LOCATION FENDERSFLAT CAEstablished Series
TAXONOMIC CLASS: Ashy-skeletal, glassy Vitrandic Argicryolls
TYPICAL PEDON: Fendersflat gravelly ashy loam--rangeland (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; grayish brown (10YR 5/2) crushed gravelly ashy loam, very dark grayish brown (10YR 3/2) crushed moist; moderate fine granular structure; soft, very friable, slightly sticky, nonplastic; many very fine roots; many very fine interstitial pores; 5 percent cobbles and 20 percent pebbles; slightly acid, (pH 6.4); clear smooth boundary. (1 to 6 inches thick)
Bt1--2 to 7 inches; grayish brown (10YR 5/2) crushed very gravelly ashy loam, very dark grayish brown (10YR 3/2) crushed moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; common fine roots and many very fine roots; common very fine interstitial and tubular pores; 15 percent faint clay bridges between sand grains; 5 percent cobbles and 30 percent pebbles; slightly acid, (pH 6.5); clear wavy boundary. (3 to 10 inches thick)
Bt2--7 to 18 inches; dark grayish brown (10YR 4/2) crushed extremely cobbly ashy loam, very dark brown (10YR 2/2) crushed moist; moderate fine subangular blocky structure; slightly hard, very friable, moderately sticky, slightly plastic; common very fine to medium roots; common very fine interstitial and tubular pores; 2 percent distinct clay films on all faces of peds and 2 percent distinct clay films on surfaces along pores and 15 percent faint clay bridges between sand grains; 10 percent paragravel, 25 percent pebbles and 40 percent cobbles; neutral, (pH 6.6); clear wavy boundary. (8 to 14 inches thick)
Bt3--18 to 25 inches; dark grayish brown (10YR 4/2) crushed very cobbly ashy loam, very dark brown (10YR 2/2) crushed moist; strong fine and medium subangular blocky structure; hard, very friable, moderately sticky, slightly plastic; common very fine to coarse roots; common very fine interstitial and tubular pores; 15 percent faint clay films on surfaces along pores and 15 percent faint clay films on faces of peds; 15 percent pebbles, 20 percent paragravel and 45 percent cobbles; neutral, (pH 6.6); clear irregular boundary. (0 to 11 inches thick)
Cr--25 to 30 inches; weathered andesitic tuff-breccia.
TYPE LOCATION: Modoc County, California; on the Modoc National Forest in the Warner Mountains; 2,350 feet south and 2500 feet west of the northeast corner of section 5, T42N, R15E; Payne Peak 7.5 minute topographic quadrangle; 41 degrees 30 minutes 32.3 seconds north latitude and 120 degrees 15 minutes 37.7 seconds west longitude, NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in winter, spring, and early summer, dry later in summer and fall; xeric moisture regime.
Mean annual soil temperature - 43 to 46 degrees F.
Mean summer soil temperature - 57 to 59 degrees F.
Depth to bedrock - 20 to 40 inches.
Oxalate extractable Al + 1/2 iron: 0.2 to 0.4 percent.
Volcanic glass content - 50 to 80 percent in the coarse silt through fine sand fractions.
Mollic epipedon thickness - 20 to 40 inches.
Control section - Clay content: 18 to 25 percent;
Rock fragments: Averages 35 to 60 percent, mainly gravel and cobbles, with greater than 60 percent in some subhorizon in some pedons. Lithology of fragments is pyroclastic volcanic rock such as andesitic tuff.
Profile reaction - Slightly acid or neutral.
A horizon - Hue: 10YR or 7.5 YR.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 to 4 percent.
Bt horizon - Hue: 10YR or 7.5YR.
Value: 2 or 3 moist.
Chroma: 2 or 3, dry or moist..
Clay content: 18 to 25 percent.
Rock fragments: Average 35 to 60 percent, dominated by cobbles or gravel.
Structure: Angular blocky or subangular blocky.
Organic matter content: 1 to 2 percent.
COMPETING SERIES: These are the Ashflat, Boulderfan, Cowbell, Paynepeak, Pryopatti, Snag, and Tusune soils. Ashflat, Boulderfan, Cowbell, Paynepeak, Pryopatti, and Snag are deeper than 40 inches to bedrock. Tusune soils have 25 to 30 percent clay in the control section.
GEOGRAPHIC SETTING: Fendersflat soils are on backslopes of mountains. They formed in colluvium and residuum derived from volcanic ash and andesitic tuff and similar volcanic rocks. Slopes are 15 to 50 percent. Elevations range from 5,200 to 8,970 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 20 to 40 inches, mean annual temperature is 41 to 44 degrees F., and the frost-free period is 50 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Fingerridge, Nowack and competing Paynepeak series. Fingerridge soils have bedrock within 14 inches. Nowack soils have bedrock within 40 to 60 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium surface runoff; moderate permeability; moderately high and high saturated hydraulic conductivity class.
USE AND VEGETATION: Fendersflat soils are used for livestock grazing and wildlife habitat. The present vegetation is mainly mountain big sagebrush, bitterbrush, wheatgrass, needlegrass, and mountain brome.
DISTRIBUTION AND EXTENT: Eastern Modoc County, California, Surprise Valley-Home Camp Area. These soils are not extensive. MLRA 21.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Surprise Valley-Home Camp Area, California and Nevada, 2005.
REMARKS: The name is from Fenders Flat.
The soil type location was moved to better reflect the concept.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 25 inches (A1, A2, Bt1 and Bt2 horizons).
Vitrandic intergrade feature - High volcanic glass content in the .02 to 2mm fraction from the mineral soil surface to 25 inches (A1, A2, Bt1 and Bt2 horizons).
Argillic horizon - The zone from 2 to 25 inches (Bt1, Bt2 and the Bt3 horizons).
Paralithic contact - The boundary at 25 inches to underlying soft bedrock (Cr layer).