LOCATION HAVENSNECK CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, semiactive, isomesic Typic Haplustults
TYPICAL PEDON: Havensneck sandy loam - on a southwest facing slope of 17 percent under Bishop pine, manzanita and tanoak at 980 feet elevation. (Colors are for dry soil unless otherwise stated. When described on October 30, 1986, the soil was slightly moist throughout.)
Oi--2 inches to 0; litter of tanoak, Bishop pine and manzanita.
A1--0 to 3 inches; yellowish brown (10YR 5/4) sandy loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium granular structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine interstitial and common very fine tubular pores; strongly acid (pH 5.5); clear wavy boundary. (1 to 5 inches thick)
A2--3 to 7 inches; pale brown (10YR 6/3) sandy loam, yellowish brown (10YR 5/4) moist; moderate fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine tubular and interstitial pores; strongly acid (pH 5.5); clear wavy boundary. (3 to 6 inches thick)
Bw--7 to 14 inches; pink (7.5YR 7/4) sandy loam, strong brown (7.5YR 4/6) moist; weak fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; few very fine and fine roots; many very fine tubular and interstitial pores; very strongly acid (pH 4.8); clear wavy boundary. (5 to 10 inches thick)
Bt1--14 to 21 inches; pink (7.5YR 7/4) sandy loam, strong brown (7.5YR 5/6) moist; massive; slightly hard, friable, nonsticky and nonplastic; few very fine and fine roots; many very fine tubular and interstitial pores; few thin clay films bridging sand grains; very strongly acid (pH 4.8); clear wavy boundary. (5 to 10 inches thick)
Bt2--21 to 32 inches; reddish yellow (7.5YR 6/6) sandy clay loam, strong brown (7.5YR 5/8) moist; strong fine and medium subangular blocky structure; very hard, firm, slightly sticky and slightly plastic; few very fine and fine roots; few very fine tubular and interstitial pores; many moderately thick clay films on faces of peds and lining pores; extremely acid (pH 4.3) abrupt wavy boundary. (10 to 15 inches thick)
Cr--32 to 34 inches; soft interlayered coarse grained sandstone and shale.
TYPE LOCATION: Mendocino County California, about 650 feet south and 2,025 feet west of the northeast corner of section 21, T.12 N., R.16 W., MDBM, Point Arena quadrangle.
RANGE IN CHARACTERISTICS; Thickness of the solum and depth to paralithic contact ranges from 20 to 40 inches. The mean annual soil temperature is 53 to 57 degrees F. The difference between mean summer and mean winter temperature is 6 to 9 degrees F. The soil between the depths of 9 and 25 inches or between 9 inches and paralithic contact if contact is less than 25 inches deep, is moist in all parts from November 1 to August 1 and is dry in some or all parts from September 1 to October 1 in most years. The particle-size control section averages 20 to 25 percent clay.
The A horizon is 10YR 5/3, 5/4, 5/6, 6/2, 6/3, 6/4; 2.5Y 6/3 or 6/4. Moist color is 10YR 4/4, 5/3, 5/4, 2.5Y 5/4 or 6/2. Clay content is 10 to 15 percent. Base saturation (sum) is 30 to 45 percent. Reaction is very strongly or strongly acid.
The B horizon is 7.5YR 6/4, 6/6, 7/4 or 7/6. Moist color is 7.5YR 4/6, 5/6, 5/8, 6/6, 6/8. Clay content is 10 to 25 percent. It is sandy loam or sandy clay loam. Base saturation (sum) is 15 to 30 percent. Reaction is very strongly acid or extremely acid (pH 4.0 to 5.0).
COMPETING SERIES: These are the Goldridge (CA) series. The Goldridge soils are greater than 40 inches to bedrock.
GEOGRAPHIC SETTING: Havensneck soils are on ridges and upper sideslopes of coastal hills. Slopes are 2 to 30 percent. Elevation is 400 to 1100 feet. Soil formed in material weathered from interlayered sandstone and shale. The climate is humid with cool foggy summers and cool moist winters. A moderate marine influence limits the diurnal and annual range in temperature. Mean annual precipitation is 45 to 55 inches. Mean January temperature is about 50 degrees F., mean July temperature is about 58 degrees F. and the mean annual temperature is about 54 degrees F. The frost-free period is about 250 to 330 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ferncreek, Fishrock, Gibney, Iversen, Quinliven and Shinglemill series. Ferncreek, Gibney, Quinliven and Shinglemill soils are very deep. They formed in marine sediments and are on remnant marine terraces below the ridge system on which Havensneck soils are found. Fishrock and Iversen soils are clayey. They are found in the same landscape position as Havensneck but formed dominantly from shale parent material.
DRAINAGE AND PERMEABILITY: Well drained; surface runoff under bare soil conditions is slow through rapid; moderate permeability.
USE AND VEGETATION: The soil is used for homesite development, watershed and as wildlife habitat. Vegetation consists of Bishop pine, Douglas-fir, tanoak, manzanita huckleberry, salal, madrone, with scattered, stunted redwood.
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: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 7 inches (A1, A2)
Argillic horizon - the zone from 21 to 32 inches (Bt2)
Many areas now mapped as the Havensneck series were mapped as Gualala series in the Wildland Soils and Associated Vegetation of Mendocino County, California State Cooperative Soil-Vegetation Survey, 1947-1950.