LOCATION BIAGGI CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, isomesic Humic Dystrustepts
TYPICAL PEDON: Biaggi loam - on a south facing slope of 2 percent under annual and perennial grasses and forbs at 315 feet elevation. (Colors are for dry soil unless otherwise stated. When described on October 30, 1986, the soil was moist throughout).
A1--0 to 6 inches; brown (10YR 5/3) loam, very dark brown (10YR 2/2), moist; moderate very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular and interstitial pores; 2 percent hard subrounded pebbles (2-10mm); very strongly acid (pH 5.0); clear wavy boundary. (5 to 12 inches thick)
A2--6 to 23 inches; brown (10YR 5/3) loam, very dark grayish brown (10YR 3/2), moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine tubular and interstitial pores; 5 percent hard subrounded pebbles (2-30mm); very strongly acid (pH 4.8); abrupt wavy boundary. (12 to 30 inches thick)
R--23 to 25 inches; hard fractured sandstone.
TYPE LOCATION: Mendocino County, California; about 800 feet south and about 2,100 feet west of the northeast corner of sec. 31, T. 13 N., R. 16 W., MDBM, Point Arena quadrangle.
RANGE IN CHARACTERISTICS: Thickness of the solum and depth to lithic contact ranges from 20 to 40 inches. The umbric epipedon is 20 to 40 inches thick. The mean annual soil temperature ranges from 50 to 56 degrees F. The difference between the 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 dry in some or all parts from July 1 to October 1 and is moist in all parts from November 1 to June 1 in most years. Organic carbon content in the upper cubic meter is 12 to 20 kg.
The A horizon is 10YR 4/3 or 5/3. Moist color is 10YR 2/2, 3/2 or 3/3. Clay content is 18 to 27 percent. Gravel content is 0 to 15 percent. Base saturation (ammonium acetate) is 20 to 50 percent. Reaction is very strongly acid through slightly acid. Organic carbon content ranges from 2 to 4 percent. Some pedons have a thin Bw horizon above the lithic contact.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Biaggi soils are on marine terraces. They occur in areas along the front edge of terraces, along terrace shoulders, and in other areas where the underlying wavecut bedrock platform is closer to the soil surface. Slopes are 0 to 15 percent. Elevations range from 100 to 400 feet. The soil formed in material weathered from sandstone or shale. The climate is humid with cool foggy summers and cool moist winters. A strong marine influence limits the diurnal and annual range in temperature. Mean annual precipitation ranges from 35 to 45 inches. Mean January temperature is about 48 degrees F. Mean July temperature is about 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 Cabrillo, Crispin, Flumeville, Heeser, Mallopass, and Windyhollow series. The Crispin soils, in a similar geographic setting, are underlain by a dense, gravelly pan at a depth of 20 to 40 inches. The Cabrillo, Flumeville, Heeser, Mallopass and Windyhollow series are more than 60 inches deep and are on areas of the marine terraces that have received accumulations of sediment.
DRAINAGE AND PERMEABILITY: Well drained; surface runoff under bare soil conditions is very slow to medium; moderate permeability.
USE AND VEGETATION: This soil is used for livestock grazing and wildlife habitat. A few areas are used for homesite development. Vegetation consists of perennial and annual grasses and forbs.
DISTRIBUTION AND EXTENT: Northern coastal California. The series is not extensive. MLRA is 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:
Umbric epipedon -- the zone from 0 to 23 inches (A1, A2)
Many areas now mapped as the Biaggi series were mapped as the Kneeland series in the Soil Survey of the Mendocino County Bottomlands, 1973.