LOCATION LOMPICO CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Ultic Argixerolls
TYPICAL PEDON: Lompico loam - forested but recently harvested. (Colors are for dry soil unless otherwise noted.)
A1--0 to 5 inches; brown (7.5YR 5/2) loam, dark brown (7.5YR 3/2) moist; moderate coarse subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many fine, medium, coarse and common very fine roots; common very fine interstitial and fine tubular, and many very fine tubular pores; slightly acid (pH 6.5); clear wavy boundary. (5 to 16 inches thick)
B21t--5 to 11 inches; brown (7.5YR 5/4) clay loam, dark brown (7.5YR 3/2) moist; moderate coarse subangular blocky structure; hard, friable, sticky and plastic; common fine and very fine, many coarse and medium roots; many very fine and fine tubular, common very fine interstitial pores; few thin clay films lining pores; strongly acid (pH 5.5); gradual wavy boundary. (6 to 14 inches thick)
B22t--11 to 20 inches; brown (7.5YR 5/4) clay loam, dark brown (7.5YR 4/4) moist; moderate medium and coarse subangular blocky structure; hard, friable, sticky and plastic; common coarse and medium, few fine roots; many very fine and fine, common medium and coarse tubular lining pores; strongly acid (pH 5.5); gradual wavy boundary. (6 to 18 inches thick)
B31t--20 to 29 inches; mixed brown (7.5YR 5/4) and strong brown (7.5YR 5/6) sandy clay loam, dark brown (7.5YR 4/4) broken, dark yellowish brown (10YR 4/4) rubbed, moist; moderate medium and coarse angular blocky structure; hard, friable, sticky and plastic; common coarse and medium, few fine roots; many very fine tubular, common fine tubular and very fine interstitial pores; many thin clay films lining pores and on faces of peds; moderately acid (pH 6.0); clear irregular boundary. (0 to 12 inches thick)
B32t--29 to 37 inches; yellowish brown (10YR 5/4) shaly sandy clay loam, dark brown (10YR 4/3) broken, dark yellowish brown (10YR 4/4) rubbed, moist; moderate medium angular blocky structure; hard, friable, slightly sticky and slightly plastic; common coarse and medium, few fine roots; common fine and very fine tubular pores; common thin clay films as bridges between mineral grains and few thin clay films lining pores; moderately acid (pH 6.0); estimated 60 percent soft, highly weathered shale and sandstone gravel-sized fragments; diffuse broken boundary. (0 to 10 inches thick)
Cr--37 to 48 inches; soft, highly weathered sandstone, easily crushed.
TYPE LOCATION: Santa Cruz County, California; about 1,700 feet north-northwest of Zayante Road Crossing of Mountain Charlie Gulch and 800 feet due west of Zayante Road; southwest 1/4, northeast 1/4, northeast 1/4 of section 36 (projected), T. 9 S., R. 2 W.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact is 20 to 40 inches. The soil between depths of 6 to 16 inches usually becomes moist in mid-October or November and remains moist until the end of April. Mean annual soil temperature is about 56 degrees to 58 degrees F. Organic matter is more than 1 percent at depth of 10 inches and less than 1 percent at depth of 20 inches. Base saturation is more than 50 percent in all parts and less than 75 percent in some or all parts of the profile to a depth of 30 inches. Small areas have O horizons of leaf and twig litter. Pebbles range from 0 to 15 percent by volume, except for the horizon immediately above the paralithic contact which may range to 65 percent pebbles.
The A horizon is grayish brown or brown (10YR 5/2, 5/3; 7.5YR 5/2, 5/4). It is sandy loam, fine sandy loam, very fine sandy loam, or loam. This horizon is slightly acid or neutral.
The Bt horizon is brown, yellowish brown, light yellowish brown, strong brown, reddish brown, or reddish yellow (10YR 5/3, 5/4, 6/4; 7.5YR 4/4, 5/4, 5/6; 5YR 5/4, 6/6). It is loam, sandy clay loam, or clay loam. This horizon ranges from very strongly acid to moderately acid.
In a few places is a C horizon with a color of brown, pale brown, light yellowish brown, or reddish yellow (10YR 5/3, 6/3, 6/4; 7.5YR 6/8). It is sandy clay loam or clay loam. This horizon ranges from very strongly acid to moderately acid.
COMPETING SERIES: These are the Brownlee, Felton, Schumacher, and Van Horn series. All of these soils are deeper than 40 inches to bedrock. Also, the Brownlee, Schumacher, and Van Horn soils have a mean annual soil temperature of 47 degrees to 52 degrees F. and a frost-free growing season of less than 180 days.
GEOGRAPHIC SETTING: Lompico soils are on uplands and have slopes of 5 to 75 percent. They formed in material weathered from sandstone, shale, conglomerate, and granodiorite at elevations from 400 to 3,000 feet. The climate is humid mesothermal having warm, dry but foggy summers and cool, moist winters. Mean annual precipitation is 35 to 60 inches. Average January temperature is 45 degrees F., average July temperature is 65 degrees F., mean annual temperature is 54 degrees to 57 degrees F. Frost-free season is 220 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Felton soils and the Aptos, Ben Lomond, Catelli, Nisene, Soquel, and Sur soils. Aptos and Nisene soils have a mollic epipedon thicker than 20 inches, and Nisene soils have a paralithic contact at depths of more than 40 inches. Ben Lomond and Catelli soils have less than 18 percent clay and Ben Lomond soils are deeper than 40 inches to bedrock. Soquel soils do not have an argillic horizon. Sur soils have more than 35 percent rock fragments and have hard rock at depths of 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; moderate permeability.
USE AND VEGETATION: Used for timber production, recreation, wildlife, watershed, and in some areas, homesites. Vegetation is redwoods, madrone, tanoaks, ferns, poison oak, and some Douglas-fir.
DISTRIBUTION AND EXTENT: Central part of the Coast Range of California. The soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Santa Cruz County, California, 1976.
REMARKS: The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET