LOCATION ALCOT OREstablished Series
TAXONOMIC CLASS: Ashy-pumiceous, amorphic, mesic Typic Vitrixerands
TYPICAL PEDON: Alcot paragravelly sandy loam, forested. (Colors are for moist soil unless otherwise noted.)
Oi--2 inches to 0; needles, twigs and moss.
A--0 to 4 inches; brown (10YR 4/3) paragravelly sandy loam, pale brown (10YR 6/3) dry; weak fine granular structure; soft, very friable, nonsticky and nonplastic; common very fine, fine, medium and coarse roots; many very fine irregular pores; 20 percent paragravel and 5 percent paracobbles; coarse fragments are pumice; slightly acid (pH 6.4); abrupt smooth boundary. (3 to 6 inches thick)
Bw--4 to 11 inches; brown (7.5YR 4/4) paragravelly sandy loam, light yellowish brown (10YR 6/4) dry; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine, fine, medium and coarse roots; many very fine irregular pores; 25 percent paragravel and 10 percent paracobbles; coarse fragments are pumice; moderately acid (pH 5.6); abrupt wavy boundary. (7 to 20 inches thick)
C1--11 to 44 inches; dark yellowish brown (10YR 4/6) very paracobbly sandy loam, light yellowish brown (10YR 6/4) dry; massive; soft, very friable, nonsticky and nonplastic; common very fine, fine, medium, and coarse roots; many very fine irregular pores; 30 percent paragravel and 30 percent paracobbles; coarse fragments are pumice; moderately acid (pH 5.6); abrupt wavy boundary. (15 to 33 inches thick)
C2--44 to 60 inches; olive brown (2.5Y 4/3) very paracobbly sandy loam, light gray (2.5Y 7/2) dry; massive; slightly hard, friable, nonsticky and nonplastic; few very fine, fine and medium roots; common very fine irregular pores; 30 percent paragravel and 30 percent paracobbles; coarse fragments are pumice; moderately acid (pH 5.6).
TYPE LOCATION: Jackson County, Oregon; about 1 mile south of Prospect, approximately 1,500 feet east and 1,100 feet south of the northwest corner of sec. 32, T. 32 S., R. 3 E.
RANGE IN CHARACTERISTICS: These soils are usually moist but are dry for 45 to 60 consecutive days during the summer months. The mean annual soil temperature ranges from 47 to 52 degrees F. Depth to bedrock is over 60 inches. The particle-size control section contains more than 60 percent volcanic ash and pumice, of which 35 percent or more is pumice. It is moderately or slightly acid.
The A horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 5 or 6 dry, and chroma of 2 through 4 moist and dry.
The Bw horizon has hue of 7.5YR or 10YR, value of 3 through 5 moist, 6 or 7 dry and chroma of 3 or 4 moist and dry.
The C horizon has hue of 7.5YR through 2.5Y, value of 4 or 5 moist, 6 or 7 dry, and chroma of 3 through 6 moist and 2 through 4 dry. It is sandy loam or loamy sand with para fragments consisting of rounded pumice ranging from 15 to 35 percent paragravel and 20 to 35 percent paracobbles. The C horizons below 40 inches can be stratified.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Alcot soils are on plateaus and hillslopes. They have formed in deep ash-flow deposits of volcanic ash and pumice at elevations of 1,500 to 4,000 feet. Slopes are 1 to 35 percent. The climate is characterized by hot dry summers and cool moist winters. The mean annual temperature is 45 to 50 degrees F. The mean annual precipitation is about 40 to 55 inches. The frost-free period is 100 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Barhiskey, Coyata, Crater Lake and Dumont soils. Barhiskey soils have an umbric epipedon and are sandy. Coyata soils have an umbric epipedon and are loamy-skeletal. Dumont soils have an argillic horizon. Crater Lake soils are ashy.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow runoff; rapid permeability.
USE AND VEGETATION: This soil is used mainly for timber production, water supply and wildlife habitat. The native vegetation consists of Douglas fir, white fir, western hemlock, cascade Oregongrape, twinflower, vine maple and princes pine.
DISTRIBUTION AND EXTENT: Western Cascades of southern Oregon; MLRA 5. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Jackson County Area, Oregon, 1988.
REMARKS: This draft reflects a change in classification from Cindery, mesic Typic Vitrandepts based on the Andisol Order.
Diagnostic horizons and features:
Ochric epipedon - 0 to 10 inches which includes part of the cambic horizon.
Cambic horizon - 4 to 11 inches (Bw horizon)
Assume over 60 percent vitric material throughout the profile and 15 bar water of less than 15 percent throughout the profile.
Particle-size control section - from 0 to 40 inches having ashy fine-earth material with 15-bar moisture of less than 12 percent and a weighted average of 52 percent pumice parafragments (A, Bw, and 29 inches of the C1 horizon)