LOCATION DEVEN CA+ID NVEstablished Series
TAXONOMIC CLASS: Clayey, smectitic, mesic Lithic Argixerolls
TYPICAL PEDON: Deven loam on a 1 percent slope under western juniper, bitterbrush, cheatgrass and squawapple at 4920 feet elevation. (Colors are for dry soil unless otherwise stated. When described (8/24/73) the soil was dry throughout.)
A--0 to 2 inches; brown (10YR 5/3) heavy loam, dark brown (7.5YR 3/2) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine interstitial pores; slightly acid (pH 6.3); clear smooth boundary. (1 to 6 inches thick)
BA--2 to 7 inches; brown (7.5YR 4/2) heavy clay loam, dark brown (7.5YR 3/2) moist; moderate medium and coarse subangular blocky structure; hard, very friable, sticky and plastic; common very fine, fine and medium roots; common very fine tubular and few very fine interstitial pores; many moderately thick clay films on faces of peds and in pores; slightly acid (pH 6.5); clear wavy boundary. (2 to 5 inches thick)
Bt1--7 to 16 inches; dark reddish brown (5YR 3/4) light clay, dark reddish brown (5YR 3/2) moist; moderate medium and coarse angular blocky structure; hard, very friable, sticky and plastic; few very fine, common fine and medium roots; few very fine tubular and interstitial pores; continuous moderately thick clay films on faces of peds and in pres; slightly acid (pH 6.5); abrupt irregular boundary. (7 to 13 inches thick)
R--16 to 24 inches; gray (N 5/ ) hard fractured basalt.
TYPE LOCATION: Modoc County, California; about 5 miles northwest of Alturas; about 0.75 mile south on Croder Flat Road from the Modoc National Forest boundary and 75 feet east of the road in the northeast 1/4 southwest 1/4 section 6, T.42 N., R.12 E.
RANGE IN CHARACTERISTICS: Depth to a lithic contact of hard fractured basalt is 10 to 20 inches.
The mean annual soil temperature is about 47 to 55 degrees F. The soil temperature is warmer than 41 degrees F. from March 1 to December 15. The soil temperature is warmer than 47 degrees F. from April 15 to December 1. The soil between depths of 4 to 12 inches is usually dry in all parts from June 1 until October 30 and is moist in some or all parts the rest of the year.
In some places stones or cobbles range from 35 to 60 percent of the surface. The soil is slightly acid to mildly alkaline.
The A horizon is dark grayish brown, dark brown, grayish brown or brown (10YR 4/2, 4/3, 5/2, 5/3; 7.5YR 4/2, 5/2). Moist color is very dark brown, very dark grayish brown or dark brown (10YR 2/2, 3/2, 3/3; 7.5YR 3/2). It is loam or clay loam with 20 to 35 percent clay. It has weak or moderate very fine to medium platy subangular blocky or granular structure. Rock fragments, mostly cobbles or stones, range from 0 to 60 percent
The B2t horizon ranges from yellowish brown and brown to dark reddish brown (10YR 5/4, 5/3, 5/2, 4/4, 4/3, 4/2, 3/4, 3/3, 3/2; 7.5YR 5/4, 5/2, 4/4, 4/2, 3/4, 3/2; 5YR 3/4). Moist color ranges from dark yellowish brown to dark reddish brown (10YR 4/4, 4/3, 4/2, 3/4, 3/3, 3/2; 7.5YR 4/4, 4/2, 3/4, 3/2; 5YR 3/2). It is clay loam or clay with 35 to 50 percent clay and has at least 8 percent more clay than the A horizon. It has angular blocky or prismatic structure. Rock fragments increase with increasing depth and make up to 25 percent of the volume and are most common in the lower part. These fragments consist of basalt pebbles, cobblestones and stones.
Some pedons have a B22t horizon, a transitional B3t horizon or a C horizon. These are similar to the B2t horizon but commonly have subangular blocky structure or are massive. The soil fills the space between the fractures in the bedrock and is in pockets. Some pedons have a very thin discontinuous coating of lime and silica capping the bedrock.
COMPETING SERIES: These are the Devada, Dilison (T), Dunnlake (T). Devada soils have aridic moisture regime and have abrupt clay increase of 20 percent between the A and B horizons. Dilanson soils have 10 to 30 percent pumiceous ash in the upper part of the solum. Dunnlake soils have aridic moisture regime.
GEOGRAPHIC SETTING: Deven soils are on hummocky plateaus and steep plateau escarpments. Slopes are 0 to 50 percent. The soils formed in material weathered from basalt, andesite and hard tuff. Elevations are 3500 and 6500 feet. Deven soils are commonly in association or complex with rock outcrop. The climate is cool semiarid mesothermal with warm dry summers and cold moist winters. Mean annual precipitation is 10 to 18 inches. Seasonal snowfall is 24 to 48 inches. Mean January temperature is 28 degrees F.; mean July temperature is 67 degrees F.; mean annual temperature is 44 to 49 degrees F. Frost-free season is 70 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ditchcamp, Karcal, Packwood and the competing Ninekar and Pulls soils. Ditchcamp and Packwood soils have a fine-loamy control section and have a duripan at a depth of 20 to 35 inches and 5 to 20 inches respectively. Both are over hard basalt. Karcal soils have a lithic contact at a depth of 20 to 40 inches, have cracks that extend to the surface, and are clayey.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; slow permeability.
USE AND VEGETATION: Used mainly for rangeland and as habitat for wildlife. Vegetation is western juniper, bitterbrush, low sagebrush, squawapple, Sandberg bluegrass, stipa, squirreltail, cheatgrass and mustard.
DISTRIBUTION AND EXTENT: Northeastern California in Modoc County. The soils are moderately extensive.
MLRA OFFICE RESPONSIBLE: Reno, Nevada
SERIES ESTABLISHED: Modoc County (Alturas Area), California, 1974.
REMARKS: Deven soils were originally mapped as Madeline series. During the correlation of Surprise Valley-Home Camp Soil Survey, Madeline soils were found to have frigid temperature regimes.
Last revised by the state on 4/88.
ADDITIONAL DATA: Riverside Laboratory, Pedon S73 Calif 25-10, not yet published.