LOCATION PATBURN CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Pachic Argixerolls
TYPICAL PEDON: Patburn loam on a west facing 2 percent slope under a cover of silver sagebrush and perennial grasses at an elevation of 4250 feet. (Colors are for dry soil unless otherwise stated. When described August 20, 1987, the soil was moist below 50 inches.)
A--0 to 2 inches; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; common fine prominent strong brown (7.5YR 5/6) mottles; moderate thin platy structure; hard, friable, slightly sticky and slightly plastic; common very fine roots; common very fine and fine tubular pores; neutral (pH 6.6); abrupt smooth boundary. (2 to 4 inches thick)
Bt1--2 to 7 inches; brown (10YR 5/3) clay loam, dark brown (7.5YR 3/2) moist; few fine distinct dark yellowish brown (10YR 4/6) mottles; moderate fine subangular blocky structure; very hard, friable, slightly sticky and plastic; common very fine and fine roots; common very fine and fine tubular pores; few thin clay films on ped faces; neutral (pH 6.6); clear smooth boundary. (4 to 7 inches thick)
Bt2--7 to 13 inches; grayish brown (10YR 5/2) clay loam, dark brown (7.5YR 3/2) moist; common fine prominent strong brown (7.5YR 4/6) mottles; moderate fine subangular blocky structure; very hard, firm, slightly sticky and plastic; few very fine roots; common very fine and fine tubular pores; common moderately thick clay films on ped faces; neutral (pH 7.0); abrupt smooth boundary. (6 to 14 inches thick)
Bt3--13 to 32 inches; brown (10YR 5/3) clay, dark brown (7.5YR 3/2) moist; common fine and medium prominent strong brown (7.5YR 4/6) mottles; coarse prismatic structure parting to moderate medium subangular blocky; extremely hard, very firm, sticky and plastic; few very fine roots; few very fine tubular pores; common thin clay films in pores; slightly alkaline (pH 7.8); clear smooth boundary. (5 to 19 inches thick)
2Bt4--32 to 38 inches; brown (10YR 5/3) loam, dark brown (7.5YR 4/2) moist; common medium prominent strong brown (7.5YR 4/6) mottles; moderate fine subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; common thin clay films in pores; slightly alkaline (pH 7.8); abrupt smooth boundary. (2 to 8 inches thick)
2Bt5--36 to 44 inches; light brown (7.5YR 6/4) loam, brown (7.5YR 4/4) moist; weak fine subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few very fine roots; common very fine and fine and few medium tubular pores; few thin clay films in pores; slightly alkaline (pH 7.8); abrupt smooth boundary. (6 to 10 inches thick)
2Bt6--44 to 50 inches; light brown (7.5YR 6/4) clay loam, brown (7.5YR 4/4) moist; few fine distinct strong brown (7.5YR 4/6) mottles; weak very fine subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; many very fine and fine tubular pores; common thin clay films on ped faces; slightly alkaline (pH 7.8); abrupt smooth boundary. (5 to 8 inches thick)
3Bt7--50 to 72 inches; light brown (7.5YR 6/4) sandy clay loam, brown (7.5YR 4/4) moist; few fine distinct strong brown (7.5YR 4/6) mottles; weak fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many very fine and common fine tubular pores; few thin clay films on ped faces; moderately alkaline (pH 8.0).
TYPE LOCATION: Modoc County, California; approximately 8 miles northwest of Lookout, 1900 feet north and 550 feet west of the southeast corner of section 33, T.41N., R.6E., Whitehorse SE (Egglake) Quadrangle (7.5 minute series).
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 52 degrees F. The soil temperature exceeds 41 degrees F. from early March to late December (300 days) and exceeds 47 degrees F. from mid April to mid November. The soil moisture control section is dry in all parts from early July to early November (110 to 120 days) and is moist in all parts from mid November to late June. The particle size control section averages 35 to 50 percent clay. Base saturation by ammonium acetate ranges from 80 to 100 percent.
The A horizon color is 10YR 4/2, 5/3 or 5/2. Moist color is 10YR 3/2, or 3/3. Organic matter ranges from 2 to 4 percent. Texture is loam or clay loam with 15 to 40 percent clay modified by 0 to 15 percent gravel. Reaction is slightly acid to neutral. Base saturation by ammonium acetate ranges from 80 to 90 percent.
The Bt horizons color is 10YR 5/2, 5/3 4/3; 7.5YR 4/3, or 4/4 dry. Moist color is 10YR or 7.5YR 3/2. Organic matter ranges from 1 to 2 percent. Clay is 30 to 55 percent modified by 0 to 10 percent gravel. Base saturation by ammonium acetate ranges from 90 to 100 percent. Reaction is neutral to slightly alkaline.
The 2Bt and 3Bt horizons color is 10YR 6/2, 6/4, 5/2, 5/3, 5/4; 7.5YR 5/4, 4/4, or 4/6. Moist color is 7.5YR 4/2, 4/4 or 10YR 3/4, 3/3 or 4/3. Organic matter is less than 2 percent. Clay is 25 to 35 percent modified by 0 to 15 percent gravel. Base saturation by ammonium acetate ranges from 90 to 100 percent. Reaction is neutral to moderately alkaline.
COMPETING SERIES: These are Denbar (CA), Deshler (ID), Deter (OR), Deterson (ID), Esperanza (T CA), Jacknife (ID), Medford (OR), Mindego (CA) and Nebeker (UT) series. Denbar soils are moderately to mildly alkaline, have a solum thickness of 25 to 37 inches, have a duripan at depths of 40 to 60 inches. Deshler soils are 20 to 40 inches to bedrock and are dry 45 to 70 consecutive days. Deter soils are dry 90 to 110 consecutive days. Jacknife soils are moist in some part of the moisture control section for more than 90 days when the soil temperature is above 47 degrees F, and are dry for 60 to 80 consecutive days. Medford soils have soil temperatures of 54 to 57 degrees F and are dry 45 to 80 consecutive days. Mindego soils have a soil temperature of 55 degrees F or warmer, and have a (9 to 11 degrees F) summer-winter temperature difference. Nebeker soils are dry for 60 to 75 consecutive days and have calcareous C horizons.
GEOGRAPHIC SETTING: Patburn soils are on terraces and in drainageways. Slopes are 0 to 2 percent. These soils formed in alluvium from extrusive igneous rock. Elevation is 3400 to 4700 feet. The climate is subhumid with warm dry summers and cold moist winters. Mean annual precipitation is 16 to 25 inches. Snowfall is 24 to 48 inches. The mean annual temperatures is 45 to 50 degrees F. The mean January temperature is about 27 degrees F. The mean July temperature is about 6 degrees F. Frost-free period is 80 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Jellycamp (T), Lassen, longcreek, Ravendale and Vansickle (T) soils. Jellycamp soils are shallow in intermounds on lava plateaus. Lassen soils are moderately deep on lava plateaus. Longcreek soils are shallow, clayey-skeletal near ridges on lava plateaus. Ravendale soils are fine throughout the profile and in basins. Vansickle soils are shallow, clayey-skeletal near ridges and in intermounds on plateaus.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; ponded to slow runoff; slow permeability. The drainage of this soil has been altered by recent down cutting. The soils are occasionally flooded for long periods in January to May. A fluctuating water table occurs at depths of 24 to 60 inches from December through May.
USE AND VEGETATION: This soil is mainly used for livestock grazing. The natural vegetation is Beardless wildrye, mearow barley, bluegrass, and silver sagebrush.
DISTRIBUTION AND EXTENT: Northeastern 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 from the Hayden Hill Quadrangle.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 32 inches (A1, Bt1, Bt2, Bt3)
Argillic Horizon - 2 to 72 inches (Bt1, Bt2, Bt3, 2Bt4, 2Bt5, 2Bt6, and 2Bt7)