LOCATION CONKLIN CA
Established Series
REV: JWH/JTB/ET
07/2016
CONKLIN SERIES
The Conklin series consists of very deep, well drained soils formed in alluvium derived from mixed sedimentary sources. Conklin soils are on stream terraces in mountain river valleys. Slopes range from 0 to 2 percent. Mean annual precipitation is about 2030 mm and the mean annual temperature is about 14 degrees C.
TAXONOMIC CLASS: Fine-loamy, isotic, thermic Cumulic Humixerepts
TYPICAL PEDON: Conklin loam on a northwest facing 1 percent slope under grass at an elevation of 55 meters. (Colors are for dry soil unless otherwise noted.) When described on 5/04/05, the soil was moist throughout.
Ap--0 to 18 centimeters; grayish brown (10YR 5/2) loam, very dark gray (10YR 3/1) moist; strong medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and medium roots throughout; common very fine tubular pores; 12 percent gravel; very strongly acid (pH 4.9); abrupt smooth boundary.
A--18 to 52 centimeters; grayish brown (10YR 5/2) sandy clay loam, very dark gray (10YR 3/1) moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots throughout; common very fine tubular pores; 13 percent gravel; strongly acid (pH 5.5); gradual wavy boundary. (Combined thickness of the A horizons is 50 to 100 centimeters)
Bw1--52 to 78 centimeters; light yellowish brown (2.5Y 6/3) sandy clay loam, dark olive brown (2.5Y 3/3) moist; weak fine subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; few very fine and few medium roots throughout; few very fine and medium tubular pores; 2 percent gravel; moderately acid (pH 5.6); gradual wavy boundary. (0 to 50 centimeters)
Bw2--78 to 125 centimeters; light yellowish brown (2.5Y 6/3) loam, olive brown (2.5Y 4/4) moist; weak medium subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; 1 percent gravel; moderately acid (pH 5.7); gradual wavy boundary.
Bw3--125 to 160 centimeters; light yellowish brown (10YR 6/4) sandy clay loam, olive brown (2.5Y 4/4) moist; weak medium subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; 2 percent gravel; moderately acid (pH 5.7); clear smooth boundary.
2C--160 to 200 centimeters; 40 percent light yellowish brown (10YR 6/4), 30 percent light yellowish brown (2.5Y 6/3), and 30 percent grayish brown (10YR 5/2) extremely gravelly loamy coarse sand, dark yellowish brown (10YR 4/4), olive brown (2.5Y 4/3), and very dark grayish brown (2.5Y 3/2) moist; single grain; loose, loose, nonsticky and nonplastic; 70 percent gravel and 5 percent cobbles; moderately acid (pH 5.6). (Combined thickness of the C horizons is 50 to 100 centimeters)
TYPE LOCATION: Humboldt County, California; about 9 kilometers northwest of the town of Honeydew; USGS 7.5 minute Quadrangle Buckeye Mountain, CA; WGS84 Decimal degrees 40.2711111 latitude, -124.2244444 longitude; UTM Zone 10 395891mE, 4458554mN; NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is dry in all parts for 45 or more consecutive days after the summer solstice and moist in all parts from November through May. The soils have a xeric moisture regime
Soil Temperature: The mean annual soil temperature at 50 centimeters is 15 to 18 degrees C and the difference between mean summer and mean winter soil temperatures is 6 degrees C or greater. The soil has a thermic temperature regime.
Thickness of the umbric epipedon: 50 to 100 centimeters thick
Base Saturation: less than 60 percent by ammonium acetate in all horizons between 25 and 75 centimeters from the mineral soil surface
Particle size control section (weighted average):
Rock fragments: 0 to 35 percent gravel, 0 to 5 percent cobbles and stones
Clay content: 18 to 25 percent
A horizon:
Hue: 10YR or 2.5Y
Value: 3 to 5, 2 or 3 moist
Chroma: 1 to 3, moist or dry
Clay content: 10 to 25 percent
Rock fragments: 0 to 15 percent gravel
Reaction: strongly acid
Bw horizon:
Hue: 10YR or 2.5Y
Value: 5 or 6, 3 or 4 moist
Chroma: 2 to 4, moist or dry
Clay content: 10 to 25 percent
Rock fragments: 0 to 35 percent gravel, 0 to 5 percent cobbles
Reaction: strongly to moderately acid
C horizon:
Hue: 10YR or 2.5Y
Value: 5 or 6, 3 or 4 moist
Chroma: 2 to 4, moist or dry
Texture: loamy sand or sand
Clay content: 5 to 25 percent
Rock fragments: 15 to 75 percent gravel, 5 to 35 percent cobbles, 0 to 5 percent stones
Reaction: moderately acid
COMPETING SERIES: There are no competing series in this family.
GEOGRAPHIC SETTING: Conklin soils are on linear to slightly convex positions on stream terraces in mountain river valleys. Slopes are 0 to 2 percent. Elevations are 18 to 100 meters. These soils formed in alluvium from mixed sedimentary sources including sandstone and mudstone. The climate is subhumid with warm, dry summers with a marine layer influenceand cool, wet winters. Mean annual precipitation is 1525 to 2500 millimeters. The mean annual temperature is 13 to 15 degrees C. Frost free season is about 240 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the
Mattole (CA) soil. Mattole soils have less than 15 percent (by weight) particles with diameters 0.1 to 75 millimeters in the particle size control section and have a 15 bar water/clay of 0.6 or more in all horizons. Mattole soils occur on linear to slightly concave positions on stream terraces.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; negligible to low runoff; moderately high saturated hydraulic conductivity.
USE AND VEGETATION: This soil is used mainly for pasture, hay, and orchards. The vegetation is perennial and annual grasses and forbs including oats, soft brome, smooth brome, ryegrass, bristly dogstail grass, foxtail, and medusahead.
DISTRIBUTION AND EXTENT: Coastal Redwood Belt, MLRA 4B. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Humboldt County Soil Survey, Southern Part, California, 2010. The name is from Conklin Creek.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Umbric epipedon: The zone from 0 to 52 centimeters. (Ap and A horizons)
2. Cambic horizon: The zone from 52 to 160 centimeters. (Bw1, Bw2, and Bw3 horizons)
3. Particle size control section: The zone from 25 to 100 centimeters averages 22 percent clay, and 41 percent fine sand or coarser, by weight, and 4 percent gravel (A, Bw1, and Bw2 horizons)
4. Isotic feature: 15 bar water/clay is 0.63 or more and the NaF pH is greater than 8.8 in all horizons
5. Clay content for particle size family determination was calculated due to poor dispersion.
6. Cumulic feature: Holocene organic carbon content .46 percent at a depth of 125 centimeters below the mineral surface.
ADDITIONAL DATA:
NASIS User Pedon ID 05CA601438
NSSL, Pedon No. 05N0654
Soil classified using Keys to Soil Taxonomy, 12th edition.
National Cooperative Soil Survey
U.S.A.