LOCATION GREENGULCH OREstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Ultic Haploxeralfs
TYPICAL PEDON: Greengulch silt loam-clearcut, on a southwest-facing slope of 33 percent at an elevation of 1700 feet. (Colors are for moist soil unless otherwise stated.)
Oi--1 1/2 inches to 0; partially decomposed grasses, twigs, bark, and leaves.
A--0 to 3 inches; dark yellowish brown (10YR 3/4) silt loam, dark yellowish brown (10YR 4/4) dry; moderate fine, medium, and coarse granular and moderate very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, and common fine, medium, and coarse roots; common very fine and fine irregular pores; slightly acid (pH 6.1); clear smooth boundary. (2 to 5 inches thick)
AB--3 to 10 inches; dark brown (7.5YR 3/3) silty clay loam, yellowish brown (10YR 5/4) dry; moderate very fine and fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine, and few fine, medium and coarse roots; common very fine, and few fine and medium irregular pores; moderately acid (pH 5.9); gradual wavy boundary. (5 to 9 inches thick)
Bt1--10 to 14 inches; dark brown (7.5YR 4/4) clay, dark yellowish brown (10YR 4/4) dry; moderate medium and coarse subangular blocky structure; hard, firm, sticky and plastic; few very fine, fine, medium and coarse roots; common very fine and few fine irregular pores; common faint dark brown (7.5YR 3/2) clay films on faces of peds and in pores; moderately acid (pH 5.7); gradual wavy boundary.
Bt2--14 to 20 inches; strong brown (7.5YR 4/6) clay, dark yellowish brown (10YR 4/4) dry; few fine prominent pinkish white (7.5YR 8/2) variegations; strong medium and coarse subangular blocky structure; hard, firm, sticky and plastic; few very fine, and fine roots; common very fine, and few fine irregular pores; common distinct dark brown (7.5YR 3/2) clay films on faces of peds and in pores; moderately acid (pH 6.0); gradual wavy boundary.
Bt3--20 to 30 inches; dark brown (7.5YR 4/4) clay, dark yellowish brown (10YR4/4) dry; few fine prominent pinkish white (7.5YR 8/2) variegations; strong medium and coarse subangular blocky structure; hard, very firm, sticky and plastic; few very fine roots; common very fine irregular pores; many distinct dark brown (7.5YR 3/2) clay films on faces of peds and in pores; moderately acid (pH 5.9); gradual wavy boundary. (Combined thickness of the Bt horizon is 13 to 26 inches)
Crt--30 inches; strong brown (7.5YR 4/6) highly weathered granodiorite saprolite; dark yellowish brown (10YR 4/4) dry; common fine prominent pinkish white (7.5YR 8/2) and few fine prominent light reddish brown (5YR 6/4) variegations; many faint dark brown (7.5YR 3/2) clay films along rock fractures.
TYPE LOCATION: Douglas County, Oregon, 1 1/2 miles northwest of the town of Days Creek, Oregon, 3250 feet north and 2000 feet west of the southeast corner of section 4, T. 30 S., R. 4 W., W.M. (Latitude 42 degrees, 59 minutes, 46 seconds N, Longitude 123 degrees, 10 minutes, 27 seconds W)
RANGE IN CHARACTERISTICS: Solum thickness and depth to soft bedrock is 20 to 40 inches. The mean annual soil temperature is 50 to 56 degrees F. The soil is usually moist but is dry within all parts of the moisture control section for 60 to 90 consecutive days following the summer solstice. It has 0 to 10 percent rock fragments throughout the solum. Hue is 10YR or 7.5YR.
The A and AB horizon has value of 3 moist, 4 or 5 dry and chroma of 3 or 4 moist and dry. It is silt loam in the upper part of the horizon and silty clay loam in the lower part. It is slightly acid to moderately acid. After mixing the upper 7 inches, chroma moist is 4.
The Bt horizon has value of 3 or 4 moist, 4 to 6 dry, and chroma of 3 to 6 moist and dry. It is silty clay or clay with 40 to 55 percent clay. It is slighty acid to strongly acid. Base saturation by sum is 50 to 75 percent.
COMPETING SERIES: These are the Cedargrove, Cornutt, Freezener, Jumpoff, Mildred, Oak Grove, Oakland, Rainier, Sweetbriar, and Veneta soils. Sweetbriar soils are dry 45 to 60 consecutive days and are deeper than 40 inches to a paralithic contact. Cedargrove, Freezener, and Oak Grove soils are deeper than 60 inches to bedrock. Cornutt soils have a Ca/Mg ratio of more than 1, and sola deeper than 40 inches to paralithic contact. Jumpoff soils are over 40 inches to bedrock. Mildred soils are dry for more than 90 days. Oakland soils have 35 to 45 percent clay in the particle-size control section, have 15 to 40 percent soft fragments and 10 to 25 percent rock fragments in the lower part of the profile and are formed over sandstone, siltstone, or shale. Rainier soils are moderately well drained, and are 40 to 60 inches to a lithic contact. Veneta soils are moderately well drained, and deeper than 60 inches.
GEOGRAPHIC SETTING: Greengulch soils are on mountain sideslopes and ridges. These soils formed in fine textured residuum and colluvium derived from granodiorite intrusions in the Dothan, Galice, and Rogue formations. Slopes are 3 to 60 percent. Elevation ranges from 800 to 2200 feet. The climate is characterized by warm, wet winters and hot, dry summers. The mean annual temperature is 49 to 55 degrees F, and the mean annual precipitation is 30 to 40 inches. The frost free period is 120 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Beekman, Josephine, Siskiyou, Speaker, Tethrick, Vermisa, Wolfpeak, and Zing series. Beekman and Vermisa soils are loamy-skeletal and are formed on metasediments. Josephine and Speaker soils are fine-loamy and are formed on metasediments. Wolfpeak soils are fine-loamy and are over 60 inches to bedrock. Siskiyou and Tethrick soils are coarse-loamy. Zing soils are over 60 inches to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: These soils are used for timber production, hay and pasture, wildlife habitat and watershed. The native vegetation includes Douglas fir, incense cedar, ponderosa pine, Pacific madrone, and grand fir with an understory of western swordfern, deerfoot vanillaleaf, tall oregongrape, Pacific poison oak, creambush oceanspray, and rattlesnake plantain.
DISTRIBUTION AND EXTENT: Southwestern Oregon, MLRA 5. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Douglas County, Oregon, 1994.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon
Argillic horizon and particle-size control section - from 10 to 30 inches. (Bt1, Bt2, and Bt3 horizons)
Ultic subgroup - base saturation is assumed to be less than 75 percent throughout the argillic horizon.
Mollic subgroup - the upper 4 inches of the soil has value of 3 moist and contains 2 to 4 percent organic matter.