LOCATION PORTERFIELD CAEstablished Series
TAXONOMIC CLASS: Ashy, glassy, nonacid, mesic, shallow Vitrandic Torriorthents
TYPICAL PEDON: Porterfield loam - on a west facing convex slope of 22 percent under gray rabbitbrush, juniper, cheatgrass, big sagebrush and bluebunch wheatgrass at 4,360 feet elevation. (When described on October 11, 1978, the soil was dry throughout. Colors are dry unless otherwise stated).
A1--0 to 2 inches; light gray (10YR 7/2) loam, very dark grayish brown (10YR 4/2) moist; moderate very fine and fine platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; many very fine tubular and interstitial and few very fine viscular pores; 1 percent pebbles, 3 percent cobbles, 1 percent stones; neutral (pH 7.2); clear smooth boundary. (0 to 3 inches thick)
A2--2 to 6 inches; light gray (10YR 7/2) loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; few very fine tubular and many very fine interstitial pores; 1 percent pebbles, 3 percent cobbles, 1 percent stones; neutral (pH 7.0); clear smooth boundary. (3 to 5 inches thick)
C1--6 to 13 inches; very pale brown (10YR 7/3) loam, brown (10YR 4/3) moist; massive; soft, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; many very fine interstitial pores; 6 percent pebbles, 3 percent cobbles; neutral (pH 7.2); abrupt smooth boundary. (5 to 9 inches thick)
C2--13 to 15 inches; very pale brown (10YR 7/3) very gravelly loam, brown (10YR 4/3) moist; massive; soft, slightly sticky and slightly plastic; common very fine and few fine roots; many very fine interstitial pores; 55 percent pebbles; neutral (pH 7.2) abrupt smooth boundary. (1 to 3 inches thick)
Cr--15 inches; white (10YR 8/1) diatomaceous earth and lacustrine tuff.
TYPE LOCATION: Siskiyou County, California; about 12 miles southeast of Dorris, on the west slope of the Little Tablelands, 200 feet south and 200 feet east of the northwest corner of sec. 10, T. 46 N., R. 2 E.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact is 14 to 20 inches. The mean annual soil temperature is 48 to 52 degrees F. The soil temperature is warmer than 41 degrees F between March 15 to December 1 and is warmer than 47 degrees F between April 15 and November 15. The soil is dry from June 15 to November 10 and is never moist 90 consecutive days when the soil temperature is greater than 47 degrees F. Reaction is neutral to moderately alkaline. Clay content ranges from 18 to 30 percent.
The A horizon has dry color of 10YR 7/2 or 6/2 and moist color of 10YR 4/2, 3/2 or 3/3. Rock fragments range from 5 to 50 percent. Textures are loam, stony loam or very stony loam. Thickness ranges from 3 to 9 inches.
The C horizon has dry color of 10YR 7/3, 6/3 or 7/2 and moist color of 10YR 4/3, 4/2 or 3/3. In the upper C horizon rock fragments range from 5 to 30 percent. In the lower C horizon rock fragments range from 35 to 60 percent. The total amount of rock fragments in the control section of 14 to 20 inches or to bedrock is less than 35 percent.
COMPETING SERIES: These are the Budiho, Haar and Nicanor series. These soils have a paralithic contact at 6 to 14 inches and have lithic contacts at 30 to 40 inch depths.
GEOGRAPHIC SETTING: Porterfield soils are on hills and side slopes of plateaus. Slopes are 5 to 30 percent. The soils formed in material weathered from diatomaceous earth and lacustrine tuff. Elevations are from 3,400 to 4,800 feet. The climate is semiarid with hot dry summers and cool moist winters. The mean annual precipitation is 9 to 14 inches. The mean annual temperature is about 48 degrees F. Frost-free season is about 50 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hammond (T), Deven and Eastable (T) soils. Hammond soils are 20 to 40 inches deep and are on concave positions within areas of Porterfield soils. Deven soils have mollic epipedons, argillic horizons, and are on plateaus above Porterfield soils. Eastable soils are greater than 60 inches deep and are on alluvial fans below Porterfield soils.
DRAINAGE AND PERMEABILITY: Well drained; runoff is rapid; moderate permeability.
USE AND VEGETATION: Used for woodland and rangeland. Native vegetation is bluebunch wheatgrass, Idaho fescue, big sage and western juniper.
DISTRIBUTION AND EXTENT: Northern California and Southeastern Oregon Uplands. Soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Siskiyou County, California, Butte-Valley-Tule Lake Area, 1985.
ADDITIONAL DATA: Sampled for characterization 8/80 by Lincoln Laboratory. Pedon No. S 8CA-090-016.