LOCATION WINDYHOLLOW CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, isomesic Udic Argiustolls
TYPICAL PEDON: Windyhollow loam on a southwest facing slope of 3 percent under annual and perennial grasses and forbs at 370 feet elevation. (Colors are for dry soil unless otherwise stated. When described October 16, 1986 the soil was moist throughout.)
A1--0 to 9 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure parting to moderate fine granular; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine interstitial and common very fine tubular pores; 10 percent hard rounded pebbles (2-5mm); strongly acid (pH 5.3); clear wavy boundary. (5 to 15 inches thick)
A2--9 to 16 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure parting to moderate fine granular; slightly hard, friable, sticky and plastic; common very fine roots; many very fine interstitial and common very fine tubular pores; 10 percent hard rounded pebbles (2-50mm); moderately acid (pH 5.6); clear wavy boundary. (5 to 10 inches thick)
Bt1--16 to 24 inches; light yellowish brown (10YR 6/4) clay loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; hard, firm, sticky and plastic; few very fine roots; common very fine tubular and interstitial pores; few thin clay films on peds and in pores; 14 percent hard subangular pebbles (2-40mm); moderately acid (pH 5.9); clear wavy boundary. (5 to 15 inches thick)
Bt2--24 to 30 inches; very pale brown (10YR 8/3) gravelly clay loam, yellowish brown (10YR 5/4) moist; few fine prominent brownish yellow (10YR 6/8) mottles, yellowish brown (10YR 5/8) moist; moderate fine and medium subangular blocky structure; hard, firm, sticky and plastic; few very fine roots, many very fine tubular and common very fine interstitial pores; few thin clay films on peds and in pores; 25 percent hard subangular pebbles (2-20mm); moderately acid (pH 5.9); gradual wavy boundary (5 to 20 inches thick)
Bt3--30 to 43 inches; very pale brown (10YR 8/3) gravelly clay loam, yellowish brown (10YR 5/4) moist; many fine and medium prominent brownish yellow (10YR 6/8) mottles, yellowish brown (10YR 5/8) moist; weak medium subangular block structure; slightly hard, firm, slightly sticky and plastic; few very fine roots; common very fine tubular and interstitial pores; few moderately thick clay films on fracture faces and lining pores; 30 percent hard subangular pebbles (2-30mm); slightly acid (pH 6.2); clear wavy boundary. (0 to 15 inches thick)
Bt4--43 to 61 inches; white (2.5Y 8/2) clay loam, pale yellow (2.5Y 7/4) moist; common fine and medium prominent brownish yellow (10YR 6/8) mottles, strong brown (7.5YR 5/8) moist; weak medium subangular blocky structure; hard, firm, slightly sticky and plastic; few very fine roots; few very fine tubular and interstitial pores; few moderately thick clay films on fracture faces; 10 percent hard angular pebbles (2-20mm); slightly acid (pH 6.2).
TYPE LOCATION: Mendocino County, California; about 800 feet north and 2,100 feet east of the southwest corner of sec. 6, T.13N., R.16W., MDBM, Mallo Pass Creek quadrangle.
RANGE IN CHARACTERISTICS: Thickness of the solum and depth to bedrock is greater than 60 inches. Thickness of the mollic epipedon is 10 to 20 inches. Organic carbon content ranges from 0.6 to 4.0 percent decreasing regularly with depth. The mean annual soil temperature ranges from 50 to 56 degrees F. The difference between mean summer and mean winter soil temperature ranges from 6 to 9 degrees F. The soil between the depths of 6 and 19 inches is moist in all parts from November 1 to June 1. It is dry in some or all parts from July 1 to October 1 in most years. The particle-size control section averages 25 to 35 percent clay.
The A horizon is 10YR 4/1, 4/2, 4/3, 5/2 or 5/3. Moist color is 10YR 2/1, 2/2, 3/1, 3/2 or 3/3; clay content is 20 to 27 percent. Hard gravel content ranges from 5 to 15 percent. Base saturation (ammonium acetate) ranges from 50 to 70 percent. Reaction is strongly or moderately acid.
The Bt horizon is 2.5Y 7/2, 8/2; 10YR 6/3, 6/4, 7/2, 8/2 or 8/3. Moist color is 2.5Y 5/4, 6/4, 7/4; 10YR 4/4, 5/3, 5/4, 6/3 or 6/4. Mottle colors are 10YR 6/6 or 6/8. Moist mottle colors are 10YR 5/6, 5/8 or 7.5YR 5/8. Colors with chromas of 2 occur with mottles between the depths of 30 and 50 inches and continue to a depth of 60 inches or more. The Bt horizon is a gravelly clay loam, clay loam or clay. Clay content ranges from 27 to 45 percent. Hard gravel content ranges from 5 to 30 percent. Base saturation (ammonium acetate) ranges from 70 to 100 percent. Reaction is moderately or slightly acid.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: The Windyhollow soils occur on marine terraces. Slopes are 0 to 30 percent. Elevations are 80 to 900 feet. The soils formed in alluvium derived from mixed rock sources. The climate is humid with cool foggy summers and cool moist winters. A strong marine influence limits the diurnal and annual range of temperature. Mean annual precipitation ranges from 35 to 45 inches. Mean January temperature is 48 degrees F., mean July temperature is 57 degrees F., and the mean annual temperature is 53 degrees F. The frost-free period is 250 to 330 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Biaggi, Bruhel, Cabrillo, Crispin, Flumeville, Mallopass, and Stornetta soils. Biaggi, Bruhel, Cabrillo, Crispin, Flumeville and Mallopass soils are also on marine terraces. Biaggi, Bruhel, Crispin and Mallopass soils are often in slightly higher positions. Biaggi soils are moderately deep to lithic contact. Bruhel soils lack mottling, and have a thicker mollic epipedon. Crispin soils lack mottling, and are moderately deep to a cemented pan. Mallopass soils have mottles below 50 inches, and have a thicker mollic epipedon. Cabrillo soils have a loamy sand umbric epipedon. Flumeville soils are often in subtle depressions, have mottles between 10 and 30 inches, and have a fine particle-size control section. Stornetta soils occur on flood plains, have mottles above 10 inches, and lack argillic horizons.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; the soil is saturated with water for extended periods following episodes of heavy rain from December through April. The saturated zone starts between the depths of 30 and 50 inches and extends to greater than 60 inches. Surface runoff under bare soil conditions is very slow through rapid. Permeability is moderately slow.
USE AND VEGETATION: This soil is used for livestock grazing and as wildlife habitat. A few areas are cultivated. Vegetation consists of perennial and annual grasses and forbs.
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:
Mollic epipedon -- the zone from 0 to 16 inches (A1, A2)
Argillic horizon -- the zone from 16 to 61 inches (Bt1, Bt2, Bt3, Bt4)
Many areas mapped as the Windyhollow series were mapped as Kneeland loam, deep variant, Noyo clay loam, dark variant, and Kneeland loam, hardpan variant in the Soil Survey of the Mendocino County Bottomlands, 1973.