LOCATION LEPOIL CA
Established Series
Rev. ACF/JPS/ET/RLM
10/2016
LEPOIL SERIES
The Lepoil series consists of very deep, well drained soils formed in marine deposits derived from mixed sources. Lepoil soils are on nearly level to steeply sloping, dissected marine terraces and have slopes 0 to 50 percent. The mean annual precipitation is about 1500 millimeters (59 inches) and the mean annual temperature is about 11 degrees C (52 degrees F).
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, isomesic Typic Palehumults
TYPICAL PEDON: Lepoil loam - on a nearly level, linear slope of 2 percent under coast redwood, red alder, swordfern, salal, redwood sorrel, cascara and red huckleberry at 17 meters (55 feet) elevation. (Colors are for moist soil unless otherwise stated. When described on August 28,2007 the soil was moist throughout).
A1--0 to 27 centimeters (0 to 11 inches); dark brown (7.5YR 3/3) loam, brown (7.5YR 5/3) dry; moderate very fine subangular blocky structure; slightly sticky and slightly plastic; few very fine and common fine and medium roots throughout; common very fine and fine tubular, and common very fine and fine irregular pores; moderately acid (pH 5.8); clear smooth boundary.
A2--27 to 50 centimeters (11 to 20 inches); dark brown (7.5YR 3/3) loam, brown (7.5YR 5/4) dry; moderate very fine and weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine, medium and coarse roots throughout; common very fine and fine irregular, and common very fine and fine tubular pores; moderately acid (pH 5.9); clear smooth boundary. (Combined thickness of A horizon is 25 to 50 centimeters thick)
AB--50 to 68 centimeters (20 to 27 inches); dark brown (7.5YR 3/4) loam, brown (7.5YR 5/4) dry; moderate fine and weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and common medium roots throughout; common very fine and fine irregular, and common fine tubular pores; moderately acid (pH 5.9); clear wavy boundary.
Bt1--68 to 90 centimeters (27 to 35 inches); dark yellowish brown (10YR 4/4) sandy clay loam, brownish yellow (10YR 6/6) dry; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common very fine and fine irregular pores; few faint clay films on all faces of peds; 1 percent paragravel; moderately acid (pH 5.6); clear smooth boundary.
Bt2--90 to 120 centimeters (35 to 47 inches); dark yellowish brown (10YR 4/4) clay loam, brownish yellow (10YR 6/6) dry; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; few fine and medium roots throughout; common very fine and few fine irregular pores; very few faint clay films on all faces of peds; 5 percent gravel; moderately acid (pH 5.6); clear smooth boundary.
Bt3--120 to 140 centimeters (47 to 55 inches); dark yellowish brown (10YR 4/6) clay loam, brownish yellow (10YR 6/6) dry; weak very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; few very fine irregular pores; very few faint clay films on all faces of peds; 3 percent gravel; moderately acid (pH 5.6); clear smooth boundary.
Bt4--140 to 160 centimeters (55 to 63 inches); dark yellowish brown (10YR 4/6) clay loam, brownish yellow (10YR 6/6) dry; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; few fine and medium roots throughout; common very fine and few fine irregular pores; very few faint clay films on all faces of peds; 5 percent gravel; moderately acid (pH 5.6); clear smooth boundary.
TYPE LOCATION: Del Norte County, California; located approximately 12 kilometers north east of Crescent City, California; USGS Crescent City Quadrangle; WGS84 Decimal degrees 41.8603889 latitude and -124.1525833 longitude, UTM Zone 10 404336mE 4634918mN; NAD83.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil is usually moist in all parts in the soil moisture control section in most years, but becomes nearly dry in the upper part from about September 15 to October 15 in most years. The soils have an udic soil moisture regime.
Soil temperature: The mean annual soil temperature is 11 to 13 degrees C (52 to 55 degrees F). The difference between mean summer and mean winter temperature is 2 to 4 degrees C. The soils have an isomesic temperature regime.
The umbric epipedon is 25 to 50 centimeters thick.
Organic matter: greater than 0.9 percent organic carbon in the upper 15 centimeters of the argillic horizon.
Particle-Size Control Section (weighted average):
Clay content 25 to 30 percent
Rock fragments: 0-5 percent gravel and 0 to 5 percent paragravel
Reaction: Very strongly to moderately acid
A horizon
Hue: 7.5 YR or 10YR
Value: 2 or 3, 3 through 5 dry
Chroma: 2 or 3, 2 or 4 dry
Texture of fine earth: loam
Rock fragments: 0 to 5 percent gravel or paragravelClay content: 18 to 27 percent
Reaction: slightly to moderately acid
Upper Bt horizon
Hue: 7.5YR or 10YR
Value: 3 through 5, 4 through 6 dry
Chroma: 3 through 5, 5 through 7 dry
Texture of fine earth: sandy clay loam, clay loam, or loam
Rock fragments: 0 to 10 percent paragravel or gravel
Clay content: 25 to 35 percent
Reaction: slightly to moderately acid
Lower Bt horizon
Hue: 7.5YR or 10YR
Value: 3 through 5, 4 through 7 dry
Chroma: 3 through 5, 4 through 7 dry
Texture of fine earth: clay, sandy clay loam, clay loam, or loam
Rock fragments: 0 to 10 percent paragravel or gravel
Clay content: 25 to 45 percent
Reaction: slightly to moderately acid
Some pedons have C horizons
C horizon
Hue: 2.5Y
Value: 3 or 4, 6 dry
Chroma: 3 dry and moist
Texture of fine earth: fine sandy loam, very fine sandy loam, or fine sand
Rock fragments: 0 to 5 percent gravel or paragravel
Clay content: 3 to 5 percent.
Reaction: strongly acid
COMPETING SERIES: These are the
Littleriver and
Sasquatch soils. Sasquatch soils are formed in colluvium and residuum derived from sandstone and siltstone. The Littleriver soil has 5 to 35 percent well rounded gravels in the particle size control section.
GEOGRAPHIC SETTING: Lepoil soils are on gently sloping to steeply sloping dissected marine terraces and have slopes of 0 to 50 percent. Steep sloping terrace sides have had the riser component replaced by a hillslope component. Elevations are 12 to 183 meters (40 to 600 feet). These soils formed in marine deposits derived from mixed sources. The climate is humid with cool, foggy summers and cool, wet winters. A strong marine influence limits the diurnal and annual range of temperature. Mean annual precipitation is 890 to 2085 millimeters (35 to 90 inches). Mean annual temperature is 10 to 12 degrees C (50 to 53 degrees F). Frost free season is about 275 to 325 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Candymountain,
Espa, and
Timmons soils. Candymountian soils have greater than 15 percent particles with a diameter between 0.1 to 75 millimeters in the particle size control section. Espa soils are formed in weekly consolidated beach and dune deposits, and lack a clay increase of 20 percent or greater with in a vertical distance of 30 centimeters. Timmons soils occur under cultivated or cleared conditions where the difference between mean winter and mean summer soil temperature is 6 degrees C or greater.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; low to medium runoff; moderately low saturated hydraulic conductivity.
USE AND VEGETATION: This soil is used for timber production and urban development. Natural vegetation includes redwood with scattered Sitka spruce and red alder, salal, western swordfern, redwood sorrel, cascara and red huckleberry.
DISTRIBUTION AND EXTENT: California Coastal Redwood Belt; MLRA 4B. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Humboldt and Del Norte Counties Soil Survey, Northern Part, California, January 2013. Proposed 2010.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Umbric epipedon - the zone from to 50 centimeters (A horizons).
2. Argillic horizon - the zone from 68 to 160 centimeters (Bt1, Bt2, Bt3).
3. Particle-size control section - the zone from 68 to 118 centimeters (Bt1 and Bt2 horizons) averages 28 percent clay and 24 percent fine sand and coarser.
4. Palehumult feature: clay percent does not decrease with depth.
Additional Data:
NASIS User Pedon ID: 07CA605180
Keys to Soil Taxonomy, 12th edition.
National Cooperative Soil Survey
U.S.A.