LOCATION CHALKFORD CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Pachic Haploxerolls
TYPICAL PEDON: Chalkford loam on a south facing 2 percent slope under a cover of alfalfa at an elevation of 4258 feet. (Colors are for dry soil unless, otherwise stated. When described May 2, 1986, the soil was moist throughout.)
Ap1--0 to 2 inches; dark grayish brown (10YR 4/2) loam, very dark gray (10YR 3/1) moist; moderate fine granular structure; slightly hard, friable, nonsticky and slightly plastic; common very fine and few coarse roots; common very fine tubular pores; mildly alkaline (pH 7.8); abrupt smooth boundary.
Ap2--2 to 9 inches; dark grayish brown (10YR 4/2) loam, very dark gray (10YR 3/1) moist; moderate fine angular blocky structure; hard, firm, nonsticky and slightly plastic; common very fine and fine and few coarse roots; common very fine tubular pores; mildly alkaline (pH 7.5); clear wavy boundary. (Combined thickness of the Ap horizon is 9 to 12 inches).
Bw1--9 to 18 inches; dark grayish brown (10YR 4/2) clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine angular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; few very fine, fine and coarse roots; common very fine tubular pores; mildly alkaline (pH 7.5) gradual wavy boundary.
Bw2--18 to 26 inches; dark grayish brown (10YR 4/2) clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine angular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; common fine and medium roots; common very fine tubular pores; mildly alkaline (pH 7.5); clear wavy boundary.
Bw3--26 to 35 inches; gray (10YR 5/1) clay loam, dark brown (10YR 3/3) moist; moderate fine prismatic structure parting to moderate fine angular blocky; hard, firm, slightly sticky and plastic; few very fine and fine roots; few very fine tubular pores; mildly alkaline (pH 7.6); gradual smooth boundary.
Bw4--35 to 62 inches; light gray (10YR 6/1) clay loam, dark brown (10YR 3/3) moist; few fine faint 2.5Y 6/2 and 5GY 4/1 moist mottles; strong fine angular blocky structure; hard, firm, slightly sticky and slightly plastic; few very fine and fine roots; few very fine tubular pores; mildly alkaline (pH 7.8). (Combined thickness of the Bw horizon is 51 to 60 inches).
TYPE LOCATION: Modoc County, California; about 3.5 miles northeast of Adin; about 1200 feet east and 1200 feet north of the southwest corner of sec. 3, T. 39 N., R. 9 E., Adin NW (Adin) Quadrangle (7.5 minutes series).
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 52 degrees F. The soil temperature exceeds 41 degrees F. from mid March to late November (260 days) and exceeds 47 degrees F. from mid May to early November. The soil moisture control section is dry in all parts from early July to mid October (100 to 110 days) and is moist in all parts from early November to mid June. The particle size control section averages 27 to 35 percent clay. Mineralogy is mixed. Reaction is neutral to mildly alkaline. Base saturation by sum of cations ranges from 80 to 90 percent. Organic matter ranges from 2 to 4 percent to a depth of 26 inches and decreases regularly with depth. Mottles occur at a depth of 35 to 60 inches.
The Ap horizon color is 10YR 4/1, 4/2 or 5/2. Moist color is 10YR 2/1, 3/1 or 3/2. Organic matter ranges from 2 to 4 percent. Clay content ranges from 25 to 27 percent.
The upper Bw horizon color is 10YR 4/2, 5/1 or 5/3. Moist color is 10YR 3/2 or 3/3. Organic matter ranges from 1 to 2 percent. Texture is clay loam or silty clay loam. Clay content ranges from 27 to 35 percent.
The lower Bw horizon color is 10YR 6/1, 6/2, 6/3, 7/2 or 7/3. Moist color is 10YR 3/3, 4/2, 4/3 or 5/3. Texture is clay loam, silty clay loam or clay. Clay content ranges from 35 to 42 percent. Mottles are few to common, fine to medium, faint to distinct, and are 2.5YR 6/2 dry and 2.5Y 4/2, 5Y 4/1 or 5GY 4/1 moist.
COMPETING SERIES: These are the Alicel (OR), Anaverde (CA), Calimus (OR), Linville (WA), Sinamox (OR), Sweeney (CA) and Watama (OR) soils. Watama soils are moderately deep. Calimus soils have aridic moisture regimes. Anaverde soils have 20 to 40 percent mica and 18 to 27 percent clay in the control section. Linville soils have 18 to 27 percent clay in the control section. Sweeney soils have mean annual soil temperatures of 55 to 59 degrees F. Alicel lack saturated horizons within 40 inches. Sinamox soils have gravelly or very gravelly 2C horizon at 30 to 40 inches and lack saturated horizons within 40 inches.
GEOGRAPHIC SETTING: Chalkford soils are on stream terraces. Slopes are 0 to 2 percent. These soils formed in alluvium from extrusive igneous rock. Elevation is 4200 to 4300 feet. The climate is semiarid with warm dry summers and cold moist winters. Mean annual precipitation is 14 to 16 inches. Snowfall is 24 to 48 inches. The mean annual temperature is 45 to 48 degrees F. The mean January temperature is about 35 degrees F. The mean July temperature is about 65 degrees F. Frost-free period is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dotta, Henhill, Oxendine and Sweagert soils. Dotta soils are very deep, are on terraces, have argillic horizons and are fine-loamy. Henhill soils are deep, are on terraces, have argillic horizons, have silt loam and silty clay loam textures and are fine-loamy. Oxendine soils are shallow, are on intermounds, have gravelly duripans and are loamy. Sweagert soils are moderately deep, are on mounds, have gravelly duripans and are fine-loamy.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow to ponded runoff; moderately slow permeability. The Chalkford soils are subject to occasional flooding for up to a period of 1 month in December through April. A fluctuating water table occurs at depths of 36 to 60 inches from April through June.
USE AND VEGETATION: This soil is mainly used for cropland. Small areas are used as pasture. Soils are cropped to alfalfa or grass hay.
DISTRIBUTION AND EXTENT: Modoc County, California. The soils are not extensive. MLRA is 21.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Modoc County, Intermountain Soil Survey Area, California 1994. Source of name is the original name for the town of Bieber, California.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the soil surface to 35 inches (Ap1, Ap2, Bw1, Bw2, Bw3).
Cambic horizon - the zone from 35 to 62 inches (Bw4).
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.