LOCATION ZYZZUG OREstablished Series
TAXONOMIC CLASS: Fine-silty, isotic, acid, mesic Typic Humaquepts
TYPICAL PEDON: Zyzzug silt loam - on a plane slope of 1 percent in pasture at 100 feet elevation. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; very dark grayish brown (10YR 3/2) silt loam, brown (10YR 5/3) dry; moderate medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and common medium roots; common very fine irregular pores; strongly acid; clear smooth boundary.
A--8 to 12 inches; very dark grayish brown (10YR 3/2) silt loam, brown (10YR 5/3) dry; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine roots; common fine irregular pores; common fine faint very dark grayish brown (10YR 3/2), dark gray (10YR 4/1), and grayish brown (10YR 5/2) iron depletions; moderately acid; clear wavy boundary. (combined thickness of the A horizon is 10 to 20 inches)
Bg1--12 to 21 inches; very dark gray (10YR 3/1) silty clay loam, grayish brown (10YR 5/2) dry; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, friable, sticky and plastic; few very fine roots; many fine tubular pores; common fine faint dark brown (10YR 3/3) and brown (10YR 5/3) masses of iron accumulation; moderately acid; clear wavy boundary.
Bg2--21 to 30 inches; dark gray (10YR 4/1) silty clay loam, pale brown (10YR 6/3) dry; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, friable, moderately sticky and moderately plastic; few very fine roots; many fine and very fine tubular pores; many fine distinct dark yellowish brown (10YR 4/6) and brownish yellow (10YR 6/6) masses of iron accumulation; moderately acid; clear wavy boundary. (Combined thickness of the Bg horizon is 15 to 30 inches)
Bw--30 to 38 inches; dark yellowish brown (10YR 4/6) silty clay, brownish yellow (10YR 6/6) dry; moderate coarse prismatic structure parting to moderate medium and coarse subangular blocky; hard, friable, moderately sticky and moderately plastic; common fine tubular and few medium tubular pores; many fine distinct grayish brown (10YR 5/2) and dark gray (10YR 4/1) iron depletions, and pale brown (10YR 6/3) masses of iron accumulation; moderately acid; clear wavy boundary. (0 to 10 inches thick)
BC--38 to 45 inches; dark yellowish brown (10YR 4/6) silty clay loam; brownish yellow (10YR 6/6) dry; moderate coarse prismatic structure; hard, friable, slightly sticky and slightly plastic; few very fine tubular pores; many fine and medium distinct grayish brown (10YR 5/2) and light brownish gray (10YR 6/2) iron depletions; strongly acid; clear wavy boundary. (4 to 8 inches thick)
C--45 to 60 inches; dark yellowish brown (10YR 4/6) silt loam, brownish yellow (10YR 6/6) dry; massive; hard, friable, slightly sticky and slightly plastic; many fine and medium distinct grayish brown (10YR 5/2) and light brownish gray (10YR 6/2) iron depletions; strongly acid.
TYPE LOCATION: Coos County, Oregon; about 2 miles southwest of Gaylord; 1,320 feet east and 2,640 feet north of the SW corner, sec. 34, T. 30 S., R. 12 W.; Dement Creek, OR 7.5 minute USGS Quad; NAD 1927.
RANGE IN CHARACTERISTICS: The soil is usually moist and is saturated with water for several months each year when not artificially drained. It is dry for a short period of less than 45 consecutive days between depths of 4 to 12 inches in the four month period following the summer solstice in most years. The mean annual soil temperature is 49 to 55 degrees F. The umbric epipedon is 10 to 20 inches thick. Depth to bedrock is greater than 60 inches. The particle-size control section is 25 to 35 percent clay and has less than 15 percent coarser than very fine sand. Redox depletions are with 10 inches of the mineral surface. Redox features are faint to distinct in the solum and distinct to prominent in the substratum. The solum is 40 to 60 inches thick and is strongly acid or moderately acid. Hue is 10YR, 2.5Y, or 5Y.
The A or Ap horizon has value of 2 or 3 moist, 4 or 5 dry and chroma of 1 or 2 moist and 2 or 3 dry. Texture is silt loam with 20 to 27 percent clay.
The Bg horizon has value of 3 to 5 moist, 5 to 7 dry and chroma of 1 or 2 moist, 2 to 6 dry. Texture is silt loam or silty clay loam with 25 to 35 percent clay. It has common to many redox concentrations.
The Bw horizon, when present, has value of 4 or 5 moist, 5 to 7 dry and chroma of 4 to 6 moist and dry. Texture is silty clay, clay loam, silt loam or silty clay loam with 25 to 45 percent clay. It has common to many redox concentrations and depletions.
The BC horizon has characteristics similar to the Bw horizon.
The C horizon has value of 4 or 5 moist, 5 to 7 dry, and chroma of 4 to 6 moist or dry. Texture is silty clay loam, silt loam, or clay loam with 25 to 35 percent clay. It is stratified in some pedons with thin discontinuous lenses of coarser material in the lower C horizons.
COMPETING SERIES: This is the Stimson series. Stimson soils have a solum 13 to 25 inches thick and an umbric epipedon less than 10 inches thick.
GEOGRAPHIC SETTING: Zyzzug soils occur in shallow swales and concave depressions on low stream terraces. These soils formed in mixed silty alluvium derived from sedimentary and volcanic rock types. Elevations are 50 to 800 feet. Slopes are 0 to 3 percent. The climate is characterized by warm wet winters and hot moist summers. The mean annual precipitation is typically 50 to 100 inches. The mean annual temperature is 48 to 53 degrees F. The frost-free period is 140 to 220 days. Zyzzug soils occur on the Tenmile geomorphic surface in Coos and Curry Counties, and in depressional areas on low stream terraces in Benton County.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Eilertsen, Gardiner, Kirkendall, Meda, Quosatana, Treharne, and Wasson soils. Eilertsen soils occur on low stream terraces, are well drained, and have an argillic horizon. Gardiner, Kirkendall, and Quosatana soils occur on flood plains. Gardiner soils have an ochric epipedon and are sandy. Kirkendall soils are well drained. Meda soils are well drained, fine-loamy, and occur on alluvial fans. Quosatana soils are nonacid and have an irregular decrease in organic-carbon content. Wasson soils are coarse-loamy and have an irregular decrease in organic-carbon content. Treharne soils are moderately well drained, have an argillic horizon, and occur on low stream terraces.
DRAINAGE AND PERMEABILITY: Poorly drained; moderately slow permeability. These soils are subject to rare periods of flooding. A seasonal water table is at its uppermost limit from November through April.
USE AND VEGETATION: Zyzzug soils are used for hay and pasture. Native vegetation is red alder, western redcedar, willows, evergreen huckleberry, western swordfern, brackenfern, sedge, Douglas iris, soft rush, and skunkcabbage.
DISTRIBUTION AND EXTENT: Stream terraces of interior river valleys in the Coast Range Mountains in western Oregon; MLRA 1. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Coos County, Oregon, 1983. The name is coined.
REMARKS: Diagnostic horizons and features recognized:
Umbric epipedon - from 0 to 12 inches (Ap and A horizons).
Cambic horizon - from 12 to 38 inches (Bg1, Bg2, and Bw horizons). The Bg1 horizon lacks organic matter to quality as umbric.
Aquic conditions - from 16 to 20 inches having aquic conditions and chroma of 1 with associated redox concentrations.
Acid reaction feature - from 10 to 40 inches having pH less than 5.5.
Classification revised 08/2002 from mixed mineralogy to isotic mineralogy based on geographically associated soils.