LOCATION DRYCREEK CA

Established Series
CES/AGB
09/2025

DRYCREEK SERIES

The Drycreek series consists of very deep, well drained soils formed in alluvium. The Drycreek soils are on stream terraces. Slopes range from 0 to 2 percent. The mean annual precipitation is about 570 mm and the mean annual air temperature is about 17 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, thermic Pachic Haploxerolls

TYPICAL PEDON: Drycreek silt loam on a north-facing, linear slope of 1 percent. Vegetation is oats, vetch, and wheat planted in a non-irrigated hay field (Colors are for dry soil unless otherwise noted. When described on Thursday, June 6, 2024 the soil was dry to 11 cm and moist below).

Ap--0 to 11 cm; brown (7.5YR 4/2) silt loam, dark brown (7.5YR 3/2) moist; 10 percent clay; weak very thick platy parting to moderate medium granular structure; moderately hard, firm, slightly sticky, nonplastic; many very fine and common fine and very coarse roots throughout; common very fine, fine, and medium tubular pores; 1 percent rounded indurated mixed gravel; moderately acid (pH 5.6); clear smooth boundary. (6 to 25 cm thick)

BA--11 to 30 cm; brown (7.5YR 4/3) silt loam, very dark brown (7.5YR 2.5/2) moist; 12 percent clay; moderate very coarse prismatic structure; very hard, extremely firm, slightly sticky, nonplastic; common very fine, fine , and very coarse roots throughout; common very fine and few fine irregular pores; 1percent subangular weakly coherent sedimentary gravel; moderately acid (pH 5.6); clear smooth boundary. (0 to 25 cm thick)

Bw1--30 to 50 cm; brown (7.5YR 4/3) silt loam, very dark brown (7.5YR 2.5/2) moist; 13 percent clay; moderate very coarse prismatic structure; hard, very firm, slightly sticky, nonplastic; common very fine and fine roots throughout; common very fine and fine tubular pores; 1 percent subangular weakly coherent sedimentary gravel; moderately acid (pH 5.6); clear smooth boundary. (combined thickness of Bw horizons is 100 to 150 cm)

Bw2--50 to 95 cm; brown (7.5YR 4/3) silt loam, very dark brown (7.5YR 2.5/3) moist; 14 percent clay; moderate medium subangular blocky structure; hard, very firm, slightly sticky, nonplastic; common very fine roots throughout; few very fine and fine irregular pores; 1 percent subangular weakly coherent sedimentary gravel; moderately acid (pH 6.0); clear smooth boundary.

Bw3--95 to 115 cm; brown (7.5YR 5/3) loam, dark brown (7.5YR 3/3) moist; 12 percent clay; moderate medium subangular blocky structure; hard, very firm, slightly sticky, nonplastic; common fine roots throughout; few very fine and fine irregular pores; 2 percent subangular moderately coherent sedimentary gravel; neutral (pH 7.2); clear smooth boundary.

Bw4--115 to 160 cm; brown (7.5YR 5/3) fine sandy loam, dark brown (7.5YR 3/3) moist; 10 percent clay; weak medium subangular blocky structure; moderately hard, firm, nonsticky, nonplastic; few very fine roots throughout; few very fine and fine irregular pores; 2 percent rounded indurated mixed gravel; very slight effervescence; slightly alkaline (pH 7.4).

TYPE LOCATION: Amador County, California, about 3.8 km NW of Ione and about 575 m WSW of intersection of Highway 104 and Winter Road; 240 m N of the SE corner of sec. 15, T. 6 N., R. 9 E. (estimated in unsectionized area), MDB&M. WGS84 38.370423 latitude and -120.973123 longitude. UTM Zone 10 677064 meters E 4248860 meters N NAD83.

RANGE IN CHARACTERISTICS:
Soil temperature: The mean annual soil temperature at 50 cm depth is 15 to 17 degrees. The difference between mean summer and mean winter soil temperature is greater than 6 degrees C. The soils have a thermic temperature regime.

Soil moisture: The soils have a xeric soil moisture regime. The soil moisture control section is dry in all parts from about June to October (about 120 days).

Diagnostic Feature(s):
Mollic epipedon thickness: 50 to 75 cm
Cambic horizon thickness: 60 to 130 cm

Depth to redoximorphic features: greater than 75 cm to oxidized iron or iron/manganese masses.

Particle size control section weighted average:

Rock fragments: 0 to 15 percent gravel
Clay content: 5 to 18 percent

A or Ap horizon
Hue: 7.5YR, 10YR
Value: 4 or 5 dry, 2.5 or 3 moist
Chroma: 3 dry, 2 or 3 moist
Texture: fine sandy loam, silt loam, loamy sand
Clay content: 4 to 15 percent
Rock fragments: 0 to 15 percent gravel
Reaction: slightly to strongly acid

BA horizon, where present
Hue: 7.5YR, 10YR
Value: 4 or 5 dry, 2.5 or 3 moist
Chroma: 2 to 4, dry or moist
Texture: silt loam, loamy fine sand, loamy sand
Clay content: 5 to 18 percent
Rock fragments: 0 to 15 percent gravel
Reaction: slightly to strongly acid

Bw horizons
Hue: 7.5YR, 10YR
Value: 4 or 5 dry, 2.5 to 4 moist
Chroma: 2 to 4 dry, 2 or 3 moist
Texture: loam, silt loam, very fine sandy loam, fine sandy loam, sandy loam
Clay content: 5 to 27 percent
Rock fragments: 0 to 15 percent gravel
Reaction: moderately acid to neutral

COMPETING SERIES: These are the Ignord, Pillars, Sheridan, and Vina soils. The Ignord soils have disseminated lime present throughout the profile, and do not have hues redder than 10YR. The Pillars soils have a lithic contact within 100 cm and do not include hues redder than 10YR. The Sheridan soils do not have cambic horizons and have a paralithic contact within 100 cm. The Vina soils do not have cambic horizons and do not include hues redder than 10YR.

GEOGRAPHIC SETTING: The Drycreek soils are on stream terraces. Slopes range from 0 to 2 percent. These soils formed in alluvium from mixed sources. Elevation is 55 to 200 meters. The climate is Mediterranean with warm, dry summers and cool, moist winters. The mean annual precipitation is 540 to 660 mm and the mean annual air temperature is 16 to 17 degrees C. The frost-free season is 330 to 350 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hicksville soils. The Hicksville soils are fine-loamy, are on flood-plain steps and lower stream terraces, and are occasionally flooded.

DRAINAGE AND PERMEABILITY: Well drained. Saturated hydraulic conductivity is moderately high to high throughout the soil profile. Redoximorphic features, when present, are deeper than 75 cm.

USE AND VEGETATION: This soil is used for pasture and hay land. Vegetation is native, naturalized, and cultivated grasses and forbs, with small amounts of valley oak.

DISTRIBUTION AND EXTENT: Sierra Nevada Foothills of California; MLRA 18. These soils are of small extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Amador County, California, 2025. The name comes from Dry Creek, a local physiographic feature near where the series originated.

REMARKS:
Particle Size Control Section for this pedon: 25 to 100 cm
Diagnostic horizons and features recognized in this pedon are:
Mollic Epipedon 0 to 50 cm
Cambic Horizon 50 to 160 cm

ADDITIONAL DATA:

NASIS User Pedon ID: 2024CA0055029

Soil classified using the 13th Edition of the Keys to Soil Taxonomy.

National Cooperative Soil Survey
U.S.A.