LOCATION DEHAVEN CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, active, isomesic Mollic Hapludalfs
TYPICAL PEDON: Dehaven gravelly loam - on an east facing slope of 75 percent under redwood, Douglas-fir, tanoak and swordfern at 400 feet elevation. (Colors are for dry soil unless otherwise stated. When described on September 19, 1978 the soil was moist throughout).
Oi--2 inches to 0; litter of redwood leaves and twigs.
A1--0 to 6 inches; brown (10YR 5/3) gravelly loam, dark brown (10YR 3/3) moist; strong very fine and fine granular structure; slightly hard, friable, slightly sticky and plastic; many very fine and fine and medium roots; many very fine and fine interstitial pores; 15 percent pebbles (2-5mm); slightly acid (pH 6.1); clear irregular boundary. (5 to 9 inches thick)
A2--6 to 17 inches; pale brown (10YR 6/3) gravelly loam, dark brown (10YR 4/3) moist; moderate very fine and fine granular structure; slightly hard, friable, slightly sticky and plastic; many very fine and fine and few medium and coarse roots; many very fine and fine interstitial pores; 20 percent pebbles (2-15mm); moderately acid (pH 6.0); gradual wavy boundary. (9 to 12 inches thick)
Bt1--17 to 34 inches; brownish yellow (10YR 6/6) very gravelly sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate very fine and fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine and few medium, coarse and very coarse roots; many very fine and fine interstitial pores; few thin clay films bridging mineral grains; 55 percent pebbles (2-25mm); moderately acid (pH 5.6); gradual irregular boundary. (11 to 19 inches thick)
Bt2--34 to 52 inches; brownish yellow (10YR 6/6) extremely gravelly sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate very fine and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine, fine and medium roots; many very fine and fine interstitial pores; common moderately thick clay films bridging mineral grains and on faces of peds; 70 percent pebbles (2-25mm); 2 percent cobbles; moderately acid (pH 5.6); clear wavy boundary. (12 to 21 inches thick)
R--52 inches; hard, fractured sandstone; fractures are about 1mm wide and 1cm to 10cm apart; rock does not slake in water.
TYPE LOCATION: Mendocino County, California; about 2250 feet north and 1400 feet east of the southwest corner of sec. 24, T.11N., R.15W., MDBM, Ornbaun Valley Southwest quadrangle.
RANGE IN CHARACTERISTICS: Depth to a lithic contact and thickness of the solum is 40 to 60 inches. The mean annual soil temperature ranges from 50 to 56 degrees F. The difference between mean summer and mean winter soil temperature ranges from 3 to 6 degrees F. The soil between the depths of 7 and 27 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. The particle-size control section averages 25 to 30 percent clay. Reaction is moderately or slightly acid.
The A horizon is 10YR 3/2, 3/4, 4/3, 4/4, 5/2, 5/3, 6/2, 6/3, 6/4 or 7/3. Moist color is 10YR 2/2, 3/2, 3/3, 3/4, 4/2, 4/3 or 4/4. Where mollic colors occur the thickness requirement for a mollic epipedon is not met. Gravel content is 15 to 35 percent. Base saturation (sum) is 50 to 75 percent.
The Bt horizon is 10YR 4/3, 5/3, 5/4, 5/6, 5/8, 6/3, 6/4, 6/6, 7/3 or 7/4. Moist color is 10YR 3/4, 4/3, 4/4, 4/6, 5/3, 5/4, 5/6 or 6/4. It is very gravelly clay loam or sandy clay loam or extremely gravelly clay loam or sandy clay loam. Clay content is 20 to 35 percent. Gravel content is 35 to 80 percent. Cobble content is 0 to 15 percent. Base saturation (sum) is 65 to 85 percent
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Dehaven soils occur on hills. Slopes are 30 to 99 percent. Elevation is 10 to 800 feet. These soils formed in material weathered from sandstone. 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 40 to 70 inches. Mean January temperature is 50 degrees F., mean July temperature is 55 degrees F., and mean annual temperature is 53 degrees F. The frost-free period is 290 to 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hotel, Irmulco, Tramway and Vandamme soils. Hotel soils are 20 to 40 inches deep to a lithic contact. Irmulco and Tramway soils are fine-loamy. Vandamme soils are clayey.
DRAINAGE AND PERMEABILITY: Well drained; surface runoff under bare soil conditions is rapid or very rapid; moderate permeability.
USE AND VEGETATION: This soil is used for commercial timber production, wildlife habitat and watershed. Vegetation consists of redwood, Douglas-fir, tanoak, California huckleberry, swordfern and oxalis.
DISTRIBUTION AND EXTENT: Northern coastal California. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Mendocino County, California, Western part, 1993.
REMARKS: The activity class was added to the classification in January of 2003. Competing series were not checked at that time. - ET
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon -- the zone from 0 to 17 inches (A1, A2).
Argillic horizon - the zone from 17 to 52 inches (Bt1, Bt2).
Lithic contact - the boundary at 52 inches (R).
Many areas mapped as Dehaven soils were mapped as Hugo soils by the California Soil Vegetation Survey 1947-1950.
ADDITIONAL DATA: Lincoln Lab reference samples: 80P2490-2494