LOCATION MACKERRICHER CAEstablished Series
TAXONOMIC CLASS: Sandy, mixed, isomesic Humic Dystrudepts
TYPICAL PEDON: Mackerricher sandy loam on a south facing slope of 25 percent under redwood, grand fir and Douglas-fir at 200 feet elevation. (Colors are for dry soil unless otherwise stated. When described on September 27, 1985 the soil was dry throughout).
A1--0 to 5 inches; dark brown (10YR 3/3) sandy loam, black (10YR 2/1) moist; weak very fine and fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and common fine roots; common very fine and many fine interstitial pores; neutral (pH 7.0); clear wavy boundary. (4 to 8 inches thick)
A2--5 to 12 inches; brown (10YR 4/3) sandy loam, very dark brown (10YR 2/2) moist; moderate fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; neutral (pH 7.0); clear wavy boundary. (0 to 8 inches thick)
Bw1--12 to 22 inches; brown (7.5YR 4/4) loamy sand, dark brown (7.5YR 3/4) moist; moderate very fine and fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine and coarse and common fine and medium roots; common very fine and fine interstitial and few very fine and fine tubular pores; slightly acid (pH 6.5); gradual wavy boundary. (8 to 14 inches thick)
Bw2--22 to 30 inches; strong brown (7.5YR 4/6) loamy sand, dark brown (7.5YR 3/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common fine and medium and few coarse roots; common very fine interstitial and few fine tubular pores; slightly acid (pH 6.3); clear wavy boundary. (0 to 12 inches thick)
C--30 to 62 inches; yellowish brown (10YR 5/6) sand, dark yellowish brown (10YR 4/6) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common medium and coarse roots; common very fine interstitial and few fine tubular pores; moderately acid (pH 6.0).
TYPE LOCATION: Mendocino County, California; about 650 feet south and 4150 feet east of the northwest corner of sec. 16, T.19N., R.17W., MDBM, Inglenook quadrangle.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 25 to 40 inches. Depth to bedrock is greater than 60 inches. The mean annual soil temperature ranges from 50 to 56 degrees F. The difference between mean winter and mean summer soil temperature ranges from 3 to 6 degrees F. The soil between the depths of 9 and 36 inches is moist in all parts from November 1 to August 1 and is dry in some part from September 1 to October 1 in most years. Organic carbon content in the upper cubic meter of soil ranges from 12 to 15kg. Less than 50 percent base saturation in some subhorizon between 10 and 40 inches.
The A horizon is 10YR 3/2, 3/3, 4/2, 4/3; or 7.5YR 3/2. Moist color is 10YR 2/1, 2/2, 3/1, 3/2; 7.5YR 2/2 or 3/2. Clay content is 6 to 12 percent. Base saturation (ammonium acetate) is 40 to 70 percent. Reaction is moderately acid through neutral. Organic carbon content ranges from 1.0 to 4.0 percent. Thickness of the A horizon ranges from 7 to 15 inches.
The Bw horizon is 7.5YR 4/4 or 4/6. Moist color is 7.5YR 3/4 or 4/4. Clay content is 4 to 12 percent. Base saturation (ammonium acetate) is 25 to 50 percent. Reaction is moderately or slightly acid.
The C horizon is 10YR 4/4, 4/6, 5/4, 5/6; 7.5YR 4/4 or 4/6. Moist color is 10YR 4/4, 4/6, 5/4; 7.5YR 3/4, 4/4, or 4/6. It is loamy sand or sand. Clay content is 2 to 8 percent. Nodule content (2-50mm in diameter) ranges from 0 to 10 percent. Base saturation (ammonium acetate) is 20 to 40 percent. Reaction is moderately or slightly acid.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: The Mackerricher soils are on stabilized sand dunes. Slopes are 2 to 30 percent. Elevations are 175 to 700 feet. The soils formed in eolian sands. The climate is characterized by cool foggy summers and cool moist winters. A strong marine influence limits the diurnal and annual range of temperature. Mean annual precipitation ranges from 40 to 55 inches. Mean January temperature is 48 degrees F., mean July temperature is 57 degrees F., and mean annual temperature is 53 degrees F. Frost-free period is 290 to 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the closely related Heeser and Sirdrak soils and the Branscomb, Cabrillo, Sirdrak and Usal soils. Branscomb and Usal soils are on mountains adjacent to the marine terraces on which Mackerricher soils are found. Branscomb soils are loamy skeletal. Heeser soils have a coarse-loamy particle-size control section and an ustic soil moisture regime. Sirdrak soils have an ustic soil moisture regime and do not have as much as 12kg organic carbon in the upper cubic meter of the soil. Usal soils are fine-loamy and are 20 to 40 inches deep to a lithic contact. Cabrillo and Heeser soils are on marine terraces. They are on slightly older landscapes. Cabrillo soils have a fine-loamy particle-size control section and Heeser soils have a coarse-loamy particle-size control section. Sirdrak soils are on sand dunes thought to be slightly younger than those on which Mackerricher soils have formed. Sirdrak soils support grass vegetation, have an ustic soil moisture regime and do not contain as much as 12kg organic carbon in the upper cubic meter of the soil.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; surface runoff is slow through rapid; permeability is moderately rapid in the surface layer and rapid in the subsoil.
USE AND VEGETATION: This soil is used for timber production, homesite development, and as watershed. Vegetation consists of redwood, grand fir, Douglas-fir and tanoak.
DISTRIBUTION AND EXTENT: Northern coastal California. The series is not extensive. MLRA 4
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Mendocino County, California, Western part, 1993.
REMARKS: The classification was updated in February 2001 using the Eighth Edition to Soil Taxonomy. This series was formerly classified as sandy, mixed, isomesic Typic Humitropepts. The range of characteristics for the A horizon causes this series to fall into two classifications, soils with a thin (less than 10 inch) sandy loam horizon will have sandy textures throughout the textural control section which classify as Humic Psammentic Dystrudepts. Soils with sandy loam textures extending into the control section will classify as Humic Dystrudepts. Competing series were not checked at that time.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon -- the zone from 0 to 12 inches (A1, A2)
Many areas mapped as Mackerricher soils were mapped as Empire soils by the California Soil Vegetation Survey 1947-1950.