LOCATION MAUPIN OREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Haploduridic Durixerolls
TYPICAL PEDON: Maupin loam, cultivated. (Colors are for dry soil unless otherwise noted.)
Ap1--0 to 6 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak very fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine irregular pores; neutral (pH 6.7); abrupt smooth boundary.
Ap2--6 to 10 inches; grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; neutral (pH 6.8); abrupt smooth boundary. (Combined thickness of the A horizon is 7 to 14 inches)
Bw--10 to 20 inches; pale brown (10YR 6/3) loam, dark brown (10YR 3/3) moist; weak medium prismatic and moderate medium subangular blocky structure; friable, hard, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; few hard nodules; neutral (pH 7.0); abrupt wavy boundary. (4 to 13 inches thick)
Bk1--20 to 25 inches; pale brown (10YR 6/3) loam, dark brown (10YR 4/3) moist; weak subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine tubular pores; few brittle and hard nodules; slightly effervescent; (lime in mycelium form); mildly alkaline (pH 7.8); clear wavy boundary.
Bk2--25 to 31 inches; pale brown (10YR 6/3) loam, dark brown (10YR 4/3) moist; massive; hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine tubular pores; common hard, nodules; 5 percent gravel; strongly effervescent (lime in mycelium form); moderately alkaline (pH 8.2); abrupt wavy boundary. (Combined thickness of the Bk horizon is 4 to 16 inches.)
Bkqm--31 to 37 inches; pale brown (10YR 6/3) and brown (10YR 4/3) moist duripan; platy; very firm; indurated silica laminar capping nearly continuous; strongly effervescent. (1/2 to 10 inches thick)
2R--37 inches; fractured bedrock.
TYPE LOCATION: Wasco County, Oregon; 35 feet south of Oregon 216 in the NW1/4 SW1/4 SW1/4 section 2, T. 5 S., R. 13 E.
RANGE IN CHARACTERISTICS: The soils are usually dry in all parts of the control section for at least half the time (cumulative) during the period the soil temperature is above 5 degrees C. (41 degrees F.) but are moist in the control section more than 60 consecutive days following the winter solstice. The mean annual soil temperature is 47 to 57 degrees F. The solum is 20 to 32 inches thick. The mollic epipedon is 10 to 20 inches thick and may include the upper part of the Bw horizon. Depth to the duripan is 20 to 40 inches and depth to bedrock is 25 to 45 inches. The texture control section is 18 to 25 percent clay and more than 15 percent coarser than very fine sand.
The A horizon has value of 5 or 4 dry, 2 or 3 moist and chroma of 2 or 3 dry or moist. It is loam or silt loam with 0 to 10 percent gravel. The soil reaction is neutral to mildly alkaline.
The Bw horizon has value of 5 or 6 dry and 3 or 4 moist. It is loam or silt loam, has 18 to 25 percent clay, and has 0 to 10 percent gravel. The soil reaction is neutral to moderately alkaline.
The Bk horizon has value of 6 or 7 dry, 4 or 5 moist, and chroma of 3 or 4 dry and moist. It is loam, silt loam, gravelly loam, or gravelly silt loam with 0 to 30 percent gravel and 0 to 5 percent hard nodules. It has 18 to 25 percent clay. It is strongly to violently effervescent. The soil reaction is neutral to moderately alkaline.
The duripan (Bkqm horizon) has nearly continuous to continuous indurated laminar capping. Other parts of the duripan range from weakly cemented to indurated.
COMPETING SERIES: This is the Harwood series. Harwood soils lack secondary carbonates in and above the duripan and are very deep to bedrock.
GEOGRAPHIC SETTING: The Maupin soils are on mesas or plateaus and have slopes of 0 to 35 percent. Elevations are 1,600 to 3,400 feet. The soils formed in mixed loess and volcanic ash over a duripan. The climate is characterized by cool moist winters and hot dry summers. The mean annual precipitation is 9 to 12 inches. The mean annual temperature is 45 to 56 degrees F. The frost-free period (32 degrees F.) is 110 to 170 days and (28 degrees F.) 170 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bakeoven soils in the innermound position. Bakeoven soils are less than 12 inches deep to bedrock and lack duripans.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Principal use is for production of grain crops. Other uses are hay, pasture, and livestock grazing. Native vegetation is mainly bluebunch wheatgrass, Idaho fescue, Sandberg bluegrass and buckwheat.
DISTRIBUTION AND EXTENT: North-central Oregon; MLRA B8, B10. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wasco County, Oregon, 1975.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon - from surface to 10 inches (Ap1 and Ap2 horizons).
Cambic horizon - from 10 to 25 inches (Bw, and Bk1 horizons).
Duripan - from 31 to 37 inches (Bkqm horizon).
Particle-size control section - from 10 to 31 inches (Bw, Bk1, and Bk2 horizons.
In some pedons, the Bw and Bk horizons may have few to common clay films but a ratio of clay in the illuvial horizon to that in the eluvial horizon of less than 1.2.
ADDITIONAL DATA: Partial lab data available for this series. Reference sample S9110R065-101 from WASCO County, Oregon: sampled NSSL, Lincoln, NE., 5/91.
NSTH 17, RECLASSIFICATION ONLY, 3/95