LOCATION ARCATA CA
Established Series
Rev. FWH/FFH/JJJ/SAA
10/2016
ARCATA SERIES
The Arcata series consists of very deep well drained soils formed in marine deposits derived from mixed sources. Arcata soils are on nearly level to gently sloping, dissected marine terraces and have slopes of 0 to 9 percent. The mean annual precipitation is about 1500 millimeters (59 inches) and mean annual temperature is about 12 degrees C (54 degrees F).
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Pachic Humudepts
TYPICAL PEDON: Arcata loam on a southeast facing, linear slope of 2 percent under pasture grasses and forbs at an elevation of 46 meters (150 feet). (Colors are for moist soils unless otherwise stated. When described on November 3, 2009 the soil was moist throughout).
A1--0 to 17 centimeters (0 to 7 inches); very dark brown (10YR 2/2) loam, dark grayish brown (10YR 4/2) dry; weak medium subangular structure; moderately hard, firm, nonsticky and slightly plastic; common very fine and fine roots throughout; common very fine and fine tubular pores; strongly acid (pH 5.2); clear wavy boundary.
A2--17 to 36 centimeters (7 to 14 inches); very dark brown (10YR 2/2) fine sandy loam, dark grayish brown (10YR 4/2) dry; weak fine subangular structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots throughout; common very fine tubular pores; strongly acid (pH 5.4); clear wavy boundary.
A3--36 to 69 centimeters (14 to 27 inches); dark brown (10YR 3/3) loam, brown (10YR 5/3) dry; moderate fine and medium subangular structure; soft, friable, nonsticky and slightly plastic; common very fine and fine roots throughout; common very fine tubular pores; strongly acid (pH 5.4); clear smooth boundary. (Combined thicknesses of A horizons are 50 to 120 centimeters).
AB--69 to 92 centimeters (27 to 36 inches); dark brown (10YR 3/3) loam, pale brown (10YR 6/3) dry; weak medium and coarse subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine and fine roots throughout; common very fine tubular pores; strongly acid (pH 5.4); gradual wavy boundary.
Bw1--92 to 115 centimeters (36 to 45 inches); dark yellowish brown (10YR 3/4) loam, yellowish brown (10YR 5/4) dry; weak fine and moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine roots throughout; common very fine and fine tubular pores; strongly acid (pH 5.2); clear wavy boundary.
Bw2--115 to 150 centimeters (45 to 59 inches); dark yellowish brown (10YR 4/6) sandy loam, brownish yellow (10YR 6/6) dry; weak medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine tubular pores; strongly acid (pH 5.2); gradual wavy boundary.
Bw3--150 to 160 centimeters (59 to 63 inches); yellowish brown (10YR 5/6) sandy loam, yellow (10YR 7/6) dry; weak fine and medium subangular blocky structure; slightly hard, friable, nonsticky and slightly plastic; common very fine and fine irregular pores; common fine distinct yellowish brown (10YR 5/6) masses of oxidized iron, and common fine distinct olive brown (2.5Y 4/3) iron depletions in the matrix; strongly acid (pH 5.2). (Combined thicknesses of Bw horizon are 25 to 70 centimeters).
TYPE LOCATION: Humboldt County, California; south of school road in McKinleyville, California; USGS Arcata North Quadrangle; WGS84 Decimal degrees 40.9312500 latitude and -124.1064722 longitude, UTM Zone 10 406845mE 4531716mN; NAD83.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil is usually moist in all parts in the soil moisture control section in most years, but becomes nearly dry in the upper part from about September 15 to October 15 in most years. The soils have a udic soil moisture regime.
Soil temperature: The mean annual soil temperature at 50 centimeters (20 inches) is 12 to 14 degrees C (53 to 57 degrees F). The average summer soil temperature is about 18 degrees C and the average winter soil temperature is about 9 degrees C. The difference between average summer and winter soil temperatures is about 6 to 9 degrees C. The soils have a mesic temperature regime.
The umbric epipedon is 50 to 125 centimeters (20 to 50 inches) thick.
Base Saturation, by ammonium acetate, is less than 60 percent between depths of 29 to 79 centimeters.
Particle-Size Control Section (weighted average):
Clay content: 10 to 18 percent
A or Ap horizon
Hue: 10YR
Value: 1 through 3, or 3 through 5 dry
Chroma: 1 through 3, or 2 or 3 dry
Texture of fine earth: fine sandy loam or loam
Rock fragments: 0 to 2 percent gravel
Clay content: 10 to 19 percent
Reaction: very strongly to moderately acid
Bw horizon
Hue: 10YR
Value: 3 through 5, 5 through 8 dry
Chroma: 3 through 6 moist and dry
Texture of fine earth: very fine sandy loam, fine sandy loam, sandy loam or loam
Rock fragments: 0 to 3 percent gravel
Clay content: 8 to 16 percent
Reaction: very strongly to strongly acid
Some pedons have C horizons
C horizon
Hue: 2.5Y or 10YR
Value: 3 through 5, or 6 or 7 dry
Chroma: 2 or 3 dry and moist
Texture of fine earth: loamy fine sand, fine sandy loam, or fine sand
Rock fragments: 0 to 5 percent gravel
Clay content: 2 to 10 percent.
Reaction: strongly to moderately acid
COMPETING SERIES: There are no competing series at this time.
GEOGRAPHIC SETTING: Arcata soils are on slightly dissected marine terraces. Slopes are 0 to 9 percent. The soils formed in marine sediments derived from mixed sources. Elevations are 4 to 183 meters (10 to 600 feet). A strong marine influence limits the diurnal and annual range of temperature. The climate is humid with cool, foggy summers and cool, wet winters. The mean annual temperature is 11 to 13 degrees C (50 to 55 degrees F). The mean annual precipitation is 890 to 2285 millimeters (35 to 90 inches). The frost-free period is 275 to 325 days.
GEOGRAPHICALLY ASSOCIATED SOILS: Arcata soils are associated with the
Candymountain series. Candymountain soils have an umbric epipedon less than 50 centimeters thick.
DRAINAGE AND PERMEABILITY: Well drained; moderate runoff; saturated hydraulic conductivity is moderately high.
USE AND VEGETATION: This soil is used predominantly for pasture, recreation and urban development. Vegetation includes bentgrass, sweet vernalgrass, brome, common velvetgrass, hairy cat's ear and California blackberry.
DISTRIBUTION AND EXTENT: Coastal Redwood Belt; MLRA 4B. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Humboldt and Del Norte Counties Area, California, 2013. The name is from the town of Arcata, California.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Umbric epipedon - the zone from 0 to 69 centimeters (A1, A2 and A3 horizons).
2. Cambic horizon - the zone from 69 to 160 centimeters (AB, Bw1, Bw2 and Bw3 horizons).
3. Particle-size control section - the zone from 25 to 100 centimeters, averages 13 percent clay and 34 percent fine sand or coarser.
ADDITIONAL DATA:
Soil classified using the 12th Edition of the Keys to Soil Taxonomy.
NASIS User Pedon ID 09CA600653
NSSL, Lincoln Lab sample number 08N0452
Edit Log: Arcata was originally proposed in 1965 with well and moderately well drained Map Units. In 2009 Arcata was revisited and decision made to separate the well and moderately well drained soils, as well as soils under forest canopy and isomesic from clear cut or developed areas that are mesic. This resulted in four separate soil series. The typical pedon was changed in January of 2010 to reflect the original well drained series concept on permanent pasture.
National Cooperative Soil Survey
U.S.A.