LOCATION APTOS CA
Established Series
Rev. CSB/RHB/RWK/WRR
04/2023
APTOS SERIES
The Aptos series consists of moderately deep, well drained soils that formed in material weathered from sandstone, mudstone or shale. Aptos soils are on uplands and have slopes of 15 to 75 percent. The mean annual precipitation is about 48 inches and the mean annual air temperature is about 55 degrees F.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Pachic Ultic Argixerolls
TYPICAL PEDON: Aptos fine sandy loam, forested. (Colors are for dry soil unless otherwise noted.)
O--0 to 1 inch; twigs and leaves of vegetative cover; slightly acid (pH 6.3); abrupt smooth boundary. (0 to 4 inches thick)
A11--1 to 10 inches; dark grayish brown (10YR 4/2) fine sandy loam, dark brown (7.5YR 3/2) moist; medium coarse angular blocky structure; slightly hard, friable, nonsticky and nonplastic; many medium and coarse, common fine and very fine roots; many medium, common fine and very fine tubular, common very fine interstitial pores; slightly acid (pH 6.3); clear wavy boundary. (7 to 9 inches thick)
A12--10 to 19 inches; brown (7.5YR 5/2) fine sandy loam, dark brown (7.5YR 3/2) moist; weak coarse angular blocky structure; slightly hard, friable, nonsticky and nonplastic; many medium and coarse, common fine and very fine roots; many very fine and fine tubular, common very fine interstitial pores; few worm casts in pores; slightly acid (pH 6.1); clear wavy boundary. (8 to 12 inches thick)
A13--19 to 24 inches; grayish brown (10YR 5/2) fine sandy loam, dark brown (7.5YR 3/2) moist; weak coarse angular blocky structure; hard, friable, slightly sticky and slightly plastic; many medium and coarse, common fine and very fine roots; common fine and very fine tubular, many fine interstitial pores; moderately acid (pH 5.9); clear wavy boundary. (0 to 8 inches thick)
B2t--24 to 30 inches; brown (10YR 5/3) clay loam, dark brown (7.5YR 3/2) moist; moderate medium and coarse angular blocky structure; hard, friable, sticky and plastic; many medium and coarse, common fine and very fine roots; many very fine, common fine tubular, few very fine interstitial pores; common thin clay films, lining pores and coating faces of peds; very strongly acid (pH 5.0); pockets of this horizon penetrate to 37 inches deep in rock fractures; gradual irregular boundary. (5 to 15 inches thick)
Cr--30 to 40 inches; highly weathered fine grained sandstone, cut with moderate difficulty with tile spade; very strongly acid (pH 4.8). Soil in fractures similar to above horizon making up less than 10 percent of volume to 37 inches depth, decreasing to nil at 40 inches depth.
TYPE LOCATION: Santa Cruz County, California; about 0.1 mile up Love Creek Road from Woodland Way and about 350 feet uphill east of Love Creek Road; NE1/4 NW1/4 section 33, T.9S., R.2W.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact of fine grained sandstone, mudstone or shale is 20 to 40 inches. The soil between depths of 7 and 21 inches is usually dry between mid-July and mid-October and usually moist between the end of December and the end of April. The mean annual soil temperature is about 56 to 59 degrees F. Organic matter content is more than 1 percent at a depth of 20 to 30 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. Fragments range from 0 to 15 percent by volume.
The A horizon is very dark grayish brown, dark gray, dark grayish brown, grayish brown, or brown (10YR 3/2, 4/1, 4/2, 5/2, 5/3; 7.5YR 5/2). Texture is sandy loam, fine sandy loam, loam or silt loam. This horizon ranges from medium acid to neutral.
The B2t horizon is dark gray, gray, grayish brown, brown or yellowish brown (10YR 4/1, 5/1, 4/2 5/2, 5/3, 5/4) and in places, at a depth greater than 20 inches, pale brown (10YR 6/3) or 2.5Y 6/4. Texture is loam, sandy clay loam, silt loam or clay loam and has 20 to 35 percent clay. This horizon ranges from very strongly acid to slightly acid. In some pedons a 3 to 5 inch thick C horizon underlies the B2t horizon.
COMPETING SERIES:These are the
Buckeye,
Campfour,
Cartwright,
Elmore, Hyprarie,
Kiakus,
Lauby,
Newlig,
Nisene,
Paragon,
Roseburg,
Rudo,
Swalecreek and
Yaxing soils.Buckeye soils have a lithic contact of greenstone at 20 to 40 inches and MAAT of 50 to 55 degrees F. Campfour soils are very deep, have MAAT of 45 to 51 degrees F. and Bt hues of 5YR and 2.5YR. Cartwright soils are greater than 60 inches deep and have MAAT of 45 to 50 degrees F. Elmore soils are 40 to 60 inches deep to rhyolitic alluvium and colluvium and have MAAT of 46 to 51 degrees F. Hyprarie soils are greater than 60 inches deep and have MAAT of 46 to 50 degrees F. Kiakus soils are 20 to 40 inches deep to a lithic contact of Basalt and have MAAT of 46 to 49 degrees F. Lauby has a paralithic contact between 40 and 80 inches and has MAAT of 47 to 50 degrees F. Newlig soils are very deep , formed in alluvium and loess and have MAAT of 45 to 52 degrees F. Nisene soils have a paralithic contact of sandstone at 40 to 60 inches. Paragon soils have Paragon soils are moderately deep to a paralithic contact of andesite and basalt and have MAAT of 45 to 51 degrees F. Roseburg soils are very deep, formed in alluvium and have MAAT of 50 to 55 degrees F. Rudo soils have a paralithic contact at 40 to 60 inches and have MAAT of 47 to 50 degrees F. Swalecreek soils are very deep and formed in alluvium from basalt and loess with MAAT of 47 to 50 degrees F. Yaxong soils are very deep and formed from sandstone and loess, and have MAAT of 46 to 48 degrees F.
GEOGRAPHIC SETTING: Aptos soils are on uplands and have slopes of 15 to 75 percent. They formed in material weathered from fine grained sandstone and shale at elevations from 400 to 3,000 feet. The climate is humid mesothermal 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 frost free season is 220 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing
Nisene and the
Felton,
Lompico,
Soquel,
Ben Lomond,
Catelli and
Sur soils. Ben Lomond and Catelli soils lack B2t horizons and have less than 18 percent clay. Sur soils have more than 35 percent rock fragments and a base saturation of more than 75 percent throughout.
DRAINAGE AND PERMEABILITY: Well drained; rapid to very rapid runoff; moderate permeability.
USE AND VEGETATION: Used for timber production, recreation, wildlife, watershed, and in some areas, homesites and orchards. Vegetation is redwoods, Douglas fir, madrone, tanoak, ferns and poison oak.
DISTRIBUTION AND EXTENT: Central part of the Coast Range of California. The soils are not extensive. MLRA 4.
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 January of 2003. Competing series were not checked at that time. - ET
Activity class updated to superactive after reviewing lab data from similar adjacent soils. WR/KP Competing series checked October 2009.
National Cooperative Soil Survey
U.S.A.