LOCATION MAGILL ORTentative Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Vitrandic Haploxerolls
TYPICAL PEDON: Magill very stony ashy loam - rangeland, on a 5 percent slope at an elevation of 4,990 feet. (When described on August 5, 2001, the soil was dry throughout. Colors are for moist soils unless otherwise noted.)
A1--0 to 5 inches; dark brown (7.5YR 3/2) very stony ashy loam, dark grayish brown (10YR 4/2) dry; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; many fine and very fine roots; common very fine irregular pores; 15 percent stones, 15 percent cobbles, and 20 percent gravel; neutral (pH 7.0); clear smooth boundary.
A2--5 to 11 inches; dark brown (7.5YR 3/2) gravelly ashy loam, brown (7.5YR 4/3) dry; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common medium, fine, and very fine roots; common very fine tubular and irregular pores; 5 percent cobbles and 20 percent gravel; neutral (pH 7.2); abrupt smooth boundary. (The combined thickness of the A horizon is 10 to 20 inches.)
C--11 to 22 inches; dark brown (7.5YR 3/3) extremely gravelly loam, brown (7.5YR 4/2) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; few medium, fine, and very fine roots; few very fine tubular pores; 10 percent cobbles and 55 percent gravel; neutral (pH 7.3); abrupt wavy boundary. (5 to 20 inches thick)
R--22 inches; fractured tuff
TYPE LOCATION: Grant County, Oregon, located about 20 miles east of Seneca; 50 feet west and 2,200 feet north of the SE corner of section 35, T. 16 S., R. 33 1/2 E. (Latitude 44 degrees, 08 minutes, 26 seconds North and Longitude 118 degrees, 36 minutes, 26 seconds West)
RANGE IN CHARACTERISTICS: These soils are usually moist, but are dry in all parts of the moisture control section for 60 to 90 consecutive days within the 4 months following the summer solstice. The mean annual soil temperature is 43 to 47 degrees F. Depth to bedrock is 20 to 40 inches. The mollic epipedon is 10 to 20 inches thick. The soil has 18 to 27 percent clay and more than 35 percent rock fragments throughout the profile.
The A horizon has hue of 7.5YR or 10YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It has 0 to 15 percent stones, 5 to 15 percent cobbles, and 15 to 25 percent gravel. It has an estimated 5 to 20 percent volcanic glass and 0.2 to 0.4 extractable Al + 1/2Fe.
The C horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 5 or 6 dry, and chroma of 3 to 5 moist and dry. It has 0 to 15 percent cobbles and 35 to 55 percent gravel.
COMPETING SERIES: These are Bearspring, Dogtown, Frint, Hogranch, Mineral, Peahke, Pelican, Scoap, and Wellspring series. Bearspring soils have 7 to 15 percent clay and are very deep to granitic bedrock. Dogtown soils are deep or very deep to quartz diorite. Frint soils have a mollic epipedon 20 to 24 inches thick and is moderately deep to basalt bedrock. Hogranch soils are deep to basalt bedrock and have a mollic epipedon 20 to 29 inches thick. Mineral soils are moderately deep to granitic bedrock and have 7 to 12 percent clay. Peahke soils are moderately deep to sedimentary rock and has channers throughout the profile. Pelican soils are deep to glacial till and have 10 to 18 percent clay. Scoap soils are very deep to bedrock, have 8 to 12 percent clay, and have a mollic epipedon 20 to 30 inches thick. Wellspring soils are very deep to sedimentary rock and have channers throughout the profile.
GEOGRAPHIC SETTING: Magill soils are on hills. They formed in residuum derived from igneous rock with an influence of ash in the surface horizons. Slopes are 2 to 15 percent. Elevation is 4,900 to 5,800 feet. The climate is characterized by cold, wet winters and hot, dry summers. The mean annual precipitation is 20 to 28 inches, and the mean annual temperature is 41 to 45 degrees F. The frost-free period is 30 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Frenchcabin, Loganvalley, Stanbro, Starglade, and Weberg soils. Frenchcabin soils are fine-silty over sandy or sandy-skeletal, somewhat poorly drained, and are on stream terraces within mountain meadows. Loganvalley soils are loamy-skeletal, well drained, and are on fan remnants. Starglade soils are very shallow, well drained, loamy-skeletal, and are on hills. Stanbro soils are very poorly drained, very deep, have a histic epipedon, and are on fens. Weberg soils are loamy-skeletal, moderately well drained, and are on glacial outwash plains.
DRAINAGE AND PERMEABILITY: Well drained; permeability is moderate.
USE AND VEGETATION: Livestock grazing and wildlife habitat. The native vegetation is mountain big sagebrush, antelope bitterbrush, Sandberg bluegrass, Ross sedge, and buckwheat.
DISTRIBUTION AND EXTENT: Mountain valleys of south-central Oregon, MLRA-10. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Grant County, Oregon, 2003. The name is derived from Magill Creek located about 1/2 mile SE of the community of Izee.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from surface to 11 inches (A1 and A2 horizons)
Particle size control section - from 10 to 22 inches ( lower part of the A2 horizon and the C horizon)
Lithic contact - at 22 inches
Xeric moisture regime