LOCATION PEASLEY IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Haplic Durixererts
TYPICAL PEDON: Peasley silty clay loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A11--0 to 3 inches; brown (10YR 5/3) silty clay loam, dark brown (10YR 3/3) moist; weak medium platy structure parting to moderate medium granular; slightly hard, friable, sticky and plastic; common very fine roots; few very fine tubular pores; neutral (pH 6.8); clear smooth boundary. (3 to 6 inches thick)
A12--3 to 7 inches; brown (10YR 5/3) silty clay, dark brown (10YR 3/3) moist; strong medium prismatic structure parting to moderate medium platy; hard, friable, sticky and very plastic; few very fine roots; common very fine tubular pores; neutral (pH 7.2); abrupt smooth boundary. (4 to 8 inches thick)
AC--7 to 16 inches; brown (10YR 5/3) silty clay, dark brown (10YR 3/3) moist; strong medium and coarse wedge-shaped peds in a near horizontal position; hard, firm, very sticky and very plastic; few very fine roots; common very fine tubular pores; about 5 percent fine granitic and basalt gravel; common pressure faces and many slickensides with striations on faces of large peds; neutral (pH 7.0); gradual wavy boundary. (8 to 12 inches thick)
C1--16 to 21 inches; light yellowish brown (10YR 6/4) clay, dark yellowish brown (10YR 4/4) moist; soil material sloughed in cracks is brown (10YR 5/3) silty clay, dark brown (10YR 3/3) moist; strong medium and coarse wedge-shaped peds inclined in a near horizontal position; hard, very firm, very sticky and very plastic; few very fine roots; common very fine tubular pores; about 10 percent fine granitic and basalt gravel; common pressure faces and many slickensides with striations on faces of large peds; mildly alkaline (pH 7.4); abrupt smooth boundary. (4 to 14 inches thick)
C2sim--21 to 35 inches; pale brown (10YR 6/3) weakly cemented duripan, brown (10YR 4/3) moist; common fine prominent very dark brown (10YR 2/2) mottles; massive pan occurs in plate-like laminations of .5 to 1 inch thick with a smooth, continuous coating of silica on the upper surface and an irregular lower surface having silica pendants; a root mat overlies the pan; very hard, extremely firm; few very thin weakly effervescent veins of lime and soluble salts; about 20 percent fine granitic and basalt gravel and 3 percent basalt stones; mildly alkaline (pH 7.6); clear smooth boundary. (14 to 18 inches thick)
C3--35 to 42 inches; very pale brown (10YR 7/4) fine gravelly loamy sand, dark yellowish brown (10YR 4/4) moist; common fine prominent very dark brown (10YR 2/2) mottles; massive; hard, firm; about 20 percent fine granitic and basalt gravel and 3 percent stones; mildly alkaline (pH 7.8). (6 to 8 inches thick)
R--42 inches; highly jointed and fractured basalt.
TYPE LOCATION: Ada County, Idaho; about 5 miles southeast of Lucky Peak Reservoir; approximately 1,155 feet south and 935 feet west of the NE corner of sec. 4, T. 1 N., R. 4 E.
RANGE IN CHARACTERISTICS: The solum ranges from 15 to 22 inches thick. Depth to the duripan ranges from 20 to 40 inches, and depth to bedrock ranges from 40 to 60 inches. Mean annual soil temperature is 49 degrees to 54 degrees F. The profile contains 0 to 3 percent stones and 0 to 15 percent gravel in the textural control section. Vertical cracks, 2 to 3 inches wide at the surface, extent to the duripan. This cracking is concentrated between polygons which are 10 to 12 inches across.
The A1 horizon has value of 4 or 5 dry and 3 or 4 moist.
The AC horizon is silty clay or clay.
The C horizon above the duripan has value of 5 or 6 dry, 3 or 4 moist, and chroma of 3 or 4. Darker soil material has accumulated in the cracks between peds in most profiles due to the churning nature of the soil. Textures are clay, heavy clay loam or silty clay. The C material below the pan ranges from fine gravelly loamy sand to gravelly loam. Percent stones range from 0 to 10 percent, and percent gravel ranges from 10 to 25 percent.
COMPETING SERIES: These are the Aikman, Jenny, Lassen and Montague series. Aikman and Lassen soils have bedrock at a depth of 20 to 40 inches. Jenny soils lack bedrock and a duripan above 60 inches. Montague soils have a bedrock or petrocalcic horizon at depths of 20 to 40 inches.
GEOGRAPHIC SETTING: Peasley soils are on basalt which have received a veneer of granitic alluvium and loess. Elevations range from 2,800 to 3,500 feet. Slopes are 2 to 6 percent. The soils formed in residuum weathered from basalt with a strong influence of granitic alluvium and loess. The climate is middle-latitude steppe (Trewartha's modified Koppen system), with cool moist winters and dry summers. Mean annual precipitation ranges from 12 to 15 inches. Mean January temperature is about 27 degrees F.; mean July temperature is about 70 degrees F.; the mean annual temperature is 47 degrees to 52 degrees F. Frost-free period is about 140 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bowns, Chilcott, Kunaton, and Sebree soils. Bowns soils have bedrock at a depth of 20 to 40 inches and lack a duripan. Chilcott and Kunaton soils do not have slickensides and vertical cracks which extend from the surface to a depth of more than 20 inches. Sebree soils have a natric horizon and have less than 35 percent clay in the textural control section.
DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff; slow permeability above and very slow permeability through the duripan.
USE AND VEGETATION: The soils are used dominantly for range. Vegetation is mainly madusa head wildrye, bluebunch wheatgrass, Sandberg bluegrass, Jim Hill mustard, antelope bitterbrush, and big sagebrush.
DISTRIBUTION AND EXTENT: Southwestern Idaho. These soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Ada County, Idaho, 1977.