LOCATION DENTDRAW OREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, calcareous, frigid Fluvaquentic Endoaquolls
TYPICAL PEDON: Dentdraw silt loam-rangeland, on a 1 percent slope at 4094 feet elevation. (When described on October 27, 1993 the pedon was dry from 0 to 1 inch, and moist from 1 to to 43 inches. A water table was at 43 inches. Colors are for moist soil unless stated otherwise.)
Akn1--0 to 6 inches; very dark grayish brown (2.5Y 3/2) silt loam, grayish brown (2.5Y 5/2) dry; weak medium and fine platy structure; common very fine, fine, and medium roots; common very fine tubular pores; hard, friable, moderately sticky and moderately plastic; strongly effervescent; very strongly alkaline (pH 9.2); clear smooth boundary.
Akn2--6 to 9 inches; dark olive gray (5Y 3/2) fine sandy loam, gray (5Y 5/1) dry; weak coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; common very fine tubular pores; strongly effervescent; strongly alkaline (pH 9.0); abrupt smooth boundary.
Akn3--9 to 11 inches; dark olive gray (5Y 3/2) silt loam, gray (5Y 5/1) dry; strong fine angular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine and fine roots; common very fine few fine tubular pores; strongly effervescent; strongly alkaline (pH 9.0); abrupt smooth boundary.
Akn4--11 to 18 inches; dark olive gray (5Y 3/2) fine sandy loam, gray (5Y 5/1) dry; weak medium and fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine and fine roots; common very fine few fine tubular pores; strongly effervescent; strongly alkaline (pH 9.0); abrupt smooth boundary. (Combined thickness of A horizons is 10 to 20 inches thick)
2Bkn--18 to 27 inches; light olive gray (5Y 6/2) clay loam, light gray (5Y 7/1) dry; strong medium and fine prismatic structure; very hard, firm, very sticky and very plastic; common very fine roots; common very fine, few fine tubular pores; strongly effervescent in spots; strongly alkaline (pH 9.0); gradual smooth boundary. (10 to 21 inches thick)
3C1--27 to 42 inches; light olive brown (2.5Y 5/3) sandy loam, light gray (2.5Y 7/2) dry; massive; few very fine roots; common very fine tubular pores; slightly hard very friable, slightly sticky and nonplastic; common fine rounded calcium carbonate concentrations ; strongly effervescent in spots; strongly alkaline (pH 9.0); clear smooth boundary.
3C2--42 to 52; light olive brown (2.5Y 5/3) loamy fine sand, light brownish gray (2.5Y 6/2) dry; massive; soft, very friable, nonsticky and nonplastic; few very fine irregular and few very fine tubular pores; common coarse rounded carbonate concentrations; strongly effervescent in spots; strongly alkaline (pH 9.0); clear smooth boundary.
3C3--52 to 60 inches; olive brown (2.5Y 4/3) loamy fine sand, light gray (2.5Y 7/2) dry; massive; soft, very friable, nonsticky and nonplastic; few very fine irregular and few very fine tubular pores; carbonates in 5 mm. filaments; strongly effervescent in filaments; strongly alkaline (pH 8.8).
TYPE LOCATION: Harney County, Oregon, near the north shore of Malheur Lake, about 2800 feet south 400 feet east of the northwest corner, section 4 T. 26 S., R. 38 E., (Lat. 43 degrees, 20 minutes, 41 seconds N, Long. 118 degrees 53 minutes, 51 seconds W.)
RANGE IN CHARACTERISTICS: The mollic epipedon is 10 to 20 inches thick. Ponding is frequent and very long duration during February to July. Redox concentrations are generally absent or faint in all horizons. Hue is typically 5Y, or 2.5Y, but ranges to 10YR. There is an irregular decrease in organic matter with depth. The mean annual soil temperature is 45 to 47 degrees F. Depth to the substratum (3C) is 25 to 40 inches. The solum has an SAR of 13 to 25 and is strongly or very strongly alkaline. The particle size control section averages 18 to 25 percent clay.
The A horizon is silt loam or fine sandy loam with 10 to 20 percent clay. It has 5 to 10 percent calcium carbonate.
The 2Bkn horizon has a value dry of 7 or 8, and moist of 5 or 6. The chroma is 1, 2, or 3. It is clay loam or sandy clay loam with 20 to 30 percent clay.
The 3C horizon has value dry of 6 through 8, and moist of 4 through 6. Chromas are 1 through 3. It is sandy loam, loamy fine sand and loamy sand with 5 to 18 percent clay. SAR is 2 to 15.
COMPETING SERIES: This is the Hussa series. Hussa soils have 25 to 35 percent clay in the particle-size control section, are moderately or strongly alkaline and are on fans and flood plains.
GEOGRAPHIC SETTING: Dentdraw soils are on lakebeds and have slopes of 0 to 2 percent. The soils formed in lacustrine sediments. Elevations are 4090 to 4100 feet. The climate is characterized by cold moist winters, and hot dry summers. The mean annual precipitation is 8 to 10 inches. The mean annual temperature is 43 to 45 degrees F. The frost free period is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ausmus, Duckclub, and Thenarrows series. Ausmus soils have a natric horizon with its lower boundary shallower than 10 inches, and are on higher lake terraces. Duckclub and Thenarrows soils do not have a mollic epipedon, and are on slightly higher lake terraces.
DRAINAGE AND PERMEABILITY: Poorly drained, ponded; moderately slow permeability. An apparent water table is at a depth of +1.0 to 3.0 feet from February to August. Ponding is frequent.
USE AND VEGETATION: The soils are used for wildlife habitat, and livestock grazing. Potential native vegetation dominated by alkaline tolerant grasses and forbs.
DISTRIBUTION AND EXTENT: Closed lake basins of southeast Oregon; MLRA 23, 24. Series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Harney County, Oregon, 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon - from 0 to 18 inches (Akn horizons)
aquic conditions - the soil is assumed to meet aquic conditions within the upper 20 inch zone. Based on laboratory data the amount of iron in these soils is extremely low and thus the formation of iron concentrations is limited.