LOCATION CASPAR CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, isomesic Typic Palehumults
TYPICAL PEDON: Caspar sandy loam - on a southeast facing slope of 20 percent under redwood, tanoak and coastal shrubs at 300 feet elevation. (Colors are for dry soil unless otherwise stated.)
Oi--1 inch to 0; coarse, slightly decomposed litter of redwood and tanoak.
E1--0 to 6 inches; light gray and white (10YR 6/1 and 8/1) sandy loam, dark gray (10YR 4/1) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine and fine interstitial pores; extremely acid (pH 4.3); clear smooth boundary. (1 to 11 inches thick)
E2--6 to 12 inches; light gray and white (10YR 7/1 and 8/1) sandy loam, grayish brown and light grayish brown (2.5Y 5/2 and 6/2) moist; very weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many fine and very fine tubular and interstitial pore; extremely acid (pH 4.4); abrupt wavy boundary with tongues of E2 into B horizon along old root channels. (5 to 12 inches thick)
Bt1--12 to 24 inches; very pale brown (10YR 7/4) sandy loam, yellowish brown (10YR 5/4) moist; strong medium angular blocky structure; slightly hard, very firm, brittle, slightly sticky and slightly plastic; few fine and medium roots; common fine and very fine tubular and interstitial pores; many thick and moderately thick clay films on faces of peds and in pores; manganese stains; strongly acid (pH 5.5); clear smooth boundary. (10 to 20 inches thick)
Bt2--24 to 30 inches; very pale brown (10YR 7/4) sandy clay loam, yellowish brown (10YR 5/6) moist; yellowish red mottles; strong medium angular blocky structure; slightly hard, firm, sticky and plastic; few fine roots; common fine and very fine tubular and interstitial pores; common thin and moderately thick clay films on faces of peds and bridging sand grains; strongly acid (pH 5.2); clear smooth boundary. (6 to 12 inches thick)
Bt3--30 to 60 inches; light yellowish brown and yellow (10YR 6/4 and 7/6) clay loam, yellowish brown and yellow (10YR 5/6 and 7/6) moist; strong coarse angular blocky structure; slightly hard, firm, sticky and very plastic; very few fine roots; few fine tubular pores; continuous thick clay films on faces of peds; strongly acid (pH 5.1). (20 to 40 inches thick)
TYPE LOCATION: Sonoma County, California, 1 mile northwest of Plantation on Kruse Rhododendron Park Road; NW 1/4, SW 1/4, section 29, T.9N, R13W., MDBM.
RANGE IN CHARACTERISTICS: Thickness of the solum and depth to bedrock is greater than 60 inches. The mean annual soil temperature is 50 to 59 degrees F. The difference between mean summer and mean winter soil temperature varies from 3 to 9 degrees F. The soil between the depths of 9 and 26 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 18 to 35 percent clay. Organic carbon content in the upper cubic meter of the soil ranges from 12 to 15 kg/m2.
The E horizon is 10YR 5/1, 5/2, 6/1, 6/4, 7/1, 7/2, 8/1 or N 8/0. Moist color is 2.5Y 5/2, 6/2; 10YR 4/1, 4/2, 5/2, 6/1, 6/2 or 7/1. It is sandy loam or loamy sand. Clay content is 5 to 20 percent. Reaction is extremely or very strongly acid (pH 4.2 to 5.0).
The Bt horizon is 10YR 5/6, 6/3, 6/4, 6/6, 7/3, 7/4, 7/6; 7.5YR 6/4, 6/6 or 7/6. Moist color is 10YR 4/4, 4/6, 5/4, 5/6, 5/8, 6/4, 6/6, 7/6; 7.5YR 4/4, 5/4, 5/6, 6/4 or 6/6. Distinct or faint mottles in hues of 7.5YR or 10YR with chromas of 6 or 8 occur in the lower part of the Bt horizon in some pedons. Textures are sandy loam, loam, sandy clay loam, clay loam or sandy clay. Clay content ranges from 15 to 40 percent. Subrounded nodule content (2-50mm in diameter) ranges from 0 to 15 percent. Base saturation (sum) ranges from 5 to 35 percent. Reaction is extremely through strongly acid (pH 4.2 to 5.5).
A C horizon is present in some pedons. The C horizon is 10YR 6/6, 7/6; 7.5YR 6/6 or 6/8. Moist color is 10YR 4/6, 5/6, 6/6; 7.5YR 4/6, 5/6 or 5/8. It is loamy sand or sandy loam. Clay content ranges from 5 to 20 percent. Base saturation (sum) ranges from 3 to 35 percent. Reaction is extremely through strongly acid (pH 4.2 to 5.5).
COMPETING SERIES: These are the Empire (CA) and Timmons (T CA) series. The Empire and Timmons series lack an albic horizon. (see remarks)
GEOGRAPHIC SETTING: The Caspar soils occur on marine terraces. Slopes are dominantly 2 to 9 percent on the terrace tops with slopes of 9 to 50 percent occurring on the terrace shoulders and in drainageways that dissect the terraces. Elevations are 100 to 1000 feet. The soils formed in marine sediments. 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 varies from 30 to 65 inches. Mean January temperature is 48 degrees F.; mean July temperature is 57 degrees F., and mean annual temperature is 53 to 56 degrees F. The frost-free period is 290 to 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Empire, Ferncreek, Hugo, Josephine, Mendocino, Noyo, Quinliven and Vandamme soils. Empire soils lack an albic horizon Ferncreek, Mendocino, Quinliven and Vandamme soils are in the clayey particle-size class. Noyo soils are somewhat poorly drained. Hugo and Josephine soils have a xeric/mesic soil climate regime.
DRAINAGE AND PERMEABILITY: Well drained; surface runoff under bare soil conditions is slow through rapid; permeability is moderately slow in the subsoil and moderately rapid in the substratum.
USE AND VEGETATION: This soil is used for commercial timber production, homesite development, recreation, wildlife habitat and watershed. Vegetation consists of redwood, Douglas-fir, Bishop pine and tanoak. Grand fir, western hemlock, madrone and golden chinquapin occur in some areas.
DISTRIBUTION AND EXTENT: Northern coastal California. The series in not extensive. MLRA 4.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Sonoma County, California, 1968.
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 (Albic horizon) -- the zone from 0 to 12 inches (E1, E2)
Argillic horizon -- the zone from 12 to 60 inches (Bt1, Bt2, Bt3)
The Empire series is broadly and vaguely defined and therefore difficult to compete with the Caspar series. The Empire series as described in the Sonoma County report ranges from 30 to greater than 60 inches deep. This range in depth is different from that given on the official series description (50 to 70 inches). Empire mapped in Sonoma Co. has silty clay loam Bt horizons.
ADDITIONAL DATA: Laboratory data is available for Caspar Type Location pedon - UCD Soil Morphology Lab Sample No. 63-49-12x (Sonoma County) and for Caspar pedon # S80-CA-045-10-(1-9), NSSL sample # 802428 - 802436 (Mendocino County).