LOCATION HARECREEK CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, semiactive, isomesic Typic Haplohumults
TYPICAL PEDON: Harecreek sandy loam - on a southwest facing slope of 3 percent under redwood, Douglas-fir and Bishop pine at 220 feet elevation. (Colors are for dry soil unless otherwise stated. When described on October 22, 1984, the soil was slightly moist throughout).
Oi--2 inches to 0; decomposing litter of redwood, Douglas fir and bishop pine.
A1--0 to 4 inches; gray (10YR 5/1) sandy loam, very dark gray (10YR 3/1) moist; weak fine, medium and coarse subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine through coarse roots; many very fine tubular and interstitial pores; moderately acid (pH 5.7); abrupt wavy boundary. (3 to 5 inches thick)
A2--4 to 8 inches; light brownish gray (10YR 6/2) sandy loam, dark grayish brown (10YR 4/2) moist; weak medium and coarse subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine ,fine medium and coarse roots; common very fine interstitial and few very fine, fine and medium tubular pores; slightly acid (pH 6.3); abrupt wavy boundary. (3 to 6 inches thick)
Bt1--8 to 12 inches; variegated light brownish gray (10YR 6/2) and pale brown (10YR 6/3) sandy loam, dark grayish brown (10YR 4/2) and brown (10YR 4/3) moist; moderate medium and coarse angular blocky structure; hard, very friable, slightly sticky and slightly plastic; brittle when moist; common very fine and fine and few medium roots; common very fine interstitial and very fine, fine and medium tubular pores; common thin clay films bridging mineral grains and few moderately thick clay films on faces of peds and lining pores; 10 percent hard iron cemented nodules (2-50mm); slightly acid (pH 6.5); gradual wavy boundary. (3 to 6 inches thick)
Bt2--12 to 16 inches; pale brown (10YR 6/3) sandy loam, brown (10YR 4/3) moist; moderate fine, medium and coarse subangular blocky structure; hard, friable, slightly sticky and nonplastic; common very fine and fine and few medium roots; common very fine interstitial and very fine, fine and medium tubular pores; many thin clay films bridging mineral grains and few thin and moderately thick clay films on faces of peds and lining pores; 5 percent hard iron cemented nodules (2-50mm); slightly acid (pH 6.5); clear wavy boundary. (3 to 6 inches thick)
Bt3--16 to 23 inches; light yellowish brown (10YR 6/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine, fine medium and through coarse roots; many very fine tubular and interstitial and few fine and medium tubular pores; few thin clay films bridging mineral grains and common thin and moderately thick clay films on faces of peds and lining pores; slightly acid (pH 6.2); clear wavy boundary. (5 to 12 inches thick)
Bt4--23 to 43 inches; strong brown (7.5YR 5/6) sandy loam, strong brown (7.5YR 4/6) moist; moderate medium, coarse and very coarse angular blocky structure; slightly hard, friable, nonsticky and nonplastic; few very fine, fine and medium roots; many very fine interstitial and many very fine and fine tubular pores; few thin clay films as bridges and few thin clay films on faces of peds and lining pores; strongly acid (pH 5.5); gradual wavy boundary. (15 to 25 inches thick)
C--43 to 63 inches; brownish yellow (10YR 6/6) sand, dark yellow brown (10YR 4/6) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine interstitial and tubular pores; strongly acid (pH 5.5)
TYPE LOCATION: Mendocino County, California; about 1,100 feet south and 1,300 feet west of the northeast corner of section 30, T.18 N., R.17 W., MDBM, Fort Bragg quadrangle.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 40 to 60 inches. Depth to bedrock is greater than 60 inches. Organic carbon content in the upper cubic meter of the soil ranges from 12 to 15 kg. The mean annual soil temperature is 50 to 56 degrees F. The difference between mean summer and mean winter temperature varies from 3 to 6 degrees F. The soil between the depths of 8 and 19 inches is moist in all parts from November 1 to August 15 and is dry in some part from September 1 to October 1 in most years. The particle-size control section averages 15 to 18 percent clay.
The A horizon is 10YR 4/1, 5/1, 5/2, 6/1, or 6/2. Moist color is 10YR 3/1, 4/1, 4/2 or 5/1. Clay content is 5 to 13 percent. Base saturation (sum) ranges from 20 to 35 percent. Reaction is strongly to slightly acid.
The Bt horizon is 10YR 6/2, 6/3, 6/4; 7.5YR 5/6 or 6/6. Moist color is 10YR 4/2, 4/3, 4/4, 5/3, 5/4; 7.5YR 4/6 or 5/6. It is sandy loam or sandy clay loam with 10 to 23 percent clay. Base saturation (sum) ranges from 10 to 35 percent. Reaction is strongly or moderately acid.
The C horizon is 10YR 6/6, 7/4 or 7/6. Moist color is 10YR 4/6, 5/4 or 5/6. It is sand, loamy sand or sandy loam with 5 to 13 percent clay. Base saturation (sum) ranges from 10 to 35 percent. Reaction is very strongly or strongly acid.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Harecreek soils occur on marine terraces. Slopes are 2 to 9 percent. Elevations are 150 to 450 feet. The soils formed in eolian sands that blanket the marine terraces. The climate is humid with cool foggy summers and cool moist winters. A strong marine influence limits the diurnal and annual ranges of temperature. Mean annual precipitation is 40 to 60 inches. Mean January temperature is 48 degrees F.; mean July temperature is 57 degree F. and mean annual temperature is 53 degrees F. Frost-free period ranges from 290 to 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Caspar, Cleone, and Tregoning soils. All occur on marine terraces with Caspar in slightly higher positions. Cleone and Tregoning soils are associated with shallow drainageways that dissect the terraces. Tregoning soils are 20 to 40 inches deep to an iron cemented hardpan. Casper soils are fine loamy. Cleone soils have mottles in the lower Bt and C horizons.
DRAINAGE AND PERMEABILITY: Well drained, surface runoff under bare soil conditions is medium or slow. Permeability is moderately rapid in the subsoil and rapid in the substratum.
USE AND VEGETATION: This soil is used for homesite development, wildlife habitat and as watershed. Vegetation consists of redwood, Douglas-fir, Bishop pine, tanoak, huckleberry, and salal.
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 8 inches (A1, A2)
Argillic horizon - the zone from 8 to 43 inches (Bt1, Bt2, Bt3, Bt4)
Many areas now mapped as the Harecreek series were mapped as the Caspar series in the Wildland Soils and Assoc. Veg. of Mendocino County, California State Cooperative Soil-Vegetation Survey, 1947-1950.
The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET