LOCATION BEN LOMOND CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Pachic Ultic Haploxerolls
TYPICAL PEDON: Ben Lomond sandy loam, forested. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 2; inches redwood needles and twigs in various stages of decomposition. (0 to 8 inches thick)
A1--2 to 9 inches; dark grayish brown (10YR 4/2) sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium granular structure; soft, friable, slightly sticky and nonplastic; many very fine and fine roots; common very fine and fine tubular pores; neutral (pH 6.8); clear smooth boundary. (6 to 10 inches thick)
A2--9 to 21 inches; dark grayish brown (10YR 4/2) sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium granular structure, massive in places; soft, friable, slightly sticky and nonplastic; many very fine, fine, and medium roots; common very fine and fine tubular pores; slightly acid (pH 6.5); clear smooth boundary. (12 to 18 inches thick)
B--21 to 32 inches; brown (10YR 4/3) sandy loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, friable, slightly sticky and nonplastic; many very fine, fine, medium, and coarse roots; common fine and very fine tubular pores; moderately acid (pH 6.0); clear wavy boundary. (10 to 15 inches thick)
C--32 to 48 inches; pale brown (10YR 6/3) sandy loam, brown (10YR 4/3)moist; massive; slightly hard, friable, nonsticky and nonplastic; common fine, many medium and coarse roots; few very fine tubular pores; moderately acid (pH 5.8); gradual wavy boundary. (12 to 20 inches thick)
Cr--48 to 52 inches; weathered sandstone.
TYPE LOCATION: Santa Cruz County, California; off Bear Creek Road, 2.5 miles west from Summit Road, 250 feet up a private road commencing at mail box number 21890, thence 70 feet uphill and near a clump of redwoods; SE1/4 of SE1/4 section 3, T.9S., R.2W.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact is 40 to 60 inches. The soil between depths of about 8 and 24 inches usually becomes moist in some part in late November or December and remains moist until the end of April. The mean annual soil temperature is about 56 degrees F. Organic matter content is more than 1 percent at a depth of 20 to 32 inches. Base saturation is more than 50 percent in all parts and less than 75 percent in some or all parts and less than 75 percent in some or all parts of the profile to a depth of 30 inches. Coarse fragments ranges from 0 to 30 percent by volume in the textural control section.
The A horizon has dry colors of 10YR 4/2, 4/3, 5/2, 5/3; 7.5YR 3/2). Texture is sandy loam, fine sandy loam, very fine sandy loam, loam or gravelly sandy loam. This horizon is medium acid or neutral.
The B horizon has dry colors of 10YR 6/4, 5/3, 5/4, 4/4; 7.5YR 5/4). Texture is sandy loam, fine sandy loam, very fine sandy loam, loam or gravelly sandy loam. This horizon is medium acid to slightly acid.
The C horizon has dry colors of 10YR 4/4, 5/3, 5/4, 6/3, 6/4) with sand grains of dark gray, dark brown, or very pale brown (10YR 4/1, 4/3, 8/3). Texture is sandy loam, fine sandy loam, very fine sandy loam, loam or gravelly sandy loam. Reaction is strongly acid or medium acid.
COMPETING SERIES: This is the Drybuck, Junipero, and Olaton series. Junipero soils have a paralithic contact at depths of 28 to 40 inches and MAAT of 45 to 55 degrees F. Drybuck soils have a lithic contact at 40 to 60 inches, have MAAT of 45 to 48 degrees F. in MLRA 43B. Olaton soils are greater than 60 inches deep and formed in colluvium and alluvium, and have MAAT of 45 to 51 degrees F. in MLRA 10.
GEOGRAPHIC SETTING: Ben Lomond soils are on uplands and have slopes of 5 to 75 percent. They formed in material weathered from sandstone, granodiorite, and quartz diorite at elevations from 400 to 3,000 feet. The climate is coastal Mediterranean having warm, dry but foggy summers and cool, moist winters. The mean annual precipitation is 35 to 60 inches. The average January temperature is about 45 degrees F.; the average July temperature is about 65 degrees F.; and the mean annual temperature is 54 to 57 degrees F. The average January-July temperature difference is about 20 degrees F. The frost free season is 220 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Catelli, Zayante , Aptos, Felton, Lompico, Nisene and Sur soils. Aptos, Felton, Lompico and Nisene soils have a Bt horizons with more than 18 percent clay. Sur soils have more than 35 percent rock fragments and have a lithic contact at depths of 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderately rapid permeability.
USE AND VEGETATION: Used for timber production, recreation, wildlife, watershed, and in some areas, homesites and orchards. Vegetation is redwood, Douglas fir, tanoak, oaks, madrone, and shrubs.
DISTRIBUTION AND EXTENT: Central part of the Coast Range of California. They are inextensive. MLRA 4B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Santa Cruz Area, Santa Cruz County, California, 1936.
REMARKS: Ben Lomond is currently mapped in MLRA 4B but occurs in MLRA 15 on the eastern flanks of mountaintops bordering 4B. Competing series updated October 2009.
ADDITIONAL DATA: NSSL Lab Data 73C0024, 73C0027, 07N0678