with clear boundaries throughout; 6 percent gravel; very strongly acid (pH 4.7); clear smooth boundary.
Bt2--77 to 105 centimeters; dark yellowish brown (10YR 4/4) silt loam, light yellowish brown (10YR 6/4) dry; moderate coarse subangular blocky structure; friable, hard, slightly sticky and very plastic; 5 percent faint clay films on all faces of peds; 8 percent fine distinct irregular iron-manganese masses with clear boundaries throughout; 3 percent gravel; extremely acid (pH 4.4); clear smooth boundary.
Bt3--105 to 135 centimeters; yellowish brown (10YR 5/6) silt loam, brownish yellow (10YR 6/6) dry; weak coarse subangular blocky structure; friable, moderately hard, nonsticky and slightly plastic; 5 percent faint clay films on all faces of peds; 1 percent fine faint irregular light yellowish brown (2.5Y 6/4) iron depletions with diffuse boundaries throughout and 15 percent fine distinct irregular iron-manganese masses with clear boundaries throughout; 6 percent gravel; strongly acid (pH 5.3); clear smooth boundary.
Bt4--135 to 170 centimeters; yellowish brown (10YR 5/4) loam, very pale brown (10YR 7/4) dry; weak coarse subangular blocky structure; friable, moderately hard, nonsticky and slightly plastic; 5 percent faint clay films on all faces of peds; 10 percent fine faint irregular light yellowish brown (2.5Y 6/4) iron depletions with diffuse boundaries throughout and 15 percent fine distinct irregular iron-manganese masses with clear boundaries throughout; 7 percent gravel; very strongly acid, pH 5.0. (Combined thickness of the B horizons is 120 to 150 cm.)
TYPE LOCATION: Humboldt County, California. Located east of Rohnerville Airport; USGS 7.5 minute Quadrangle Hydesville, CA; Std Latitude 40.551097 Std Longitude -124.1216555; UTM Zone 10 405029E, 4489531N; NAD83.
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 soils have a mean summer and mean winter soil temperature that differ by 6 degrees C or more and a mean soil temperature between 12 degrees C. and 14 degrees C. The soils have a mesic soil temperature regime.
Thickness of the umbric epipedon: 50 to 80 centimeters.
Base Saturation: Base saturation is less than 50 percent by ammonium acetate in the epipedon and to a depth of 135 centimeters.
Particle size control section (weighted average):
Rock fragments: 0 to 10 percent gravel
Clay content: 22 to 30 percent
A horizon:
Hue: 10YR or 7.5YR
Value: 4 or 5, 2 or 3 moist
Chroma: 1 to 3, moist or dry
Texture: silt loam, silty clay loam
Clay content: 22 to 30 percent
Rock fragments: 0 to 5 percent gravel
Reaction: moderately acid
Upper B horizon:
Hue: 10YR or 7.5YR
Value: 5 or 6, 4 or 5 moist
Chroma: 3 or 4, moist or dry
Texture: silt loam, silty clay loam
Clay content: 16 to 30 percent
Rock fragments: 0 to 10 percent gravel
Reaction: strongly to moderately acid
Lower B horizon:
Hue: 10YR or 7.5YR
Value: 5 or 6, 4 or 5 moist
Chroma: 3 or 4, moist or dry
Texture: loam, silt loam, silty clay loam
Clay content: 22 to 30 percent
Rock fragments: 0 to 10 percent gravel
Reaction: strongly to moderately acid
C horizon: (when present, below 150 cm)
Hue: 10YR
Value: 6 or 7, 5 or 6 moist
Chroma: 4 to 6, moist or dry
Texture: silt loam, loam, silty clay loam, or sandy clay loam
Clay content: 25 to 32 percent
Reaction: moderately or slightly acid
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Millstreet soils occur on uplifted marine and river terraces with slopes of 2 to 5 percent. The soils are formed on alluvium from sedimentary rocks, dominantly sandstone and mudstone. Elevations are 105 to 122 meters. The climate is subhumid with warm, dry summers influenced by a cooling marine layer, and cool, wet winters. Mean annual precipitation is from 1140 to 1270 millimeters. Mean annual temperature is 13 to 14 degrees C. Frost-free season is 280 to 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the
Rohnerville soils. Rohnerville soils contain more than 35 percent clay in the control section and lack redoximorphic features above 100 centimeters.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained with moderately high saturated hydraulic conductivity and low runoff.
USE AND VEGETATION: Used for dryland range and pasture. Vegetation consists of annual and perennial grasses and legumes.
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, Central Part, California, 2016; proposed 2014. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Umbric epipedon: the zone from 0 to 53 centimeters (Ap, and A horizons).
2. Cambic horizon: the zone from 53 to 170 centimeters (BA, Bt1, Bt2, Bt3, and Bt4 horizons).
3. Oxyaquic subgroup conditions: the zone from 68 to 170 centimeters (Bt2, Bt3, Bt4).
4. Particle size control section: the zone from 25 to 100 centimeters (A, BA, Bt1, and Bt2 horizons) averages 24 percent clay and 10 percent fine sand or coarser, by weight, and 3 percent rock fragments, by volume.
ADDITIONAL DATA:
NASIS User Pedon ID. 14CA600418
NSSL Pedon No. 15N0555
Keys to Soil Taxonomy, 12th edition.
National Cooperative Soil Survey
U.S.A.