LOCATION MATTOLE CA
Established Series
IRD: JTW/JWH/ET
11/2010
MATTOLE SERIES
The Mattole series consists of very deep, moderately well drained soils formed in colluvium and residuum from mudstone. Mattole soils are on hills and slopes range from 5 to 30 percent. The mean annual precipitation is about 1650 millimeters and the mean annual temperature is about 13 degrees C.
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Ultic Palexeralfs
TYPICAL PEDON: Mattole silt loam on a south facing linear slope of 28 percent under crested dogstail grass, rush, sedge, coyote brush, California wildrose, and other annual and perennial grasses and forbs, at an elevation of 158 meters. (Colors are for dry soil unless otherwise stated) When described on September 7, 2006, the soil was dry above 100 centimeters.
A1--0 to 15 centimeters; dark grayish brown (10YR 4/2) silt loam, black (10YR 2/1) moist; moderate very fine granular structure; moderately hard, friable, slightly sticky and slightly plastic; many very fine and common fine roots throughout; few very fine, fine, and medium tubular pores; moderately acid (pH 5.6); gradual wavy boundary.
A2--15 to 65 centimeters; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; common very fine and few fine roots throughout; few very fine, fine, and medium tubular pores; moderately acid (pH 5.6); clear wavy boundary.
A3--65 to 95 centimeters; grayish brown (10YR 5/2) silt loam, very dark brown (10YR 2/2) moist; moderate fine subangular blocky structure; hard, friable, slightly sticky and moderately plastic; few very fine roots throughout; common very fine, fine, and medium tubular pores; moderately acid (pH 5.6); clear wavy boundary. (Combined thickness of the A horizons is 50 to 100 centimeters)
Bt1--95 to 115 centimeters; light brownish gray (10YR 6/2) silty clay loam, dark grayish brown (10YR 4/2) moist; moderate fine subangular blocky structure; hard, friable, slightly sticky and moderately plastic; few very fine roots throughout; few very fine and fine tubular pores; 10 percent faint dark grayish brown (10YR 4/2) moist clay films on all faces of peds; 5 percent fine irregular dark yellowish brown (10YR 4/6) iron-manganese masses throughout; 5 percent paragravel; moderately acid (pH 5.6); gradual wavy boundary.
Bt2--115 to 150 centimeters; pale yellow (2.5Y 7/3) silty clay loam, light olive brown (2.5Y 5/3) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and moderately plastic; few very fine roots throughout; few very fine tubular pores; 5 percent faint dark grayish brown (10YR 4/2) moist clay films on all faces of peds; 5 percent fine irregular grayish brown (2.5Y 5/2) moist iron depletions throughout and 20 percent coarse irregular dark yellowish brown (10YR 4/6) moist iron-manganese masses throughout; 10 percent paragravel; moderately acid (pH 5.8); clear wavy boundary.
Bt3--150 to 200 centimeters; light yellowish brown (2.5Y 6/3) silty clay loam, olive brown (2.5Y 4/3) moist; weak medium and coarse subangular blocky structure; hard, friable, slightly sticky and moderately plastic; few very fine roots throughout; few very fine tubular pores; 5 percent faint dark grayish brown (10YR 4/2) moist clay films on all faces of peds; 5 percent fine irregular grayish brown (2.5Y 5/2) moist iron depletions throughout and 20 percent medium irregular strong brown (7.5YR 4/6) moist iron-manganese masses throughout; 10 percent paragravel; moderately acid (pH 5.8). (Combined thickness of the Bt horizons is 50 to 150 centimeters)
TYPE LOCATION: Humboldt County, California; about 4 kilometers west of Petrolia; USGS 7.5 minute quadrangle Petrolia, California; UTM Zone 10 0386768mE, 4463874mN; 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 soil has a xeric moisture regime.
Soil Temperature: The mean annual soil temperature at 50 centimeters is 12 to 14 degrees C. The difference between mean summer and mean winter temperature is 6 degrees C. or more. The soil has a mesic soil temperature regime
Umbric epipedon: 50 to 100 centimeters thick
Depth to iron-manganese masses: 50 to 100 centimeters
Depth to iron depletions with chroma of 2 or less: greater than 75 centimeters
Particle size control section (weighted average):
Pararock fragments: 0 to 34 percent paragravel
Clay content: 25 to 34 percent
Reaction: strongly to moderately acid
A horizon
Value: 4 or 5, 2 or 3 moist
Chroma: 1 to 4, 1 to 3 moist
Pararock fragments: 0 to 14 percent moderately cemented mudstone paragravel
Clay content: 15 to 26 percent
Upper Bt horizon
Hue: 10YR or 2.5Y, dry or moist
Value: 6 or 7, 4 or 5 moist
Chroma: 2 through 4, dry or moist
Texture of fine earth: silt loam or silty clay loam
Pararock fragments: 0 to 34 percent moderately cemented mudstone paragravel
Clay content: 20 to 34 percent
Redoximorphic Features: fine and medium iron-manganese masses
Quantity: few to many
Hue: 10YR or 7.5YR
Value: 4 to 6
Chroma: 3 to 8
Lower Bt horizon
Hue: 10YR or 2.5Y, dry or moist
Value: 6 or 7, 4 or 5 moist
Chroma: 1 to 4, dry or moist
Pararock fragments: 0 to 59 percent subangular mudstone paragravel
Clay content: 27 to 39 percent
Redoximorphic Features: fine and medium iron-manganese masses
Quantity: few to many
Hue: 10YR or 7.5YR
Value: 4 to 6
Chroma: 3 to 8
Redoximorphic features: fine and medium iron depletions
Quantity: none to common
Hue: 2.5Y or 5Y
Value: 4 or 5
Chroma: 1 or 2
COMPETING SERIES: This is the
Kelso soil. Kelso has a Bt/E horizon, has an umbric epipedon less than 50 centimeters thick, and occurs on high terraces.
GEOGRAPHIC SETTING: Mattole soils are on hillslopes on hills. Slopes range from 5 to 30 percent. Elevations range from 30 to 300 meters. These soils formed in colluvium and residuum from mudstone. The climate is humid with cool, foggy summers and cool, wet winters. Mean annual precipitation is 1525 millimeters to 1780 millimeters. The mean annual temperature is 12 to 14 degrees C. Frost free period is about 240 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Oceanhouse soil. Oceanhouse has greater than 35 percent clay in the particle size control section and has redoximorphic features within 10 centimeters of the surface.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained, very high runoff, moderately low saturated hydraulic conductivity. A water table is present between 50 and 100 centimeters December through April.
USE AND VEGETATION: This soil is used for livestock grazing, watershed, and wildlife habitat. Vegetation is wild oats, ripgut brome, soft chess, bristly dogstail grass, medusahead, crested dogstail grass, California wildrose, rush, and pennyroyal.
DISTRIBUTION AND EXTENT: Coastal Redwood Belt, MLRA 4B. The soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Humboldt County, South Part, California, 2010. Source of the name is from the Mattole River.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Umbric epipedon - the zone from 0 to 95 centimeters (A1, A2, and AB horizons)
2. Argillic horizon - the zone from 65 to 200 centimeters (A3, Bt1, Bt2, and Bt3 horizons)
3. Particle-size control section - the zone from 65 to 105 centimeters (A3 and Bt1 horizons)
ADDITIONAL DATA:
Keys to Soil Taxonomy, 11th edition
National Cooperative Soil Survey
U.S.A.